The Koehler Junction site is located within the Bonita Peak Mining District Superfund Site, and consists of three mines: Koehler Tunnel, Junction Mine, and Longfellow Mine. The Koehler Junction site is a popular recreational area and is commonly used for dispersed camping. Visitors to the area may be exposed to hazardous substances and contaminated mine waste that is present on site. The three mines are co-located at the headwaters of Mineral Creek, approximately 6 miles north-northwest of Silverton, San Juan County, Colorado, and are situated along Red Mountain Pass just east of Highway 550 at latitude 37°53'45.25" N and longitude 107°42'42.46" W at an elevation of approximately 11,100 to 11,600 feet above mean sea level.
The Koehler Tunnel is a draining adit that drains into a pond, which also collects water from the Junction Mine. The tunnel has a hydrologic bulkhead 300 feet inside the portal that prevents most of the mine drainage from draining out the tunnel, but there still remains some mine drainage at the site. The Koehler waste rock pile was relocated to the Mayflower tailings pond in 1997. The EPA installed a culvert at the Koehler, Junction, and Longfellow Mines in 2020 and periodically removes sediment from the pond.
EPA is planning a time-critical removal action this summer. Construction work will include installing additional ground support and reinforcing the
portal shed at the Koehler Tunnel. This work includes reinforcing the portal shed, improving drainage, and installing rock bolts/mine mesh to provide more permanent support within the tunnel. The construction is expected to last approximately three weeks and no road closures are anticipated at this time. This work is important for long term stability of the adit, and supports further assessment work within the tunnel, necessary to cleanup of the Bonita Peak Mining District Superfund Site.
