0001193125-24-164729 | 40-F | XBRL Viewer

Income Tax Expense

12 Months Ended

Mar. 31, 2024

24.	INCOME TAX EXPENSE

The components of income tax expense for the years ended March 31, 2024 and March 31, 2023 are as follows:



Year ended,	March 31, 2024		March 31, 2023

Income tax expense (recovery) recognized in net income:

Current tax expense	$	38.5	$	89.6

Deferred income tax expense (recovery)		1.2		(12.0	)


	$	39.7	$	77.6

Income taxes in the consolidated statements of net income for the years ended March 31, 2024 and March 31, 2023 vary from amounts that would be computed by applying statutory income tax rates for the following reason:



Year ended,	March 31, 2024			March 31, 2023

Income before income taxes	$	144.9		$	376.1


Income tax expense based on the applicable tax rate of 25%	$	36.2		$	94.0

Add / (deduct):

Non-deductible post-employment benefits payments		3.4			3.3

Non-deductible pension contributions		3.4			0.9

Non-deductible accretion of financial obligations		1.8			0.8

Adjustment in respect of prior years		(1.7	)		(1.3	)

Changes in fair value of warrant liability		(3.1	)		(12.3	)

Changes in fair value of earnout liability		-			(1.7	)

Changes in fair value of share-based payment liability		0.3			(3.3	)

Other		(0.6	)		(2.8	)



Income tax expense	$	39.7		$	77.6

The applicable tax rate is the aggregate of the Canadian federal income tax rate of 15.0% and the Canadian provincial income tax rate of 10.0%.

The

tax-effected

temporary differences which result in deferred income tax assets and (liabilities) and the amount of deferred income taxes recognized in the consolidated statements of comprehensive income for the year ended March 31, 2024 are as follows:


	Balance at March 31, 2023			Movements in:								Balance at March 31, 2024
	Balance at March 31, 2023			Net Income			Foreign Exchange			Other Comprehensive Income		Balance at March 31, 2024

Accounting reserves	$	2.2		$	(0.9	)	$	-		$	-	$	1.3

Inventory reserve		(0.1	)		(1.8	)		-			-		(1.9	)

Defined benefit pension - past service costs (Note 20)		12.6			-			-			-		12.6

Other post-employment benefits - past service costs (Note 21)		1.0			-			-			-		1.0

Capital tax loss carryforward		2.1			-			-			-		2.1

Property, plant and equipment and intangible assets		(150.9	)		10.7			(0.3	)		-		(140.5	)

Unrealized exchange loss (gain) on US dollar debt		(0.3	)		0.2			-			-		(0.1	)

Governmental loans benefit		(18.4	)		(10.6	)		0.1			-		(28.9	)

Financing expenses		0.5			0.4			-			-		0.9

Deferred revenue		51.5			(1.3	)		0.1			-		50.3

SRED expenditures		(0.1	)		-			-			-		(0.1	)

Transaction costs		3.9			(1.3	)		-			-		2.6

Unrealized loss on cash flow hedges		-			1.5			-			-		1.5

Realized exchanged loss on governmental loans		-			0.4			-			-		0.4

Share-based payment compensation		-			1.8			-			-		1.8

Other		(0.7	)		(0.3	)		-			-		(1.0	)


	$	(96.7	)	$	(1.2	)	$	(0.1	)	$	-	$	(98.0	)

The

tax-effected


	Balance at March 31, 2022			Movements in:									Balance at March 31, 2023
	Balance at March 31, 2022			Net Income			Foreign Exchange			Other Comprehensive Income			Balance at March 31, 2023

Accounting reserves	$	2.6		$	(0.3	)	$	(0.1	)	$	-		$	2.2

Inventory reserve		(3.5	)		3.2			0.2			-			(0.1	)

Defined benefit pension - past service costs (Note 20)		-			12.2			0.4			-			12.6

Other post-employment benefits - past service costs (Note 21)		-			1.0			-			-			1.0

Capital tax loss carryforward		1.9			-			0.2			-			2.1

Property, plant and equipment and intangible assets		(144.4	)		5.3			(11.8	)		-			(150.9	)

Unrealized exchange loss (gain) on US dollar debt		0.9			(1.2	)		-			-			(0.3	)

Governmental loans benefit		(10.3	)		(7.0	)		(1.1	)		-			(18.4	)

Financing expenses		-			0.5			-			-			0.5

Deferred revenue		48.7			(1.2	)		4.0			-			51.5

SRED expenditures		(0.1	)		-			-			-			(0.1	)

Transaction costs		5.1			(1.6	)		0.4			-			3.9

Unrealized loss on cash flow hedges		6.5			1.4			(0.1	)		(7.8	)		-

Other		(0.3	)		(0.3	)		(0.1	)		-			(0.7	)


	$	(92.9	)	$	12.0		$	(8.0	)	$	(7.8	)	$	(96.7	)

Derivative Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2024

Disclosure of detailed information about financial instruments [abstract]

Summary of Movements in Cash Flow Hedge Reserve

The movements in the cash flow hedge reserve for the period as a component of accumulated other comprehensive income is as follows:



	March 31, 2024		March 31, 2023

Opening balance	$	-	$	24.7

Income arising on changes in fair value of cash flow hedges, net of tax expense of nil and $7.8 million , respectively		-		(34.0	)

Loss reclassified to net income		-		9.3



Income on cash flow hedges, recognized in Cash Flow Hedge Reserve in Other Comprehensive Income		-		(24.7	)



Ending balance	$	-	$	-

Subsequent Events

12 Months Ended

Mar. 31, 2024

Disclosure of non-adjusting events after reporting period [abstract]

Subsequent Events

36.	SUBSEQUENT EVENT

On April 5, 2024, the Company’s indirect wholly-owned subsidiary, ASI, issued an aggregate of US $

350.0 million of 9.125

% Senior Secured Second Lien Notes (the “Notes”) due April 15, 2029. The Notes are guaranteed on a senior secured basis by ASI’s immediate parent company and all of ASI’s subsidiaries.

Bank Indebtedness - Additional Information (Detail) $ in Millions		1 Months Ended	12 Months Ended
	Nov. 30, 2018 CAD ($)	May 31, 2023 CAD ($)	Mar. 31, 2024 CAD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	May 31, 2023 USD ($)	Mar. 31, 2023 CAD ($)	Mar. 31, 2023 USD ($)	Nov. 30, 2018 USD ($)
Disclosure Of Bank Indebtedness [Line Items]
Current secured bank loans outstanding			$ 300,000				$ 1,900,000	$ 1.4
Secured Asset Based Revolving Credit Facility [Member]
Disclosure Of Bank Indebtedness [Line Items]
Proceeds from non-current borrowings			300,000	$ 0.2
Libor [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member]
Disclosure Of Bank Indebtedness [Line Items]
Line of credit maximum borrowing capacity									$ 250.0
Debt instrument unused borrowing capacity			347,100,000		$ 256.2		279,200,000	206.3
Letters of credit outstanding and borrowing base reserves			$ 59,100,000		$ 43.6		57,300,000	$ 42.3
SOFR [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member] \| Major Borrowings Transactions [Member]
Disclosure Of Bank Indebtedness [Line Items]
Borrowings maturity			May, 2028	May, 2028
Borrowings, interest rate basis			Secured Overnight Financing Rate (“SOFR”) plus a credit spread adjustment of 10 basis points plus an applicable margin, which varies depending on usage.	Secured Overnight Financing Rate (“SOFR”) plus a credit spread adjustment of 10 basis points plus an applicable margin, which varies depending on usage.
SOFR [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member] \| Major Borrowings Transactions [Member] \| Bottom of range [member]
Disclosure Of Bank Indebtedness [Line Items]
Line of credit maximum borrowing capacity						$ 250.0
SOFR [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member] \| Major Borrowings Transactions [Member] \| Top of range [member]
Disclosure Of Bank Indebtedness [Line Items]
Line of credit maximum borrowing capacity						$ 300.0
Other Non Current Assets [Member] \| Libor [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member]
Disclosure Of Bank Indebtedness [Line Items]
Debt issuance costs incurred	$ 7,000,000
Unamortized debt issuance costs			$ 1,400,000				$ 900,000
Other Non Current Assets [Member] \| Libor [Member] \| Floating interest rate [member] \| Secured Asset Based Revolving Credit Facility [Member] \| Additional Borrowing Cost [Member]
Disclosure Of Bank Indebtedness [Line Items]
Debt issuance costs incurred		$ 1,700,000

Consolidated Statements of Financial Position $ in Millions, $ in Millions	Mar. 31, 2024 CAD ($)	Mar. 31, 2023 CAD ($)
Current
Cash	$ 97.9	$ 247.4
Restricted cash	3.9	3.9
Taxes receivable	20.0	0.0
Accounts receivable, net	246.7	291.2
Inventories	807.8	722.7
Prepaid expenses and deposits	80.5	94.4
Other assets	5.7	6.7
Total current assets	1,262.5	1,366.3
Non-current
Property, plant and equipment, net	1,405.2	1,081.3
Intangible assets, net	0.7	0.9
Other assets	7.6	7.1
Total non-current assets	1,413.5	1,089.3
Total assets	2,676.0	2,455.6
Current
Bank indebtedness	0.3	1.9
Accounts payable and accrued liabilities	286.8	204.6
Taxes payable and accrued taxes	30.1	14.4
Current portion of other long-term liabilities	1.4	0.4
Current portion of governmental loans	16.2	10.0
Current portion of environmental liabilities	3.1	4.5
Warrant liability	44.9	57.3
Earnout liability	13.8	16.8
Share-based payment compensation liability	31.9	33.5
Total current liabilities	428.5	343.4
Non-current
Long-term governmental loans	127.4	110.4
Accrued pension liability	238.0	184.0
Accrued other post-employment benefit obligation	229.5	222.9
Other long-term liabilities	17.0	3.7
Environmental liabilities	35.2	32.3
Deferred income tax liabilities	98.0	96.7
Total non-current liabilities	745.1	650.0
Total liabilities	1,173.6	993.4
Shareholders' equity
Capital stock	963.9	958.4
Accumulated other comprehensive income	267.1	313.6
Retained earnings	288.4	211.6
Contributed deficit	(17.0)	(21.4)
Total shareholders' equity	1,502.4	1,462.2
Total liabilities and shareholders' equity	$ 2,676.0	$ 2,455.6

Other Post-Employment Benefits - Summary of Other Comprehensive Income (Loss) in the Consolidated Statements of Changes in Shareholder's Equity (Detail) - Other Post Employment Benefits [Member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement [Line Items]
Beginning balance , Actuarial (gain) loss immediately recognized	$ (76.8)	$ (54.0)
Actuarial (gain) loss immediately recognized , Actuarial gain immediately recognized	3.3	(22.8)
Ending balance , Actuarial gain immediately recognized	(73.5)	(76.8)
Beginning balance , Tax effect	0.0	0.0
Actuarial loss immediately recognized , Tax effect	0.0	0.0
Ending balance , Tax effect	0.0	0.0
Beginning balance , Actuarial (gain) immediately recognized, net of tax	(76.8)	(54.0)
Actuarial gain immediately recognized , Actuarial (gain) immediately recognized, net of tax	3.3	(22.8)
Ending balance , Actuarial (gain) immediately recognized, net of tax	$ (73.5)	$ (76.8)

Other Post-Employment Benefits - Additional Information (Detail) - Other Post Employment Benefits [Member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Statement [Line Items]
Contribution to defined benefit plan		$ 10.4	$ 10.8
Estimate of contribution expected to be paid to plan	$ 13.1
Past service cost adjustment		3.8
Cost of sales [member]
Statement [Line Items]
Past service cost adjustment		3.4
Administrative And Selling Expenses [Member]
Statement [Line Items]
Past service cost adjustment		$ 0.4
Current Service Costs [Member] \| Bottom of range [member]
Statement [Line Items]
Weighted average duration of defined benefit obligation		13 years 2 months 12 days
Current Service Costs [Member] \| Top of range [member]
Statement [Line Items]
Weighted average duration of defined benefit obligation		27 years 10 months 24 days

Inventories - Summary of Inventories Net Explanatory (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Classes of current inventories [abstract]
Raw materials and consumables	$ 580.3	$ 485.7
Work in progress	152.9	168.1
Finished goods	74.6	68.9
Inventories	$ 807.8	$ 722.7

Property, Plant and Equipment, Net - Summary of Changes in Cost of Property Plant and Equipment (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	$ 1,081.3
Ending balance	1,405.2	$ 1,081.3
Freehold Land [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	6.6
Ending balance	6.7	6.6
Buildings [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	39.2
Ending balance	52.4	39.2
Machinery & Equipment [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	691.7
Ending balance	697.6	691.7
Computer Hardware [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	1.9
Ending balance	4.0	1.9
Right-of-use assets [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	3.4
Ending balance	6.2	3.4
Property under construction [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	338.5
Ending balance	638.3	338.5
Gross carrying amount [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	1,528.3	1,096.5
Additions	439.9	333.3
Transfers	0.0	0.2
Disposals	(42.0)	(0.2)
Foreign exchange	4.1	98.5
Ending balance	1,930.3	1,528.3
Gross carrying amount [member] \| Freehold Land [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	6.6	6.1
Additions	0.0	0.0
Transfers	0.1	0.0
Disposals	0.0	0.0
Foreign exchange	0.0	0.5
Ending balance	6.7	6.6
Gross carrying amount [member] \| Buildings [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	73.1	65.9
Additions	0.0	0.0
Transfers	17.9	1.6
Disposals	(0.1)	0.0
Foreign exchange	0.1	5.6
Ending balance	91.0	73.1
Gross carrying amount [member] \| Machinery & Equipment [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	1,102.8	900.3
Additions	3.3	3.2
Transfers	115.1	121.6
Disposals	(41.7)	(0.1)
Foreign exchange	1.5	77.8
Ending balance	1,181.0	1,102.8
Gross carrying amount [member] \| Computer Hardware [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	3.0	1.4
Additions	0.0	0.0
Transfers	2.6	1.5
Disposals	0.0	0.0
Foreign exchange	0.0	0.1
Ending balance	5.6	3.0
Gross carrying amount [member] \| Right-of-use assets [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	4.3	4.0
Additions	0.0	0.0
Transfers	3.3	0.0
Disposals	0.0	0.0
Foreign exchange	0.1	0.3
Ending balance	7.7	4.3
Gross carrying amount [member] \| Property under construction [member]
Disclosure Of Detailed Information About Changes In Cost Of Property Plant And Equipment [Line Items]
Beginning balance	338.5	118.8
Additions	436.6	330.1
Transfers	(139.0)	(124.5)
Disposals	(0.2)	(0.1)
Foreign exchange	2.4	14.2
Ending balance	$ 638.3	$ 338.5

Derivative Financial Instruments

12 Months Ended

Mar. 31, 2024

Disclosure of detailed information about financial instruments [abstract]

Derivative Financial Instruments

19.	DERIVATIVE FINANCIAL INSTRUMENTS

The Company is party to an International Swaps and Derivatives Association, Inc. (ISDA) 2002 master agreement with an investment and financial services company to hedge the commodity price risk associated with various commodities.

As at

March 31, 2024 and March 31, 2023, the Company had no outstanding hedging agreements. The commodity contracts to hedge the NYMEX price of the hot rolled coil price of steel are derivatives, which are designated as cash flow hedges for which hedge effectiveness is measured for the duration of the agreements and therefore carried at fair value through other comprehensive income or loss. As of March 31, 2024 and March 31, 2023, the company had no outstanding steel derivative contracts and as a result, the fair value liability was nil.

The cumulative amount of gains and losses on cash flow hedging instruments assessed as effective are presented in the cash flow hedge reserve through other comprehensive income or loss and is recognized in profit or loss only when the hedged transaction impacts the profit or loss, or is included directly in the initial cost or other carrying amount of the hedged

non-financial

items (basis adjustment).

During the year ended March 31, 2023, the realized income resulting from the steel hedge of $9.3 million, was subsequently reclassified from Other Comprehensive Income and recognized in revenue.

The movements in the cash flow hedge reserve for the period as a component of accumulated other comprehensive income is as follows:



	March 31, 2024		March 31, 2023

Opening balance	$	-	$	24.7

Income arising on changes in fair value of cash flow hedges, net of tax expense of nil and $7.8 million , respectively		-		(34.0	)

Loss reclassified to net income		-		9.3



Income on cash flow hedges, recognized in Cash Flow Hedge Reserve in Other Comprehensive Income		-		(24.7	)



Ending balance	$	-	$	-

Taxes Payable and Accrued Taxes

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Taxes Payable and Accrued Taxes

17.	TAXES PAYABLE AND ACCRUED TAXES



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Payroll taxes payable	$	3.0	$	4.3

Sales taxes payable		1.6		-

Carbon tax accrual		23.4		8.4

Income taxes payable		2.1		1.7


	$	30.1	$	14.4

Derivative Financial Instruments - Summary of Movements in Cash Flow Hedge Reserve (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Movements In Cash Flow Hedge Reserve [Line Items]
Income arising on changes in fair value of cash flow hedges, net of tax expense of nil and $7.8 million, respectively	$ 0.0	$ 34.0
Loss reclassified to net income	0.0	(9.3)
Steel [Member]
Disclosure Of Movements In Cash Flow Hedge Reserve [Line Items]
Opening balance	0.0	24.7
Income arising on changes in fair value of cash flow hedges, net of tax expense of nil and $7.8 million, respectively	0.0	(34.0)
Loss reclassified to net income	0.0	9.3
Income on cash flow hedges, recognized in Cash Flow Hedge Reserve in Other Comprehensive Income	0.0	(24.7)
Ending balance	$ 0.0	$ 0.0

Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information Financial Assets And Liabilities Classified And Measured

The Company’s financial assets and liabilities are classified and measured as follows:


As at,		March 31, 2024				March 31, 2023
	Category	Carrying Value		Fair Value		Carrying Value		Fair Value

Financial assets

Cash (1)	Financial assets at amortized cost	$	97.9	$	97.9	$	247.4	$	247.4

Restricted cash (1)	Financial assets at amortized cost	$	3.9	$	3.9	$	3.9	$	3.9

Accounts receivable (2)	Financial assets at amortized cost	$	246.7	$	246.7	$	291.2	$	291.2

Financial liabilities

Bank indebtedness (1)	Financial liabilities at amortized cost	$	0.3	$	0.3	$	1.9	$	1.9

Accounts payable and accrued liabilities (1)	Financial liabilities at amortized cost	$	286.8	$	286.8	$	204.6	$	204.6

Current portion of governmental loans (3)	Financial liabilities at amortized cost	$	16.2	$	16.2	$	10.0	$	10.0

Current portion of financing arrangement (1)	Financial liabilities at amortized cost	$	0.9	$	0.9	$	-	$	-

Long-term governmental loans (3)	Financial liabilities at amortized cost	$	127.4	$	127.4	$	110.4	$	110.4

Long-term portion of financing arrangement (1)	Financial liabilities at amortized cost	$	10.4	$	10.4	$	-	$	-

Warrant liability (4)	Financial instruments at FVTP(L)	$	44.9	$	44.9	$	57.3	$	57.3

Earnout liability (4)	Financial instruments at FVTP(L)	$	13.8	$	13.8	$	16.8	$	16.8

Share-based payment compensation liability (4)	Financial instruments at FVTP(L)	$	31.9	$	31.9	$	33.5	$	33.5

- Initial measurement at fair value and subsequent remeasurement at amortized cost.

- Initial measurement at transaction price and subsequent remeasurement at amortized cost.

- Level 2; Initial measurement at fair value and subsequent remeasurement at FVTOCI(L)

- Level 1; Initial measurement at fair value and subsequent remeasurement at FVTP(L)

Summary of Company's Canadian Dollar Denominated Financial Instruments

The Company’s Canadian dollar denominated financial instruments as at March 31, 2024 and March 31, 2023, were as follows:



As at,	March 31, 2024			March 31, 2023

Cash	$	1.5		$	51.2

Restricted cash		3.9			3.9

Accounts receivable		78.0			127.1

Accounts payable and accrued liabilities		(145.5	)		(147.1	)

Governmental loans		(143.6	)		(120.4	)

Other long-term liabilities		(17.0	)		(3.3	)



Net Canadian dollar denominated financial instruments	$	(222.7	)	$	(88.6	)

Summary of Company's Contractually Agreed (Undiscounted) Cash Flows Payable Under Financial Liabilities

The following table discloses the Company’s contractually agre

d (undiscounted) cash flows payable under financial liabilities, as at March 31, 2024:



	Carrying Amount		Contractual Cash Flows			Year 1			Year 2			Years 3 to 5			Greater than 5 Years

Revolving Credit Facility	$	0.3	$	(0.3	)	$	(0.3	)	$	-		$	-		$	-

Accounts payable and accrued liabilities		286.8		(286.8	)		(286.8	)		-			-			-

Taxes payable		30.1		(30.1	)		(30.1	)		-			-			-

Governmental Loans		143.6		(254.2	)		(16.2	)		(25.0	)		(61.7	)		(151.3	)

Financing arrangement		11.3		(11.3	)		(0.9	)		(1.0	)		(9.4	)		-

Interest on Provincial MENDM Loan		3.5		(8.3	)		(0.9	)		(2.1	)		(5.3	)		-


	$	475.6	$	(591.0	)	$	(335.2	)	$	(28.1	)	$	(76.4	)	$	(151.3	)

The following table discloses the Company’s contractually agreed (undiscounted) cash flows payable under financial liabilities, as at March 31, 2023:



	Carrying Amount		Contractual Cash Flows			Year 1			Year 2			Years 3 to 5			Greater than 5 Years

Revolving Credit Facility	$	1.9	$	(1.9	)	$	(1.9	)	$	-		$	-		$	-

Accounts payable and accrued liabilities		204.6		(204.6	)		(204.6	)		-			-			-

Taxes payable		14.4		(14.4	)		(14.4	)		-			-			-

Governmental Loans		120.4		(189.7	)		(10.0	)		(18.1	)		(79.8	)		(81.8	)

Interest on Provincial MENDM Loan		2.6		(5.8	)		-			(0.6	)		(5.2	)		-



	$	343.9	$	(416.4	)	$	(230.9	)	$	(18.7	)	$	(85.0	)	$	(81.8	)

Governmental Loans (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Details in Tabular Form of Governmental Loans



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Long-term portion

Federal AMF Loan, denominated in Canadian dollars, due March 1, 2028	$	21.7	$	27.9

Provincial MENDM Loan, denominated in Canadian dollars, due November 30, 2028		42.8		45.4

Federal SIF Agreement loan, denominated in Canadian dollars, due April 30, 2031		9.4		9.7

Federal SIF EAF Agreement loan, denominated in Canadian dollars, due January 1, 2030		53.5		27.4



	$	127.4	$	110.4


Current portion

Federal AMF Loan, denominated in Canadian dollars	$	10.0	$	10.0

Provincial MENDM Loan, denominated in Canadian dollars		6.2		-


	$	16.2	$	10.0


	$	143.6	$	120.4

Summary of Company's Long-term Debt Facilities Arising From Financing Activities

The changes in the Company’s governmental loan facilities arising from financing activities are presented below:



	Governmental Loan Issued (Repaid)			Governmental loan benefit recognized immediately			Accretion of governmental loan benefit		Carrying value

Federal AMF Loan

Balance at March 31, 2023	$	49.2		$	(26.5	)	$	15.0	$	37.9

Movement in the period		(10.0	)		-			3.8		(6.2	)


Balance at March 31, 2024	$	39.2		$	(26.5	)	$	18.8	$	31.7


Provincial MENDM Loan

Balance at March 31, 2023	$	60.0		$	(26.4	)	$	11.9	$	45.4

Movement in the period		-			-			3.6		3.6


Balance at March 31, 2024	$	60.0		$	(26.4	)	$	15.5	$	49.0


Federal SIF Loan

Balance at March 31, 2023	$	15.0		$	(7.8	)	$	2.5	$	9.7

Movement in the period		-			(1.4	)		1.1		(0.3	)


Balance at March 31, 2024	$	15.0		$	(9.2	)	$	3.6	$	9.4


Federal SIF EAF Loan

Balance at March 31, 2023	$	65.5		$	(38.7	)	$	0.6	$	27.4

Movement in the period		74.4			(51.7	)		3.4		26.1


Balance at March 31, 2024	$	139.9		$	(90.4	)	$	4.0	$	53.5


Total, Governmental Loans

Balance at March 31, 2023	$	189.8		$	(99.4	)	$	30.0	$	120.4

Movement in the period		64.4			(53.1	)		11.9		23.2


Balance at March 31, 2024	$	254.2		$	(152.5	)	$	41.9	$	143.6

Property, Plant and Equipment, Net - Summary of Property Plant and Equipment, Net (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	$ 1,405.2	$ 1,081.3
Freehold land [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	6.7	6.6
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	52.4	39.2
Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	697.6	691.7
Computer hardware [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	4.0	1.9
Right-of-use assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	6.2	3.4
Property under construction [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, net	$ 638.3	$ 338.5

Derivative Financial Instruments - Summary of Movements in Cash Flow Hedge Reserve (Parenthetical) (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Movements In Cash Flow Hedge Reserve [Line Items]
Income tax component in other comprehensive income relating to cash flow hedges	$ 0.0	$ 7.8
Steel [Member]
Disclosure Of Movements In Cash Flow Hedge Reserve [Line Items]
Income tax component in other comprehensive income relating to cash flow hedges	$ 0.0	$ 7.8

Capital Stock - Additional Information (Detail) $ / shares in Units, $ / shares in Units, $ in Millions, $ in Millions						12 Months Ended
	Feb. 28, 2023 shares	Jul. 27, 2022 CAD ($) $ / shares shares	Jul. 27, 2022 USD ($) $ / shares shares	Jun. 21, 2022 USD ($) $ / shares	Feb. 18, 2022 shares	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2023 CAD ($) $ / shares shares	Mar. 31, 2023 USD ($) shares	Mar. 31, 2023 $ / shares	Mar. 03, 2022 shares
Disclosure of classes of share capital [line items]
Number of shares issued during period					147,957,790
Number Of Shares Authorized To Be Repurchased										7,397,889
Percentage Of Shares Authorized To Be Repurchased As Of Shares Issued										5.00%
Maximum Number Of Shares To Be Repurchased Per Day					16,586
Common shares issued upon exercise of earnout rights						464,268
Deferred Share Units [Member]
Disclosure of classes of share capital [line items]
Conversion of Shares Converted						70,920
Normal Course Issuer Bid [Member]
Disclosure of classes of share capital [line items]
Stock Repurchased During Period Shares							(3,364,262)	(3,364,262)
Stock repurchase per share \| (per share)							$ 9.25		$ 7.3
Payments to acquire or redeem entity's shares							$ 37.1	$ 28.6
Excess fair value over purchase price of entity shares \| $							$ 5.9
Renewed Normal Course Issuer Bid [Member]
Disclosure of classes of share capital [line items]
Number of shares issued during period	103,567,884
Number Of Shares Authorized To Be Repurchased	5,178,394
Percentage Of Shares Authorized To Be Repurchased As Of Shares Issued	5.00%
Maximum Number Of Shares To Be Repurchased Per Day	50,984
Stock Repurchased During Period Shares						0	0	0
Substantial Issuer Bid [Member]
Disclosure of classes of share capital [line items]
Stock Repurchased During Period Shares		41,025,641	41,025,641				(41,025,641)	(41,025,641)
Stock repurchase per share \| $ / shares			$ 9.75
Excess fair value over purchase price of entity shares		$ 127.4	$ 99.3
Increment per Share \| $ / shares				$ 0.1
Weighted average book value \| (per share)		$ 9.11	$ 7.33
Transaction costs \| $						$ 1.1
Aggregate purchase price		$ 514.9	$ 400.0	$ 400.0
Substantial Issuer Bid [Member] \| Bottom of range [member]
Disclosure of classes of share capital [line items]
Stock repurchase per share \| $ / shares				$ 8.75
Substantial Issuer Bid [Member] \| Top of range [member]
Disclosure of classes of share capital [line items]
Stock repurchase per share \| $ / shares				$ 10.25

Environmental Liabilities (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Environmental Liabilities



As at,	March 31, 2024		March 31, 2023

The carrying amount of Environmental liabilities in respect of:

The Company’s Operation Site	$	33.8	$	32.7

Northern Ontario mine sites owned by Old Steelco Inc.		4.5		4.1


	$	38.3	$	36.8


Current portion	$	3.1	$	4.5

Long-term portion		35.2		32.3


	$	38.3	$	36.8

Summary of Reconciliation of Environmental Liabilities


	The Company’s Operation Site			Northern Ontario mine sites owned by Old Steelco Inc.			Total

Balance at March 31, 2022	$	33.7		$	4.3		$	38.0

Payments		(4.1	)		(0.7	)		(4.8	)

Accretion of discount		3.1			0.5			3.6



Balance at March 31, 2023	$	32.7		$	4.1		$	36.8


Payments		(5.3	)		(0.3	)		(5.6	)

Accretion of discount		3.0			0.3			3.3

Revaluation for change in discount rate		3.4			0.4			3.8



Balance at March 31, 2024	$	33.8		$	4.5		$	38.3

Cost of Sales - Summary of Detailed Information About Cost of Sales Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Cost of Sales [Line Items]
Cost of sales	$ 2,513.5	$ 2,388.7
Cost of sales [member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Inventories recognized as cost of sales	2,315.2	2,206.4
Net inventory write-downs as a result of net realizable value lower than cost included in cost of sales	13.5	23.0
Steel [Member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Cost of sales	2,263.0	2,160.2
Freight [Member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Cost of sales	198.3	182.4
Non Steel [Member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Cost of sales	$ 52.2	$ 46.1

Pension Benefits (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of principal assumptions used for the purposes of the actuarial valuations

The principal assumptions used for the purposes of the actuarial valuations were as follows:



Year ended,	March 31, 2024		March 31, 2023 1		March 31, 2023 2

Assumptions for determination of defined benefit cost:

Defined obligation and past service cost		4.85%		4.25%		4.73%

Net interest cost		4.94%		3.86%		4.50%

Current service cost		5.05%		4.35%		4.85%

Interest cost on current service cost		5.00%		4.18%		4.71%

Discount rate for determination of defined benefit obligation		4.98%		4.98%		4.98%

Assumptions for determination of defined benefit cost and defined benefit obligation:

Ultimate rate of compensation increase		3.00% per annum until 2027 2.00% thereafter		3.00% per annum until 2027 2.00% thereafter		3.00% per annum until 2027 2.00% thereafter

Mortality		105% CPM2014 Private Projection CPM-B		105% CPM2014 Private Projection CPM-B		105% CPM2014 Private Projection CPM-B

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of April 1, 2022 to July 31, 2022

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of August 1, 2022 to March 31, 2023 and past service cost as of August 1, 2022

Summary of Pension benefit expense recognized in profit or loss, defined benefit plans

The components of amounts recognized in the consolidated statements of net income in respect of the defined benefit plans are presented below:



Year ended,	March 31, 2024		March 31, 2023

Amounts recognized in net income were as follows:

Current service cost	$	16.8	$	16.5

Past service cost		-		49.5

Net interest cost		8.6		7.3


	$	25.4	$	73.3


Defined benefit costs recognized in:

Cost of sales	$	15.2	$	59.4

Administrative and selling expenses		1.6		6.6

Interest on pension liability		8.6		7.3


	$	25.4	$	73.3

Summary of Pension Benefits Recognized in Statements of Other Comprehensive income Loss

The amounts recognized in the consolidated statements of other comprehensive income in respect of the defined benefit plans are presented below:



Year ended,	March 31, 2024		March 31, 2023

Amounts recognized in other comprehensive income, were as follows:

Actuarial loss on accrued pension liability	$	46.3	$	9.0

The amounts included in the consolidated statements of financial position in respect of the Company’s net obligation in respect of its defined benefit plans are as follows:



As at,	March 31, 2024		March 31, 2023

Present value of defined benefit obligation	$	1,302.9	$	1,264.9

Fair value of plan assets		1,064.8		1,080.9


Net accrued pension liability	$	238.0	$	184.0

Summary of Continuities of the defined benefit plan assets and obligations

Continuities of the defined benefit plan assets and obligations are as follows:



Year ended,	March 31, 2024			March 31, 2023

Movements in the present value of the plan assets were as follows:

Fair value of plan assets at beginning of year	$	1,080.9		$	1,225.5

Actual return (net of investment management expenses)		51.6			(75.4	)

Administration expenses		(1.7	)		(1.5	)

Employer contributions		17.5			16.5

Benefits paid		(83.4	)		(84.2	)

Fair value of plan assets at end of the year



March 31, 2024 and March 31, 2023, respectively	$	1,064.8		$	1,080.9


Movements in the present value of the defined benefit obligation were as follows:

Defined benefit obligation at the beginning of the year	$	1,264.9		$	1,343.6

Current service cost		15.2			15.0

Interest cost		60.3			55.4

Past service cost		-			49.5

Actuarial losses (gains) arising from financial assumptions		33.0			(112.2	)

Effect of experience adjustments		12.9			(2.2	)

Benefits paid		(83.4	)		(84.2	)

Defined benefit obligation at end of the year



March 31, 2024 and March 31, 2023, respectively	$	1,302.9		$	1,264.9

Summary of Reconciliation of the amounts recognized in accumulated other comprehensive income (loss)

Reconciliation of the amounts recognized in accumulated other comprehensive income in the consolidated statements of changes in shareholders’ equity were as follows:


	Actuarial (gain) loss immediately recognized			Tax effect			Actuarial (gain) immediately recognized, net of tax

Balance at March 31, 2022	$	(138.8	)	$	(0.3	)	$	(139.1	)

Actuarial loss immediately recognized		9.0			-			9.0


Balance at March 31, 2023	$	(129.8	)	$	(0.3	)	$	(130.1	)


Actuarial loss immediately recognized		46.3			-			46.3


Balance at March 31, 2024	$	(83.5	)	$	(0.3	)	$	(83.8	)

Summary of major categories of plan assets

The major categories of plan assets were as follows:



As at	March 31, 2024	March 31, 2023

Cash and cash equivalents	1%	1%

Equity instruments	55%	33%

Debt instruments	41%	39%

Other	3%	27%



	100%	100%

Summary of sensitivity the defined benefit obligation to the key actuarial assumptions

The sensitivity of the defined benefit obligation to the key actuarial assumptions is as follows:



Year ended,	March 31, 2024		March 31, 2023

Effect of change in discount rate assumption

One percentage point increase	$	(123.1)	$	(118.5)

One percentage point decrease	$	147.4	$	141.8

Effect of change in salary scale

One percentage point increase	$	17.4	$	18.8

One percentage point decrease	$	(15.9)	$	(17.0)

Effect of change in mortality assumption

Set forward one year	$	33.1	$	31.5

Set back one year	$	(34.0)	$	(32.4)

Warrant Liability - Additional Information (Detail) $ / shares in Units, $ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2024 CAD ($) $ / shares shares	Mar. 31, 2023 CAD ($)	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 USD ($)
Warrant Liability [Line Items]
Liabilities	$ 1,173.6	$ 1,173.6	$ 993.4
Legato [Member] \| Warrants [Member]
Warrant Liability [Line Items]
Class of warrants or rights warrants outstanding \| shares	24,179,000	24,179,000		24,179,000
Warrants estimated fair value per share \| $ / shares		$ 1.37
Liabilities	$ 44.9	$ 44.9	57.3	$ 33.1	$ 42.3
Gains (losses) recognised in profit or loss excluding exchange differences, fair value measurement, liabilities	$ 12.1		$ 47.7

Other Post-Employment Benefits

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Other Post Employment Benefits [Member]

Statement [Line Items]

Disclosure In Tabular Form Of Acturial Assumptons For Pension Plans [Table Text Block]

The principal assumptions used for the purposes of the actuarial valuations were as follows:



Year ended,	March 31, 2024		March 31, 2023 1		March 31, 2023 2

Assumptions for determination of defined benefit cost:

Discount rate

Defined benefit obligation		5.04%		4.31%		4.79%

Current service cost		5.07%		4.46%		4.88%

Interest cost on benefit obligation		4.95%		4.01%		4.59%

Interest cost on current service cost		5.07%		4.42%		4.86%

Health care cost immediate trend rate		4.96%		5.00%		4.99%

Assumptions for determination of defined benefit obligation:

Effective discount rate		4.85%		4.79%		5.04%

Health care cost immediate trend rate		4.90%		4.99%		4.96%

Assumptions for determination of defined benefit cost and defined benefit obligation:

Health care cost ultimate trend rate		4.00%		4.00%		4.00%

Year ultimate health care cost trend rate reached		2040		2040		2040

Salary Increases per annum		2.00%		2.00%		2.00%

Mortality		105%CPM 2014 Private Projection CPM-B		105%CPM 2014 Private Projection CPM-B		105%CPM 2014 Private Projection CPM-B

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of April 1, 2022 to July 31, 2022

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of August 1, 2022 to March 31, 2023

Disclosure of Detailed Information About Other Post Employment Benefits Recognized in Statements of Income Loss Explanatory

The components of amounts recognized

the consolidated statements

net income in respect of the other post-employment benefit plans are presented below:



Year ended,	March 31, 2024		March 31, 2023

Amounts recognized in net income were as follows:

Current service cost	$	3.0	$	3.0

Past service cost		-		3.8

Net interest cost		10.7		9.9


	$	13.7	$	16.7


Post employment benefit costs recognized in:

Cost of sales	$	2.6	$	6.0

Administrative and selling expenses		0.4		0.8

Interest on pension liability		10.7		9.9



	$	13.7	$	16.7

Summary of Financial Position in Respect of its Other Post-Retirement Benefit Plans

The amounts included in the consolidated statements

financial position arising from the Company’s obligation in respect of its other post-retirement benefit plans were as follows:



As at,	March 31, 2024		March 31, 2023

Present value of post-employment benefit obligation	$	229.5	$	222.9

Fair value of plan assets		-		-



Accrued other post-employment benefit obligation	$	229.5	$	222.9

Summary of Other Comprehensive Income (Loss) in the Consolidated Statements of Changes in Shareholder's Equity

Reconciliation of the amounts recognized in accumulated other comprehensive income in the consolidated statements of changes in shareholders’ equity were as follows:


	Actuarial (gain) loss immediately recognized			Tax effect		Actuarial (gain) loss immediately recognized, net of tax

Balance at March 31, 2022	$	(54.0	)	$	-	$	(54.0	)

Actuarial gain immediately recognized		(22.8	)		-		(22.8	)



Balance at March 31, 2023	$	(76.8	)	$	-	$	(76.8	)


Actuarial gain immediately recognized		3.3			-		3.3



Balance at March 31, 2024	$	(73.5	)	$	-	$	(73.5	)

Summary of Other Post-Employment Benefit Obligation to Changes in the Discount Rate, Health Care Cost Trend Rate and Mortality Assumptions

The sensitivity of the other post-employment benefit obligation to changes in the discount rate, health care cost trend rate and mortality assumptions are as follows:



Year ended,	March 31, 2024		March 31, 2023

Effect of change in discount rate assumption

One percentage point increase	$	(26.4)	$	(25.2)

One percentage point decrease	$	33.2	$	31.7

Effect of change in health care cost trend rates

One percentage point increase	$	27.9	$	25.8

One percentage point decrease	$	(24.2)	$	(22.2)

Effect of change in mortality assumption

Set forward one year	$	8.6	$	8.3

Set back one year	$	(8.5)	$	(8.1)

Environmental Liabilities - Additional Information (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement [Line Items]
Letters Of Credit	$ 14.5	$ 15.1
Environmental costs recognized ,captalized in period	20 years
Environmental liabilities [member]
Statement [Line Items]
Increase In Liability	$ 3.8
Environmental liabilities [member] \| Top of range [member]
Statement [Line Items]
Environmental costs recognized ,discount rate	9.00%
Environmental liabilities [member] \| Bottom of range [member]
Statement [Line Items]
Environmental costs recognized ,discount rate	7.40%
The companys operation site [member]
Statement [Line Items]
Letters Of Credit	$ 13.7	13.7
Northern ontario mine sites owned by old steelco inc [member]
Statement [Line Items]
Letters Of Credit	$ 0.8	$ 1.4

Income Tax Expense - Summary of Income taxes in the consolidated statements of net (loss) income (Parenthetical) (Detail)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Reconciliation Of Tax Expense Income At Applicable Tax Rate To Provision For Income Taxes [Abstract]
Applicable tax rate	25.00%	25.00%

Administrative and Selling Expenses

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Administrative and Selling Expenses

8.	ADMINISTRATIVE AND SELLING EXPENSES



Year ended,	March 31, 2024		March 31, 2023

Administrative and selling expense is comprised of:

Personnel expenses	$	43.3	$	39.3

Share-based compensation expense (Note 34)		5.2		3.9

Professional, consulting, legal and other fees		18.8		20.7

Insurance		25.6		21.8

Software licenses		5.9		5.2

Amortization of intangible assets and non-producing assets		0.3		0.3

Other administrative and selling		15.9		8.1


	$	115.0	$	99.3

Past service

cost

recognition

The collective bargaining agreements with Local 2251 and Local 2724 were ratified in August 2022 and September 2022, respectively; and became effective as of August 1, 2022. The settlement resulted in a past service cost adjustment related to the defined benefit pension plan and other post-employment benefits of $5.0 million and $0.4 million, respectively, of which $5.4 million was recorded in administrative and selling expenses for the year ended March 31, 2023.

Inventories (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Inventories Net Explanatory



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Raw materials and consumables	$	580.3	$	485.7

Work in progress		152.9		168.1

Finished goods		74.6		68.9


	$	807.8	$	722.7

Consolidated Statements of Cash Flows $ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($)	Mar. 31, 2023 CAD ($)
Operating activities
Net income	$ 105.2	$ 298.5
Items not affecting cash:
Depreciation of property, plant and equipment and intangible assets	115.0	95.3
Deferred income tax expense (recovery)	1.2	(12.0)
(Pension funding in excess of expense) pension expense in excess of funding	(0.8)	49.6
Post-employment benefit funding in excess of expense	(7.5)	(4.0)
Unrealized foreign exchange gain on:
accrued pension liability	(0.9)	(14.2)
post-employment benefit obligations	(0.7)	(17.7)
Finance costs	25.2	17.9
Loss on disposal of property, plant and equipment	0.5	0.1
Interest on pension and other post-employment benefit obligations	19.3	17.2
Interest on finance lease	0.4	0.1
Accretion of governmental loans and environmental liabilities	19.2	13.0
Unrealized foreign exchange gain on government loan facilities	(0.7)	(7.6)
Decrease in fair value of warrant liability	(12.1)	(47.7)
Increase (decrease) in fair value of earnout liability	0.1	(5.9)
Increase (decrease) in fair value of share-based payment compensation liability	1.2	(12.7)
Other	4.7	(7.6)
Adjustments to reconcile profit (loss)	269.3	362.3
Net change in non-cash operating working capital	33.1	(178.7)
Share-based payment compensation and earnout units settled	(2.5)	(4.6)
Environmental liabilities paid	(5.0)	(1.7)
Cash generated by operating activities	294.9	177.3
Investing activities
Acquisition of property, plant and equipment	(490.1)	(371.1)
Cash used in investing activities	(490.1)	(371.1)
Financing activities
Bank indebtedness (repaid) advanced, net	(1.7)	1.8
Transaction costs on bank indebtedness	(1.7)	0.0
Governmental loans received	74.8	63.3
Repayment of governmental loans	(10.0)	(10.0)
Interest paid	(0.3)	(0.2)
Dividends paid	(27.9)	(30.7)
Common shares repurchased and cancelled	0.0	(553.2)
Other	11.2	(3.0)
Cash generated by (used in) financing activities	44.4	(532.0)
Effect of exchange rate changes on cash	1.3	57.9
Cash
Decrease in cash	(149.5)	(667.9)
Opening balance	247.4	915.3
Ending balance	$ 97.9	$ 247.4

Finance Costs (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information About Finance Cost Explanatory



Year ended,	March 31, 2024		March 31, 2023

Finance costs are comprised of:

Interest on the Revolving Credit Facility (Note 15)	$	-	$	0.2

Interest on financing arrangement (Note 22)		0.2		-

Revaluation of discount rate for environmental liabilities		3.8		-

Other interest expense		2.3		0.8

Revolving Credit Facility fees		2.9		2.5

Unwinding of issuance costs of debt facilities (Note 15) and accretion of governmental loan benefits and discounts on environmental liabilities		16.4		14.4


	$	25.6	$	17.9

Pension Benefits - Summary of Pension Benefits Recognized in Statements of Other Comprehensive Income Loss (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension defined benefit plans [member]
Amounts recognized in other comprehensive income, were as follows:
Actuarial loss on accrued pension liability	$ 46.3	$ 9.0

Other Post-Employment Benefits - Disclosure of the consolidated statements of comprehensive loss in respect of these defined benefit plans (Detail) - Other Post Employment Benefits [Member] - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Disclosure of defined benefit plans [line items]
Present value of post-employment benefit obligation	$ 229.5	$ 222.9	$ 239.8
Fair value of plan assets	0.0	0.0
Accrued other post-employment benefit obligation	$ 229.5	$ 222.9

Earnout Liability - Additional Information (Detail) $ / shares in Units, $ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2023 CAD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)
Earnout Liability [Line Items]
Liabilities	$ 1,173.6	$ 993.4
Earnout Liability [Member]
Earnout Liability [Line Items]
Earnout shares outstanding \| shares	1,196,157		1,196,157
Earnout shares fair value per share \| $ / shares			$ 8.49
Liabilities	$ 13.8	16.8	$ 10.2	$ 12.4
Loss (gain) on earn out liability	0.1	(5.9)
Earnout liability right settled	$ 2.5	$ 0.0

Dividends (Tables)

12 Months Ended

Mar. 31, 2024

Disclosure of Detailed Information About Dividends [Abstract]

Summary of Dividends



Record date	Payment date	Total Dividends on Common Stock

July 5, 2023	July 24, 2023	$	7.0

August 25, 2023	September 29, 2023		6.9

November 30, 2023	December 29, 2023		6.9

February 29, 2024	March 28, 2024		7.1


		$	27.9

Pension Benefits - Summary of Pension benefit expense recognized in profit or loss, defined benefit plans (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Amounts recognized in net income were as follows:
Net interest cost	$ 19.3	$ 17.2
Pension Benefits [Member]
Amounts recognized in net income were as follows:
Current service cost	16.8	16.5
Past service cost	0.0	49.5
Net interest cost	8.6	7.3
Defined benefit costs recognized	25.4	73.3
Pension Benefits [Member] \| Cost of sales [member]
Amounts recognized in net income were as follows:
Defined benefit costs recognized	15.2	59.4
Pension Benefits [Member] \| Administrative and selling expenses [Member]
Amounts recognized in net income were as follows:
Defined benefit costs recognized	1.6	6.6
Pension Benefits [Member] \| Interest on pension liability [Member]
Amounts recognized in net income were as follows:
Defined benefit costs recognized	$ 8.6	$ 7.3

Other Long-Term Liabilities

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Other Long-Term Liabilities

22.	OTHER LONG-TERM LIABILITIES



As at,	March 31, 2024		March 31, 2023

The carrying amount of the following other long term liabilities:

Accrued interest payable, Provincial MENDM Loan	$	3.5	$	2.6

Financing arrangement		10.4		-

Long-term disability plan obligation		0.9		0.7

Long-term portion of lease liability		2.2		0.4


	$	17.0	$	3.7

Accrued interest payable, Provincial MENDM Loan

As disclosed in Note 18, the Company has entered into an agreement with the Ministry of Energy, Northern Development and Mines under which the Company received a $60.0 million low interest loan. At March 31, 2024, the accrued interest payable under this agreement was $3.5 million (March 31, 2023 – $2.6 million).

Financing arrangement

On December 7, 2023, the Company completed a financing arrangement with the Bank of Montreal for total cash consideration of $11.7 million. The financing arrangement bears interest at 7.5% with monthly payments of $0.1 million. At March 31, 2024, current portion totalling $0.9 million is presented in current portion of other long-term liabilities on the consolidated statements of financial position.

Long-term disability plan obligation

The Company maintains a long-term disability plan. Under this plan, the Company offers continuation of medical and dental benefits for employees on long-term disability leaves of absence. The Company recognizes the present value of the long-term disability benefit obligation based on the number of employees on long-term disability. The most recent actuarial determination of the Company’s long-term disability obligation was carried out at March 31, 2024. At March 31, 2024, the long-term disability plan had a carrying value of $0.9 million (March 31, 2023 - $0.7 million).

Cost of Sales (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information About Cost of Sales Explanatory



Year ended,	March 31, 2024		March 31, 2023

Total cost of sales is comprised of:

Cost of steel revenue	$	2,263.0	$	2,160.2

Cost of freight revenue		198.3		182.4

Cost of non-steel revenue		52.2		46.1


	$	2,513.5	$	2,388.7


Inventories recognized as cost of sales:	$	2,315.2	$	2,206.4


Net inventory write-downs as a result of net realizable value lower than cost included in cost of sales:	$	13.5	$	23.0

Governmental Loans - Summary of Details in Tabular Form of Governmental Loans (Parenthetical) (Detail)			12 Months Ended
	Mar. 29, 2019	Nov. 30, 2018	Mar. 31, 2024	Mar. 31, 2023
Federal AMF Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Borrowings maturity		March 1, 2028	March 1, 2028	March 1, 2028
Decription of currency used			Canadian dollars	Canadian dollars
MENDM Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Borrowings maturity		November 30, 2028	November 30, 2028	November 30, 2028
Decription of currency used			Canadian dollars	Canadian dollars
Federal SIF Agreement Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Borrowings maturity	April 30, 2034		April 30, 2031	April 30, 2031
Decription of currency used			Canadian dollars	Canadian dollars
Federal SIF EAF Agreement Loan Due January One Two Thousand And Thirty [Member]
Disclosure Details Of Governmental Loans [Line Items]
Borrowings maturity			January 1, 2030	January 1, 2030
Decription of currency used			Canadian dollars	Canadian dollars

Financial Instruments

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Financial Instruments

29.	FINANCIAL INSTRUMENTS

Fair value of financial instruments

The fair value of cash, restricted cash, accounts receivable, accounts payable and accrued liabilities approximates their carrying value due to the short-term nature of these instruments. The fair value of the Revolving Credit Facility, disclosed in Note 15 approximates the respective carrying value due to variable interest rates.

The fair value of the financing arrangement included in other long-term liabilities

approximates

the carrying value due to prevailing interest rates and the risk characteristics of the instrument.

The fair value of the various government funding are classified as Level 2 and are estimated based on a discounted cash flow model applying current rates offered to the Company for financial instruments subject to similar risk and maturities. The carrying value of government funding generally approximate its fair value.

The fair value of steel commodity swaps are classified as Level 2 and is calculated using the

mark-to-market

forward prices of NYMEX hot rolled coil steel based on the applicable settlement dates of the outstanding swap contracts.

The fair values of the warrant liability, earnout liability and the share-based payment compensation liability are classified as Level 1 and are calculated using the quoted market price of the Company’s common shares at the end of each reporting period.

The Company’s financial assets and liabilities are classified and measured as follows:


As at,		March 31, 2024				March 31, 2023
	Category	Carrying Value		Fair Value		Carrying Value		Fair Value

Financial assets

Cash (1)	Financial assets at amortized cost	$	97.9	$	97.9	$	247.4	$	247.4

Restricted cash (1)	Financial assets at amortized cost	$	3.9	$	3.9	$	3.9	$	3.9

Accounts receivable (2)	Financial assets at amortized cost	$	246.7	$	246.7	$	291.2	$	291.2

Financial liabilities

Bank indebtedness (1)	Financial liabilities at amortized cost	$	0.3	$	0.3	$	1.9	$	1.9

Accounts payable and accrued liabilities (1)	Financial liabilities at amortized cost	$	286.8	$	286.8	$	204.6	$	204.6

Current portion of governmental loans (3)	Financial liabilities at amortized cost	$	16.2	$	16.2	$	10.0	$	10.0

Current portion of financing arrangement (1)	Financial liabilities at amortized cost	$	0.9	$	0.9	$	-	$	-

Long-term governmental loans (3)	Financial liabilities at amortized cost	$	127.4	$	127.4	$	110.4	$	110.4

Long-term portion of financing arrangement (1)	Financial liabilities at amortized cost	$	10.4	$	10.4	$	-	$	-

Warrant liability (4)	Financial instruments at FVTP(L)	$	44.9	$	44.9	$	57.3	$	57.3

Earnout liability (4)	Financial instruments at FVTP(L)	$	13.8	$	13.8	$	16.8	$	16.8

Share-based payment compensation liability (4)	Financial instruments at FVTP(L)	$	31.9	$	31.9	$	33.5	$	33.5

- Initial measurement at fair value and subsequent remeasurement at amortized cost.

- Initial measurement at transaction price and subsequent remeasurement at amortized cost.

- Level 2; Initial measurement at fair value and subsequent remeasurement at FVTOCI(L)

- Level 1; Initial measurement at fair value and subsequent remeasurement at FVTP(L)

Financial risk management

The Company’s activities expose it to a variety of financial risks including credit risk, liquidity risk, interest rate risk and market risk. The Company may use derivative financial instruments to hedge

certain

of these risk exposures. The use of derivatives is based on established practices and parameters, which are subject to the oversight of the Board of Directors. The Company does not utilize derivative financial instruments for trading or speculative purposes.

Credit risk

Credit risk is the risk of financial loss to the Company if a customer or counterparty to a financial instrument fails to meet its contractual obligations, and arises primarily from the Company’s receivables from customers. The Company has an established credit policy under which each new customer is analyzed individually for creditworthiness before the Company’s standard payment and delivery terms and conditions are offered. The Company’s review includes a review of the potential customer’s financial information, external credit ratings and bank and supplier references. Credit limits are established for each new customer and customers that fail to meet the Company’s credit requirements may transact with the Company only on a prepayment basis.

The maximum credit exposure at March 31, 2024 is the carrying amount of accounts receivable of $

246.7

million (March 31, 2023 - $

291.2

million). At March 31, 2024, there was one customer account greater than

% of the carrying amount of accounts receivable. At March 31, 2023, there was no customer account greater than

% of the carrying amount of accounts receivable. As at March 31, 2024, $

6.2

million, or

2.5

% (March 31, 2023 - $

2.0

million, or

0.7

%), of accounts receivable were more than

days old.

The Company establishes an allowance for doubtful accounts that represents its estimate of losses in respect of accounts receivable. The main components of this allowance are a specific provision that relates to individual exposures and a provision for expected losses that have been incurred but not yet identified. The allowance for doubtful accounts at March 31, 2024 was $3.1 million (March 31, 2023 - $0.5 million), as disclosed in Note 12.

The Company may be exposed to certain losses in the event of

non-performance

by counterparties to derivative financial instruments such as commodity price contracts and foreign exchange contracts. The Company mitigates this risk by entering into transactions with highly rated major financial institutions.

Liquidity risk

Liquidity risk is the risk that the Company will not be able to meet its financial obligations as they come due. The Company manages liquidity risk by maintaining adequate cash balances. The Company continuously monitors and reviews actual and forecasted cash flows to ensure adequate liquidity and anticipate liquidity requirements. The Company’s objectives and processes for capital management, including the management of long-term debt, are described in Note 5.

The following table discloses the Company’s contractually agre

d (undiscounted) cash flows payable under financial liabilities, as at March 31, 2024:



	Carrying Amount		Contractual Cash Flows			Year 1			Year 2			Years 3 to 5			Greater than 5 Years

Revolving Credit Facility	$	0.3	$	(0.3	)	$	(0.3	)	$	-		$	-		$	-

Accounts payable and accrued liabilities		286.8		(286.8	)		(286.8	)		-			-			-

Taxes payable		30.1		(30.1	)		(30.1	)		-			-			-

Governmental Loans		143.6		(254.2	)		(16.2	)		(25.0	)		(61.7	)		(151.3	)

Financing arrangement		11.3		(11.3	)		(0.9	)		(1.0	)		(9.4	)		-

Interest on Provincial MENDM Loan		3.5		(8.3	)		(0.9	)		(2.1	)		(5.3	)		-


	$	475.6	$	(591.0	)	$	(335.2	)	$	(28.1	)	$	(76.4	)	$	(151.3	)

The following table discloses the Company’s contractually agreed (undiscounted) cash flows payable under financial liabilities, as at March 31, 2023:



	Carrying Amount		Contractual Cash Flows			Year 1			Year 2			Years 3 to 5			Greater than 5 Years

Revolving Credit Facility	$	1.9	$	(1.9	)	$	(1.9	)	$	-		$	-		$	-

Accounts payable and accrued liabilities		204.6		(204.6	)		(204.6	)		-			-			-

Taxes payable		14.4		(14.4	)		(14.4	)		-			-			-

Governmental Loans		120.4		(189.7	)		(10.0	)		(18.1	)		(79.8	)		(81.8	)

Interest on Provincial MENDM Loan		2.6		(5.8	)		-			(0.6	)		(5.2	)		-



	$	343.9	$	(416.4	)	$	(230.9	)	$	(18.7	)	$	(85.0	)	$	(81.8	)

Market risk

Market risk is the risk that changes in market prices, such as foreign exchange rates, interest rates and commodity prices, will affect the Company’s income or the value of its holdings of financial instruments. The objective of market risk management is to manage and control market risk exposures within acceptable parameters, while optimizing the return on risk. As disclosed in Note 19, during the years ended March 31, 2024 and March 31, 2023, the Company was not a party to agreements to hedge the commodity price risk associated with the revenue on the sale of steel. When the Company is party to hedging agreements, these activities are carried out under the oversight of the Company’s Board of Directors.

Currency risk

The Company is exposed to currency risk on purchases, labour costs and pension and other post retirement employment benefits liabilities that are denominated in Canadian dollars. The prices for steel products sold in Canada are derived mainly from price levels in the US market in US dollars converted into Canadian dollars at the prevailing exchange rates. As a result, a stronger US dollar relative to the Canadian dollar increases the Company’s Canadian dollar selling prices for sales within Canada.

The Company’s Canadian dollar denominated financial instruments as at March 31, 2024 and March 31, 2023, were as follows:



As at,	March 31, 2024			March 31, 2023

Cash	$	1.5		$	51.2

Restricted cash		3.9			3.9

Accounts receivable		78.0			127.1

Accounts payable and accrued liabilities		(145.5	)		(147.1	)

Governmental loans		(143.6	)		(120.4	)

Other long-term liabilities		(17.0	)		(3.3	)



Net Canadian dollar denominated financial instruments	$	(222.7	)	$	(88.6	)

A $0.01 decrease (or increase) in the US dollar relative to the Canadian dollar for the year ended March 31, 2024 would

not

have decreased (or increased) income (loss) from operations

(March 31, 2023 - $0.2 million).

Interest rate risk

Interest rate risk is the risk that the value of the Company’s assets and liabilities will be affected by a change in interest rates. The Company’s interest rate risk mainly arises from the interest rate impact on its banking facilities and debt. The Company may manage interest rate risk through the periodic use of interest rate swaps.

For the years ended March 31, 2024 and March 31, 2023, a

one percent

increase (or decrease) in interest rates would have decreased (or increased) net income (loss) by approximately nil.

Commodity price risk

The Company is subject to price risk from fluctuations in the market prices of commodities, including natural gas, iron ore and coal. The Company enters into supply agreements for certain of these commodities as disclosed in Note 25. To manage risks associated with future variability in cash flows attributable to certain commodity purchases, the Company may use derivative instruments with maturities of 12 months or less as disclosed in Note 19 to hedge the commodity price risk associated with the revenue on the sale of steel. At March 31, 2024 and March 31, 2023, the Company had no commodity-based swap contracts.

Key Management Personnel (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Remuneration of the Company's Board of Directors and ELT

Remuneration of the Company’s Board of Directors and ELT for the respective periods are as follows:



Year ended,	March 31, 2024		March 31, 2023

Salaries and benefits	$	5.7	$	12.3

Director fees		2.5		1.5

Share-based compensation (Note 34)		5.4		4.4


	$	13.6	$	18.2

Income Tax Expense - Summary of Detailed Information About Components of Income Tax Expense Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Major components of tax expense (income) [abstract]
Current tax expense	$ 38.5	$ 89.6
Deferred income tax expense (recovery)	1.2	(12.0)
Income Tax Expense Continuing Operations	$ 39.7	$ 77.6

- Definition

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

+ References + Details

Net Income Per Common Share - Additional Information (Detail) $ in Millions, $ in Millions			12 Months Ended
	Mar. 31, 2023 yr	May 17, 2022 yr	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 CAD ($) shares	Mar. 31, 2023 USD ($) shares
Earnings per share [line items]
Increase decrease to profit loss to reflect dilutive effect resulting from gain loss on change in fair value of warrants			$ 12.1	$ 9.2	$ 47.7	$ 37.2
Dilutive effect of restricted share units and performance share units			376,268	376,268	92,293	92,293
Weighted average shares issued			103,793,360	103,793,360	117,945,286	117,945,286
Weighted average shares outstanding			103,793,360	103,793,360	117,945,286	117,945,286
Weighted average shares basic net			108,400,000	108,400,000	122,700,000	122,700,000
Weighted average shares diluted net			133,000,000	133,000,000	147,000,000	147,000,000
Replacement Long Term Incentive Plan Awards [Member]
Earnings per share [line items]
Weighted average shares basic net			2,925,499	2,925,499	3,100,535	3,100,535
Weighted average shares diluted net			2,925,499	2,925,499	3,100,535	3,100,535
Deferred Share Units [Member]
Earnings per share [line items]
Weighted average shares basic net			272,166	272,166	108,628	108,628
Weighted average shares diluted net			272,166	272,166	108,628	108,628
Earnouts Rights [Member]
Earnings per share [line items]
Weighted average shares basic net			1,404,357	1,404,357	1,557,026	1,557,026
Weighted average shares diluted net			1,404,357	1,404,357	1,557,026	1,557,026
Restricted share units [member]
Earnings per share [line items]
Number of other equity instruments granted	457,935	141,203	457,935	457,935	141,203	141,203
Performance Share Units [Member]
Earnings per share [line items]
Number of other equity instruments granted \| yr	404,211	556,348
Merger [Member]
Earnings per share [line items]
Warrants converted			24,179,000	24,179,000

Subsequent Events - Additional Information (Detail) - Subsequent Event [Member] - Senior Secured Second Lien Note [Member] $ in Millions	Mar. 26, 2024 CAD ($)
Disclosure of non-adjusting events after reporting period [line items]
Non-current debt instruments issued	$ 350.0
Proportion of debt instrument issued	9.125%

Property, Plant and Equipment, Net - Summary of Changes to Accumulated Depreciation of Property Plant and Equipment (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	$ (1,081.3)
Depreciation expense	118.8	$ 95.2
Ending balance	(1,405.2)	(1,081.3)
Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	447.0	322.8
Depreciation expense	118.8	95.2
Disposals	(41.7)	0.1
Foreign exchange	1.0	28.9
Ending balance	525.1	447.0
Freehold Land [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(6.6)
Ending balance	(6.7)	(6.6)
Freehold Land [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	0.0	0.0
Depreciation expense	0.0	0.0
Disposals	0.0	0.0
Foreign exchange	0.0	0.0
Ending balance	0.0	0.0
Buildings [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(39.2)
Ending balance	(52.4)	(39.2)
Buildings [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	33.9	26.6
Depreciation expense	4.8	5.0
Disposals	(0.1)	0.0
Foreign exchange	0.0	2.3
Ending balance	38.6	33.9
Machinery & Equipment [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(691.7)
Ending balance	(697.6)	(691.7)
Machinery & Equipment [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	411.1	294.8
Depreciation expense	112.9	89.6
Disposals	(41.6)	0.1
Foreign exchange	1.0	26.6
Ending balance	483.4	411.1
Computer Hardware [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(1.9)
Ending balance	(4.0)	(1.9)
Computer Hardware [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	1.1	0.8
Depreciation expense	0.5	0.3
Disposals	0.0	0.0
Foreign exchange	0.0	0.0
Ending balance	1.6	1.1
Right-of-use assets [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(3.4)
Ending balance	(6.2)	(3.4)
Right-of-use assets [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	0.9	0.6
Depreciation expense	0.6	0.3
Disposals	0.0	0.0
Foreign exchange	0.0	0.0
Ending balance	1.5	0.9
Property under construction [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	(338.5)
Ending balance	(638.3)	(338.5)
Property under construction [member] \| Accumulated depreciation and amortisation [member]
Disclosure Of Detailed Information About Changes To Accumulated Amortisation Of Property Plant And Equipment [Line Items]
Beginning balance	0.0	0.0
Depreciation expense	0.0	0.0
Disposals	0.0	0.0
Foreign exchange	0.0	0.0
Ending balance	$ 0.0	$ 0.0

Pension Benefits - Summary of major categories of plan assets (Detail) - Pension defined benefit plans [member]	Mar. 31, 2024	Mar. 31, 2023
Disclosure In Tabular Form Of Portfolio Of Plan Assets In Percentage Terms [Line Items]
Cash and cash equivalents	1.00%	1.00%
Equity instruments	55.00%	33.00%
Debt instruments	41.00%	39.00%
Other	3.00%	27.00%
Percentage Contributed To Fair Value Of Plan Assets	100.00%	100.00%

Environmental Liabilities

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Environmental Liabilites

23.	ENVIRONMENTAL LIABILITIES



As at,	March 31, 2024		March 31, 2023

The carrying amount of Environmental liabilities in respect of:

The Company’s Operation Site	$	33.8	$	32.7

Northern Ontario mine sites owned by Old Steelco Inc.		4.5		4.1


	$	38.3	$	36.8


Current portion	$	3.1	$	4.5

Long-term portion		35.2		32.3


	$	38.3	$	36.8

On November 30, 2018, the Company entered into agreements with the Province of Ontario, through the Ministry of the Environment, Conservation and Parks and the Ministry of Energy, Northern Development and Mines. These agreements relate to the Company’s operation site, and certain Northern Ontario mine sites owned by Old Steelco Inc., and not purchased by the Company. These agreements limit the Company’s obligations with respect to legacy environmental contamination, and impose certain risk management, risk mitigation, site remediation and funding obligations on the Company. The Company recognizes the present value of these environmental liabilities over 20

years commencing November 2018. Based on management’s review of the discount rate, at March 31, 2024, the discount rate was changed from

9.0% to 7.4% resulting in an increase in environmental liability of $3.8 million.

At March 31, 2024, the Company has provided letters of credit totalling of $14.5 million (March 31, 2023 - $15.1 million) to the Ministry of Energy, Northern Development and Mines; $13.7 million in respect of the Company’s operation site (March 31, 2023 - $13.7 million) and $0.8 million (March 31, 2023 - $1.4 million) in respect of certain Northern Ontario mine sites owned by Old Steelco Inc. Letters of credit are disclosed in Note 11 and Note 15.

Reconciliation of Environmental liabilities


	The Company’s Operation Site			Northern Ontario mine sites owned by Old Steelco Inc.			Total

Balance at March 31, 2022	$	33.7		$	4.3		$	38.0

Payments		(4.1	)		(0.7	)		(4.8	)

Accretion of discount		3.1			0.5			3.6



Balance at March 31, 2023	$	32.7		$	4.1		$	36.8


Payments		(5.3	)		(0.3	)		(5.6	)

Accretion of discount		3.0			0.3			3.3

Revaluation for change in discount rate		3.4			0.4			3.8



Balance at March 31, 2024	$	33.8		$	4.5		$	38.3

Dividends

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Dividends

35.

DIVIDENDS



Record date	Payment date	Total Dividends on Common Stock

July 5, 2023	July 24, 2023	$	7.0

August 25, 2023	September 29, 2023		6.9

November 30, 2023	December 29, 2023		6.9

February 29, 2024	March 28, 2024		7.1


		$	27.9

During the year ended March 31, 2024, the Company paid ordinary dividends to common shareholders on a quarterly basis at US $0.05 per common share in the aggregate amount of $27.9 million (March 31, 2023 - $30.7 million), recorded as a distribution through retained earnings.

Other Post-Employment Benefits - Disclosure of Detailed Information About Other Post Employment Benefits Recognized in Statements of Other Comprehensive income Loss Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Amounts recognized in other comprehensive (income) loss, were as follows
Actuarial loss (income) on accrued post employment benefit liability	$ (49.6)	$ 13.8
Other Post Employment Benefits [Member]
Amounts recognized in other comprehensive (income) loss, were as follows
Actuarial loss (income) on accrued post employment benefit liability	$ 3.3	$ (22.8)

Earnout Liability (Tables)

12 Months Ended

Mar. 31, 2024

Earnout Liability [Abstract]

Summary of Continuity of Earnout Rights

Continuity of earnout rights are as follows:



	March 31, 2024			March 31, 2023

Opening balance		1,537,184			1,616,305

Dividend equivalents and other adjustments		37,534			46,802

Vested and settled		(378,561	)		(125,923	)


Ending balance		1,196,157			1,537,184

Inventories

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Inventories

13.	INVENTORIES



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Raw materials and consumables	$	580.3	$	485.7

Work in progress		152.9		168.1

Finished goods		74.6		68.9


	$	807.8	$	722.7

Key Management Personnel - Summary of Remuneration of the Company's Board of Directors and ELT (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of transactions between related parties [abstract]
Salaries and benefits	$ 5.7	$ 12.3
Director fees	2.5	1.5
Share-based compensation (Note 34)	5.4	4.4
Key management personnel compensation	$ 13.6	$ 18.2

Governmental Loans - Summary of Details in Tabular Form of Governmental Loans (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure Details Of Governmental Loans [Line Items]
Long-term governmental loans	$ 127.4	$ 110.4
Current portion of governmental loans	16.2	10.0
Governmental loans current and non current	143.6	120.4
Federal AMF Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Long-term governmental loans	21.7	27.9
Current portion of governmental loans	10.0	10.0
MENDM Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Long-term governmental loans	42.8	45.4
Current portion of governmental loans	6.2	0.0
Federal SIF Agreement Loan [Member]
Disclosure Details Of Governmental Loans [Line Items]
Long-term governmental loans	9.4	9.7
Federal SIF EAF Agreement Loan Due January One Two Thousand And Thirty [Member]
Disclosure Details Of Governmental Loans [Line Items]
Long-term governmental loans	$ 53.5	$ 27.4

Net Change In Non-Cash Operating Working Capital - Summary Of Changes In Non Cash Operating Working Capital (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Schedule Of Changes In Non Cash Operating Working Capital [Line Items]
Increase (decrease) in working capital	$ 33.1	$ (178.7)
Non Cash Item [Member]
Schedule Of Changes In Non Cash Operating Working Capital [Line Items]
Accounts receivable	45.5	119.5
Net taxes payable and accrued taxes	(4.5)	(58.3)
Inventories	(80.4)	(187.8)
Prepaid expenses and other current assets	14.9	22.8
Accounts payable and accrued liabilities	57.6	(76.6)
Derivative financial instruments (net)	$ 0.0	$ 1.7

Property, Plant and Equipment, Net (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Property Plant and Equipment, Net



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Freehold land	$	6.7	$	6.6

Buildings		52.4		39.2

Machinery and equipment		697.6		691.7

Computer hardware		4.0		1.9

Right-of-use assets		6.2		3.4

Property under construction		638.3		338.5


	$	1,405.2	$	1,081.3

Summary of Changes in Cost of Property Plant and Equipment

The following table presents the changes to the cost of the Company’s property, plant and equipment for the years ended March 31, 2024 and March 31, 2023:



Cost	Freehold Land		Buildings			Machinery & Equipment			Computer Hardware		Right-of- use assets		Property under construc- tion			Total

Balance at March 31, 2022	$	6.1	$	65.9		$	900.3		$	1.4	$	4.0	$	118.8		$	1,096.5

Additions		-		-			3.2			-		-		330.1			333.3

Transfers		-		1.6			121.6			1.5		-		(124.5	)		0.2

Disposals		-		-			(0.1	)		-		-		(0.1	)		(0.2	)

Foreign exchange		0.5		5.6			77.8			0.1		0.3		14.2			98.5



Balance at March 31, 2023	$	6.6	$	73.1		$	1,102.8		$	3.0	$	4.3	$	338.5		$	1,528.3

Additions		-		-			3.3			-		-		436.6			439.9

Transfers		0.1		17.9			115.1			2.6		3.3		(139.0	)		-

Disposals		-		(0.1	)		(41.7	)		-		-		(0.2	)		(42.0	)

Foreign exchange		-		0.1			1.5			-		0.1		2.4			4.1



Balance at March 31, 2024	$	6.7	$	91.0		$	1,181.0		$	5.6	$	7.7	$	638.3		$	1,930.3

Summary of Changes to Accumulated Depreciation of Property Plant and Equipment

The following table presents the changes to accumulated depreciation on the Company’s property, plant and equipment for the years ended March 31, 2024 and March 31, 2023:



Accumulated Depreciation:	Freehold Land		Buildings			Machinery & Equipment			Computer Hardware		Right-of- use assets		Property under construc- tion		Total

Balance at March 31, 2022	$	-	$	26.6		$	294.8		$	0.8	$	0.6	$	-	$	322.8

Depreciation expense		-		5.0			89.6			0.3		0.3		-		95.2

Disposals		-		-			0.1			-		-		-		0.1

Foreign exchange		-		2.3			26.6			-		-		-		28.9



Balance at March 31, 2023	$	-	$	33.9		$	411.1		$	1.1	$	0.9	$	-	$	447.0

Depreciation expense		-		4.8			112.9			0.5		0.6		-		118.8

Disposals		-		(0.1	)		(41.6	)		-		-		-		(41.7	)

Foreign exchange		-		-			1.0			-		-		-		1.0



Balance at March 31, 2024	$	-	$	38.6		$	483.4		$	1.6	$	1.5	$	-	$	525.1

Net Change In Non-Cash Operating Working Capital

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Net Change In Non-Cash Operating Working Capital

28.	NET CHANGE IN NON-CASH OPERATING WORKING CAPITAL



Year ended,	March 31, 2024			March 31, 2023

Accounts receivable	$	45.5		$	119.5

Net taxes payable and accrued taxes		(4.5	)		(58.3	)

Inventories		(80.4	)		(187.8	)

Prepaid expenses and other current assets		14.9			22.8

Accounts payable and accrued liabilities		57.6			(76.6	)

Derivative financial instruments (net)		-			1.7


	$	33.1		$	(178.7	)

Accounts Receivable, Net - Summary of Account Receivable Net Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Trade and Other Receivables [Line Items]
Trade accounts receivable	$ 238.5	$ 277.3
Allowance for doubtful accounts	(3.1)	(0.5)
Other accounts receivable	6.1	8.7
Total	246.7	291.2
Opening balance	(0.5)	(2.4)
Remeasurement of loss allowance	(2.6)	1.9
Ending balance	(3.1)	(0.5)
Federal Ministry of Industry, Strategic Innovation Fund ("Federal SIF") Agreement [member]
Trade and Other Receivables [Line Items]
Governmental loan claims receivable	3.0	3.0
Northern Industrial Electricity Rate program rebate receivable [member]
Trade and Other Receivables [Line Items]
Governmental loan claims receivable	$ 2.2	$ 2.7

Derivative Financial Instruments - Additional Information (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of detailed information about financial instruments [line items]
Other comprehensive gain loss from cash flow hedges reclassified to income statement after tax	$ 0.0	$ 9.3
Financial liabilities at fair value through profit or loss	0.0	0.0
Steel [Member]
Disclosure of detailed information about financial instruments [line items]
Other comprehensive gain loss from cash flow hedges reclassified to income statement after tax	$ 0.0	(9.3)
Steel [Member] \| Revenue [Member]
Disclosure of detailed information about financial instruments [line items]
Other comprehensive gain loss from cash flow hedges reclassified to income statement after tax		$ 9.3

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of comprehensive income [abstract]
Income tax relating to cash flow hedges included in other comprehensive income	$ 0.0	$ 7.8
Income tax relating to remeasurements of defined benefit plans included in other comprehensive income	$ 0.0	$ 0.0

Revenue - Additional Information (Detail) $ in Millions	12 Months Ended
Revenue - Additional Information (Detail) $ in Millions	Mar. 31, 2024 CAD ($) Customer	Mar. 31, 2023 CAD ($)
Disclosure Of Revenue [Line Items]
Revenue	$ 2,795.8	$ 2,778.5
Major Customer [Member]
Disclosure Of Revenue [Line Items]
Revenue	$ 361.5	$ 332.2
Number of customer over ten percent revenue benchmark \| Customer	1
Percentage of entities revenue	10.00%

- Definition

The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2023-01-01
-Paragraph 28
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-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2023-01-01
-Paragraph 23
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-URIDate 2023-03-23

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
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-URIDate 2023-03-23

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 5
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-Paragraph 33
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-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2023-en-r&anchor=para_33_b_i&doctype=Standard
-URIDate 2023-03-23

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2023-01-01
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-URIDate 2023-03-23

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
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-Paragraph 34
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2023-en-r&anchor=para_34&doctype=Standard
-URIDate 2023-03-23

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2023-01-01
-Paragraph B12
-Subparagraph b
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2023-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B
-URIDate 2023-03-23

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2023-01-01
-Paragraph B10
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2023-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2023-03-23

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 82
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_82_a&doctype=Standard
-URIDate 2023-03-23

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_103&doctype=Standard
-URIDate 2023-03-23

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
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-IssueDate 2023-01-01
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-URIDate 2023-03-23

+ Details

Material Accounting Policies

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Material Accounting Policies

3.	MATERIAL ACCOUNTING POLICIES

Foreign exchange transactions

Transactions in currencies other than the Company’s functional currency are recognized at the rates of exchange prevailing at the dates of the transactions. At the end of each reporting period, monetary items denominated in foreign currencies are translated at the rates prevailing at that date.

Non-monetary

items that are measured in terms of historical cost are not

re-translated.

Exchange gains or losses arising from translations of foreign currency monetary assets, liabilities and transactions are recorded in foreign exchange loss (gain) in the consolidated statements of net income.

Financial Instruments

The Company’s financial assets and liabilities (financial instruments) include cash, restricted cash, accounts receivable, bank indebtedness, accounts payable and accrued liabilities, financing arrangement, warrant liability, earnout liability, share-based payment compensation liability and governmental loans.

Recognition

Financial assets and financial liabilities are recognised in the consolidated statements of financial position when the Company becomes party to the contractual provisions of the instrument, and they are initially measured at fair value. Financial assets are derecognized when the contractual rights to the cash flows expire or when the Company transfers substantially all the risks and rewards of ownership of the financial assets to another party. Financial liabilities are derecognized when the contractual obligations are discharged, cancelled, or expired.

write-off

of a financial asset (or a portion thereof) constitutes a derecognition event.

Write-off

occurs when the Company has no reasonable expectations of recovering the contractual cash flows associated with a financial asset.

Classification and measurement

The classification of financial instruments is determined at the time of initial recognition, within the following categories:

●

Amortized cost

●

Fair value through profit (loss) (FVTP(L))

●

Fair value through other comprehensive income (loss) (FVTOCI(L))

Financial assets are classified and subsequently measured based on the business model in which they are managed

and

their cash flow characteristics. Financial assets are measured at amortized cost if they meet both of the following conditions and are not designated as FVTP(L):

●

The financial asset is held within a business model with the objective of holding the financial asset in order to collect contractual cash flows; and

●

The contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding.

All other financial assets are measured at their fair values at each subsequent reporting period, with any changes recorded through profit and loss or through other comprehensive income (loss), if the designation is made as an irrevocable election upon initial recognition.

Financial liabilities are classified as subsequently measured at amortized cost or FVTP(L). A financial liability is classified as FVTP(L) if it is contingent consideration of an acquirer in a business combination,

held-for-trading,

or designated as FVTP(L) upon initial recognition, and is remeasured at its fair value at each subsequent reporting period, with any changes recorded through profit or loss. Other financial liabilities are subsequently measured at amortised cost using the effective interest method.

Impairment of financial assets carried at amortized cost

The Company utilizes an ‘expected credit loss’ (“ECL”) model, as required by IFRS 9 –

Financial Instruments

. Accounts receivable are subject to lifetime ECL which is measured as the difference in the present value of the contractual cash flows that are due under the contract, and the cash flows that are expected to be received.

The Company reviews its accounts receivable at each reporting date and considers both current and forward-looking macro-economic factors that may affect historical default rates when estimating ECL.

Accounts receivable, together with the associated allowance, are written off when there is no realistic prospect of future recovery and all collateral has been realized or has been transferred to the Company. If, in a subsequent year, the amount of the estimated impairment loss increases or decreases because of an event occurring after the impairment was recognized, the previously recognized impairment loss is increased or decreased by adjusting the carrying value of the loan or receivable. If a past

write-off

is later recovered, the recovery is recognized in the consolidated statements of net income.

Fair value of financial instruments

Fair value is the price that would be received when selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In assessing the fair value of a particular contract, the market participant would consider the credit risk of the counterparty to the contract. Consequently, when it is appropriate to do so, the Company adjusts the valuation models to incorporate a measure of credit risk. Fair value represents management’s estimates of the current market value at a given point in time.

The Company has certain financial assets and liabilities that are measured at fair value. The fair value hierarchy establishes three levels to classify the inputs to valuation techniques used to measure fair value. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices in markets that are not active, quoted prices for similar assets or

liabilities in active markets, inputs other than quoted prices that are observable for the asset or liability (for example, interest

rate

and yield curves observable at commonly quoted intervals, forward pricing curves used to value currency and commodity contracts), or inputs that are derived principally from or corroborated by observable market data or other means. Level 3 inputs are unobservable (supported by little or no market activity). The fair value hierarchy gives the highest priority to Level 1 inputs and the lowest priority to Level 3 inputs. There were no transfers among Levels 1, 2 and 3 during the years ended March 31, 2024 and March 31, 2023. The Company’s policy is to recognize transfers into and transfers out of fair value hierarchy levels as of the date of the event or change in circumstances that caused the transfer.

The Company reclassifies financial assets only when its business model for managing those assets changes. Financial liabilities are not reclassified.

Accounts receivable

Accounts receivable are recognized initially at transaction price and are

non-interest

bearing. Management analyzes accounts receivable to determine the allowance for doubtful accounts by assessing the collectability of receivables owing from each individual customer. This assessment takes into consideration certain factors including the age of outstanding receivable, customer operating performance, historical payment patterns and current collection efforts, relevant forward looking information and the Company’s security interests, if any. Recoveries of accounts receivables previously provided for in the allowance for doubtful accounts are deducted from administrative and selling expenses in the consolidated statements of net income.

Inventories

Raw materials, work in process and finished products inventories are measured at the lower of average cost and net realizable value. Average cost for finished goods and work in process is comprised of direct costs and an allocation of production overheads, including depreciation expense. Supplies inventories are measured at the lower of average cost and net realizable value.

Property, plant and equipment, net

Items of property, plant and equipment are recorded at cost less accumulated depreciation and impairment. The cost of an item of property or equipment comprises costs that can be directly attributed to its acquisition and to bringing the asset to a working condition for its intended use, including borrowing costs that meet the criteria for capitalization and initial estimates of the cost of dismantling and removing the item and restoring the site on which it is located. The cost of self-constructed and self-installed assets includes the cost of direct labour in addition to the costs listed above.

Depreciation is calculated by the straight-line method based on estimated useful lives as follows:



Category of Property, Plant and Equipment		Range of Estimated Useful Life

Buildings		5 to 30 years

Machinery and equipment		5 to 40 years

Vehicles		6 to 12 years

Computer hardware		3 to 5 years

The Company also separately recognizes the cost of replacement parts and major overhaul or inspection costs if the cost of the item can be reliably measured or estimated and it is probable that the future economic benefits will be realized by the Company. When such items are replaced the carrying amount of the replaced component is derecognized. The costs of maintenance and repairs of property, plant and equipment are recognized in profit or loss as incurred.

Componentization

When significant components of an item of property, plant and equipment have different useful lives, they are accounted for as separate items and depreciated over the respective useful lives.

Useful life, depreciation method, residual value

Estimates of the useful lives of items of property, plant and equipment are based on management’s judgement as to the physical and economic useful lives of assets and as such are subject to change in future periods. Depreciation methods, useful lives and residual values are reviewed at each reporting date with the effect of any changes in estimate being accounted for on a prospective basis.

Derecognition of property plant and equipment

An item of property, plant and equipment is derecognized upon disposal or when no future economic benefits are expected to arise from the continued use of the asset. Any gain or loss arising on the disposal or retirement of an item of property, plant and equipment is determined as the difference between the sales proceeds and the carrying amount of the asset and is recognized in profit or loss.

Impairment of tangible and intangible assets

Property, plant and equipment and intangible assets are reviewed at the end of each reporting period to determine whether there is any indication of impairment. If any such indication exists then the recoverable amount of the asset is estimated. The recoverable amount of an asset is defined as the higher of its fair value less costs to sell and its value in use. Where it is not possible to estimate the recoverable amount of an individual asset, the Company estimates the recoverable amount of the Cash Generated Unit (“CGU”) to which the asset belongs. The CGU corresponds to the smallest identifiable group of assets whose continuing use generates cash inflows that are largely independent of the cash flows from other groups of assets.

An impairment loss is recognized when the carrying amount of an asset, or of the CGU to which it belongs, exceeds the recoverable amount. In determining value in use, the Company estimates cash flows before taxes based on most recent actual results and forecasts and then determines the current value of future estimated cash flows.

During the year ended March 31, 2024, there were no indicators of impairment in regards to the Company’s CGU however during the year ended March 31, 2023, there were indicators of impairment. The carrying value of the net assets of the Company exceeded its market capitalization on March 31, 2023 and impacts of the economic conditions pertaining to the steel manufacturing industry were two indicators identified. Management, in consultation with external specialists, conducted an impairment test and concluded that there was no impairment. The impairment test showed that the recoverable amount exceeded the carrying value of the net assets of the Company.

Impairment losses are recognized in the consolidated statements of net income. An impairment loss is reversed if there has been a change in the estimates used to determine the recoverable amount. The increased carrying amount of an asset attributable to a reversal of impairment loss may not exceed the carrying amount that would have been determined had no impairment loss been recognized in prior periods.

Leases

At inception of a contract, the Company assesses whether the contract is, or contains, a

lease

. A contract is, or contains, a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration.

The Company, as a lessee, recognizes a

right-of-use

asset and lease liability at commencement of the lease at the present value of the future lease payments using the interest rate implicit in the lease (if readily determinable) or the Company’s incremental rate of borrowing. Subsequent to initial measurement, the asset is depreciated using the straight-line method from the commencement date to the earlier of the end of its useful file or the end of the lease term. The lease liability is measured at amortized cost using the effective interest rate method. Lease related finance charges are recorded in finance costs in the consolidated statement of net income.

The Company has elected not to recognize

right-of-use

assets and lease liabilities for short-term leases defined as leases with a lease term of 12 months or less and

low-value

assets. These types of leases are recorded in the consolidated statement of net income as incurred.

Retirement benefit costs

The Company provides pensions and certain health care, dental care, life insurance and other benefits for certain retired employees pursuant to Company policy. For defined benefit pension plans and other post-employment benefits, the defined benefit cost is actuarially determined on an annual basis by independent actuaries using the projected unit credit method. Remeasurement comprising of actuarial gains and losses, the effect of the asset ceiling and the return on plan assets (excluding interest) are recognized immediately in the consolidated statements of financial position with a charge to other comprehensive income in the period in which they occur. The Company has elected to

transfer those amounts recognized in other comprehensive income (loss) to a separate reserve within equity.

Net-interest

is calculated by applying the discount rate to the net defined benefit liability. Defined benefit and other post-employment benefit costs are split into three categories:

●

service cost, past-service cost, gains and losses on curtailments and settlements;

●

net interest expense; and

●

remeasurement.

The Company recognizes the first two components of defined benefit costs in profit or loss in its consolidated statements of net income: service cost, past service cost, gains and losses on curtailments and settlements in Cost of sales and Administrative and selling expenses; and net interest expense in Interest on pension and other post-employment benefit obligations. The determination of a benefit expense requires assumptions such as the discount rate, the expected mortality, the expected rate of future compensation increases and the expected healthcare cost trend rate. Actual results will differ from estimated results which are based on these assumptions.

The asset or liability recognized in the consolidated statements of financial position represents the actual plan situation in the Company’s defined benefit and other post-employment benefit plans. All actuarial gains and losses that arise in calculating the present value of the defined benefit obligation and the plan assets, the remeasurement components, are recognized immediately in other comprehensive income (loss). Any defined benefit asset resulting from this calculation is limited to the present value of any economic benefit in the form of refunds from the plan or reduction in future contributions to the plan.

Payments to defined contribution retirement benefit plans are recognized as an expense when employees have rendered service entitling them to the contributions.

Termination benefits

Termination benefits are recognized as an expense when the Company is demonstrably committed, without realistic possibility of withdrawal, to a formal detailed plan to either terminate employment before the normal retirement date, or to provide termination benefits as a result of an offer made to encourage voluntary retirement. Termination benefits for voluntary retirements are recognized the earlier of the date when the Company recognizes related restructuring costs and the date when the Company can no longer withdraw the offer of the benefits related to the voluntary retirement.

Short-term benefits

Short-term employee benefit obligations are measured on an undiscounted basis and are expensed as the related service is provided. A liability is recognized for the amount expected to be paid under short-term cash bonus or profit-sharing plans if the Company has a present legal or constructive obligation to pay this amount as a result of past service provided by the employee and the obligation can be estimated reliably.

Environmental liabilities

An environmental liability is recognized if, as a result of an agreement, the Company has a present legal obligation that can be estimated reliably and it is probable that an outflow of economic benefits will be required to settle the obligation. The amount recognized as an environmental liability is the best estimate of the consideration required to settle the present obligation at the end of the reporting period, taking into account risks and uncertainty of cash flows. Where the effect of discounting is

material, environmental liabilities are determined by discounting the expected future cash flows at a

pre-tax

rate that reflects current market assessments of the time value of money and the risks specific to the liability. The unwinding of the discount is recognized as finance cost.

Revenue recognition

The Company’s revenue is generated primarily from contracts to produce, ship and deliver steel products, and to a lesser extent, to deliver

non-steel

by-products

of the steelmaking processes and related freight revenue.

Revenue is measured at the fair value of the consideration received or receivable, net of returns and allowances, trade discounts, volume rebates and other incentives. Revenue from the sale of goods is recognized to the extent that it is probable that the economic benefits will flow to the Company, can be reliably measured, and at a

point-in-time

when the performance obligation is satisfied by transferring the promised good to a customer. A good is considered transferred when the customer obtains control, which is defined as the ability to direct the use of and obtain substantially all of the remaining benefits of an asset. The Company’s performance obligations in respect of its steel contracts are satisfied upon loading the products onto the truck, railcar or vessel that will deliver the products to the customer (known as free on board or “FOB” shipping), at which time the products are deemed to be transferred and the customer obtains title to, and control of, such products. Upon the fulfillment of these criteria, revenue and costs associated with such are included in the consolidated statements of net income.

Freight and other transportation costs billed to customers are recorded gross within revenue and cost of goods sold.

Non-steel

revenue primarily pertains to the sale of various

by-products

such as kish, ore fines, mill scale, scrap rolls and high sulfur iron. The Company’s performance obligations in respect of its sales of

by-products

are satisfied upon loading of the applicable

by-products

on an FOB shipping basis, at which time such

by-products

are deemed to be transferred and the customer obtains title to, and control of, such

by-products.

The Company has pricing latitude in revenue arrangements and is also exposed to inventory and credit risks. The Company offers industry standard payment terms that typically requires payment from customers 30 days after title and control transfers.

Government funding

The benefit of Government funding is not recognized until there is reasonable assurance that the Company will comply with the conditions attaching to it and that the funding will be received. Benefits related to Government funding in the form of low interest rate loans, interest free loans and grants for items of capital are presented in the consolidated statements of financial position as an offset to the carrying value of the property, plant and equipment to which the benefits relate. In the case of low interest rate loans and interest free loans, the benefit is calculated as the difference between the fair value amount of the low interest rate loan or the interest free loan and the proceeds received. Claims under government grant programs related to income are recorded within the consolidated statements of net income as a reduction of the related item the grant is intended to offset, in the period in which the eligible expenses were incurred or when the services have been performed.

Research

Research costs are expensed as incurred, due to the nature of the projects. Where government incentives in the form of investment tax credits and grants are received for research projects initiated

by the Company for its own purposes, these incentives are deducted from the applicable category of expenditures.

Finance cost

Finance cost is comprised of interest expense on borrowings, amortization of issuance costs, and accretion of environmental liabilities. Borrowing costs that are not directly attributable to the acquisition, construction or production of a qualifying asset are recognized in profit or loss using the effective interest method.

Actuarially determined interest costs related to the defined benefit pension obligation and the other post-employment benefit obligation are recorded respectively as components of the carrying amount of the accrued pension liability and the accrued other post-employment benefit obligation.

Taxation

Current and deferred income tax are recognized in net income, except when they relate to items that are recognized in other comprehensive income (loss) or directly in equity, in which case, the current and deferred income tax are also recognized in other comprehensive income (loss) or directly in equity, respectively.

Current tax

The current tax expense is based on taxable income for the year. Taxable income differs from net income before taxes as reported in the consolidated statements of net income because of items of income or expense that are taxable or deductible in other years and items that are never taxable or deductible. The Company’s liability for current tax is calculated using tax rates that have been enacted or substantively enacted by the end of the reporting period.

Deferred income tax

Deferred income tax is recognized on temporary differences between the carrying amounts of assets and liabilities in the consolidated financial statements and the corresponding tax bases used in the computation of taxable income. Deferred income tax liabilities are generally recognized for all taxable temporary differences. Deferred income tax assets are generally recognized for all deductible temporary differences to the extent that it is probable that taxable income will be available against which those deductible temporary differences can be utilised.

The carrying amount of deferred income tax assets is reviewed at the end of each reporting period and reduced to the extent that it is no longer probable that sufficient taxable income will be available to allow all or part of the asset to be recovered.

Deferred income tax assets and liabilities are measured at the tax rates that are expected to apply in the period in which the asset is realised or the liability is settled, based on tax rates and tax laws that have been enacted or substantively enacted by the end of the reporting period. The measurement of deferred income tax assets and liabilities reflects the tax consequences, based on management’s expectation at the end of the reporting period, that would follow from the recovery or settlement of the carrying amount of its assets and liabilities.

Share-based payment

The Company provides certain employees with long-term incentive awards. Equity-settled share-based payments to employees and others providing similar services are measured at the fair value of the equity instruments at the grant date. The fair value includes the effect of market based vesting conditions but excludes the effect of performance conditions. Details regarding the determination of the fair value of equity-settled share-based transactions are set out in Note 34.

The fair value determined at the grant date of the equity-settled share-based payments is expensed on a straight-line basis over the expected vesting period, which is determined based on the Company’s expected timing on meeting the performance condition. The impact of the revision of the original estimates, if any, is recognized in profit or loss such that the cumulative expense reflects the revised estimate, with a corresponding adjustment to equity.

For cash-settled share-based payments, a liability is recognized for the goods or services acquired, measured initially at the fair value of the liability. At each reporting date until the liability is settled, and at the date of settlement, the fair value of the liability is remeasured, with any changes in fair value recognized in profit or loss for the year.

Comprehensive Income (Loss)

Other comprehensive income (loss) (“OCI”) includes foreign exchange gain on translation to the Company’s presentation currency from the US Dollar functional currency. OCI includes actuarially determined gains and losses on post employment benefits offered to certain employees and the effect of any limits applied to the defined benefit asset. OCI also includes unrealized loss on cash flow hedge reserve. Comprehensive income is composed of net income and OCI.

Accumulated OCI is a separate component of Shareholders’ Equity which includes the accumulated balances of all components of OCI which are recognized in comprehensive income but excluded from net income.

New IFRS Standards, Amendments and Interpretations adopted as of April 1, 2023 (effective January 1, 2023)

The Company adopted the following amendments which did not have a material impact on the consolidated financial statements:

Amended Disclosure for Accounting Policies

IAS 1 “Presentation of Financial Statements” was amended with the intention to help companies provide useful accounting policy disclosures. The key amendments include the requirement to disclose material accounting policy information rather than significant accounting policies, clarifying that accounting policies related to immaterial transactions, other events or conditions are themselves immaterial and as such need not be disclosed; and clarifying that not all accounting policies that relate to material transactions, other events or conditions are themselves material to a company’s financial statements.

Amended Scope of Recognition

IAS 12 “Income Taxes” was amended to narrow the scope of recognition exemption in paragraphs 15 and 24 (recognition exemption) so that it no longer applies to transactions that, on initial recognition, give rise

equal taxable and deductible temporary differences.

Definition of Accounting Estimates

IAS 8 “Accounting Policies, Changes in Accounting Estimates and Errors”

was

amended to introduce the definition of an accounting estimate and includes other amendments to assist entities to distinguish changes in accounting estimates from changes in accounting policies.

Standards and Interpretations issued and not yet adopted

Classification of Liabilities as Current or

Non-current

In January 2020, the IASB issued an amendment to IAS 1

Presentation of Financial Statements

to clarify its requirements for the presentation of liabilities in the statement of financial position. The limited scope amendment affected only the presentation of liabilities in the statement of financial position and not the amount or timing of its recognition. The amendment clarified that the classification of liabilities as current or

non-current

is based on rights that are in existence at the end of the reporting period and specified that classification is unaffected by expectations about whether an entity will exercise its right to defer settlement of a liability. It also introduced a definition of ‘settlement’ to make clear that settlement refers to the transfer to the counterparty of cash, equity instruments, other assets or services. On October 31, 2022, the IASB issued

Non-Current

Liabilities with Covenants (Amendments to IAS 1). These amendments specify that covenants to be complied with after the reporting date do not affect the classification of debt as current or

non-current

at the reporting date. The amendment is effective for annual reporting periods beginning on or after January 1, 2024. Earlier application is permitted. The application of these amendments are not expected to have a significant impact on the consolidated statements of financial position or on the Company’s financial reporting.

Pension Benefits - Additional Information (Detail) - Pension defined benefit plans [member] $ in Millions	12 Months Ended
	Mar. 31, 2025 CAD ($)	Mar. 31, 2024 CAD ($)	Mar. 31, 2023 CAD ($)
Disclosure of defined benefit plans [line items]
Defined Contribution Plan Per Hour Contribution		2.85	2.85
Post-employment benefit expense, defined contribution plans		$ 13.1	$ 10.2
Contribution to defined benefit plan		$ 17.5	$ 16.5
Estimate of contributions expected to be paid to plan for next annual reporting period	$ 26.9
Percentage deficit in the return on plan assets		10.00%	10.00%
Decrease In Other Comprehensive Income After Tax Due To Possible Percentage Deficit In The Return On Plan Assets		$ 105.0	$ 130.0
Past service cost			$ 49.5
Cost of steel revenue [member]
Disclosure of defined benefit plans [line items]
Past service cost		44.5
Administrative and selling expense [member]
Disclosure of defined benefit plans [line items]
Past service cost		$ 5.0
Defined Benefit Obligation [Member]
Disclosure of defined benefit plans [line items]
Weighted average duration of defined benefit obligation		10 years
Current Service Costs [Member]
Disclosure of defined benefit plans [line items]
Weighted average duration of defined benefit obligation		17 years

Accounts Receivable, Net

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Accounts Receivable, Net

12.	ACCOUNTS RECEIVABLE, NET



As at,	March 31, 2024			March 31, 2023

The carrying amount of:

Trade accounts receivable	$	238.5		$	277.3

Allowance for doubtful accounts		(3.1	)		(0.5	)

Governmental loan claims receivable

Federal Ministry of Industry, Strategic Innovation Fund (“Federal SIF”) Agreement		3.0			3.0

Northern Industrial Electricity Rate program rebate receivable		2.2			2.7

Other accounts receivable		6.1			8.7


	$	246.7		$	291.2

Allowance for doubtful accounts



Balance at March 31, 2022	$	(2.4	)

Remeasurement of loss allowance		1.9


Balance at March 31, 2023	$	(0.5	)

Remeasurement of loss allowance		(2.6	)


Balance at March 31, 2024	$	(3.1	)

Share Based Compensation

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Share Based Compensation

34.	SHARE-BASED COMPENSATION

Long-term incentive plan

On October 19, 2021, the Company approved an Omnibus Equity Incentive Plan (“Omnibus Plan”) that would allow the Company to grant various awards to its employees. Under the terms of the Omnibus Plan, the maximum number of common shares that may be awarded is 8.8 million common shares. The awards issuable under the Plan consists of Restricted Share Units (“RSU”), DSUs, Performance Share Units (“PSU”) and stock options.

Deferred share units

Under the terms of the Omnibus Plan, DSUs may be issued to members of the Board of Directors as may be designated by the Board of Directors from

time-to-time

in satisfaction of all or a portion of Director fees. The number of DSUs to be issued in satisfaction of a payment of Director fees shall be equal to the amount of the Director fees divided by the given day volume weighted average price of the Company’s common shares preceding the grant date. DSUs are equity-settled share-based payments measured at fair value at the date of grant and expensed immediately as the underlying services have been rendered. The grant date fair value is approximated by the price of the Company’s common shares on the date of grant. DSUs do not have an exercise price and become exercisable for one common share of the Company upon the retirement of the Director, or in the event of incapacity.

For the year ended March 31, 2024, the Company recorded a share-based payment compensation expense of $2.2 million (March 31, 2023 - $1.7 million) in administrative and selling expense on the consolidated statements of net income and contributed deficit on the consolidated statements of financial position.

Continuity of deferred share units are as follows:



	March 31, 2024			March 31, 2023

Opening balance		215,628			54,558

Granted		187,549			156,629

Dividend equivalents and other adjustments		12,511			4,441

Vested and settled		(70,920	)		-


Ending balance		344,768			215,628

Restricted share units and performance share units

Under the terms of the Omnibus Plan, RSUs and PSUs may be issued to employees of the Company as may be designed by the Board of Directors in order to retain and motivate employees. RSUs and PSUs are equity-settled share-based payments measured at fair value at the date of grant and expensed over the vesting period. The grant date fair value takes into account any

non-vesting

conditions. The subsequent recognition of the grant date fair value over the vesting period involves the Company’s estimation of the RSUs and PSUs that will eventually vest and adjusts for the likelihood of achieving service conditions and performance conditions. RSUs and PSUs do not have an exercise price and become exercisable for one common share of the Company on the vesting date. Holders of RSUs and PSUs are also entitled to dividend equivalents when dividends are declared to common shareholders. The price of the Company’s common shares on the grant date is used to approximate the grant date fair value of each unit of RSUs and PSUs.

FY2023 Plan

On May 17, 2022, 141,203 RSUs and 556,348 PSUs were granted to certain employees of the Company, with a grant date fair value of US $9.40 per award based on the market price of the Company’s common shares. The RSUs and PSUs vest on March 15, 2024 upon the achievement of service and performance conditions. The total grant date fair value determined is recognized on a straight-line basis over the vesting period and is subject to true-ups at each period end to reflect the likelihood of achieving certain performance conditions.

FY2024 Plan

On March 31, 2023 the Board of Directors approved a grant of 457,935 and 404,211 units of RSUs and PSUs, respectively, to various employees of the Company under the Omnibus Plan for the fiscal year ended March 31, 2024, with a grant date fair value of US $7.62 per award based on the market price of the Company’s common shares. The RSUs and PSUs vest on March 31, 2026 upon the achievement of service and performance conditions. The total grant date fair value determined is recognized on a straight-line basis over the vesting period and is subject to true-ups at each period end to reflect the likelihood of achieving certain performance conditions

For the year ended March 31, 2024, the Company recorded share-based payment compensation expense of $3.0 million in administrative and selling expenses on the consolidated statements of net income and contributed deficit on the consolidated statements of financial position (March 31, 2023 - $2.2 million).

Continuity RSUs are as follows:



	March 31, 2024		March 31, 2023

Opening balance		144,682		-

Granted based on achievement of service and performance conditions		457,935		141,203

Dividend equivalents and other adjustments, net of cancellations and forfeitures		4,635		3,479


Ending balance		607,252		144,682

Continuity of PSUs are as follows:



	March 31, 2024			March 31, 2023

Opening balance		178,407			-

Granted based on achievement of service and performance conditions		78,821			164,667

Dividend equivalents and other adjustments, net of cancellations and forfeitures		(25,331	)		13,740


Ending balance		231,898			178,407

Revenue

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Revenue

REVENUE

The Company is viewed as a single reportable segment involving steel production

for

purposes of internal performance measurement and resource allocation.


Year ended,	March 31, 2024		March 31, 2023

Total revenue is comprised of:

Sheet & Strip	$	2,035.8	$	2,161.3

Plate		506.2		387.4

Slab		3.3		1.4

Freight		198.3		182.4

Non-steel revenue		52.2		46.0


	$	2,795.8	$	2,778.5


The geographical distribution of total revenue is as follows:

Sales to customers in Canada	$	1,052.1	$	1,030.5

Sales to customers in the United States		1,704.0		1,708.1

Sales to customers in the rest of the world		39.7		39.9


	$	2,795.8	$	2,778.5

For the year ended March 31, 2024, sales of $

361.5

million to

one

customer rep

resented greater than

% of total revenue

(

March 31, 2023

332.2

million

)

Share Based Compensation (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Continuity of Deferred Share Units

Continuity of deferred share units are as follows:



	March 31, 2024			March 31, 2023

Opening balance		215,628			54,558

Granted		187,549			156,629

Dividend equivalents and other adjustments		12,511			4,441

Vested and settled		(70,920	)		-


Ending balance		344,768			215,628

Summary of Continuity RSUs

Continuity RSUs are as follows:



	March 31, 2024		March 31, 2023

Opening balance		144,682		-

Granted based on achievement of service and performance conditions		457,935		141,203

Dividend equivalents and other adjustments, net of cancellations and forfeitures		4,635		3,479


Ending balance		607,252		144,682

Summary of Continuity of PSUs

Continuity of PSUs are as follows:



	March 31, 2024			March 31, 2023

Opening balance		178,407			-

Granted based on achievement of service and performance conditions		78,821			164,667

Dividend equivalents and other adjustments, net of cancellations and forfeitures		(25,331	)		13,740


Ending balance		231,898			178,407

Financial Instruments - Summary of Company's Canadian Dollar Denominated Financial Instruments (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Statement [Line Items]
Cash	$ 97.9	$ 247.4	$ 915.3
Accounts receivable	246.7	291.2
Governmental loans	(143.6)	(120.4)
Other long-term liabilities	(17.0)	(3.7)
Currency risk [member]
Statement [Line Items]
Cash	1.5	51.2
Restricted cash	3.9	3.9
Accounts receivable	78.0	127.1
Accounts payable and accrued liabilities	(145.5)	(147.1)
Governmental loans	(143.6)	(120.4)
Other long-term liabilities	(17.0)	(3.3)
Net Canadian dollar denominated financial instruments	$ (222.7)	$ (88.6)

Capital Stock (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of classes of share capital



	Number of shares issued and outstanding			Stated capital value

Balance at March 31, 2022		147,957,787		$	1,378.0

Common shares repurchased and cancelled:

Normal Course Issuer Bid		(3,364,262	)		(31.2	)

Substantial Issuer Bid		(41,025,641	)		(388.4	)



Balance at March 31, 2023		103,567,884		$	958.4

Issuance of capital stock		535,188			5.5



Balance at March 31, 2024		104,103,072		$	963.9

Accounts Payable and Accrued Liabilities - Summary of Accounts Payable and Accrued Liabilities (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Accounts Payable and Accrued Liabilities [Line Items]
Accounts payable	$ 142.0	$ 59.8
Accrued liabilities	80.5	74.9
Wages and accrued vacation payable	64.3	69.9
Accounts Payable and Accrued Liabilities Current	$ 286.8	$ 204.6

Material Accounting Policies - Summary of Detailed Information About Estimated Useful Life (Detail)	12 Months Ended
	Mar. 31, 2024
Buildings [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	5 years
Buildings [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	30 years
Machinery and equipment [Member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	5 years
Machinery and equipment [Member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	40 years
Vehicles [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	6 years
Vehicles [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	12 years
Computer equipment [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	3 years
Computer equipment [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Useful life measured as period of time, property, plant and equipment	5 years

Financial Instruments - Summary of Company's Contractually Agreed (Undiscounted) Cash Flows Payable Under Financial Liabilities (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Maturity Analysis For Financial Liabilities [Line Items]
Bank borrowings, undiscounted cash flows	$ (0.3)	$ (1.9)
Trade and other payables, undiscounted cash flows	(286.8)	(204.6)
Taxes Payable Undiscounted Cash Flows	(30.1)	(14.4)
Government Loans Undiscounted Cash Flows	(254.2)	(189.7)
Financial Arrangement Undiscounted Cash Flow	(11.3)
Financial Liabilities Undiscounted Cash Flows	(591.0)	(416.4)
Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest Payable Undiscounted Cash Flows	(8.3)	(5.8)
Year 1 [member]
Maturity Analysis For Financial Liabilities [Line Items]
Bank borrowings, undiscounted cash flows	(0.3)	(1.9)
Trade and other payables, undiscounted cash flows	(286.8)	(204.6)
Taxes Payable Undiscounted Cash Flows	(30.1)	(14.4)
Government Loans Undiscounted Cash Flows	(16.2)	(10.0)
Financial Arrangement Undiscounted Cash Flow	(0.9)
Financial Liabilities Undiscounted Cash Flows	(335.2)	(230.9)
Year 1 [member] \| Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest Payable Undiscounted Cash Flows	(0.9)	0.0
Year 2 [member]
Maturity Analysis For Financial Liabilities [Line Items]
Bank borrowings, undiscounted cash flows	0.0	0.0
Trade and other payables, undiscounted cash flows	0.0	0.0
Taxes Payable Undiscounted Cash Flows	0.0	0.0
Government Loans Undiscounted Cash Flows	(25.0)	(18.1)
Financial Arrangement Undiscounted Cash Flow	(1.0)
Financial Liabilities Undiscounted Cash Flows	(28.1)	(18.7)
Year 2 [member] \| Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest Payable Undiscounted Cash Flows	(2.1)	(0.6)
Years 3 to 5 [member]
Maturity Analysis For Financial Liabilities [Line Items]
Bank borrowings, undiscounted cash flows	0.0	0.0
Trade and other payables, undiscounted cash flows	0.0	0.0
Taxes Payable Undiscounted Cash Flows	0.0	0.0
Government Loans Undiscounted Cash Flows	(61.7)	(79.8)
Financial Arrangement Undiscounted Cash Flow	(9.4)
Financial Liabilities Undiscounted Cash Flows	(76.4)	(85.0)
Years 3 to 5 [member] \| Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest Payable Undiscounted Cash Flows	(5.3)	(5.2)
Greater than 5 Years [member]
Maturity Analysis For Financial Liabilities [Line Items]
Bank borrowings, undiscounted cash flows	0.0	0.0
Trade and other payables, undiscounted cash flows	0.0	0.0
Taxes Payable Undiscounted Cash Flows	0.0	0.0
Government Loans Undiscounted Cash Flows	(151.3)	(81.8)
Financial Arrangement Undiscounted Cash Flow	0.0
Financial Liabilities Undiscounted Cash Flows	(151.3)	(81.8)
Greater than 5 Years [member] \| Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest Payable Undiscounted Cash Flows	0.0	0.0
Carrying Amount [member]
Maturity Analysis For Financial Liabilities [Line Items]
Revolving Credit Facility	0.3	1.9
Accounts payable and accrued liabilities	286.8	204.6
Taxes payable	30.1	14.4
Governmental Loans	143.6	120.4
Financial arrangement	11.3
Financial liabilities	475.6	343.9
Carrying Amount [member] \| Provincial MENDM Loan [member]
Maturity Analysis For Financial Liabilities [Line Items]
Interest on Provincial MENDM Loan	$ 3.5	$ 2.6

Cash and Restricted Cash - Additional Information (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Restricted Cash And Cash Equivalents [Abstract]
Cash	$ 97.9	$ 247.4
Restricted cash and cash equivalents	$ 3.9	$ 3.9

Capital Stock

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Capital Stock

26.	CAPITAL STOCK



	Number of shares issued and outstanding			Stated capital value

Balance at March 31, 2022		147,957,787		$	1,378.0

Common shares repurchased and cancelled:

Normal Course Issuer Bid		(3,364,262	)		(31.2	)

Substantial Issuer Bid		(41,025,641	)		(388.4	)



Balance at March 31, 2023		103,567,884		$	958.4

Issuance of capital stock		535,188			5.5



Balance at March 31, 2024		104,103,072		$	963.9

As at March 31, 2024, the Company converted 70,920 deferred share units (“DSUs”) to capital stock upon the resignation of two directors. The Company issued 464,268 common shares upon exercise of earnout rights, Replacement LTIP units and Omnibus Plan LTIP units. See Notes 31, 32 and 34.

Normal Course Issuer Bid

On March 3, 2022, the Company commenced a normal course issuer bid (the “2022 NCIB”) after receiving regulatory approval from the Toronto Stock Exchange. Pursuant to the NCIB, the Company was authorized to acquire up to a maximum of 7,397,889 of its shares, or 5% of its 147,957,790 issued and outstanding shares as of February

, 2022, subject to a daily maximum of 16,586 shares. The common shares were available for purchase

and

cancellation commencing on March 3,

2022 until June 14, 2022 at which time the NCIB was suspended with the launch of the Substantial Issuer Bid (“SIB”). The NCIB resumed after the completion of the SIB and the Company was permitted to acquire its shares until March 2, 2023 under the same terms and conditions.

As at March 31, 2023, the Company purchased and cancelled 3,364,262 common shares at a weighted average book value of $9.25 (US $7.30) per share for a total purchase price of approximately $37.1 million (US $28.6 million). The excess of the purchase price paid over the carrying value of the common shares purchased totalling $5.9 million, was recognized as an increase to retained earnings.

The Company renewed its NCIB to acquire a maximum of 5,178,394 of its shares, or approximately 5% of its 103,567,884 issued and outstanding shares as of February 28, 2023, subject to a daily maximum of 50,984 shares. The NCIB commenced March 6, 2023 and terminated on March 5, 2024.

he Company has not made any purchases under its renewed NCIB.

Substantial Issuer Bid

On June 21, 2022, the Company commenced a substantial issuer bid in Canada and a Tender Offer in the United States (collectively the “Offer”) to purchase for cancellation up to US $400 million of its common shares. The Offer which expired on July 27, 2022, proceeded by way of a “modified Dutch auction”, whereby, shareholders who chose to participate in the Offer could individually select the price, within a price range of not less than US $8.75 and not more than US $10.25 per share (in increments of US $0.10 per share), at which they tender their shares to the Offer. Upon expiry of the Offer, the Company determined the lowest purchase price that allowed it to purchase the maximum number of shares properly tendered to the Offer, and not properly withdrawn, having an aggregate purchase price not exceeding US $400 million.

On July 27, 2022, 41,025,641 common shares at a weighted average book value of $9.11 (US $7.33) per share were purchased for cancellation at US $9.75 per share, for an aggregate amount of $514.9 million (US $400 million). As a result, the Company subsequently adjusted the number of common shares and the reduction to retained earnings to actual. The excess of the purchase price over the carrying value of the shares purchased totalling $127.4 million (US $99.3 million) was recognized as a reduction to retained earnings. The Company incurred transaction costs of $1.1 million related to the SIB which were recorded within capital stock.

Share-Based Payment Compensation Liability (Tables)

12 Months Ended

Mar. 31, 2024

Shared Based Payment Compensation Liability [Abstract]

Summary Of Continuity of Replacement LTIP Units

Continuity of Replacement LTIP units are as follows:



	March 31, 2024			March 31, 2023

Opening balance		3,059,643			3,232,628

Dividend equivalents and other adjustments		74,126			93,201

Vested and settled		(356,900	)		(266,186	)


Ending balance		2,776,868			3,059,643

Pension Benefits

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Pension Benefits

20.	PENSION BENEFITS

Defined contribution plan

The Company maintains a defined contribution pension plan established by Old Steelco Inc.’s predecessor in 2004 for

non-unionized

employees in Canada joining the Company after January 1, 2003. As part of Old Steelco Inc.’s contract negotiations with its locals which concluded on July 31, 2010, the locals and Old Steelco Inc. agreed to include in this plan all unionized employees hired subsequent to August 1, 2010 and to offer to all the current employees the option to move to the Defined Contribution Pension Plan. The plan was revised by Old Steelco Inc. during the year ended March 31, 2011; these revisions went into effect March 1, 2011. Based on this revision, the Company is obligated to provide a base contribution of

% of salary and also match employee contributions to a maximum of

%, depending on years of service for

non-unionized

employees. Additionally, the Company is obligated to provide a contribution for unionized employees per qualified hour worked of $2.85.

The pension expense under this plan is equal to the Company’s contribution. The pension expense for the year ended March 31, 2024 was $13.1 million (March 31, 2023 was $10.2 million).

Defined benefit plans

The Company maintains

non-contributory

defined benefit pension plans that are closed to new entrants and cover all employees in Canada not covered under the Defined Contribution Pension Plan. The benefits are based on years of service and average earnings for a defined period prior to retirement.

The Company also maintains a closed plan for pensioners who retired prior to January 1, 2002, that provides the pensioners with a pension benefit in excess of the limits provided by the Ontario Pension Benefit Guarantee Fund (the “Closed Retiree Plan”).

These defined benefit pension plans are registered under the Pension Benefits Act (Ontario), and are legally separated from the Company. The Pension Benefits Act (Ontario) is a regulatory framework that has jurisdiction over the administration and funding of defined benefit pension plans. Within this framework, the Company has fiduciary responsibility over the administration of the defined benefit pension plans, including the development and oversight of the investment policy for pension funds and the selection and oversight of pension fund investment managers.

The defined benefit pension plans expose the Company to various risks such as: investment risk, interest rate risk, foreign currency risk, price risk, credit risk and liquidity risk.

The most recent actuarial valuations of plan assets and the present value of the defined benefit obligation were carried out at April 1, 2023 for salaried, hourly and wrap plans.

The principal assumptions used for the purposes of the actuarial valuations were as follows:



Year ended,	March 31, 2024		March 31, 2023 1		March 31, 2023 2

Assumptions for determination of defined benefit cost:

Defined obligation and past service cost		4.85%		4.25%		4.73%

Net interest cost		4.94%		3.86%		4.50%

Current service cost		5.05%		4.35%		4.85%

Interest cost on current service cost		5.00%		4.18%		4.71%

Discount rate for determination of defined benefit obligation		4.98%		4.98%		4.98%

Assumptions for determination of defined benefit cost and defined benefit obligation:

Ultimate rate of compensation increase		3.00% per annum until 2027 2.00% thereafter		3.00% per annum until 2027 2.00% thereafter		3.00% per annum until 2027 2.00% thereafter

Mortality		105% CPM2014 Private Projection CPM-B		105% CPM2014 Private Projection CPM-B		105% CPM2014 Private Projection CPM-B

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of April 1, 2022 to July 31, 2022

Weighted average assumptions to determine defined benefit cost and obligation with respect to the period of August 1, 2022 to March 31, 2023 and past service cost as of August 1, 2022

The components of amounts recognized in the consolidated statements of net income in respect of the defined benefit plans are presented below:



Year ended,	March 31, 2024		March 31, 2023

Amounts recognized in net income were as follows:

Current service cost	$	16.8	$	16.5

Past service cost		-		49.5

Net interest cost		8.6		7.3


	$	25.4	$	73.3


Defined benefit costs recognized in:

Cost of sales	$	15.2	$	59.4

Administrative and selling expenses		1.6		6.6

Interest on pension liability		8.6		7.3


	$	25.4	$	73.3

Past service cost recognition

The collective bargaining agreements with Local 2251 and Local 2724 were ratified in August 2022 and September 2022, respectively; and became effective as of August 1, 2022. The settlement resulted in a past service cost adjustment related to the defined benefit pension plan of $49.5 million, of which $44.5 million was recorded in the cost of steel revenue and $5.0 million was recorded in administrative and selling expense for the year ended March 31, 2023.

The amounts recognized in the consolidated statements of other comprehensive income in respect of the defined benefit plans are presented below:



Year ended,	March 31, 2024		March 31, 2023

Amounts recognized in other comprehensive income, were as follows:

Actuarial loss on accrued pension liability	$	46.3	$	9.0

The amounts included in the consolidated statements of financial position in respect of the Company’s net obligation in respect of its defined benefit plans are as follows:



As at,	March 31, 2024		March 31, 2023

Present value of defined benefit obligation	$	1,302.9	$	1,264.9

Fair value of plan assets		1,064.8		1,080.9


Net accrued pension liability	$	238.0	$	184.0

Continuities of the defined benefit plan assets and obligations are as follows:



Year ended,	March 31, 2024			March 31, 2023

Movements in the present value of the plan assets were as follows:

Fair value of plan assets at beginning of year	$	1,080.9		$	1,225.5

Actual return (net of investment management expenses)		51.6			(75.4	)

Administration expenses		(1.7	)		(1.5	)

Employer contributions		17.5			16.5

Benefits paid		(83.4	)		(84.2	)

Fair value of plan assets at end of the year



March 31, 2024 and March 31, 2023, respectively	$	1,064.8		$	1,080.9


Movements in the present value of the defined benefit obligation were as follows:

Defined benefit obligation at the beginning of the year	$	1,264.9		$	1,343.6

Current service cost		15.2			15.0

Interest cost		60.3			55.4

Past service cost		-			49.5

Actuarial losses (gains) arising from financial assumptions		33.0			(112.2	)

Effect of experience adjustments		12.9			(2.2	)

Benefits paid		(83.4	)		(84.2	)

Defined benefit obligation at end of the year



March 31, 2024 and March 31, 2023, respectively	$	1,302.9		$	1,264.9

Reconciliation of the amounts recognized in accumulated other comprehensive income in the consolidated statements of changes in shareholders’ equity were as follows:


	Actuarial (gain) loss immediately recognized			Tax effect			Actuarial (gain) immediately recognized, net of tax

Balance at March 31, 2022	$	(138.8	)	$	(0.3	)	$	(139.1	)

Actuarial loss immediately recognized		9.0			-			9.0


Balance at March 31, 2023	$	(129.8	)	$	(0.3	)	$	(130.1	)


Actuarial loss immediately recognized		46.3			-			46.3


Balance at March 31, 2024	$	(83.5	)	$	(0.3	)	$	(83.8	)

The major categories of plan assets were as follows:



As at	March 31, 2024	March 31, 2023

Cash and cash equivalents	1%	1%

Equity instruments	55%	33%

Debt instruments	41%	39%

Other	3%	27%



	100%	100%

Cash flow information

The Company is required to make contributions equal to current service cost. Contributions for the year ended March 31, 2024 under these regulations were $17.5 million (March 31, 2023 - $16.5 million).

The Company’s expected future contributions in respect of its defined benefit pension plans for the fiscal year ending March 31, 2025 is $26.9 million.

Sensitivity of results to actuarial assumptions

The sensitivity of the defined benefit obligation to the key actuarial assumptions is as follows:



Year ended,	March 31, 2024		March 31, 2023

Effect of change in discount rate assumption

One percentage point increase	$	(123.1)	$	(118.5)

One percentage point decrease	$	147.4	$	141.8

Effect of change in salary scale

One percentage point increase	$	17.4	$	18.8

One percentage point decrease	$	(15.9)	$	(17.0)

Effect of change in mortality assumption

Set forward one year	$	33.1	$	31.5

Set back one year	$	(34.0)	$	(32.4)

The discount rate sensitivities presented above are estimates based on plan durations. The defined benefit obligation and the current service cost have an implied duration of 10 and 17 years, respectively at current discount rates.

If the returns on plan assets had been 10% lower than the actual returns of plan assets experienced in the year ended March 31, 2024, the actuarial loss immediately recognized in other comprehensive income would have increased by approximately $105.0 million (March 31, 2023 - $130.0 million).

Consolidated Statements of Comprehensive Income - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of comprehensive income [abstract]
Net income	$ 105.2	$ 298.5
Other comprehensive (loss) income, net of income tax, that are or may be reclassified subsequently to profit or loss
(Loss) income on cash flow hedges reclassified to net income	0.0	(9.3)
Income arising on changes in fair value of cash flow hedges, net of tax expense nil and $7.8 million, respectively (Note 19)	0.0	34.0
Other comprehensive income (loss), net of income tax, that will not be reclassified subsequently to profit or loss
Foreign exchange gain on translation to presentation currency	3.1	123.1
Remeasurement of pension and other post-employment benefit obligations, net of tax nil for March 31, 2024 and 2023 (Notes 20, 21)	(49.6)	13.8
Other comprehensive income	(46.5)	161.6
Total comprehensive income	$ 58.7	$ 460.1

Bank Indebtedness - Summary of Company's Bank Indebtedness Arising from Financing Activities (Detail) - Secured Asset Based Revolving Credit Facility [Member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Bank Indebtedness [Line Items]
Beginning balance	$ 1.9	$ 0.1
Revolving Credit Facility drawn	48.1	44.8
Repayment of Revolving Credit Facility	(49.8)	(43.0)
Foreign exchange	0.1
Ending balance	$ 0.3	$ 1.9

Other Long-Term Liabilities - Summary of Detailed about Other Long term Liabilities (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	$ 17.0	$ 3.7
MENDM Loan [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	3.5	2.6
Financing Arrangement [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	10.4	0.0
Long-term disability plan obligation [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	0.9	0.7
Long-term portion of lease liability [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	$ 2.2	$ 0.4

Income Tax Expense (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information About Components of Income Tax Expense Explanatory

The components of income tax expense for the years ended March 31, 2024 and March 31, 2023 are as follows:



Year ended,	March 31, 2024		March 31, 2023

Income tax expense (recovery) recognized in net income:

Current tax expense	$	38.5	$	89.6

Deferred income tax expense (recovery)		1.2		(12.0	)


	$	39.7	$	77.6

Summary of Income taxes in the consolidated statements of net (loss) income



Year ended,	March 31, 2024			March 31, 2023

Income before income taxes	$	144.9		$	376.1


Income tax expense based on the applicable tax rate of 25%	$	36.2		$	94.0

Add / (deduct):

Non-deductible post-employment benefits payments		3.4			3.3

Non-deductible pension contributions		3.4			0.9

Non-deductible accretion of financial obligations		1.8			0.8

Adjustment in respect of prior years		(1.7	)		(1.3	)

Changes in fair value of warrant liability		(3.1	)		(12.3	)

Changes in fair value of earnout liability		-			(1.7	)

Changes in fair value of share-based payment liability		0.3			(3.3	)

Other		(0.6	)		(2.8	)



Income tax expense	$	39.7		$	77.6

Summary of tax-effected temporary differences which result in deferred income tax assets and (liabilities)

The

tax-effected


	Balance at March 31, 2023			Movements in:								Balance at March 31, 2024
	Balance at March 31, 2023			Net Income			Foreign Exchange			Other Comprehensive Income		Balance at March 31, 2024

Accounting reserves	$	2.2		$	(0.9	)	$	-		$	-	$	1.3

Inventory reserve		(0.1	)		(1.8	)		-			-		(1.9	)

Defined benefit pension - past service costs (Note 20)		12.6			-			-			-		12.6

Other post-employment benefits - past service costs (Note 21)		1.0			-			-			-		1.0

Capital tax loss carryforward		2.1			-			-			-		2.1

Property, plant and equipment and intangible assets		(150.9	)		10.7			(0.3	)		-		(140.5	)

Unrealized exchange loss (gain) on US dollar debt		(0.3	)		0.2			-			-		(0.1	)

Governmental loans benefit		(18.4	)		(10.6	)		0.1			-		(28.9	)

Financing expenses		0.5			0.4			-			-		0.9

Deferred revenue		51.5			(1.3	)		0.1			-		50.3

SRED expenditures		(0.1	)		-			-			-		(0.1	)

Transaction costs		3.9			(1.3	)		-			-		2.6

Unrealized loss on cash flow hedges		-			1.5			-			-		1.5

Realized exchanged loss on governmental loans		-			0.4			-			-		0.4

Share-based payment compensation		-			1.8			-			-		1.8

Other		(0.7	)		(0.3	)		-			-		(1.0	)


	$	(96.7	)	$	(1.2	)	$	(0.1	)	$	-	$	(98.0	)

The

tax-effected


	Balance at March 31, 2022			Movements in:									Balance at March 31, 2023
	Balance at March 31, 2022			Net Income			Foreign Exchange			Other Comprehensive Income			Balance at March 31, 2023

Accounting reserves	$	2.6		$	(0.3	)	$	(0.1	)	$	-		$	2.2

Inventory reserve		(3.5	)		3.2			0.2			-			(0.1	)

Defined benefit pension - past service costs (Note 20)		-			12.2			0.4			-			12.6

Other post-employment benefits - past service costs (Note 21)		-			1.0			-			-			1.0

Capital tax loss carryforward		1.9			-			0.2			-			2.1

Property, plant and equipment and intangible assets		(144.4	)		5.3			(11.8	)		-			(150.9	)

Unrealized exchange loss (gain) on US dollar debt		0.9			(1.2	)		-			-			(0.3	)

Governmental loans benefit		(10.3	)		(7.0	)		(1.1	)		-			(18.4	)

Financing expenses		-			0.5			-			-			0.5

Deferred revenue		48.7			(1.2	)		4.0			-			51.5

SRED expenditures		(0.1	)		-			-			-			(0.1	)

Transaction costs		5.1			(1.6	)		0.4			-			3.9

Unrealized loss on cash flow hedges		6.5			1.4			(0.1	)		(7.8	)		-

Other		(0.3	)		(0.3	)		(0.1	)		-			(0.7	)


	$	(92.9	)	$	12.0		$	(8.0	)	$	(7.8	)	$	(96.7	)

Cost of Sales - Additional Information (Detail) - Cost of sales [member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Cost of Sales [Line Items]
Carbon tax recognized as expense	$ 24.6	$ 7.2
Steel [Member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Depreciation expense	114.7	95.0
Wages and benefit costs	365.3	375.6
Past service cost	47.9	$ 47.9
Steel [Member] \| Pension defined benefit plans [member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Past service cost	44.5
Steel [Member] \| Post-employment medical defined benefit plans [member]
Disclosure of Detailed Information About Cost of Sales [Line Items]
Past service cost	$ 3.4

Governmental Loans

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Governmental Loans

18.	GOVERNMENTAL LOANS



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Long-term portion

Federal AMF Loan, denominated in Canadian dollars, due March 1, 2028	$	21.7	$	27.9

Provincial MENDM Loan, denominated in Canadian dollars, due November 30, 2028		42.8		45.4

Federal SIF Agreement loan, denominated in Canadian dollars, due April 30, 2031		9.4		9.7

Federal SIF EAF Agreement loan, denominated in Canadian dollars, due January 1, 2030		53.5		27.4



	$	127.4	$	110.4


Current portion

Federal AMF Loan, denominated in Canadian dollars	$	10.0	$	10.0

Provincial MENDM Loan, denominated in Canadian dollars		6.2		-


	$	16.2	$	10.0


	$	143.6	$	120.4

Federal Economic Development Agency for Southern Ontario

On November 30, 2018, the Company entered into an agreement with the Federal Economic Development Agency, through

the

Advanced Manufacturing Fund (“Federal AMF Loan”). The Company received a $60.0 million interest free loan as reimbursement for certain defined capital expenditures. The Company commenced equal monthly installments on April 1, 2022, with the final installment payable on March 1, 2028. Under the General Security Agreement, this facility has a third priority claim on all of the Company’s assets which is

pari passu

with the Provincial MENDM Loan, defined below.

As at March 31, 2024, the Company had applied for reimbursements of $60.0 million (March 31, 2023 - $60.0 million) and recognized a benefit, net of accretion, of $7.7 million (March 31, 2023 - $11.5 million). During the year ended March 31, 2023, the Company made repayments totalling $10.0 million (March 31, 2023 - $10.0 million). Accordingly, the carrying value of the Federal AMF Loan was $31.7 million at March 31, 202

(March 31, 2023 - $37.9 million).

Ministry of Energy, Northern Development and Mines

On November 30, 2018, the Company entered into an agreement with the Ministry of Energy, Northern Development and Mines (the “Provincial MENDM Loan”) under which, the Company received a $60.0 million low interest loan as reimbursement for certain defined capital expenditures. The Company will repay the loan in monthly blended payments of principal and interest beginning on December 31, 2024 and ending on November 30, 2028. This facility bears interest at an annual interest rate equal to the greater of 2.5% per annum; and the lenders cost of funds. Under the General Security Agreement, this facility has a third priority claim on all of the Company’s assets which is

pari passu

with the Federal AMF Loan.

As at March 31, 2024, the Company had applied for and received reimbursements of $60.0 million (March 31, 2023 - $60.0 million) and recognized a benefit, net of accretion, of $10.9 million (March 31, 2023 - $14.5 million). Accordingly, the carrying value of the Provincial MENDM Loan was $49.0 million at March 31, 2024 (March 31, 2023 - $45.4 million).

Ministry of Industry

On March 29, 2019, the Company, together with the government of Canada, entered into an agreement whereby a benefit of $30.0 million flowed to the Company; $15.0 million in the form of a grant, and $15.0 million in the form of an interest free loan; from the Ministry of Industry, Strategic Innovation Fund (the “SIF Agreement”). Under the terms of this agreement, the Company was reimbursed for certain defined capital. On March 25, 2024, the Company amended the SIF Agreement and will repay in equal annual instalments, the $

15.0

million interest free loan portion of this funding beginning on April 30, 2027 and ending on April 30, 2034. The agreement is guaranteed by the Company’s subsidiary, Algoma Steel Intermediate Holdings Inc.

At March 31, 2024, the Company had applied for reimbursements of $15.0 million each under the grant and loan portions of the agreement (March 31, 2023 - $15.0 million each under the grant and loan portions), and recognized a benefit of $15.0 million (March 31, 2023 - $15.0 million). Additionally, at March 31, 2024, the Company had recognized a benefit, net of accretion, of $5.6 million (March 31, 2023 – $5.3 million). The carrying value of the Federal SIF Agreement was $9.4 million at March 31, 2024 (March 31, 2023 – $9.7 million).

On September 20, 2021, the Company, together with the government of Canada, entered into an agreement of which a benefit of up to $200.0 million would flow to the Company in the form of a loan from the SIF. Under the terms of the SIF agreement, the Company will be reimbursed for certain defined capital expenditures incurred to transition from blast furnace steel production to EAF steel production between March 3, 2021 and March 31, 2025.

For the year ended March 31, 2024, the Company had applied for reimbursements under the SIF loan agreement of $

74.4 million (March 31, 2023 – $63.3 million) and recognized a benefit, net of accretion, in respect of this agreement of $48.2 million (March 31, 2023 – $37.0 million). Accordingly, the carrying value of the SIF EAF Agreement was $53.5 million (March 31, 2023 – $27.4 million).

Canada Infrastructure Bank

On November 26, 2021, the Company, entered into an agreement of which a benefit of up to $220.0

million would flow to the Company in the form of a loan from the CIB. CIB is a federal Crown corporation established under the Canada Infrastructure Bank Act which is not an agency of the government of Canada, but is accountable to the government of Canada through the Minister of Infrastructure and Communities. Pursuant to its terms, the CIB credit availability was reduced as a result of share repurchases and dividends paid by the Company, and

the loan was undrawn as of March 31, 2024 with limited credit availability remaining. Given that the Company did not expect to draw on the CIB Loan, the parties agreed to terminate the agreement on March 7, 2024.

The Company has recognized the governmental loan claims receivable, governmental loan payable and benefit associated with these agreements because the Company has fulfilled its obligations under the respective agreements.

The changes in the Company’s governmental loan facilities arising from financing activities are presented below:



	Governmental Loan Issued (Repaid)			Governmental loan benefit recognized immediately			Accretion of governmental loan benefit		Carrying value

Federal AMF Loan

Balance at March 31, 2023	$	49.2		$	(26.5	)	$	15.0	$	37.9

Movement in the period		(10.0	)		-			3.8		(6.2	)


Balance at March 31, 2024	$	39.2		$	(26.5	)	$	18.8	$	31.7


Provincial MENDM Loan

Balance at March 31, 2023	$	60.0		$	(26.4	)	$	11.9	$	45.4

Movement in the period		-			-			3.6		3.6


Balance at March 31, 2024	$	60.0		$	(26.4	)	$	15.5	$	49.0


Federal SIF Loan

Balance at March 31, 2023	$	15.0		$	(7.8	)	$	2.5	$	9.7

Movement in the period		-			(1.4	)		1.1		(0.3	)


Balance at March 31, 2024	$	15.0		$	(9.2	)	$	3.6	$	9.4


Federal SIF EAF Loan

Balance at March 31, 2023	$	65.5		$	(38.7	)	$	0.6	$	27.4

Movement in the period		74.4			(51.7	)		3.4		26.1


Balance at March 31, 2024	$	139.9		$	(90.4	)	$	4.0	$	53.5


Total, Governmental Loans

Balance at March 31, 2023	$	189.8		$	(99.4	)	$	30.0	$	120.4

Movement in the period		64.4			(53.1	)		11.9		23.2


Balance at March 31, 2024	$	254.2		$	(152.5	)	$	41.9	$	143.6

Pension Benefits - Summary of principal assumptions used for the purposes of the actuarial valuations (Detail) - Pension defined benefit plans [member] - $ / t	4 Months Ended	8 Months Ended	12 Months Ended
	Jul. 31, 2022	Mar. 31, 2023	Mar. 31, 2024
Disclosure In Tabular Form Of Acturial Assumptons For Pension Plans [Line Items]
Defined obligation and past service cost	4.25%	4.73%	4.85%
Net interest cost	3.86%	4.50%	4.94%
Current service cost	4.35%	4.85%	5.05%
Interest cost on current service cost	4.18%	4.71%	5.00%
Discount rate for determination of defined benefit obligation	4.98%	4.98%	4.98%
Mortality	105	105	105
Until 2027 [Member]
Disclosure In Tabular Form Of Acturial Assumptons For Pension Plans [Line Items]
Ultimate rate of compensation increase	3.00%	3.00%	3.00%
After 2027 [Member]
Disclosure In Tabular Form Of Acturial Assumptons For Pension Plans [Line Items]
Ultimate rate of compensation increase	2.00%	2.00%	2.00%

Financial instruments - Additional Information (Detail) $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($) Tons	Mar. 31, 2023 CAD ($) Tons	Mar. 31, 2022 CAD ($)
Disclosure Of Financial Instruments [Line Items]
Current trade receivables	$ 246.7	$ 291.2
Accounts receivable overdue amount	$ 6.2	$ 2.0
Percentage of accounts receivable overdue	2.50%	0.70%
Accounts receivable overdue period	90 days
Allowance account for credit losses of financial assets	$ 3.1	$ 0.5	$ 2.4
Interest rate risk [member]
Disclosure Of Financial Instruments [Line Items]
Percentage of reasonably possible increase in unobservable input, liabilities	1.00%	1.00%
Increase (decrease) in fair value measurement due to reasonably possible increase in unobservable input, recognised in profit or loss, after tax, liabilities	$ 0.0	$ 0.0
Increase (decrease) in fair value measurement due to reasonably possible decrease in unobservable input, recognised in profit or loss, after tax, liabilities	$ 0.0	$ 0.0
Commodity price risk [member] \| Commodity Based Swap Contracts [Member]
Disclosure Of Financial Instruments [Line Items]
Aggregate notional quantity outstanding \| Tons	0	0
Accounts Receivable [Member]
Disclosure Of Financial Instruments [Line Items]
Allowance account for credit losses of financial assets	$ 3.1	$ 0.5
Bottom of range [member] \| One Customer [Member]
Disclosure Of Financial Instruments [Line Items]
Percentage of entity's revenue	10.00%	10.00%

Pension Benefits - Summary of Reconciliation of the amounts recognized in accumulated other comprehensive income (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure In Tabular Form Of Acturial Gain Loss Immediately Recognized In Other Comprehensive Income [Line Items]
Beginning balance , Actuarial (gain) loss immediately recognized	$ (129.8)	$ (138.8)
Actuarial (gain) loss immediately recognized , Actuarial gain immediately recognized	46.3	9.0
Ending balance , Actuarial gain immediately recognized	(83.5)	(129.8)
Beginning balance , Tax effect	(0.3)	(0.3)
Actuarial gain immediately recognized , Tax effect	0.0	0.0
Ending balance , Tax effect	(0.3)	(0.3)
Beginning balance , Actuarial (gain) immediately recognized, net of tax	(130.1)	(139.1)
Actuarial gain immediately recognized , Actuarial (gain) immediately recognized, net of tax	46.3	9.0
Ending balance , Actuarial (gain) immediately recognized, net of tax	$ (83.8)	$ (130.1)

Key Management Personnel

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Key Management Personnel

33.	KEY MANAGEMENT PERSONNEL

The Company’s key management personnel, and persons connected with them, are also considered to be related parties for disclosure purposes. Key management personnel are defined as those individuals having authority and responsibility for planning, directing and controlling the activities of the Company and include the executive leadership team (ELT) and the Board of Directors.

Remuneration of the Company’s Board of Directors and ELT for the respective periods are as follows:



Year ended,	March 31, 2024		March 31, 2023

Salaries and benefits	$	5.7	$	12.3

Director fees		2.5		1.5

Share-based compensation (Note 34)		5.4		4.4


	$	13.6	$	18.2

Accounts Payable and Accrued Liabilities

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Accounts Payable and Accrued Liabilities

16.	ACCOUNTS PAYABLE AND ACCRUED LIABILITIES



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Accounts payable	$	142.0	$	59.8

Accrued liabilities		80.5		74.9

Wages and accrued vacation payable		64.3		69.9


	$	286.8	$	204.6

Interest On Pension And Other Post-Employment Benefit Obligations (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Interest On Pension And Other Post Employment Benefit Obligations



Year ended,	March 31, 2024		March 31, 2023

Interest on pension and other post-employment benefit obligations is comprised of:

Interest on defined benefit pension obligation (Note 20)	$	8.6	$	7.3

Interest on other post-employment benefit obligation (Note 21)		10.7		9.9


	$	19.3	$	17.2

Basis Of Presentation - Additional Information (Detail)	12 Months Ended
Basis Of Presentation - Additional Information (Detail)	Mar. 31, 2024
Disclosure of Basis of Presentation [Line Items]
Description of functional currency	United States dollar
Description of presentation currency	Canadian dollars

Capital Stock - Summary of classes of share capital (Detail) - CAD ($) $ in Millions			12 Months Ended
	Jul. 27, 2022	Feb. 18, 2022	Mar. 31, 2024	Mar. 31, 2023
Disclosure of classes of share capital [line items]
Number of shares issued during period		147,957,790
Beginning balance			$ 958.4
Issue of equity			4.7
Ending balance			$ 963.9	$ 958.4
Normal Course Issuer Bid [Member]
Disclosure of classes of share capital [line items]
Stock Repurchased During Period Shares				(3,364,262)
Stock Repurchased During Period Value				$ (31.2)
Substantial Issuer Bid [Member]
Disclosure of classes of share capital [line items]
Stock Repurchased During Period Shares	41,025,641			(41,025,641)
Stock Repurchased During Period Value				$ (388.4)
Issued capital [member]
Disclosure of classes of share capital [line items]
Beginning balance, Shares			103,567,884	147,957,787
Ending balance, Shares			104,103,072	103,567,884
Number of shares issued during period			535,188
Beginning balance			$ 958.4	$ 1,378.0
Issue of equity			5.5
Ending balance			$ 963.9	$ 958.4

Material Accounting Policies (Policies)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Foreign exchange transactions

Non-monetary

items that are measured in terms of historical cost are not

re-translated.

Financial Instruments

Recognition

write-off

of a financial asset (or a portion thereof) constitutes a derecognition event.

Write-off

occurs when the Company has no reasonable expectations of recovering the contractual cash flows associated with a financial asset.

Classification and measurement

The classification of financial instruments is determined at the time of initial recognition, within the following categories:

●

Amortized cost

●

Fair value through profit (loss) (FVTP(L))

●

Fair value through other comprehensive income (loss) (FVTOCI(L))

Financial assets are classified and subsequently measured based on the business model in which they are managed

and

their cash flow characteristics. Financial assets are measured at amortized cost if they meet both of the following conditions and are not designated as FVTP(L):

●

The financial asset is held within a business model with the objective of holding the financial asset in order to collect contractual cash flows; and

●

The contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding.

held-for-trading,

Impairment of financial assets carried at amortized cost

The Company utilizes an ‘expected credit loss’ (“ECL”) model, as required by IFRS 9 –

Financial Instruments

The Company reviews its accounts receivable at each reporting date and considers both current and forward-looking macro-economic factors that may affect historical default rates when estimating ECL.

write-off

is later recovered, the recovery is recognized in the consolidated statements of net income.

Fair value of financial instruments

liabilities in active markets, inputs other than quoted prices that are observable for the asset or liability (for example, interest

rate

The Company reclassifies financial assets only when its business model for managing those assets changes. Financial liabilities are not reclassified.

Accounts receivable

Accounts receivable are recognized initially at transaction price and are

non-interest

Inventories

Property, plant and equipment, net

Depreciation is calculated by the straight-line method based on estimated useful lives as follows:



Category of Property, Plant and Equipment		Range of Estimated Useful Life

Buildings		5 to 30 years

Machinery and equipment		5 to 40 years

Vehicles		6 to 12 years

Computer hardware		3 to 5 years

Componentization

When significant components of an item of property, plant and equipment have different useful lives, they are accounted for as separate items and depreciated over the respective useful lives.

Useful life, depreciation method, residual value

Derecognition of property plant and equipment

Impairment of tangible and intangible assets

Leases

At inception of a contract, the Company assesses whether the contract is, or contains, a

lease

. A contract is, or contains, a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration.

The Company, as a lessee, recognizes a

right-of-use

The Company has elected not to recognize

right-of-use

assets and lease liabilities for short-term leases defined as leases with a lease term of 12 months or less and

low-value

assets. These types of leases are recorded in the consolidated statement of net income as incurred.

Retirement benefit costs

transfer those amounts recognized in other comprehensive income (loss) to a separate reserve within equity.

Net-interest

is calculated by applying the discount rate to the net defined benefit liability. Defined benefit and other post-employment benefit costs are split into three categories:

●

service cost, past-service cost, gains and losses on curtailments and settlements;

●

net interest expense; and

●

remeasurement.

Payments to defined contribution retirement benefit plans are recognized as an expense when employees have rendered service entitling them to the contributions.

Termination benefits

Short-term benefits

Environmental liabilities

material, environmental liabilities are determined by discounting the expected future cash flows at a

pre-tax

rate that reflects current market assessments of the time value of money and the risks specific to the liability. The unwinding of the discount is recognized as finance cost.

Revenue recognition

The Company’s revenue is generated primarily from contracts to produce, ship and deliver steel products, and to a lesser extent, to deliver

non-steel

by-products

of the steelmaking processes and related freight revenue.

point-in-time

Freight and other transportation costs billed to customers are recorded gross within revenue and cost of goods sold.

Non-steel

revenue primarily pertains to the sale of various

by-products

such as kish, ore fines, mill scale, scrap rolls and high sulfur iron. The Company’s performance obligations in respect of its sales of

by-products

are satisfied upon loading of the applicable

by-products

on an FOB shipping basis, at which time such

by-products

are deemed to be transferred and the customer obtains title to, and control of, such

by-products.

Government funding

Research

Research costs are expensed as incurred, due to the nature of the projects. Where government incentives in the form of investment tax credits and grants are received for research projects initiated

by the Company for its own purposes, these incentives are deducted from the applicable category of expenditures.

Finance cost

Taxation

Current tax

Deferred income tax

Share-based payment

Comprehensive Income (Loss)

New IFRS Standards, Amendments and Interpretations adopted as of April 1, 2023 (effective January 1, 2023)

The Company adopted the following amendments which did not have a material impact on the consolidated financial statements:

Amended Disclosure for Accounting Policies

Amended Scope of Recognition

equal taxable and deductible temporary differences.

Definition of Accounting Estimates

IAS 8 “Accounting Policies, Changes in Accounting Estimates and Errors”

was

amended to introduce the definition of an accounting estimate and includes other amendments to assist entities to distinguish changes in accounting estimates from changes in accounting policies.

Standards and Interpretations issued and not yet adopted

Classification of Liabilities as Current or

Non-current

In January 2020, the IASB issued an amendment to IAS 1

Presentation of Financial Statements

non-current

Non-Current

Liabilities with Covenants (Amendments to IAS 1). These amendments specify that covenants to be complied with after the reporting date do not affect the classification of debt as current or

non-current

Accounts Receivable, Net (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Account Receivable Net Explanatory



As at,	March 31, 2024			March 31, 2023

The carrying amount of:

Trade accounts receivable	$	238.5		$	277.3

Allowance for doubtful accounts		(3.1	)		(0.5	)

Governmental loan claims receivable

Federal Ministry of Industry, Strategic Innovation Fund (“Federal SIF”) Agreement		3.0			3.0

Northern Industrial Electricity Rate program rebate receivable		2.2			2.7

Other accounts receivable		6.1			8.7


	$	246.7		$	291.2

Allowance for doubtful accounts



Balance at March 31, 2022	$	(2.4	)

Remeasurement of loss allowance		1.9


Balance at March 31, 2023	$	(0.5	)

Remeasurement of loss allowance		(2.6	)


Balance at March 31, 2024	$	(3.1	)

Pension Benefits - Summary of amounts included in the consolidated statements of financial position in respect of the Company's net obligation (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Disclosure of defined benefit plans [line items]
Present value of defined benefit obligation	$ 1,302.9	$ 1,264.9	$ 1,343.6
Fair value of plan assets	1,064.8	1,080.9	$ 1,225.5
Net accrued pension liability	$ 238.0	$ 184.0

Finance Costs

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Finance Costs

9.	FINANCE COSTS



Year ended,	March 31, 2024		March 31, 2023

Finance costs are comprised of:

Interest on the Revolving Credit Facility (Note 15)	$	-	$	0.2

Interest on financing arrangement (Note 22)		0.2		-

Revaluation of discount rate for environmental liabilities		3.8		-

Other interest expense		2.3		0.8

Revolving Credit Facility fees		2.9		2.5

Unwinding of issuance costs of debt facilities (Note 15) and accretion of governmental loan benefits and discounts on environmental liabilities		16.4		14.4


	$	25.6	$	17.9

Property, Plant and Equipment, Net

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Property, Plant and Equipment, Net

14.	PROPERTY, PLANT AND EQUIPMENT, NET



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Freehold land	$	6.7	$	6.6

Buildings		52.4		39.2

Machinery and equipment		697.6		691.7

Computer hardware		4.0		1.9

Right-of-use assets		6.2		3.4

Property under construction		638.3		338.5


	$	1,405.2	$	1,081.3

The following table presents the changes to the cost of the Company’s property, plant and equipment for the years ended March 31, 2024 and March 31, 2023:



Cost	Freehold Land		Buildings			Machinery & Equipment			Computer Hardware		Right-of- use assets		Property under construc- tion			Total

Balance at March 31, 2022	$	6.1	$	65.9		$	900.3		$	1.4	$	4.0	$	118.8		$	1,096.5

Additions		-		-			3.2			-		-		330.1			333.3

Transfers		-		1.6			121.6			1.5		-		(124.5	)		0.2

Disposals		-		-			(0.1	)		-		-		(0.1	)		(0.2	)

Foreign exchange		0.5		5.6			77.8			0.1		0.3		14.2			98.5



Balance at March 31, 2023	$	6.6	$	73.1		$	1,102.8		$	3.0	$	4.3	$	338.5		$	1,528.3

Additions		-		-			3.3			-		-		436.6			439.9

Transfers		0.1		17.9			115.1			2.6		3.3		(139.0	)		-

Disposals		-		(0.1	)		(41.7	)		-		-		(0.2	)		(42.0	)

Foreign exchange		-		0.1			1.5			-		0.1		2.4			4.1



Balance at March 31, 2024	$	6.7	$	91.0		$	1,181.0		$	5.6	$	7.7	$	638.3		$	1,930.3

The following table presents the changes to accumulated depreciation on the Company’s property, plant and equipment for the years ended March 31, 2024 and March 31, 2023:



Accumulated Depreciation:	Freehold Land		Buildings			Machinery & Equipment			Computer Hardware		Right-of- use assets		Property under construc- tion		Total

Balance at March 31, 2022	$	-	$	26.6		$	294.8		$	0.8	$	0.6	$	-	$	322.8

Depreciation expense		-		5.0			89.6			0.3		0.3		-		95.2

Disposals		-		-			0.1			-		-		-		0.1

Foreign exchange		-		2.3			26.6			-		-		-		28.9



Balance at March 31, 2023	$	-	$	33.9		$	411.1		$	1.1	$	0.9	$	-	$	447.0

Depreciation expense		-		4.8			112.9			0.5		0.6		-		118.8

Disposals		-		(0.1	)		(41.6	)		-		-		-		(41.7	)

Foreign exchange		-		-			1.0			-		-		-		1.0



Balance at March 31, 2024	$	-	$	38.6		$	483.4		$	1.6	$	1.5	$	-	$	525.1

Useful lives of property, plant and equipment

The Company reviews the estimated useful lives of property, plant and equipment at the end of each annual reporting period, and whenever events or circumstances indicate a change in useful life. As a result of the Company changing to electric arc furnaces (“EAF”) to replace the existing blast furnace and basic oxygen steelmaking operations, the Company has been reviewing the useful lives for those assets expected to be decommissioned once the EAF is operational. Effective October 1, 2023, there was sufficient evidence to support a change in the useful lives of machinery, equipment and buildings involved in blast furnace steelmaking operations. The remaining useful lives of this machinery, equipment and buildings have been adjusted to be fully depreciated by December 31, 2029. As a result of this change in estimate, depreciation for the year ended March 31, 2024 has increased by $12.5 million. It is expected that there will be a quarterly impact of approximately $6.1 million to $6.4 million until December 31, 2029.

Depreciation of property, plant and equipment

Depreciation of property, plant and equipment for the year ended March 31, 2024 was $118.8 million (March 31, 2023 - $95.2 million). Depreciation included in inventories at March 31, 2024, amounted to $13.9 million (March 31, 2023 - $9.7 million).

Acquisitions and disposals

During the year ended March 31, 2024, property, plant and equipment were acquired at an aggregate net cost of $439.9 million (March 31, 2023 – $333.3 million); comprised of property, plant and equipment acquired with a total cost of $493.4 million (March 31, 2023 - $371.1 million), against which the Company recognized benefits totalling $53.5 million (March 31, 2023 - $37.7 million) in respect of the governmental loans and the governmental grant discussed in Note 18.

During the year ended March 31, 2024, the Company had additions to property under construction for the EAF for an aggregate net cost of $206.0 million, including benefits in respect of the governmental loans totalling $51.7 million. During the year ended March 31, 2023, the Company had additions to property under construction for the electric arc furnace (“EAF”) for an aggregate net cost of $215.7 million, including benefits in respect of the governmental loans totalling $37.6 million.

During the year ended March 31, 2024, the Company had additions to property under construction for the plate mill modernization project for an aggregate net cost of $59.3 million (March 31, 2023 – $33.1 million). As at March 31, 2024, since inception of the project the Company had additions for the plate mill modernization project of $131.4 million.

At March 31, 2024, property under construction includes prepaid progress payments of $204.4 million for the transition from blast furnace steel production to EAF (March 31, 2023 – $188.7 million). At March 31, 2024, there was no prepaid expense pertaining to the plate mill modernization project (March 31, 2023 - $41.4 million).

Government Funding Agreements

On November 30, 2018, the Company, together with the governments of Canada and Ontario entered into agreements totalling up to $120.0 million of modernization and expansion related capital expenditure support from the governments of Canada and Ontario. Additionally, on March 29, 2019, the Company, together with the government of Canada entered into an agreement totalling up to $30.0 million of modernization and expansion related capital expenditure support from the government of Canada. On September 20, 2021, the Company, together with the government of Canada entered into an agreement for support up to $420

million related to the transition from blast furnace steel production to EAF. The $420 million of financial support consists of (i) a loan of up to $200 million from the Innovation Science and Economic Development Canada’s Strategic Innovation Fund (“SIF”) and (ii) a loan of up to $220 million from the Canada Infrastructure

Bank (“CIB”). Each of these agreements are discussed below and additional disclosures are located in Note 18.

Consolidated Statement of Changes in Shareholders' Equity - CAD ($) $ in Millions	Total	Contributed (Deficit) Surplus [member]	Foreign exchange gain (loss) on translation to presentation currency [member]	Actuarial gain (loss) on pension and other post- employment benefit obligation [member]	Cash flow hedge reserve - unrealized gain (loss) [member]	Accumulated other compre-hensive income [member]	Retained earnings [member]	Capital stock [member]
Beginning Balance at Mar. 31, 2022	$ 1,582.6	$ (25.2)	$ (16.4)	$ 193.1	$ (24.7)	$ 152.0	$ 77.8	$ 1,378.0
Net income	298.5						298.5
Other comprehensive income (loss)	161.6		123.1	13.8	24.7	161.6
Issuance of performance and restricted share units	2.2	2.2
Issuance of deferred share units	1.7	1.7
Common shares repurchased and cancelled	(553.1)						(133.5)	(419.6)
Dividend equivalent on earnout rights	(0.5)						(0.5)
Dividends paid	(30.7)						(30.7)
Ending Balance at Mar. 31, 2023	1,462.2	(21.4)	106.7	206.9	0.0	313.6	211.6	958.4
Net income	105.2						105.2
Other comprehensive income (loss)	(46.5)		3.1	(49.6)	0.0	(46.5)
Issuance of performance and restricted share units	3.0	3.0
Issuance of deferred share units	2.2	2.2
Issuance of capital stock	4.7	(0.8)						5.5
Dividend equivalent on earnout rights	(0.5)						(0.5)
Dividends paid	(27.9)						(27.9)
Ending Balance at Mar. 31, 2024	$ 1,502.4	$ (17.0)	$ 109.8	$ 157.3	$ 0.0	$ 267.1	$ 288.4	$ 963.9

- Definition

The amount of residual interest in the assets of the entity after deducting all its liabilities.

+ References + Details

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2023-01-01
-Paragraph 18
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2023-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2023-01-01
-Paragraph 32
-Subparagraph a
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2023-en-r&anchor=para_32_a_ii&doctype=Standard
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2023-03-23

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2023-en-r&anchor=para_23&doctype=Standard
-URIDate 2023-03-23

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
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-IssueDate 2023-01-01
-Paragraph B10
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2023-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_81A_a&doctype=Standard
-URIDate 2023-03-23

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph d
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_106_d_i&doctype=Standard
-URIDate 2023-03-23

+ Details

Pension Benefits - Summary of sensitivity the defined benefit obligation to the key actuarial assumptions (Parentheticals) (Detail)	Mar. 31, 2024	Mar. 31, 2023
Actuarial assumption of discount rates [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	1.00%	1.00%
Percentage of reasonably possible decrease in actuarial assumption	1.00%	1.00%
Actuarial assumption of expected rates of salary increases [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	1.00%	1.00%
Percentage of reasonably possible decrease in actuarial assumption	1.00%	1.00%
Actuarial assumption of mortality rates [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Reasonably Possible Increase In Acturial Assumption By One Year	1	1
Reasonably Possible Decrease In Acturial Assumption By One Year	1	1

Warrant Liability

12 Months Ended

Mar. 31, 2024

Warrant Liability [Abstract]

Warrant Liability

30.	WARRANT LIABILITY

As at March 31, 2024, 24,179,000 Warrants remain outstanding with an estimated fair value of US $1.37 per Warrant based on the market price of the Warrants, for which the Company recognized a liability of $44.9 million (US $33.1 million) (March 31, 2023 - $57.3 million; US $42.3

million). For the year ended March 31, 2024, a gain of $

12.1 million (March 31, 2023 – $47.7 million) on change in the fair value of the warrant liability is presented in the consolidated statements of net income. The Warrants will expire on the fifth anniversary of the merger transaction which was completed on October 19, 2021.

Other Post-Employment Benefits - Disclosure of Detailed Information About Other Post Employment Benefits Recognized in Statements of Income Loss Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of defined benefit plans [line items]
Net interest cost	$ 19.3	$ 17.2
Other Post Employment Benefits [Member]
Disclosure of defined benefit plans [line items]
Current service cost	3.0	3.0
Past service cost	0.0	3.8
Net interest cost	10.7	9.9
Post-employment benefit expense in profit or loss, defined benefit plans	13.7	16.7
Other Post Employment Benefits [Member] \| Cost of sales [member]
Disclosure of defined benefit plans [line items]
Post-employment benefit expense in profit or loss, defined benefit plans	2.6	6.0
Other Post Employment Benefits [Member] \| Administrative and Selling Expense [Member]
Disclosure of defined benefit plans [line items]
Post-employment benefit expense in profit or loss, defined benefit plans	0.4	0.8
Other Post Employment Benefits [Member] \| Interest on Pension Liability [Member]
Disclosure of defined benefit plans [line items]
Post-employment benefit expense in profit or loss, defined benefit plans	$ 10.7	$ 9.9

Other Long-Term Liabilities (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed about Other Long term Liabilities



As at,	March 31, 2024		March 31, 2023

The carrying amount of the following other long term liabilities:

Accrued interest payable, Provincial MENDM Loan	$	3.5	$	2.6

Financing arrangement		10.4		-

Long-term disability plan obligation		0.9		0.7

Long-term portion of lease liability		2.2		0.4


	$	17.0	$	3.7

Administrative and Selling Expenses - Summary of Detailed Information About Administrative and Selling Expenses (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Administrative and selling expense is comprised of:
Personnel expenses	$ 43.3	$ 39.3
Share-based compensation expense	5.2	3.9
Professional, consulting, legal and other fees	18.8	20.7
Insurance	25.6	21.8
Software licenses	5.9	5.2
Amortization of intangible assets and non-producing assets	0.3	0.3
Other administrative and selling	15.9	8.1
Selling, general and administrative expense	$ 115.0	$ 99.3

Environmental Liabilities - Summary of Environmental Liabilities (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Environmental liabilities [Line Items]
Environmental Liabilities	$ 38.3	$ 36.8
Current portion	3.1	4.5
Long-term portion	35.2	32.3
The Companys Operation Site [Member]
Disclosure of Detailed Information About Environmental liabilities [Line Items]
Environmental Liabilities	33.8	32.7
Northern Ontario mine sites owned by Old Steelco Inc [Member]
Disclosure of Detailed Information About Environmental liabilities [Line Items]
Environmental Liabilities	$ 4.5	$ 4.1

Material Accounting Policies (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information About Estimated Useful life

Depreciation is calculated by the straight-line method based on estimated useful lives as follows:



Category of Property, Plant and Equipment		Range of Estimated Useful Life

Buildings		5 to 30 years

Machinery and equipment		5 to 40 years

Vehicles		6 to 12 years

Computer hardware		3 to 5 years

Administrative and Selling Expenses (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Detailed Information About Administrative and Selling Expenses



Year ended,	March 31, 2024		March 31, 2023

Administrative and selling expense is comprised of:

Personnel expenses	$	43.3	$	39.3

Share-based compensation expense (Note 34)		5.2		3.9

Professional, consulting, legal and other fees		18.8		20.7

Insurance		25.6		21.8

Software licenses		5.9		5.2

Amortization of intangible assets and non-producing assets		0.3		0.3

Other administrative and selling		15.9		8.1


	$	115.0	$	99.3

Governmental Loans - Additional Information (Detail) - CAD ($) $ in Millions			12 Months Ended
	Mar. 29, 2019	Nov. 30, 2018	Mar. 31, 2024	Mar. 31, 2023	Dec. 07, 2023	Nov. 26, 2021	Sep. 20, 2021
Statement [Line Items]
Non current portion of governmental loans			$ 127.4	$ 110.4
Borrowings interest rate					7.50%
Repayment of government loans			(10.0)	(10.0)
Federal AMF Loan [Member]
Statement [Line Items]
Eligible interest free loan		$ 60.0	$ 60.0	$ 60.0
Borrowings maturity date		March 1, 2028	March 1, 2028	March 1, 2028
Borrowings maturity start date		Apr. 01, 2022
Income from government grants			$ 7.7	$ 11.5
Governmental loans			31.7	37.9
Non current portion of governmental loans			21.7	27.9
Repayment of government loans			10.0	10.0
MENDM Loan [Member]
Statement [Line Items]
Eligible interest free loan		$ 60.0	$ 60.0	$ 60.0
Borrowings maturity date		November 30, 2028	November 30, 2028	November 30, 2028
Borrowings maturity start date		Dec. 31, 2024
Income from government grants			$ 10.9	$ 14.5
Non current portion of governmental loans			42.8	45.4
Borrowings interest rate		2.50%
Governmental loans current and non-current			49.0	45.4
Federal SIF Agreement Loan [Member]
Statement [Line Items]
Eligible interest free loan			$ 15.0	$ 15.0
Borrowings maturity date	April 30, 2034		April 30, 2031	April 30, 2031
Borrowings maturity start date	Apr. 30, 2027
Income from government grants			$ 15.0	$ 15.0
Non current portion of governmental loans			9.4	9.7
Aggregate loan and grant eligible amount	$ 30.0
Government grant	15.0
Interest free loan amount	$ 15.0
Additional income from government grants			5.6	5.3
Canada Infrastructure Bank [Member]
Statement [Line Items]
Borrowings						$ 220.0
Federal Sif Agreement Loan Due January One Two Thousand And Thirty [Member] \| Algoma Steel Parent SCA [Member]
Statement [Line Items]
Eligible interest free loan			74.4	63.3
Income from government grants			48.2	37.0
Non current portion of governmental loans			$ 53.5	$ 27.4
Aggregate loan and grant eligible amount							$ 200.0

Dividends - Additional Information (Detail) $ in Millions	12 Months Ended
Dividends - Additional Information (Detail) $ in Millions	Mar. 31, 2024 CAD ($)	Mar. 31, 2024 $ / shares	Mar. 31, 2023 CAD ($)
Disclosure Of Dividends [Line Items]
Dividends paid, ordinary shares			$ 27.9
Common Share [Member]
Disclosure Of Dividends [Line Items]
Dividends paid, ordinary shares per share \| $ / shares		$ 0.05
Dividends paid, ordinary shares	$ 27.9		$ 30.7

Pension Benefits - Summary of Movements in the present value of the plan assets (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure In Tabular Form Of Changes In Net Defined Benefit Plan Assets At Fair Value [Line Items]
Fair value of plan assets at beginning of year	$ 1,080.9	$ 1,225.5
Actual return (net of investment management expenses)	51.6	(75.4)
Administration expenses	(1.7)	(1.5)
Employer contributions	17.5	16.5
Benefits paid	(83.4)	(84.2)
Fair value of plan assets at end of the year,	$ 1,064.8	$ 1,080.9

Consolidated Statements of Net Income - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Profit or loss [abstract]
Revenue	$ 2,795.8	$ 2,778.5
Operating expenses
Cost of sales	2,513.5	2,388.7
Administrative and selling expenses	115.0	99.3
Income from operations	167.3	290.5
Other (income) and expenses
Finance income	(10.0)	(13.3)
Finance costs	25.6	17.9
Interest on pension and other post-employment benefit obligations	19.3	17.2
Foreign exchange gain	(1.7)	(41.1)
Change in fair value of warrant liability	(12.1)	(47.7)
Change in fair value of earnout liability	0.1	(5.9)
Change in fair value of share-based compensation liability	1.2	(12.7)
Other (income) and expenses	22.4	(85.6)
Income before income taxes	144.9	376.1
Income tax expense	39.7	77.6
Net income	$ 105.2	$ 298.5
Net income per common share:
Basic	$ 0.97	$ 2.43
Diluted	$ 0.7	$ 1.71

Share Based Compensation - Summary Of Continuity Of Deferred Share Units (Detail) - Deferred Share Units [Member] - shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Terms And Conditions Of Deferred Share based Payment Arrangement [Line Items]
Opening balance	215,628	54,558
Granted	187,549	156,629
Dividend equivalents and other adjustments	12,511	4,441
Vested and settled	(70,920)	0
Ending balance	344,768	215,628

Income Tax Expense - Additional Information (Detail)	12 Months Ended
Income Tax Expense - Additional Information (Detail)	Mar. 31, 2024	Mar. 31, 2023
Statement [Line Items]
Applicable tax rate	25.00%	25.00%
Canadian Federal Income Tax [Member]
Statement [Line Items]
Applicable tax rate	15.00%	15.00%
Canadian Provincial Income Tax [Member]
Statement [Line Items]
Applicable tax rate	10.00%	10.00%

Cover Page	12 Months Ended
Cover Page	Mar. 31, 2024 shares
Document Information [Line Items]
Document Type	40-F
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--03-31
Entity Registrant Name	ALGOMA STEEL GROUP INC.
Entity Central Index Key	0001860805
Entity File Number	001-40924
Document Annual Report	true
Document Registration Statement	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Incorporation, State or Country Code	A1
Entity Address, Address Line One	105 West Street
Entity Address, State or Province	ON
Entity Address, City or Town	Sault Ste. Marie
Entity Address, Country	CA
Entity Address, Postal Zip Code	P6A 7B4
City Area Code	705
Local Phone Number	945-2351
Entity Common Stock, Shares Outstanding	104,103,072
Auditor Name	Deloitte LLP
Auditor Firm ID	1208
Auditor Location	Toronto, Canada
ICFR Auditor Attestation Flag	true
Audited Annual Financial Statements	true
Annual Information Form	true
Document Financial Statement Error Correction [Flag]	false
Business Contact [Member]
Document Information [Line Items]
Contact Personnel Name	Algoma Steel USA Inc.
Entity Address, Address Line One	1209 Orange Street
Entity Address, State or Province	DE
Entity Address, City or Town	Wilmington
Entity Address, Postal Zip Code	19801
City Area Code	705
Local Phone Number	945-2351
Common Shares [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Shares, without par value
Trading Symbol	ASTL
Security Exchange Name	NASDAQ
Warrants [Member]
Document Information [Line Items]
Title of 12(b) Security	Warrants, each whole warrant exercisable forone Common Share at an exercise price ofUS$11.50 per share
Trading Symbol	ASTLW
Security Exchange Name	NASDAQ

Revenue - Summary of Internal Performance Measurement and Resource Allocation (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	$ 2,795.8	$ 2,778.5
Canada [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	1,052.1	1,030.5
United States [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	1,704.0	1,708.1
Rest of the world [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	39.7	39.9
Steel Sheet and Strip [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	2,035.8	2,161.3
Plate [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	506.2	387.4
Slab [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	3.3	1.4
Freight [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	198.3	182.4
Non-steel revenue [Member]
Disclosure of Products and Services and Geographical Distribution Of Revenue [Line Items]
Revenue	$ 52.2	$ 46.0

Critical Estimates and Judgements

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Critical Estimates and Judgements

4.	CRITICAL ESTIMATES AND JUDGEMENTS

The preparation of these consolidated financial statements, in accordance with IFRS, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

Judgement is used mainly in determining whether a balance or transaction should be recognized in the consolidated financial statements. Estimates and assumptions are used mainly in determining the measurement of recognized transactions and balances. However, judgement and estimates are often interrelated.

In the determination of CGU, the Company assessed its identifiable group of assets that generates cash inflows and concluded the Company has a single cash generating unit. Judgements, estimates and assumptions are continually evaluated and are based on historical experience and other factors including expectations of future events that are believed to be reasonable under the circumstances.

Revisions to accounting estimates are recognized in the period in which the estimates are revised and in future periods affected.

The following discussion sets forth management’s most critical estimates and assumptions in determining the value of assets, liabilities, revenue and expenses:

Allowance for doubtful accounts

Management analyzes accounts receivable to determine the allowance for doubtful accounts by assessing the collectability of receivables owing from each individual customer. This assessment takes into consideration certain factors including the age of outstanding receivable, customer-operating performance, historical payment patterns and current collection efforts, relevant forward-looking information and the Company’s security interests, if any.

Useful lives of property, plant and equipment and Intangible assets

The Company reviews the estimated useful lives of property, plant and equipment and intangible assets at the end of each annual reporting period, and whenever events or circumstances indicate a change in useful life. Estimated useful lives of items of property, plant and equipment and intangible assets are based on a best estimate and the actual useful lives may be different.

Impairment of property, plant and equipment and Intangible assets

Determining whether property, plant and equipment and intangible assets are impaired requires the Company to determine the recoverable amount of the CGU to which the asset is allocated. To determine the recoverable amount of the CGU, management is required to estimate its fair value. To calculate the value of the CGU in use, management determines expected future cash flows, which involves, among other items, forecasted steel selling prices, forecasted tons shipped, costs and volume of production, growth rate, and the estimated selling costs, using an appropriate discount rate.

Defined Benefit Retirement Plans

The Company’s determination of employee benefit expense and obligations requires the use of assumptions such as the discount rate applied to determine the present value of all future cash flows expected in the plan. Since the determination of the cost and obligations associated with employee future benefits requires the use of various assumptions, there is measurement uncertainty inherent in the actuarial valuation process. Actual results could differ from estimated results which are based on assumptions.

Taxation

The Company computes and recognizes an income tax provision in each of the jurisdictions in which it operates. Actual amounts of income tax expense and scientific research and experimental development investment tax credits only become final upon filing and acceptance of the returns by the relevant authorities, which occur subsequent to the issuance of the consolidated financial statements.

Additionally, the estimation of income taxes includes evaluating the recoverability of deferred income tax assets based on an assessment of the ability to use the underlying future tax deductions before they expire against future taxable income. The assessment is based upon existing tax laws and estimates of future taxable income. To the extent estimates differ from the final tax return, net income will be affected in a subsequent period. The Company will file tax returns that may contain interpretations of tax law and estimates. Positions taken and estimates utilized by the Company may be challenged by the relevant tax authorities. Rulings that result in adjustments to tax returns filed will be recorded in the period where the ruling is made known to the Company.

Interest On Pension And Other Post-Employment Benefit Obligations - Summary of Interest On Pension And Other Post Employment Benefit Obligations (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest on pension and other post employment benefit obligations [Abstract]
Interest on defined benefit pension obligation	$ 8.6	$ 7.3
Interest on other post-employment benefit obligation	10.7	9.9
Interest On Pension And Other Post-Employment Benefit Obligations	$ 19.3	$ 17.2

Net Income Per Common Share - Summary of Computation of Basic and Diluted Net Income (Loss) Per Common Share (Detail) $ / shares in Units, shares in Millions, $ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($) $ / shares shares	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 CAD ($) $ / shares shares	Mar. 31, 2023 USD ($) shares
Text Block [Abstract]
Net income attributable to ordinary shareholders \| $	$ 105.2		$ 298.5
Gain on change in fair value of warrants	(12.1)	$ (9.2)	(47.7)	$ (37.2)
Net income attributable to ordinary shareholders (diluted) \| $	$ 93.1		$ 250.8
Weighted average common shares outstanding	108.4	108.4	122.7	122.7
Dilutive effect of warrants, restricted share units and performance share units	24.6	24.6	24.3	24.3
Dilutive weighted average common shares outstanding	133.0	133.0	147.0	147.0
Net income per common share:
Basic \| $ / shares	$ 0.97		$ 2.43
Diluted \| $ / shares	$ 0.7		$ 1.71

General Information

12 Months Ended

Mar. 31, 2024

Statement [Line Items]

General Information

1.	GENERAL INFORMATION

Algoma Steel Group Inc., formerly known as 1295908 B.C. Ltd. (the “Company”), was incorporated on March 23, 2021 under the Business Corporations Act of British Columbia solely for the purpose of purchasing Algoma Steel Holdings Inc. On May 24, 2021, the Company entered into a Merger Agreement (the “Merger”), by and among the Company, a wholly-owned subsidiary of the Company and Legato Merger Corp. (“Legato”). On October 19, 2021, the Company completed its merger with Legato, listing its common shares and warrants under the symbol ‘ASTL’ and ASTLW’, respectively, on the Toronto Stock Exchange (TSX) and the Nasdaq Stock Market (Nasdaq). Algoma Steel Group Inc. is the ultimate parent holding company of Algoma Steel Inc. and does not conduct any business operations.

Algoma Steel Inc. (“ASI”), the operating company and a wholly-owned subsidiary of Algoma Steel Holdings Inc. was incorporated on May 19, 2016 under the Business Corporations Act of British Columbia. ASI is an integrated steel producer with its active operations located entirely in Sault Ste. Marie, Ontario, Canada. ASI produces sheet and plate products that are sold primarily in Canada and the United States.

The registered address of the Company is 1055 West Hastings Street, Vancouver, British Columbia, Canada. The head office of the Company is located at 105 West Street, Sault Ste. Marie, Ontario, Canada.

The consolidated financial statements of the Company for the years ended March 31, 2024 and March 31, 2023 are comprised of the Company and its wholly-owned subsidiaries as follows:

●

Algoma Steel Holdings Inc.

●

Algoma Steel Intermediate Holdings Inc.

●

Algoma Steel Inc.

●

Algoma Steel Inc. USA

●

Algoma Docks GP Inc.

●

Algoma Docks Limited Partnership

Algoma Steel Holdings Inc., Algoma Steel Intermediate Holdings Inc. and Algoma Docks GP Inc. are holding companies and do not conduct any business operations.

Net Income Per Common Share (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Computation of Basic and Diluted Net Income (Loss) Per Common Share

The following table sets forth the computation of basic and diluted net income per common share:



Year ended,	March 31, 2024			March 31, 2023
(in millions)

Net income attributable to ordinary shareholders	$	105.2		$	298.5

Gain on change in fair value of warrants (i)		(12.1	)		(47.7	)


Net income attributable to ordinary shareholders (diluted)	$	93.1		$	250.8


(in millions)

Weighted average common shares outstanding (ii)		108.4			122.7

Dilutive effect of warrants, restricted share units and performance share units (i) (ii)		24.6			24.3


Dilutive weighted average common shares outstanding		133.0			147.0


Net income per common share:

Basic	$	0.97		$	2.43

Diluted	$	0.70		$	1.71

(i)

As at March 31, 2024, 24,179,000 warrants remain outstanding. For the purposes of determining diluted net income per common share, net income for the year ended March 31, 2024 was adjusted for the change in the fair value of the warrants in the amount of $12.1 million (US $9.2 million) as the warrants were determined to be dilutive (March 31, 2023 - $47.7 million; US $37.2 million).

(ii)

On May 17, 2022, the Board of Directors granted 141,203 and 556,348 restricted share units and performance share units, respectively, to various employees of the Company under the Omnibus Plan for the fiscal year ended March 31, 2023 (“FY2023 Plan”). Further, on March 31, 2023 the Board of Directors granted 457,935 and 404,211 restricted share units and performance share units, respectively, to various employees of the Company under the Omnibus Plan for the fiscal year ended March 31, 2024 (“FY2024 Plan”). For the purposes of determining diluted net income per share, the restricted share units and performance share units are considered contingently issuable potential ordinary shares. The treasury stock method is applied based on the number of units that vest based on achievement of various financial and nonfinancial targets. Based on the achievement of such targets and forfeiture of awards, the restricted share units and performance share units included in diluted net income per share for the year ended March 31, 2024 is 376,268 common shares (March 31, 2023 – 92,293 common shares). See Note 34.

Finance Costs - Summary of Detailed Information About Finance Cost Explanatory (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Detailed Information About Finance Cost Explanatory [Line Items]
Revaluation of discount rate for environmental liabilities	$ 3.8	$ 0.0
Other interest expense	2.3	0.8
Unwinding of issuance costs of debt facilities and accretion of governmental loan benefits and discounts on environmental liabilities	16.4	14.4
Finance costs	25.6	17.9
Revolving Credit Facility [Member]
Disclosure Of Detailed Information About Finance Cost Explanatory [Line Items]
Interest expense	0.0	0.2
Revolving credit facility fees	2.9	2.5
Financing Arrangement [Member]
Disclosure Of Detailed Information About Finance Cost Explanatory [Line Items]
Interest expense	$ 0.2	$ 0.0

Bank Indebtedness

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Bank Indebtedness

15.	BANK INDEBTEDNESS

On November 30, 2018, the Company obtained US $250.0

million in the form of a traditional asset-based revolving credit facility (the “Revolving Credit Facility”). The Revolving Credit Facility is secured by substantially all of the Company’s assets. Under the General Security Agreement, the Revolving Credit Facility has a priority claim on the accounts receivable and the inventories of the Company and a secondary claim on the rest of the Company’s assets. In May 2023, the Company increased its Revolving Credit Facility from US $250 million to US $300 million and extended the term to

May

2028. The interest rate on the Revolving Credit Facility is based on Secured Overnight Financing Rate (“SOFR”) plus a credit spread adjustment of 10 basis points plus an applicable margin, which varies depending on usage.

At March 31, 2024, the Company had drawn $0.3 million (US $0.2 million), and there was $347.1 million (US $256.2 million) of unused availability after taking into account $59.1 million (US $43.6 million) of outstanding letters of credit, and borrowing base reserves. At March 31, 2023, the Company had drawn $1.9 million (US $1.4 million), and there was $279.2 million (US $206.3 million) of unused availability after taking into account $57.3 million (US $42.3 million) of outstanding letters of credit and borrowing base reserves.

Initial transaction costs related to the Revolving Credit Facility obtained on November 30, 2018 amounted to $7.0 million, with additional transaction costs of $1.7 million incurred for the increase in the Revolving Credit Facility in May 2023. Transaction costs are disclosed as other

non-current

assets in the consolidated statements of financial position, and have been amortized on a straight-line basis over the life of this facility, which has a maturity date of May 31, 2028. At March 31, 2024, the unamortized transaction costs related to the Revolving Credit Facility were $1.4 million (March 31, 2023 - $0.9 million).

Reconciliation of liabilities arising from financing activities

The changes in the Company’s bank indebtedness for the year ended March 31, 2024 arising from financing activities are presented below:



Balance at March 31, 2022	$	0.1

Revolving Credit Facility drawn		44.8

Repayment of Revolving Credit Facility		(43.0	)



Balance at March 31, 2023	$	1.9


Revolving Credit Facility drawn		48.1

Repayment of Revolving Credit Facility		(49.8	)

Foreign exchange		0.1



Balance at March 31, 2024	$	0.3

Taxes Payable and Accrued Taxes - Summary of Taxes Payable and Accrued Taxes (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Taxes Payable and Accrued Taxes [Abstract]
Payroll taxes payable	$ 3.0	$ 4.3
Sales taxes payable	1.6	0.0
Carbon tax accrual	23.4	8.4
Income taxes payable	2.1	1.7
Taxes Payable and Accrued Taxes Current	$ 30.1	$ 14.4

Share-Based Payment Compensation Liability - Summary Of Continuity of Replacement LTIP Units (Detail) - Replacement Long Term Incentive Plan Awards [Member] - shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Replacement Long Term Incentive Plan Awards [Line Items]
Opening balance	3,059,643	3,232,628
Dividend equivalents and other adjustments	74,126	93,201
Vested and settled	(356,900)	(266,186)
Ending balance	2,776,868	3,059,643

Share Based Compensation - Additional Information (Detail) $ in Millions				12 Months Ended
	Mar. 31, 2023 yr	May 17, 2022 yr $ / shares	Oct. 19, 2021 shares	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2023 CAD ($) shares	Mar. 31, 2023 $ / shares
Statement [Line Items]
Expense from share-based payment transactions				$ 5.2	$ 3.9
Deferred Share Units [Member]
Statement [Line Items]
Contributed Surplus Deficit Reserve for share-based payment compensation expense				$ 2.2	$ 1.7
Number of other equity instruments granted in share-based payment arrangement \| shares				187,549	156,629
Restricted Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement	457,935	141,203		457,935	141,203
Performance Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement \| yr	404,211	556,348
Administrative And Selling Expenses [Member]
Statement [Line Items]
Expense from share-based payment transactions				$ 2.2
Financial Year 2023 Plan [Member] \| Restricted Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement \| yr		141,203
Financial Year 2023 Plan [Member] \| Performance Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement \| yr		556,348
Weighted average exercise price of other equity instruments granted in share-based payment arrangement \| $ / shares		$ 9.4
Financial Year 2024 Plan [Member]
Statement [Line Items]
Contributed Surplus Deficit Reserve for share-based payment compensation expense					$ 2.2
Financial Year 2024 Plan [Member] \| Restricted Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement \| shares					457,935
Financial Year 2024 Plan [Member] \| Performance Share Units [Member]
Statement [Line Items]
Number of other equity instruments granted in share-based payment arrangement \| shares					404,211
Financial Year 2024 Plan [Member] \| Restricted Share Units And Performance Share Units [Member]
Statement [Line Items]
Weighted average exercise price of other equity instruments granted in share-based payment arrangement \| $ / shares						$ 7.62
Financial Year 2024 Plan [Member] \| Administrative And Selling Expenses [Member]
Statement [Line Items]
Expense from share-based payment transactions					$ 3.0
Longterm Incentive Plan [Member]
Statement [Line Items]
Maximum number of common shares that may be awarded under Omnibus Plan \| shares			8,800,000

Basis of Presentation

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Basis of Presentation

2.	BASIS OF PRESENTATION

Statement of compliance

These consolidated financial statements have been prepared in accordance with International Financial Reporting Standard (“IFRS”) as issued by the International Accounting Standards Board (“IASB”).

These consolidated financial statements have been approved by the Board of Directors, and authorized for issuance on June 19, 2024.

Functional and presentation currency

The Company and its subsidiaries’ functional currency is the United States dollar (“US dollar”). The US dollar is the currency of the primary economic environment in which the Company and its subsidiaries operate.

For reporting purposes, the consolidated financial statements are presented in millions of Canadian dollars (“$C”). The assets

and

liabilities are translated into the reporting currency using exchange rates prevailing at the end of each reporting period. Income and expense items are translated at average exchange rates for the reporting period. Exchange differences arising are recognized in other comprehensive income and accumulated in equity under the heading ‘Foreign exchange on translation to presentation currency’.

Equity transactions, as disclosed in Note 26, are translated at the historical exchange rates. The resulting net translation adjustment has been recorded in other comprehensive income for the year.

Pension Benefits - Summary of sensitivity the defined benefit obligation to the key actuarial assumptions (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Actuarial assumption of discount rates [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption	$ (123.1)	$ (118.5)
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption	147.4	141.8
Actuarial assumption of expected rates of salary increases [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption	17.4	18.8
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption	(15.9)	(17.0)
Actuarial assumption of mortality rates [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption	33.1	31.5
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption	$ (34.0)	$ (32.4)

Dividends - Summary of Dividends (Detail) $ in Millions	12 Months Ended
Dividends - Summary of Dividends (Detail) $ in Millions	Mar. 31, 2023 CAD ($)
Disclosure of Detailed Information About Dividends [Line Items]
Dividends paid, ordinary shares	$ 27.9
July 24, 2023 [member]
Disclosure of Detailed Information About Dividends [Line Items]
Dividends Record Date	July 5, 2023
Dividends Payment Date	July 24, 2023
Dividends paid, ordinary shares	$ 7.0
September 29, 2023 [member]
Disclosure of Detailed Information About Dividends [Line Items]
Dividends Record Date	August 25, 2023
Dividends Payment Date	September 29, 2023
Dividends paid, ordinary shares	$ 6.9
December 29, 2023 [member]
Disclosure of Detailed Information About Dividends [Line Items]
Dividends Record Date	November 30, 2023
Dividends Payment Date	December 29, 2023
Dividends paid, ordinary shares	$ 6.9
March 28, 2024 [member]
Disclosure of Detailed Information About Dividends [Line Items]
Dividends Record Date	February 29, 2024
Dividends Payment Date	March 28, 2024
Dividends paid, ordinary shares	$ 7.1

Earnout Liability - Summary Of Continuity Of Earnout Rights (Detail) - shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnout Liability [Line Items]
Opening balance	1,537,184	1,616,305
Dividend equivalents and other adjustments	37,534	46,802
Vested and settled	(378,561)	(125,923)
Ending balance	1,196,157	1,537,184

Commitments and Contingencies

12 Months Ended

Mar. 31, 2024

Statement [Line Items]

Commitments and Contingencies

25.	COMMITMENTS AND CONTINGENCIES

Property, plant and equipment

In the normal course of business operations the Company has certain commitments for capital expenditures related to the maintenance and acquisition of property, plant and equipment.

Key inputs to production

The Company requires large quantities of iron ore, coal, oxygen, electricity and natural gas in order to satisfy the demands of the steel manufacturing operation. The Company makes most of its purchases of these principal raw materials at negotiated prices under annual and multi-year agreements. These agreements provide the Company with comfort that an adequate supply of these key raw materials will be available to the Company at a price acceptable to the Company.

Legal Matters

Additionally, from time to time, in the ordinary course of business, the Company is a defendant or party to a number of pending or threatened legal actions and proceedings. Although such matters cannot be predicted with certainty, management currently considers the Company’s exposure to such ordinary course claims and litigation, to the extent not covered by the Company’s insurance policies or otherwise provided for, not to have a material adverse effect on these consolidated financial statements. In addition, the Company is involved in and potentially subject to regular audits from federal and provincial tax authorities relating to income, capital and commodity taxes and, as a result of these audits, may receive assessments and reassessments.

Other Post-Employment Benefits - Summary of statements of financial position (Detail) - Other Post Employment Benefits [Member]	4 Months Ended	8 Months Ended	12 Months Ended
	Jul. 31, 2022	Mar. 31, 2023	Mar. 31, 2024
Statement [Line Items]
Defined benefit obligation	4.31%	4.79%	5.04%
Current service cost	4.46%	4.88%	5.07%
Interest cost on benefit obligation	4.01%	4.59%	4.95%
Interest cost on current service cost	4.42%	4.86%	5.07%
Health care cost immediate trend rate	5.00%	4.99%	4.96%
Effective discount rate	4.79%	5.04%	4.85%
Health care cost immediate trend rate	4.99%	4.96%	4.90%
Health care cost ultimate trend rate	4.00%	4.00%	4.00%
Year ultimate health care cost trend rate reached	2040 years	2040 years	2040 years
Salary Increases per annum	2.00%	2.00%	2.00%
Mortality	105	105	105

Share-Based Compensation - Summary Of Continuity of PSUs (Detail) - Performance Share Units [Member] - shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Terms And Conditions Of Performance Share based Payment Arrangement [Line Items]
Opening balance	178,407	0
Granted based on achievement of service and performance conditions	78,821	164,667
Dividend equivalents and other adjustments, net of cancellations and forfeitures	(25,331)	13,740
Ending balance	231,898	178,407

Other Post-Employment Benefits - Summary of Other Post-Employment Benefit Obligation to Changes in the Discount Rate, Health Care Cost Trend Rate and Mortality Assumptions (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Actuarial assumption of discount rates [member]
Statement [Line Items]
One percentage point increase	$ (123.1)	$ (118.5)
One percentage point decrease	147.4	141.8
Actuarial assumption of discount rates [member] \| Other Post Employment Benefits [Member]
Statement [Line Items]
One percentage point increase	(26.4)	(25.2)
One percentage point decrease	33.2	31.7
Health care cost trend rates [Member] \| Other Post Employment Benefits [Member]
Statement [Line Items]
One percentage point increase	27.9	25.8
One percentage point decrease	(24.2)	(22.2)
Actuarial assumption of mortality rates [member]
Statement [Line Items]
One percentage point increase	33.1	31.5
One percentage point decrease	(34.0)	(32.4)
Actuarial assumption of mortality rates [member] \| Other Post Employment Benefits [Member]
Statement [Line Items]
One percentage point increase	8.6	8.3
One percentage point decrease	$ (8.5)	$ (8.1)

Share-Based Compensation - Summary Of Continuity RSUs (Detail) - Restricted share units [member]			12 Months Ended
	Mar. 31, 2023 shares yr	May 17, 2022 yr	Mar. 31, 2024 shares	Mar. 31, 2023 shares
Disclosure Of Terms And Conditions Of Restricted Share based Payment Arrangement [Line Items]
Opening balance			144,682	0
Granted based on achievement of service and performance conditions	457,935	141,203	457,935	141,203
Dividend equivalents and other adjustments, net of cancellations and forfeitures			4,635	3,479
Ending balance	144,682		607,252	144,682

Pension Benefits - Summary of Movements in the present value of the defined benefit obligation (Detail) - Pension defined benefit plans [member] - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure In Tabular Form Of Changes In Net Defined Benefit Obligation At Present Value [Line Items]
Defined benefit obligation at the beginning of the year	$ 1,264.9	$ 1,343.6
Current service cost	15.2	15.0
Interest cost	60.3	55.4
Past service cost	0.0	49.5
Actuarial losses (gains) arising from financial assumptions	33.0	(112.2)
Effect of experience adjustments	12.9	(2.2)
Benefits paid	(83.4)	(84.2)
Defined benefit obligation at end of the year,	$ 1,302.9	$ 1,264.9

Environmental Liabilities - Summary of Reconciliation of Environmental Liabilities (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of Detailed Information About Reconciliation of Environmental Liabilities Explanatory [Line Items]
Beginning balance	$ 993.4
Ending balance	1,173.6	$ 993.4
Environmental Liabilities [Member]
Disclosure of Detailed Information About Reconciliation of Environmental Liabilities Explanatory [Line Items]
Beginning balance	36.8	38.0
Payments	(5.6)	(4.8)
Accretion of discount	3.3	3.6
Revaluation for change in discount rate	3.8
Ending balance	38.3	36.8
Environmental Liabilities [Member] \| The Companys Operation Site [Member]
Disclosure of Detailed Information About Reconciliation of Environmental Liabilities Explanatory [Line Items]
Beginning balance	32.7	33.7
Payments	(5.3)	(4.1)
Accretion of discount	3.0	3.1
Revaluation for change in discount rate	3.4
Ending balance	33.8	32.7
Environmental Liabilities [Member] \| Northern Ontario mine sites owned by Old Steelco Inc [Member]
Disclosure of Detailed Information About Reconciliation of Environmental Liabilities Explanatory [Line Items]
Beginning balance	4.1	4.3
Payments	(0.3)	(0.7)
Accretion of discount	0.3	0.5
Revaluation for change in discount rate	0.4
Ending balance	$ 4.5	$ 4.1

Taxes Payable and Accrued Taxes (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Taxes Payable and Accrued Taxes



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Payroll taxes payable	$	3.0	$	4.3

Sales taxes payable		1.6		-

Carbon tax accrual		23.4		8.4

Income taxes payable		2.1		1.7


	$	30.1	$	14.4

Income Tax Expense - Summary of Income taxes in the consolidated statements of net (loss) income (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure Of Reconciliation Of Tax Expense Income At Applicable Tax Rate To Provision For Income Taxes [Abstract]
Income before income taxes	$ 144.9	$ 376.1
Income tax expense based on the applicable tax rate of 25%	36.2	94.0
Non-deductible post-employment benefits payments	3.4	3.3
Non-deductible pension contributions	3.4	0.9
Non-deductible accretion of financial obligations	1.8	0.8
Adjustment in respect of prior years	(1.7)	(1.3)
Changes in fair value of warrant liability	(3.1)	(12.3)
Changes in fair value of earnout liability	0.0	(1.7)
Changes in fair value of share-based payment liability	0.3	(3.3)
Other	(0.6)	(2.8)
Income tax expense	$ 39.7	$ 77.6

Other Post-Employment Benefits - Summary of Continuities of the Defined Benefit Plan Assets and Obligations (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Post Employment Benefits [Member]
Statement [Line Items]
Fair value of plan assets at beginning of year	$ 0.0
Employer contributions	10.4	$ 10.8
Fair value of plan assets at end of the year,	0.0	0.0
Defined benefit obligation at the beginning of the year	222.9	239.8
Current service cost	3.0	3.0
Interest cost	10.7	9.9
Past service cost	0.0	3.8
Actuarial losses (gains) arising from financial assumptions	5.5	(20.7)
Actuarial gains from experience adjustments	(2.2)	(2.1)
Benefits paid	(10.4)	(10.8)
Defined benefit obligation at end of the year,	229.5	222.9
Postemployment benefit plan assets [Member]
Statement [Line Items]
Fair value of plan assets at beginning of year	0.0	0.0
Employer contributions	10.4	10.8
Benefits paid	10.4	(10.8)
Fair value of plan assets at end of the year,	$ 0.0	$ 0.0

Cash and Restricted Cash

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Cash and Restricted Cash

11.	CASH AND RESTRICTED CASH

At March 31, 2024, the Company had $97.9 million of cash (March 31, 2023 – $247.4 million) and restricted cash of $3.9 million (March 31, 2023 – $3.9 million). Restricted cash was held to provide collateral for letters of credit and

other

obligations of the Company at both March 31, 2024 and March 31, 2023.

Cost of Sales

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Cost of Sales

7.	COST OF SALES



Year ended,	March 31, 2024		March 31, 2023

Total cost of sales is comprised of:

Cost of steel revenue	$	2,263.0	$	2,160.2

Cost of freight revenue		198.3		182.4

Cost of non-steel revenue		52.2		46.1


	$	2,513.5	$	2,388.7


Inventories recognized as cost of sales:	$	2,315.2	$	2,206.4


Net inventory write-downs as a result of net realizable value lower than cost included in cost of sales:	$	13.5	$	23.0

Depreciation included in cost of steel revenue for the year ended March 31, 2024 was $114.7 million (March 31, 2023 - $95.0 million). Wages and benefits included in cost of steel revenue for the year ended March 31, 2024 was $365.3 million (March 31, 2023 - $375.6 million). Past service costs of $47.9 million, as described below, are included in cost of steel revenue for the year ended March 31, 2023.

Federal Greenhouse Gas Pollution Pricing Act

During the year ended March 31, 2024, total Carbon Tax recognized

cost of sales as an expense was $24.6 million

(

March 31, 2023

$7.2 million

)

Past service cost recognition

The collective bargaining agreements with Local 2251 and Local 2724 were ratified in August 2022

and

September 2022, respectively; and became effective as of August 1, 2022. The settlement resulted in a past service cost adjustment related to the defined benefit pension plan and other post-employment benefits of $44.5 million and $3.4 million, respectively, of which $47.9 million was recorded in cost of steel revenue for the year ended March 31, 2023.

Net Change In Non-Cash Operating Working Capital (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary Of Changes In Non Cash Operating Working Capital



Year ended,	March 31, 2024			March 31, 2023

Accounts receivable	$	45.5		$	119.5

Net taxes payable and accrued taxes		(4.5	)		(58.3	)

Inventories		(80.4	)		(187.8	)

Prepaid expenses and other current assets		14.9			22.8

Accounts payable and accrued liabilities		57.6			(76.6	)

Derivative financial instruments (net)		-			1.7


	$	33.1		$	(178.7	)

Other Long-Term Liabilities - Additional Information (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Dec. 07, 2023	Mar. 31, 2023
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	$ 17.0		$ 3.7
Non-current loans and receivables	60.0
Cash Consideration Of Financing Arrangement		$ 11.7
Borrowings, interest rate		7.50%
Monthly Interest Payables For Financing Arrangement		$ 0.1
Current borrowings and current portion of non-current borrowings	0.9
Long-term disability plan obligation [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	0.9		0.7
MENDM Loan [Member]
Disclosure of Detailed about Other Long term Liabilities [Line Items]
Other non-current non-financial liabilities	3.5		2.6
Non-current loans and receivables	$ 3.5		$ 2.6

Income Tax Expense - Summary of tax-effected temporary differences which result in deferred income tax assets and (liabilities) (Detail) - CAD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	$ (96.7)	$ (92.9)
Deferred tax expense (income) recognised in profit or loss	(1.2)	12.0
Foreign Exchange	(0.1)	(8.0)
Income tax relating to components of other comprehensive income	0.0	(7.8)
Ending balance	(98.0)	(96.7)
Accounting Reserves [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	2.2	2.6
Deferred tax expense (income) recognised in profit or loss	(0.9)	(0.3)
Foreign Exchange	0.0	(0.1)
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	1.3	2.2
Inventory Reserve [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(0.1)	(3.5)
Deferred tax expense (income) recognised in profit or loss	(1.8)	3.2
Foreign Exchange	0.0	0.2
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	(1.9)	(0.1)
Defined benefit pension - past service costs [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	12.6	0.0
Deferred tax expense (income) recognised in profit or loss	0.0	12.2
Foreign Exchange	0.0	0.4
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	12.6	12.6
Other post-employment benefits - past service costs [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	1.0	0.0
Deferred tax expense (income) recognised in profit or loss	0.0	1.0
Foreign Exchange	0.0	0.0
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	1.0	1.0
Capital Tax Loss Carryforward [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	2.1	1.9
Deferred tax expense (income) recognised in profit or loss	0.0	0.0
Foreign Exchange	0.0	0.2
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	2.1	2.1
Property Plant And Equipment And Intangible Assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(150.9)	(144.4)
Deferred tax expense (income) recognised in profit or loss	10.7	5.3
Foreign Exchange	(0.3)	(11.8)
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	(140.5)	(150.9)
Unrealized exchange loss (gain) on US dollar debt [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(0.3)	0.9
Deferred tax expense (income) recognised in profit or loss	0.2	(1.2)
Foreign Exchange	0.0	0.0
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	(0.1)	(0.3)
Governmental Loans Benefit [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(18.4)	(10.3)
Deferred tax expense (income) recognised in profit or loss	(10.6)	(7.0)
Foreign Exchange	0.1	(1.1)
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	(28.9)	(18.4)
Financing Expenses [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	0.5	0.0
Deferred tax expense (income) recognised in profit or loss	0.4	0.5
Foreign Exchange	0.0	0.0
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	0.9	0.5
Deferred Revenue [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	51.5	48.7
Deferred tax expense (income) recognised in profit or loss	(1.3)	(1.2)
Foreign Exchange	0.1	4.0
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	50.3	51.5
SRED Expenditures [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(0.1)	(0.1)
Deferred tax expense (income) recognised in profit or loss	0.0	0.0
Foreign Exchange	0.0	0.0
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	(0.1)	(0.1)
Transaction Costs [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	3.9	5.1
Deferred tax expense (income) recognised in profit or loss	(1.3)	(1.6)
Foreign Exchange	0.0	0.4
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	2.6	3.9
Unrealized Loss On Cash Flow Hedges [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	0.0	6.5
Deferred tax expense (income) recognised in profit or loss	1.5	1.4
Foreign Exchange	0.0	(0.1)
Income tax relating to components of other comprehensive income	0.0	(7.8)
Ending balance	1.5	0.0
Realized Exchanged Loss On Governmental Loans [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	0.0
Deferred tax expense (income) recognised in profit or loss	0.4
Foreign Exchange	0.0
Income tax relating to components of other comprehensive income	0.0
Ending balance	0.4	0.0
Share Based Payment Compensation [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	0.0
Deferred tax expense (income) recognised in profit or loss	1.8
Foreign Exchange	0.0
Income tax relating to components of other comprehensive income	0.0
Ending balance	1.8	0.0
Other temporary differences [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(0.7)	(0.3)
Deferred tax expense (income) recognised in profit or loss	(0.3)	(0.3)
Foreign Exchange	0.0	(0.1)
Income tax relating to components of other comprehensive income	0.0	0.0
Ending balance	$ (1.0)	$ (0.7)

Property, Plant and Equipment, Net - Additional Information (Detail) $ in Millions, $ in Millions		12 Months Ended
	Oct. 01, 2023 CAD ($)	Mar. 31, 2024 CAD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 CAD ($)	Mar. 31, 2023 USD ($)	Sep. 20, 2021 CAD ($)	Sep. 20, 2021 USD ($)	Mar. 29, 2019 USD ($)	Nov. 30, 2018 USD ($)
Disclosure of detailed information about property, plant and equipment [line items]
Government grants in respect of property plant and equipment value		$ 53.5		$ 37.7
Purchase of property plant and equipment		490.1	$ 493.4	371.1	$ 371.1
Acquisitions of property plant and equipment		439.9		333.3
Depreciation, property, plant and equipment		118.8		95.2
Increase decrease depreciation property plant and equipment		12.5
Plate Mill Modernization [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Additions in property plant and equipment		131.4
Construction in progress		59.3		33.1
Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Quarterly impact on depreciation property plant and equipment	$ 6.1
Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Quarterly impact on depreciation property plant and equipment	$ 6.4
Electric Arc Furnace [Member] \| Plate Mill Modernization [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Additions in property plant and equipment		0.0		41.4
Government Funding Agreements [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment, expenditures recognised in course of its construction								$ 30.0	$ 120.0
Construction in progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Payments for construction in progress		204.4		188.7
Inventories [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Depreciation, property, plant and equipment		13.9		9.7
Property Under Construction For EAF [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Government grants in respect of property plant and equipment value		51.7		37.6
Purchase of property plant and equipment		$ 206.0		$ 215.7
CANADA \| Electric Arc Furnace [Member] \| Canada Infrastructure Bank Fund [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Borrowings						$ 200.0
CANADA \| Electric Arc Furnace [Member] \| Strategic Innovation Fund [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Borrowings						220.0
CANADA \| Government Funding Agreements [Member] \| Electric Arc Furnace [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Borrowings						$ 420.0	$ 420.0

Administrative and Selling Expenses - Additional Information (Detail) - Selling, general and administrative expense [member] $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($)
Statement [Line Items]
Past service cost	$ 5.4
Pension defined benefit plans [member]
Statement [Line Items]
Past service cost	5.0
Post-employment medical defined benefit plans [member]
Statement [Line Items]
Past service cost	$ 0.4

Net Income Per Common Share

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Net Income Per Common Share

27.	NET INCOME PER COMMON SHARE

The following table sets forth the computation of basic and diluted net income per common share:



Year ended,	March 31, 2024			March 31, 2023
(in millions)

Net income attributable to ordinary shareholders	$	105.2		$	298.5

Gain on change in fair value of warrants (i)		(12.1	)		(47.7	)


Net income attributable to ordinary shareholders (diluted)	$	93.1		$	250.8


(in millions)

Weighted average common shares outstanding (ii)		108.4			122.7

Dilutive effect of warrants, restricted share units and performance share units (i) (ii)		24.6			24.3


Dilutive weighted average common shares outstanding		133.0			147.0


Net income per common share:

Basic	$	0.97		$	2.43

Diluted	$	0.70		$	1.71

(i)

(ii)

For the year ended March 31, 2024, the total weighted average common shares issued and outstanding is 103,793,360 (March 31, 2023 – 117,945,286).

The Company issued earnout rights and Replacement LTIP awards in connection with the Company’s merger transaction from fiscal 2022. For the year ended March 31, 2024, 1,404,357 (March 31, 2023 – 1,557,026) weighted average earnout rights have been included in the calculation of basic and diluted net income per common share. Replacement LTIP awards are included within the weighted

average

common shares outstanding, as the Replacement LTIP Awards are fully vested and exercisable for a nominal price. For the year ended March 31, 2024, 2,925,499 (March 31, 2023 - 3,100,535) weighted average

Replacement LTIP awards have been included in the calculation of basic and diluted net income per common share. See Note 31 and Note 32.

The Company also routinely grants DSUs to Directors of the Company under its Omnibus Equity Incentive Plan (“Omnibus Plan”). DSUs as vested to various Directors of the Company in respect of their annual retainers. The DSUs recognized under the Omnibus Plan are included within the weighted average common shares outstanding, as the units are exercisable for no consideration. For the year ended March 31, 2024, 272,166 (March 31, 2023 – 108,628) weighted average DSUs have been included in the calculation of basic and diluted net income per common share. See Note 34.

Accounts Payable and Accrued Liabilities (Tables)

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Summary of Accounts Payable and Accrued Liabilities



As at,	March 31, 2024		March 31, 2023

The carrying amount of:

Accounts payable	$	142.0	$	59.8

Accrued liabilities		80.5		74.9

Wages and accrued vacation payable		64.3		69.9


	$	286.8	$	204.6

Financial Instruments - Summary of Detailed Information Financial Assets And Liabilities Classified And Measured (Detail) - CAD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Financial assets at amortised cost, category [member] \| Cash [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial assets - Carrying Value	$ 97.9	$ 247.4
Financial assets - Fair Value	97.9	247.4
Financial assets at amortised cost, category [member] \| Restricted Cash [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial assets - Carrying Value	3.9	3.9
Financial assets - Fair Value	3.9	3.9
Financial assets at amortised cost, category [member] \| Trade receivables [member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial assets - Carrying Value	246.7	291.2
Financial assets - Fair Value	246.7	291.2
Financial liabilities at amortised cost, category [member] \| Bank Indebtedness [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	0.3	1.9
Financial liabilities - Fair Value	0.3	1.9
Financial liabilities at amortised cost, category [member] \| Accounts Payable and Accrued Liabilities [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	286.8	204.6
Financial liabilities - Fair Value	286.8	204.6
Financial liabilities at amortised cost, category [member] \| Current Portion Of Governmental Loans [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	16.2	10.0
Financial liabilities - Fair Value	16.2	10.0
Financial liabilities at amortised cost, category [member] \| Current portion of financing arrangement [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	0.9	0.0
Financial liabilities - Fair Value	0.9	0.0
Financial liabilities at amortised cost, category [member] \| Long Term Governmental Loans [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	127.4	110.4
Financial liabilities - Fair Value	127.4	110.4
Financial liabilities at amortised cost, category [member] \| Longterm portion of financing arrangement [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	10.4	0.0
Financial liabilities - Fair Value	10.4	0.0
Financial Instruments Measured At Fair Value Through Profit Or Loss Category [Member] \| Warrant Liability [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	44.9	57.3
Financial liabilities - Fair Value	44.9	57.3
Financial Instruments Measured At Fair Value Through Profit Or Loss Category [Member] \| Earnout Liability [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	13.8	16.8
Financial liabilities - Fair Value	13.8	16.8
Financial Instruments Measured At Fair Value Through Profit Or Loss Category [Member] \| Share Based Payment Compensation Liability [Member]
Disclosure Of Detailed Information Financial Assets And Liabilities Classified And Measured [Line Items]
Financial liabilities - Carrying Value	31.9	33.5
Financial liabilities - Fair Value	$ 31.9	$ 33.5

Capital Management

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Capital Management

5.	CAPITAL MANAGEMENT

The Company’s objectives when managing capital are:

(a)

to maintain a flexible capital structure which optimizes the cost of capital at acceptable risk;

(b)

to meet external capital requirements on debt and credit facilities;

(c)

to ensure adequate capital to support long-term growth strategy; and

(d)

to provide an adequate return to shareholders.

The Company continuously monitors and reviews the capital structure to ensure the objectives are met.

Management defines capital as the combination of its indebtedness, as disclosed in Note 15, its governmental loans, as disclosed in Note 18 and the equity balance, as disclosed in Note 26. The Company manages the capital structure within the context of the business strategy, general economic conditions, market conditions in the steel industry and the risk characteristics of assets.

The Company is in compliance with the covenants under its existing debt agreements at March 31, 2024 and March 31, 2023, as disclosed in Note 15.

Bank Indebtedness (Tables)

12 Months Ended

Mar. 31, 2024

Disclosure Of Bank Indebtedness [Line Items]

Summary of Company's Bank Indebtedness Arising from Financing Activities

The changes in the Company’s bank indebtedness for the year ended March 31, 2024 arising from financing activities are presented below:



Balance at March 31, 2022	$	0.1

Revolving Credit Facility drawn		44.8

Repayment of Revolving Credit Facility		(43.0	)



Balance at March 31, 2023	$	1.9


Revolving Credit Facility drawn		48.1

Repayment of Revolving Credit Facility		(49.8	)

Foreign exchange		0.1



Balance at March 31, 2024	$	0.3

Interest On Pension And Other Post-Employment Benefit Obligations

12 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Interest On Pension And Other Post-Employment Benefit Obligations

10.	INTEREST ON PENSION AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS



Year ended,	March 31, 2024		March 31, 2023

Interest on pension and other post-employment benefit obligations is comprised of:

Interest on defined benefit pension obligation (Note 20)	$	8.6	$	7.3

Interest on other post-employment benefit obligation (Note 21)		10.7		9.9


	$	19.3	$	17.2

Share-Based Payment Compensation Liability - - Additional Information (Detail) $ / shares in Units, $ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2024 CAD ($) shares	Mar. 31, 2023 CAD ($) shares	Mar. 31, 2024 USD ($) shares $ / shares	May 31, 2023 CAD ($)	May 31, 2023 USD ($)	Mar. 31, 2022 shares
Shared Based Payment Compensation Liability [Line Items]
Liabilities \| $	$ 1,173.6	$ 993.4
Replacement Long Term Incentive Plan Awards [Member]
Shared Based Payment Compensation Liability [Line Items]
Number of other equity instruments outstanding in share-based payment arrangement \| shares	2,776,868	3,059,643	2,776,868			3,232,628
Number of other equity instruments granted in share-based payment arrangement \| shares	0
Number of instruments other equity instruments settled value \| $		$ 4.6
Replacement Long Term Incentive Plan Awards [Member] \| Share Based Payment Compensation Liability [Member]
Shared Based Payment Compensation Liability [Line Items]
Loss (gain) on earn out liability \| $	$ 1.2	$ (12.7)
Number of other equity instruments outstanding in share-based payment arrangement \| shares	2,776,868		2,776,868
Estimated fair value of other equity instruments outstanding in a share based payment arrangement \| $ / shares			$ 8.49
Liabilities	$ 31.9		$ 23.6	$ 33.5	$ 24.7