PROJECT OVERVIEW

The Upper Blackfoot Mining Complex (UBMC) is a state superfund facility located about 15 miles east of Lincoln. Seeps from the tailings and waste rock dumps along with acid mine drainage from old adits have contaminated surface water, sediments, soils and groundwater. Additional contamination exists due to the 1975 dam failure that washed metals-laden tailings down the Beartrap Creek drainage and into the upper Blackfoot River.

DEQ has led cleanup efforts in coordination with the United States Forest Service (USFS) and Montana Natural Resource Damage Program (NRDP) over the past severalears. The primary goal of the cleanup is to remove approximately 1 million cubic yards of tailings and mine waste to protect human health and the environment. This protection will be accomplished by minimizing direct contact with contaminants and limiting migration and mobility of contaminants within the environment.

HISTORY

The UBMC, also known as the Heddleston District, is an inactive mining district which was mined intermittently from 1889 to the 1950s and explored intermittently up to the present. The UBMC is located in the headwaters of the Blackfoot River in a fairly remote location on and near national forest land, which is used by hunters and other recreationists. The town of Lincoln is about 15 miles downstream.

The main mine workings at the UBMC are the Mike Horse, Anaconda, Carbonate, Edith, Mary P, and Paymaster mines and a tailings impoundment on Beartrap Creek. Tailings are the materials created during the processing of the ore rock. They are generally fine-grained and may contain elevated levels of metals. The historic mining and exploration activities in this area have resulted in numerous tailings and waste rock dumps. Erosion from the tailings and waste rock dumps along with acidic seeps and mine drainage from old adits have contaminated surface water, sediments, soils and groundwater. Additional contamination exists due to the 1975 tailings impoundment failure that washed metal-laden tailings down the Beartrap Creek drainage and into the upper Blackfoot River.

SETTLEMENT

The State of Montana and the USFS successfully reached a settlement with ARCO and Asarco for environmental damages at the UBMC. Claims and interest paid amounted to approximately $39 million. More detail on the settlement can be found at the NRDP website. DEQ will lead cleanup efforts in coordination with the USFS and NRDP.