Peru Basin acid mine drainage cleanup update

From the Environmental Protection Agency via Summit County (Brian Lorch):

The U.S. Environmental Protection Agency (EPA) is taking immediate action to perform mine cleanup activities at the Jumbo Mine in Summit County’s Peru Creek Basin, approximately seven miles east of Keystone Resort.

The Jumbo Mine, which produced gold, copper, lead and silver, operated from 1915 to 1918. Historic mine operations also generated significant volumes of waste rock and tailings piles. Inactive and abandoned for a century, the mine site was identified in the early 1990s by EPA and the Colorado Department of Public Health & Environment (CDPHE), as well as in the Snake River Watershed Plan, as a significant point-source contributor of metal-contaminated flows into Peru Creek and the downstream Snake River.

Historic hard-rock mining in the Peru Creek Basin left a legacy of contaminated and abandoned mine sites, whose acid mine drainage significantly degrades water quality. Much has been done to study the problems in the Snake River watershed, beginning in the early 1970s. Most studies have focused on the Peru Creek drainage, which is home to the Pennsylvania Mine, the largest, longest-operating mine in the watershed. In coordination with Summit County and the Colorado Division of Reclamation, Mining and Safety (DRMS), EPA completed cleanup actions at the Pennsylvania Mine in 2016.

The Jumbo Mine is another high-priority abandoned mine site in the Peru Creek Basin identified by the Snake River Watershed Coalition as a remediation project site capable of significantly improving water quality in the Snake River watershed.

Summit County purchased the land surrounding the abandoned Jumbo Mine in early 2016 for public open space. A restrictive covenant placed on the adjacent property containing the abandoned mine site allows for EPA’s cleanup actions to occur, but also limits the County’s liability for the existing environmental issues and associated cleanup actions.

“We had been looking to acquire this piece of property for a long time, recognizing that it has many open space values,” said Brian Lorch, Summit County Open Space and Trails director. “But before we could take steps to purchase the property, we needed to ensure that it could be cleaned up in an economical manner.”

EPA is implementing the cleanup work as a time-critical removal action under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Last week, the agency began the work, which it plans to complete in about three weeks.

Cleanup activities involve diverting water draining from a mine adit around or over adjacent tailings piles in a limestone and membrane-lined ditch. According to EPA studies, water quality of the adit drainage degrades as it crosses the mine tailings, contributing high levels of suspended and dissolved lead, zinc and other metals into the stream. Diverting drainage around the tailings into a lined ditch should greatly improve water quality.

“The overall approach will help reduce the discharge of metals into Peru Creek,” Lorch said. “A passive treatment approach at the Jumbo Mine site is quite similar to numerous mine cleanups performed elsewhere by the County.”

Since 2001, Summit County has worked with EPA to identify and prioritize mine sites in need of cleanup in the Peru Creek Basin. The County’s proactive coordination with EPA facilitated recent cleanup efforts at the Pennsylvania Mine and numerous other sites in the area.

“We are really happy and grateful to see EPA continue its mine cleanup efforts in the Peru Creek Basin,” Summit County Commissioner Karn Stiegelmeier said. “The Summit County community is very supportive of our efforts to clean up abandoned mine sites on County property, voting in 2015 for a mill levy that provides funding for cleaning up mine-impacted sites.”