Portal, Leadville Mine Drainage Tunnel
Portal, Leadville Mine Drainage Tunnel

Leadville Mine Drainage Tunnel and Treatment Plant Information


Since 1992, water treatment technologies have evolved and new treatment technologies may provide a better alternative than the current treatment process provides. During the Spring of 2018, Reclamation will study new processes for treating water from the tunnel to determine whether new technologies or combinations of processes might offer increased efficiency and optimization to treat the tunnel water in the future. In addition, Reclamation will be investigating the potential of adding a plug in the mine drainage tunnel just below the pump installed by EPA in 2008. This investigation will occur during the summer and fall of 2018.

Reclamation is fully committed to ensuring that the Leadville Mine Drainage Tunnel Treatment Plant will continue to treat the water from the LMDT and maintain a long-term, on-going commitment to mitigate groundwater contamination and release clean water to the Arkansas River headwaters.


The Leadville Mine Drainage Tunnel, or “LMDT,” was purchased by the Bureau of Reclamation from the Bureau of Mines in 1959. Originally, the Tunnel was a potential source of water for the Fryingpan-Arkansas Project. However, poor water quality required that the water be treated before it could be released to the Arkansas River. As a result, Reclamation designed and constructed the LMDT Treatment Plant. It has been safely and effectively treating water released from the Tunnel to the Arkansas River since 1991.

The tunnel is long, stretching southeast under the Town of Leadville and into an area of the Environmental Protection Agency’s California Gulch Superfund Site known as Operable Unit 6. To learn more about the EPA and the California Gulch, please visit their website at http://www.epa.gov/region8/superfund/co/calgulch/index.html.

Throughout its history, Reclamation has performed monitoring and safety studies on the LMDT. The most recent study, completed in the fall of 2008 concluded that the LMDT continues to operate safely.

Last Updated: 5/7/18