Mines became a separate department in 1939, when Public Works and Mines was broken up and responsibility for public works was transferred to the Department of Highways. The Department of Mines was exclusively responsible for mines and mining, especially in relation to coal. In 1979 the department was restructured as the Department of Mines and Energy, with a view to energy and mineral resources conservation and, especially, petroleum resources development. In 1991 Mines and Energy was merged with Lands and Forests in the new Department of Natural Resources.