The USGS Water Science School
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Mining water use
Hydraulic mining at the Malakoff Diggings in the foothills of the Sierra Nevada. Like all other industries, mining corporations need water to make bare rock give up its valuable minerals. Mining has played an important part in the development of this Nation. Even before the first European settlers set foot on this continent and mined coal to heat their homes, Native Americans were using coal to bake clay for vessels. The United States now produces a wide variety of mined commodities from gold to coal to "exotic" minerals used in everything from pharmaceuticals to jewelry to high-tech products. All these products would not be possible without the use of water in mining.
Mining withdrawals for the Nation, 2005
During 2005, an estimated 4,020 million gallons per day (Mgal/d) was withdrawn for mining purposes. (All 2005 water use information is from the report Estimated use of water in the United States in 2005.) Mining withdrawals were about 1 percent of total withdrawals and about 2 percent of total withdrawals for all categories excluding thermoelectric power. Groundwater was the source for 63 percent of total withdrawals for mining. Sixty percent of the groundwater withdrawals for mining were saline. Most of the surface-water withdrawals (87 percent) were freshwater. Saline groundwater withdrawals and fresh surface-water withdrawals together represented 70 percent of the total withdrawals for mining. Mining withdrawals, by State, 2005
Texas, Minnesota, and California accounted for 34 percent of the total withdrawals for mining. Sand and gravel operations in Indiana and iron ore mining in Michigan and Minnesota accounted for the largest fresh surface-water withdrawals. Mineral salt extraction from the Great Salt Lake in Utah accounted for the largest saline surface-water withdrawals for mining in the United States. Florida, Ohio, Nevada, Arizona, and Pennsylvania accounted for 52 percent of fresh groundwater withdrawals. Gas and oil operations in Texas, California, Oklahoma, Wyoming, and Louisiana were responsible for the large saline groundwater withdrawals in those States, because saline water is a byproduct of mining operations.
About 52 percent (1,390 Mgal/d) of groundwater mining withdrawals were considered saline in 2000; in 2005 about 60 percent (1,520 Mgal/d) of groundwater mining withdrawals were considered saline. Estimated surface-water mining withdrawals that were considered saline decreased from 238 Mgal/d in 2000 to 190 Mgal/d in 2005, but in both years saline surface water represented 13 percent of the total surface water used for mining.
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