Mineral resource of the month: sulfur

Since domestic sulfur production peaked at nearly 11 million metric tons in 1974, the sulfur industry has undergone dramatic change. In 1974, mined sulfur produced using the Frasch hot water method provided 8 million tons of sulfur, representing 75 percent of total elemental sulfur production. (In the Frasch process, hot water is injected directly into the sulfur-containing mineral strata, melting the crystalline sulfur, which then lifts to the surface with air.) The remaining 25 percent was produced as byproduct sulfur.