Upper Blackfoot Mining Complex CECRA Facility (UBMC)
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.
The Department of Environmental Quality (DEQ) will lead cleanup efforts in coordination with the United States Forest
Service (USFS) and Montana Natural Resource Damage Program (NRDP) over the next few years. The primary goal of the
cleanup is to remove approximately 1 million cubic yards of tailings and mine waste for protection of 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 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 contain metals at levels that are toxic to human health and the environment. 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.
Click map above for larger view of area descriptions.
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.
What's New?
Waste Repository Selected
After preparing a technical analysis and considering public comments, the USFS has selected Section 35 as the most
protective waste repository location for mine waste removed from the UBMC, which includes the Mike Horse Dam. In July
2012, the USFS issued an amendment to its 2007 Action Memorandum for wastes on National Forest Land. This selection
follows extensive analysis of alternative repository sites after investigations revealed concerns that substantially limited the
possible use of the originally planned Paymaster repository. Section 35 best meets the selection criteria under federal
environmental law (the Comprehensive Environmental Response, Compensation, and Liability Act) for protectiveness,
feasibility, and cost.
DEQ has concurred in the decision and will implement the site cleanup actions under a 2008 agreement between the USFS
and state. No other changes are being made to the 2007 Action Memorandum.
Section 35 is located east of Highway 279's crossing of the Blackfoot River, about 8.5 road miles from the Mike Horse Dam
and approximately 13 road miles east of Lincoln. In 2011, a repository study was prepared by Pioneer Technical Services,
Inc. to review previous repository information, take a fresh look at potential sites, and make a recommendation for the
most appropriate location. The USFS released the study for public comment in September 2011. The decision can be
viewed at the Helena Forest website at www.fs.fed.us/rl/helena/.
What's Next?
Work to Do
In summer 2012, the agencies will be investigating the floodplain in the mining area to collect design-level information for
cleanup and fine tuning waste quantities. At the repository site, scientists will dig sample test pits and install additional
monitoring wells to further ensure that a protective repository can be built on Section 35 and to determine the most
protective location and design for a repository within Section 35.
DEQ's construction manager plans to meet with nearby residents to discuss the implementation of the project and how the
residents' concerns will be addressed throughout the project. These meetings will begin the same week the decision is
released.
The agencies will move into the design phase of the project this fall and winter. This includes conceptual design of the
repository site and removal of the Mike Horse dam and tailings.
Our goal is to have a construction bid package for repository preparation by winter-spring 2012-2013 for bidders. Designlevel investigations are necessary before we can move to construction. Construction (dam removal) should begin in
summer 2014. Hauling is expected to last 4 construction seasons (approximately 100 days between July and October).
With cleanup and restoration, the area should reap the benefits of a restored fishery and other amenities of the Blackfoot
River headwaters as they were more than a century ago.