 Roe.By the mid-1960s, it identified the coal mines and steel mill on Cape Breton Island for closure; these operations were nationalized by the federal and provincial governments under the Cape Breton Development Corporation (DEVCO) and Sydney Steel Corporation (SYSCO) respectively in 1968.Hawker Siddeley shares in what was left of DOSCO were purchased that year by Sidbec, a provincial Crown corporation in Quebec, which sought to nationalize DOSCO operations in that province.