Uranium mining in southwest Colorado is as much a part of the region’s history as the iconic Dolores River. The U.S. Department of Energy (DOE) Office of Legacy Management (LM) is currently working towards protecting the Dolores River by addressing sedimentation issues stemming from the historic Burro Mines Complex in San Miguel County, Colorado.  

The Burro Mines Complex includes three separate and distinct uranium mine sites: the Burro Tunnel Mine, the Burro No. 3 Mine, and the Burro No. 5 Mine. The Burro Tunnel Mine site is located along the east side of County Road S8, which is adjacent to the Dolores River.  

The Bureau of Land Management (BLM) and the Colorado Division of Reclamation, Mining and Safety (DRMS) consider the sites as legacy, or “pre-law,” mines, because they operated prior to the present era of permitting by the Colorado DRMS. As such, there are no requirements for reclamation, and the mines could remain in their current condition. Nevertheless, to protect the Dolores River from further sediment, LM intends to begin work on a reclamation at the mine complex later this year. 

“LM’s goal with this project is to protect the Dolores River from further sediment load running off from legacy waste rock at the Burro Mines Complex,” said Deborah Barr, the program manager for the LM Uranium Leasing Program. “The health of this river corridor impacts the habitat for wildlife and recreational usage. LM is working hard to accomplish these goals while preserving the unique mining heritage of this area.” 

The project is the culmination of several years of planning. In 2019, LM began drafting an Environmental Assessment (EA) for the project in accordance with the National Environmental Policy Act (NEPA). As part of the EA process, LM made the draft EA available for public review and comment last summer. Based on the EA findings, this reclamation project does not constitute a major federal action significantly affecting the quality of the human health and the environment within the context of NEPA. LM is expected to sign a Finding of No Significant Impact at the end of March 2021. 

Collaboration has been a key element of the reclamation project. LM has engaged with BLM, Colorado DRMS, the Colorado State Historic Preservation Office (SHPO), the San Miguel County Planning Department, and the public to better understand any potential impacts of the project on the environment and community.  

For instance, ongoing collaboration with Colorado SHPO resulted in significant changes to the engineering design in order to protect the historical integrity of the mine complex. Working closely with Colorado SHPO, LM revised the engineering design to better preserve the area’s unique mining heritage, while still protecting the Dolores River.  

The Burro Mines Complex is on land that LM manages as part of its Uranium Leasing Program (ULP). The ULP includes 31 lease tracts within the Uravan Mineral Belt of southwestern Colorado. The Burro Mines Complex is within DOE lease tract C-SR-13.