Between 1871 and 1935, an estimated 8.6 million short tons of mine tailings were deposited directly into the Animas River. Decades of industrial and mining impacts brought myriad environmental regulations, but none that required mining companies to reclaim the disturbed land and tailing piles. In the Animas Watershed, an estimated 5,397 mine shafts, adits, and tunnels created new pathways for increased water flow through the rocks and reduced weathering process time to years. Many of the tailing piles remain in the same location for decades, slowly eroding into the watershed. Thus, acid mine drainage has been chronic in the Animas Watershed for more than a century.
On August 5, 2015 while assessing the feasibility for mine remediation, the U.S. Environmental Protection Agency (EPA) accidentally triggered the release of mine-impacted water from the Gold King Mine in Silverton, Colorado. Over a seven-hour period approximately three million gallons of acid mine waste flowed from Cement Creek into the Animas and then San Juan Rivers and ultimately ended up in Lake Powell in Utah. Numerous federal, state, and mainly, local agencies responded.
The Gold King Mine release created a spike in dissolved heavy metals in the waterway, most coming from the rapid erosion of the adjacent mine tailing piles. According to an EPA report, mines in the Upper Animas Watershed discharge an average of 5.4 million gallons per day. The volume of the release was equivalent to four days of current acid mine drainage (EPA, 2016).
Monitoring started immediately following the spill and is still ongoing. Several agencies and universities analyzed soil and water samples to understand the fate of the metals from the Gold King spill. Water and soil samples were collected at 310 locations between the Gold King Mine and Lake Powell. The results of the continued monitoring suggest that metals from the Gold King Mine spill were flushed from the rivers and delivered to Lake Powell by the end of May 2016.
Members of the community are concerned with the negative attention the event brought to the area, particularly the impact on agriculture. Researchers assured the audience that in fact, there appears to be no negative impacts on agricultural products from the area from the Gold King Mine release. However, researchers are still concerned about the social and economic fall-out from the spill. During the final conference panel discussion, those involved in the response to the Gold King Spill provided their perspective on what would help make the community whole again. Community members in attendance were encouraged to direct concerns and questions to the panel. The State of New Mexico continues to seek compensation from the EPA for those who have been damaged. Preparedness was a common theme in the discussion, in particular, the ability of the EPA to coordinate response efforts more effectively in situations where watersheds cross multiple EPA regional jurisdictions (three for the Gold King Mine). Navajo agriculturalists have concerns with water quality and the emotional impacts from the spill. Outreach efforts are underway by extension agents and citizens’ advisory committees to ease concerns over water quality.
The problem of acid mine drainage is this region is well known, and the spill brought heightened awareness to communities and researchers. Emergency response to potential future releases is being improved. The EPA designated the Gold King Mine a Superfund site, and it now operates a treatment facility to manage water from the Gold King Mine. Further work needs to be done to address the hundreds of other mines that are actively discharging acid mine drainage into the Animas Watershed.
A third conference will be held in the summer of 2018.
For links to the presentations click here.
Environmental Protection Agency (EPA). 2016. One Year After the Gold King Mine Incident: A Retrospective of EPA’s Efforts to Restore and Protect Impacted Communities. August 1, 2016. https://cfpub.epa.gov/si/si_public_file_download.cfm?p_download_id=530074