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Men and a bulldozer, Los Ochos mine, 1959, Colorado Mining Association Collection, Colorado School of Mines


Los Ochos Uranium Mine

The Los Ochos mine is an inactive uranium mine located in Saguache County, Colorado, approximately twenty miles from Gunnison, CO.

Craig S. Goodknight, “Uranium in the Gunnison County, Colorado," in Western Slope Colorado, eds. Rudy C. Epis and Jonathan F. Callender, New Mexico Geological Society Guidebook 32nd Annual Fall Conference, 1981, accessed June 22, 2021, https://nmgs.nmt.edu/publications/guidebooks/downloads/32/32_p0183_p0190.pdf.Uranium deposits were discovered at Los Ochos in 1954 and the mine was in operation until 1962. Uranium prospecting spread eastward from the Colorado Plateau in the middle and late 1950s to a more hard-rock environment in the area surrounding Gunnison. Subsidized by the U.S. government, mining spread throughout the Gunnison Valley. Craig S. Goodknight, “Uranium in the Gunnison County, Colorado," in Western Slope Colorado, eds. Rudy C. Epis and Jonathan F. Callender, New Mexico Geological Society Guidebook 32nd Annual Fall Conference, 1981, accessed June 22, 2021, https://nmgs.nmt.edu/publications/guidebooks/downloads/32/32_p0183_p0190.pdf.The Los Ochos mine resides in the Cochetopa Uranium District, one of two major uranium districts (along with Marshall Pass) established during that time.

The U.S. Bureau of Land Management (BLM) oversees the land that Los Ochos occupies. The natural environment surrounding the mine site is an arid, sagebrush steppe ecosystem. Plants found on site include sagebrush, rabbitbrush, and yucca. Waste rock piles are scattered over the site, and the physical geography creates erosion ditches that extend the runoff of radioactive uranium deposits downslope into areas of vegetation. Wood and metal debris from mining operations are abundant, found dispersed across the site.

The Department of Energy (DOE) inventory of the site maps the perimeter of the mining area and identifies geo-located mining-related features, such as open shafts, closed adits, a trestle, open pits, trenches, and waste rock dump piles. Dosimeter testing shows the site is still radioactive, and the DOE has indicated plans to conduct a gamma radiation survey and collect soil samples from waste rock piles in 2021. This information will be used to create a more comprehensive profile of the disturbed area to better inform future management decisions.

In the popular outdoor recreation landscape of Western Colorado, abandoned mines such as Los Ochos may receive increased visitation, and thus pose unique risks to recreationists. As a destination, the Los Ochos mine site features expansive mountain views, past mining structures, and close proximity to a network of BLM roads popular for recreation. There is currently no information posted to communicate to visitors that the site is radioactive, nor other dangers to long-term (overnight) visitors.

The Los Ochos mine site is easily accessible and marked by a BLM sign that designates the multiple modes of transportation permitted on the dirt road, including hiking, horseback riding, bicycling, dirt bike riding, ATV and OHV use. As of 2020 this is the only informational signage at the site. The road leads into the disturbed area, where there is minimal tree coverage and uneven terrain. Fire rings are commonly found on site, indicating overnight camping use. Dispersed camping is permitted on public lands, away from developed recreational facilities. The BLM allows for stays up to 14 days at a time at a specific location. These dispersed sites and any associated hazards are not marked.

The BLM has addressed problems caused by the region's mining legacy by removing metals, unsafe structures, and radiation debris, sealing mine entrances, stabilizing slopes, and planting vegetation to absorb further contamination and erosion. While the BLM has pursued mine reclamation projects in the American West due to ecological concerns, the Bureau increasingly contends with safety issues surrounding the growing recreational visitation to mines. 

The nonprofit Western Alliance for Restoration Management (WARM) seeks to clean up Colorado’s abandoned mine legacy using best practices, such as re-grading to discourage recreational use, closing mine entrances, and installing gates to allow bats to move in and out of the mine shaft to their roosts. In collaboration with Western Colorado University, state and federal agencies, and the private sector, WARM is pursuing funding to initiate a remediation project at the Los Ochos Mine. Options include developing educational signage, removing hazardous structures, and implementing a re-vegetation plan that would improve the condition of the mine and better accommodate users.


"A Threatening Legacy: Tens of Thousands of Abandoned Mine Lands Pose Serious Risks to Our Environment and Our Health." AbandonedMines.gov. Accessed April 13, 2021.

Goodknight, Craig S. “Uranium in the Gunnison County, Colorado.” In Western Slope Colorado, eds. Rudy C. Epis and Jonathan F. Callender, 183-190. New Mexico Geological Society Guidebook 32nd Annual Fall Conference, 1981. Accessed March 22, 2021.

The Western Alliance for Restoration Management. Accessed March 22, 2021.

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