McLaren Tailings Reclamation

National Award Winning project.

The McLaren Tailings Abandoned Mine Site (Site) is an abandoned hardrock mine/mill site listed on the DEQ/MWRCB Priority Sites List based on site assessment conducted by Pioneer in 1993. The site is located adjacent to Cooke City, Montana at an elevation of approximately 7,500 feet and is immediately upgradient of the Lamar River located in Yellowstone National Park. Because of the site location and the potential impacts to surface waters entering Yellowstone National Park, the work required close communications and cooperation between the National Park Service, USFS, DEQ, Beartooth Coalition, and the Park County.

The DEQ retained Pioneer Technical Services, Inc. to perform site investigations and conduct a risk assessment for the Site and determined the preferred remedial alternative for the Site. Based on the risk assessment results a preferred alternative was selected for the Site and additional site investigations were completed at the Site. Based on the additional site investigation, groundwater/surface water modeling, soil stability analysis and modeling, and sediment transport modeling results, Pioneer developed a remedial design for the Site that proposes to stabilize and remove 239,000 cubic yards of mine tailings, mine wastes, and impacted soils; construct an on-site repository; reconstruct 2,000 linear feet of Soda Butte Creek and Miller Creek; construct a site wide dewatering system and water treatment system; construct 4,000 linear feet of storm water conveyance channels and infiltration systems; and revegetate 25 acres.

2014 Update: On September 8, 2014, Montana Governor. Steve Bullock, toured the nearly completed McClaren Tailings site near Cooke City, Montana. He praised the work, designed by Pioneer Technical Services and constructed by Knife River for the Montana DEQ, for helping restore Soda Butte Creek and protecting Yellowstone National Park. After 4 years, over 20 million dollars in federal reclamation money, and 256 cubic yards of waste removal, more than 100 million gallons of contaminated groundwater has been pumped and treated and the water now meets state safety standards.  Pioneer provided design and construction administration on the McLaren Tailings project. The McLaren Tailings Site is located near Cooke City, MT in a valley drained by Soda Butte Creek, which runs through the site and through Yellowstone National Park, approximately five miles downstream. 

2015 Update: For this project the team received a national recognition award for exemplary engineering achievement in the American Council of Engineering Companies (ACEC) 49th annual 2015 Engineering Excellence Awards competition. Previously, the team won a Montana ACEC award and the Montana Contractors Construction Excellence Award (2015). More project details here.