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

Leadville Mine Drainage Tunnel and Treatment Plant Information


The existing facility is approaching its 30-year expected service life and has received few upgrades over the years. Reclamation’s Technical Service Center engineers are currently designing a replacement water treatment plant (WTP). Final design, early site preparatory work and preliminary purchase of treatment process equipment components are anticipated to take place in 2021, with construction beginning in 2023. The replacement WTP will bring the facility into compliance with current codes to ensure safety of WTP personnel and the public, will improve and extend plant operations, and will ensure ongoing compliance with the EPA’s National Pollutant Discharge Elimination System (NPDES) permit.

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: 12/15/20