Idarado Mine Cleanup, Two Decades Later
by Watch Staff
Mar 24, 2013 | 2039 views | 0 0 comments | 10 10 recommendations | email to a friend | print

Public Invited to Presentations in Telluride, Ouray Next Week


By Watch Staff


WESTERN SAN JUANS – The Colorado Department of Public Health and the Environment and Idarado Mining Co. present a status report to the public on the 20-year-old Idarado Mine Remediation Project in Telluride on Monday March 25, and in Ouray on Tuesday, March 26.  

Monday’s presentation in the Wilkinson Public Library Program Room at 6:30 p.m. will focus on Idarado’s remediation in the San Miguel River Basin. Tuesday’s presentation in Ouray focuses on Idarado’s remediation in the Red Mountain Creek watershed, and is hosted by Uncompahgre Watershed Partnership at the Ouray Community Center at 7 p.m.  

It’s been 30 years since the State of Colorado sued Idarado for natural resource damages, transforming what was once one of the top gold-producing mines in Colorado into a Superfund site. 

In July 1992, after a decade of legal wrangling, and Idarado and Newmont Mining Corp., its parent company, signed a consent decree with the State of Colorado to settle the lawsuit, with Idarado agreeing to undertake specified remediation work at its former mining site straddling Ouray and San Miguel Counties. The ensuing $20 million cleanup was spelled out in a Remedial Action Plan which got underway exactly 20 years ago, in 1993. 

Lying beneath a high ridge between Red Mountain Pass and Telluride, the Idarado Mine contains more than 80 miles of interconnected drifts or crosscuts. Access to the mine is through either the Treasury tunnel, whose portal is below Red Mountain Pass on U.S. Highway 550 at an altitude of 10,600 feet, or the Mill Level tunnel entrance two miles east of Telluride at an altitude of 9,060 feet. The two tunnel entrances are connected via six miles of interconnecting drifts and raises.

During its most productive years, according to one account, the Idarado ranked first or second in Colorado in yearly production of gold, silver, copper, lead, and zinc. The mine operated until 1978.

Reclamation efforts, as outlined on the CDPHE’s website, included revegetating 11 large lead-contaminated tailings piles in Ouray and San Miguel Counties, clearing sediments from the underground mine, diverting surface runoff around historic mine waste rock and portals, and re-routing internal mine waters away from highly mineralized regions in the vast underground workings.

The Idarado Mine’s Remedial Action Plan was completed by 1998 and deemed largely successful by the Colorado Department of Public Health and the Environment, which continues to closely monitor the project area for water quality, revegetation and site maintenance.

The health of the two watersheds impacted by the Idarado tells the tale of a project whose success remains somewhat skewed.

The San Miguel River has been shown to meet the performance objectives specified in the cleanup plan, as has the revegetation of the tailing piles along the San Miguel River and Red Mountain Creek, said Camille Price, the CDPHE manager overseeing the project.

Remediation in the Red Mountain watershed, meanwhile, is still ongoing due to significant zinc loading in several segments of Red Mountain Creek. According to the CDPHE, Idarado is currently working with the State to conduct additional investigation and remediation in order to meet the performance objectives specified in the cleanup plan. This work will be guided by the report, “Evaluation of Zinc Loading for Red Mountain Creek,” which was completed in December 2012.  

The report represents the results of a water quality sampling investigation during low-flow conditions in late September 2012, and describes further sampling and investigations to be conducted in 2013 to confirm the report findings and develop information necessary to evaluate potential remedial measures. 

The report is available to the public on UWP’s Documents site at

“Many people, including myself, have worked on the Idarado project for over 20 years,” said Price. “I am thankful for Idarado’s commitment to meeting the water quality and tailings vegetation improvements agreed upon in the Consent Decree, and for the positive results we see from all the work completed in our important headwater regions.”  

Everyone is welcome to attend the upcoming free public forums.  For more information, please contact Price at 

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