Animas River Quality

When Sunnyside Mining Company ended operations in Silverton in 1991, it negotiated a court decree to plug mine outlet tunnels, including the main access, the American Tunnel, with bulkheads. But the bulkheads raised the subterranean water level tremendously, increasing pressure that created drainage in nearby mines that had been mostly dry. Since 2004, when treatment of mine drainage ceased at the American Tunnel, discharge has increased to a total of 700 gallons a minute from other mines in the Gladstone area. The American Tunnel still discharges 100 gallons a minute. The water, containing zinc, iron, lead, copper, aluminum, cadmium, and manganese, finds its way to Cement Creek and then to the Animas River. Therefore, according to Peter Butler, a member of the Animas River Stakeholders Group (ARSG) and chairman of the Colorado Water Quality Control Commission, water quality in the Animas has decreased. The water quality at Bakers Bridge in the north Animas Valley is the worst its been in 20 years, he said.

Steve Fearn, also with the ARSG commented that "preliminary analysis of data collected over the last 20 years indicates that water quality at Baker's Bridge has deteriorated since bulkheading of the American Tunnel and cessation of water treatment at Gladstone. Remediation work over the last 20 years by private companies, the ARSG, and public agencies has resulted in significant improvement in water quality in some segments of the upper Animas River basin.” Fearn continued, “however, the issues related to the Gladstone area, where there are several draining mines, may be overshadowing those improvements. The Gladstone situation has been a topic of discussion and investigation by the ARSG and the EPA over the last 6 or 7 years and is considered the single largest loading of metals in the upper Animas Basin, and is apparently being reflected by the water quality measurements at Baker's Bridge."