Dominion Steel and Coal Corporation

The Dominion Steel and Coal Corporation, Limited, known commonly as Dosco, was a Canadian coal mining and steel manufacturing company. Incorporated in 1928 and operational by 1930, DOSCO was predated by the British Empire Steel Corporation (BESCO), which was a merger of the Dominion Coal Company, the Dominion Iron and Steel Company and the Nova Scotia Steel Company. DOSCO was one of the largest private employers in Canada during the 1930s–1950s. In 1957, DOSCO was acquired by Avro Canada, which in 1962 became Hawker Siddeley Canada.

In 1965, Dosco began losing money and the parent company started to liquidate its operations. In 1966 Dosco sold its iron mines to the Newfoundland government and its hydroelectric operations to Nova Scotia Power. The following year it sold its steel to the Nova Scotia government, which created the Sydney Steel Corporation and later in 1968 Lester Pearson's minority government created Cape Breton Development Corporation to take over the coal operations. In December 1968, the corporation, whose sole remaining property was the steel mill at Contrecoeur, was acquired by Sidbec. Subsequently, Dosco was renamed Sidbec-Dosco and continued as a subsidiary of Sidbec. In 1997, the company was acquired by Ispat and renamed Ispat Sidbec, then was renamed Mittal Canada in 2005 and ArcelorMittal Montréal in 2008.

The original legal entity from 1928, which was a Nova Scotia corporation number 1002023, remained in existence until 4 March 2016. At the time it was cancelled, it was called ArcelorMittal Montréal Inc. In 2016, it was imported to federal jurisdiction and merged into ArcelorMittal Canada Inc.