Algoma Steel Says it Just Might Restart This 73-Year-Old Blast Furnace

May 27, 2026

Algoma Steel’s No. 6 blast furnace was commissioned in 1953. The company quietly keeps it as a backup. [Soo Today File Photo]

SAULT STE. MARIE, ON – On Jan. 18 of this year, Algoma Steel announced it had permanently shut down its No. 7 blast furnace and its associated coke batteries. That, we were told, was the end of coal-based integrated steelmaking in Sault Ste. Marie. Going forward, Algoma would now make steel in electric arc furnaces (EAFs). The federal and provincial governments had provided a total of $500 million in financing on the understanding that the transition would cut carbon emissions by about 70 per cent. But not so fast. The days of smoke-belching blast furnaces in Sault Ste. Marie – and delivery of raw materials by Great Lakes freighter – may not be over.

Speaking to investors during a conference call last week, Rajat Marwah, Algoma’s chief executive officer, mentioned the possible reactivation of a 73-year-old blast furnace. The company’s No. 6 blast furnace was commissioned in 1953, replacing the aging No. 3 and 4 furnaces. It was superceded in 1975 by No. 7 furnace, which at the time was the largest blast furnace in the British Commonwealth. No. 6 has been left in place for use in case backup was ever needed. Idle for more than a decade around the turn of the millennium, the smaller furnace was briefly restarted in 2008 after a $40-million rebuild. The plan in 2008 was to expand Algoma’s capacity to four million saleable tons, but it was idled once again as an economic downturn affected demand for steel. There was also talk of firing up No. 6 in 2014.

During this week’s presentation to investors, Marwah mentioned No. 6 blast furnace as part of a contingency plan if Algoma has trouble finding enough material to feed its EAFs. In addition to scrap metal, ore-based metallics including direct reduced iron (DRI), hot briquetted iron (HBI) and pig iron may also be fed into EAFs. These materials are valued for their ability to shape the chemical specification of steel at low cost.

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