The U.S.S.R. has maintained its position as the world's leading producer of iron, manganese and chromium ores, pig iron, crude steel, platinum-group metals, lead, potassium salts, and cement. It occupies second place, following the United States, in world output of aluminum, copper, petroleum, natural gas, coal, and phosphate rock; it ranks after Canada in the production of zinc, nickel, silver, and asbestos; and it follows South Africa in gold production. The expansion of the mineral industry continues to be achieved mainly through increased labor and capital rather than through advancing technology. The productivity of labor and equipment is below planned levels, and practically all sectors of the mineral industry maintain greater numbers of production personnel than called for by plan targets. During the present (1971- 75) five-year plan, however, efforts are being made to increase recoveries, and of the planned rise in production, about half is expected to come from improved productivity and technology, the balance from new investment. Soviet mineral policy has continued to emphasize maximum self-sufficiency. It has become the most self-sufficient of the world's leading industrial nations in minerals and metals.