The Shirley Basin is a northwest trending asymmetric basin that formed by subduction-driven Late Cretaceous to early Tertiary tectonism called the Laramide Orogeny. Laramide structuring created the basement cored uplifts that surround the basin. The basin is named for the Shirley Mountains that lie on the southwestern margin. The mountains were named after freighter John Shirley who hauled supplies to homesteaders there in the mid-1800’s (Shirley’s Mountains). The Granite Mountains (aka Sweetwater Arch) lie to the west and Bates Hole, a prominent erosional feature drained by Stinking Creek, is the north margin of the basin. The Laramie Range marks the northeastern and eastern border. Northeast-trending Flat Top anticline is the basin’s structural divide with the Laramie Basin to the south. This feature is part of the Wyoming Lineament which is a broad zone of east northeast-trending folds above a major Precambrian shear zone in central Wyoming formed during the assembly of the Wyoming Craton (Ransome,1915,Blackstone,1983).
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Uranium deposits in the Eocene Wind River Formation were discovered by Teton Exploration in 1955. The leasing boom took off in 1957 with several companies acquiring leases. Utah Mining began underground mining in 1959 in the northwestern part of the district. In 1964 they converted to In-Situ Recovery (“ISR”). This was the first use of the ISR uranium mining technique in the United States. After 1968, Utah Mining began strip mining of the ore. Uranium ore was shipped to the Lucky Mc mill in the Gas Hills, 145 miles west, before an onsite mill was constructed in 1969. The mill began operations in 1971.  Conventional mine operations were suspended by Pathfinder in the 1990s due to low uranium pricing.