Mining has been enormously important in British economic history. Salt mining dates from prehistoric times, and in ancient times traders from the Mediterranean shipped tin from the mines of Cornwall. These tin mines are almost completely exhausted today, and the last tin mine in Britain closed in March 1998. Britain's abundant coal resources were critical during the Industrial Revolution, especially because the coal was sometimes conveniently located near iron and could be used in the iron and steel manufacturing processes. These mined resources were so important to the Industrial Revolution that entire populations moved to work at coal and iron sites in the north and Midlands of England. Today the iron is almost exhausted, and even though most good-quality coal seams are depleted, coal is still the third most mined mineral in Britain.
Besides coal, raw materials for construction form the bulk of mineral production, including limestone, dolomite, sand, gravel, sandstone, common clay, and shale. Some china clay and salt are also extracted. Small amounts of zinc, lead, tin, silver, and gold are mined. According to British law, the owners of land have title to the minerals below the surface. The only exceptions are gold, silver, oil, and natural gas, which the Crown owns and leases to producers. Mining and quarrying, including oil and gas extraction, accounted for 2.8 percent of the GDP in 1996 and employed 1 percent of the labor force.