Economy, Mining

In the early 1990s the most important nonfuel minerals (with annual production in metric tons) included gypsum (532,000), rock salt (895,000), limestone (8.8 million), and silica sand (154,000). In 1999 coal production was 3.47 million metric tons, crude petroleum production reached 20.8 million barrels, and production of natural gas was 22.1 billion cubic meters (780 billion cubic feet).