Wyoming

WYOMING (EN: Wyoming; RU: Вайоминг) is the uranium ore region, the second according to the significance (after the Colorado plateau) on the territory of the USA. The region includes the deposits: Gus Hills, Shirley Basin, Crooks Gap, Powder River Basin, and others. For the first time, the uranium mineralization has been uncovered during the 1936; most of the deposits have been discovered during the period of 1951-59. The deposits are situated within the intermountain depressions, which are filled with the fluvial depositions. The mineralization is mostly confined to the Lower Carboniferous Madison formation, to the Eocene Wind River and Wasatch formations, and to the Miocene Browns Park formation. The uranium-containing rocks are represented mostly as the arkose sandstones and conglomerates, which are interlaying with argillites and aleurolites. With the rare exclusions, the layers are embedded horizontally. The ore bodies, which are having the shape of the rolls, lenses, and ribbon-shaped depositions, are located at the depths from several metres to 300 metres below the surface. The length of these ore bodies is usually measured as the hundreds of metres, the width is measured as the tens of metres, and the average thickness does not exceed 3.5 metres.

The main ore minerals are uraninite (pitchblende) and coffinite; there associate with them carnotite, tyuyamunite, and also the sulfides of molybdenum, arsenic, and cobalt. The reserves of uranium (in terms of the metal) are estimated at 83 thousand tonnes, including 51 thousand tonnes at the deposits, which are being operated. The average content of uranium within the ore is 0.15%. Approximately 45% of all the reserves are accessible for the development with the usage of the opencast method. The main deposits, namely, Gus Hills and Shirley Basin, have the reserves of 7.6 and 3.9 thousand tonnes, with the content of the metal within the ore of 0.204 and 0.127%, respectively. Besides these deposits, the great amount of the uranium ore is being extracted at the Crooks Gap, Powder River Basin, and other deposits. The development is conducted with the usage of the opencast and underground methods. The ore, which has been extracted, is processed at several hydrometallurgical plants, with the total productive capacity of 9 thousand tonnes of the ore per day. There is mostly used the acidic scheme with the ion-exchange extraction. The marketable product is the chemical concentrate with the 75% content of the U3O8 compound. Approximately 3% of the metal is being extracted with the usage of the method of the heap leaching, and of the underground leaching. During the 1976, there have been extracted 3392 tonnes of the U3O8 compound.