Paper No. 24
Presentation Time: 9:00 AM-6:30 PM


WILSON, Anna Burack, U.S. Geological Survey, Central Mineral and Environmental Science Center, Box 25046, MS 973, Denver Federal Center, Lakewood, CO 80225,

Historically, mining was a major and diverse industry in southwest Wyoming, but in recent years only a few mineral resources (other than coal) are actively being sought or exploited. Within the Wyoming Landscape Conservation Initiative (WLCI), there are 16 regions, covering less than 20% of the total study area, where interest in mineral resources is, or has been, concentrated. Current significant mining activity for trona (soda ash) and uranium in the WLCI is focused in only 3 of the 16 regions. Near-future activity, although uncertain, is likely to be sought on a large-scale for only trona and uranium. Other industrial minerals, such as sand and gravel, stone, gypsum, barite, etc. are not included in this study.

The world’s largest trona deposit (covering almost 3,600 km2), located in the southwestern part of WLCI, remains an economically viable commodity in today’s market. Uranium exploration was intense in the late 1950s into the 1970s, with activity in Ketchum Buttes, Poison Basin, Crooks Gap-Green Mountain, Shirley Basin, and Great Divide Basin. Today, the major mines in Crooks Gap-Green Mountain are either reclaimed or idle, Shirley Basin has been almost entirely reclaimed, and Ketchum Buttes appears abandoned, but there are proposed in-situ recovery projects being pursued in Great Divide Basin and Poison Basin.

Base- and precious-metals (gold, silver, copper, lead, zinc resources) are in the Lake Alice, Encampment, Seminoe, Iron Formation NE, Big Creek, Cooper Hill, Gold Hill, Herman, and Keystone mineralized areas. Most of these mineral “districts” were first explored and developed in the late 1800s and abandoned by the early 1900s. Some of them were re-explored or reactivated in the World War II era. Only a few were active in the 1970s to 1980s and nearly all have been abandoned. All the phosphate mines (such as at Leefe and South Mountain) and prospects in the western part of the study area appear to have been either abandoned or reclaimed.