The Green Mountain Mining District site (Site) includes historic mine features within several watersheds south of Jeffrey City, Wyoming where Tronox once operated. The northern portion of Green Mountain slopes from an elevation of about 7,000 feet northward for seven miles to the Sweetwater River at about 6,300 feet. This surface is bounded on the south by the high north facing escarpment of flat-topped erosional mountains collectively called the "Green Mountains" and extends eastward across the south-central part of the range.
Several mining districts are located along the Green Mountains. The individual mountain peaks situated in the Green Mountains (from west to east) are Crooks Mountain, Crooks Peak , Sheep Mountain, Green Mountain, and Whiskey Peak. The western slopes of the Green Mountains are known as the Crooks Gap Mining District (Crooks Gap), which was a prominent mining district in the Green Mountains area from 1954 to 1989. Uranium ore reserves (in situ and mined) were reportedly on the order of 10,000 tons, of which some 8,000 tons were produced by 17 underground mines and open-pit operations. The largest mines in Crooks Gap included Big Eagle Pit, McIntosh Pit, Golden Goose, and Sheep Mountain.
EPA expects to conduct a Removal Assessment in the area in Spring/Summer 2024.
