A discussion of Wyoming's geology would not be complete without elaborating on the treasure house of valuable minerals and rocks located in the state. Wyoming is perhaps best known for its abundance of energy minerals. Vast reserves of oil, natural gas, coal, and uranium underlie many areas of the state. Wyoming's more than 1,000 oil and gas fields produce more than 50 million barrels of oil and more than 2.4 trillion cubic feet of natural gas each year: the state ranks first in the Rocky Mountain region. Wyoming has more than doubled its proved reserves of natural gas in the last 10 years, thanks mainly to the development of coal bed natural gas (CBNG) in the Powder River Basin, and the development of tight gas sands in the Lance Formation at Jonah and Pinedale fields in the northern Green River Basin. Wyoming's 29.7 trillion cubic feet of proved natural gas reserves is second to only Texas, and is enough to supply the entire United States for more than a year and a half. The state's petroleum industry also produces large quantities of helium and carbon dioxide, as well as by-product sulfur from sour-gas processing plants.
The state also hosts 25 percent of the nation's coal resources, or more than one trillion tons of coal. From this resource, coal companies mine more than 450 million tons of coal each year, ranking Wyoming first in coal production since 1988. More than 98 percent of Wyoming's coal production comes from Campbell and Converse counties in northeastern Wyoming's Powder River Basin. This Powder River Basin production comes from mines on the Wyodak coal deposit. Fifty to 110 feet thick where it is mined, the Wyodak is the thickest coal mined in the United States.
Although Wyoming’s annual uranium production has declined substantially from its peak in the early 1980s, the state is still a major uranium producer. In addition to these actively mined energy resources, Wyoming has a vast untapped resource of oil shale beneath the Green River and Washakie basins of southwestern Wyoming.
Wyoming's mineral wealth does not stop at energy resources: the world’s largest known trona resource is found in the Green River Basin of southwestern Wyoming. Trona is a naturally-occurring hydrated sodium carbonate and sodium bicarbonate used to produce industrial soda ash. Soda ash is vitally important in the glass, paper, soap, petroleum-refining, and textile industries. Baking soda is also a product of soda ash. Presently, five underground trona mines in Wyoming together produce approximately 17.5 million tons of trona each year, more than 95 percent of U.S. production. Soda ash is also exported to a number of countries. Wyoming is also the largest producer of bentonite, a valuable expanding clay, in the country. When mixed with water, Wyoming bentonite expands up to 15 times its dry volume. This unique clay is very useful in drilling muds used by the petroleum industry, for pelletizing taconite in the iron ore industry, and for binding foundry sands.
Limestone, gypsum, construction aggregate, jade, and some placer gold are also mined in Wyoming. Many other valuable mineral resources occur in Wyoming, including copper, iron ore, silica sand, molybdenum, feldspar, phosphate rock, anorthosite (an aluminum-rich rock), and diamond. Although the first seven of these mineral resources have been mined in the past, the economic value of Wyoming's diamond occurrences is still being evaluated.
The diversity of Wyoming's mineral resources constitutes one of the state's
greatest long-term economic assets. Few other states have such a variety of
presently or potentially economic resources with which to meet changing market