Belgium's only remaining active mining operations in 2001 were for the production of sand and gravel and the quarrying of some stone, including specialty marbles and the Belgian blue-gray limestone called "petit granite." An important producer of marble for more than 2,000 years, Belgium was recognized for the diversity and quality of its dimension stone. All the marble quarries are in Wallonia, and red, black, and gray are the principal color ranges of the marble. The country was an important producer of such industrial materials as carbonates, including limestone, dolomite, silica sand, whiting, and sodium sulfate.
The mineral-processing industry was a significant contributor to the Belgian economy in 2001. The refining of copper, zinc, and minor metals, and the production of steel (all from imported materials), were the most developed mineral industries in Belgium. The country possessed Europe's largest electrolytic copper and zinc refineries, and one of the continent's largest lead refineries. In addition, Belgium retained its position as the world's diamond capital. Estimated production figures for 2001, in tons, included: secondary copper, 139,000; primary zinc, 230,000; hydraulic cement, 8 million tons; lime and dead-burned dolomite, 1.7 million tons; and quarried Belgian bluestone, or petit granite, 1.2 million cu m. Petite granite, which is actually a dark blue– gray crinoidal limestone, was one of the most important facing stones the country produces.
Belgium was once a major producer of coal, as the Belgian coal mining industry dates back to the 12th century. Coal was mined in the Sambre-Meuse Valley; the last mines closed in 1992. Metallic mining was in its heyday from 1850 to 1870, after which mining activity decreased until the last iron ore operations at Musson and Halanzy were closed in 1978. Belgium has no economically exploitable reserves of metal ores.