During 2003 BLM began investigation and cleanup of petroleum that had leaked from the Red Devil Mine's fuel storage and distribution system. Five large aboveground fuel storage tanks (ASTs) with estimated combined capacity of about 850,000 gallons had been installed at the mine during 1953-1955 and remained in service until the mine closed in 1971. It is unknown if any fuel remained in the tanks when the mine closed, but none of the inspections and investigations of the mine since then noted fuel being present, although some fuel was removed from the supply line running from AST #5 to the mill in 2002. This work is being conducted following Alaska Department of Environmental Conservation’s (ADEC) regulations.
In 2003 BLM secured funding to demolish the ASTs and conduct a site characterization. The characterization revealed petroleum contamination to be present in soil at four of the five ASTs, at the loading end of a steel pipeline which was used to transfer fuel from barges at the river bank into the ASTs, and at a joint in the supply line that ran from AST #5 to the mercury production facilities.
In 2005 and 2006 BLM’s contractor excavated petroleum contaminated soil from the locations identified during the 2003 characterization. The contaminated soil was stockpiled in two containment cells to await remediation. Petroleum contaminated soil encountered at the AST #5 site greatly exceeded the estimate made during 2003 in both depth and quantity; excavation was stopped by BLM when depth of the excavation made it unsafe to continue working with the equipment on-hand.
Utilizing funds provided under the American Recovery and Reinvestment Act the petroleum cleanup advanced into final stages during 2009-2010. Contract award was made the Marsh Creek, LLC in late 2009 to develop and execute ADEC approved plans to treat the stockpiled soils and investigate and cleanup as needed the residual contamination at the AST #5 site.
During summer 2010 BLM’s contractor treated the petroleum-contaminated soil by setting up a 1.5-acre landspread remediation cell. This cell allows natural biological action over time to remove petroleum hydrocarbons from the soil. The contractor used methods suggested by the Sleetmute Traditional Council to reduce the risk of erosion of the contaminated soil, such as hydroseeding with mulch and native grass seed. Monitoring of the landspread will continue until the petroleum concentrations in the soil reach the target cleanup levels.
Transporting soils from stockpiles to the landspread called for crossing of Red Devil Creek hundreds of times by heavy dumps trucks, excavators, and other vehicles. The existing crossing was a ford within the mine tailings dump. To avoid disturbing the creek bed, BLM’s contractor installed a temporary highway bridge and blazed an unimproved access road at the site. The bridge will remain until all the cleanup actions are complete and will either be dismantled at that time or left in place at the request of the future landowner.
While clearing brush around the east approach of the bridge BLM's contractors discovered a partial full drum of mixed tar and fuel in vicinity of where the mine's sawmill had once stood. After developing an ADEC approved work plan, the drum was removed and the surrounding area was completely cleaned-up. The tar/fuel mixture and several yards of impacted soil were transported to Anchorage for proper disposal.
To investigate the AST #5 site, BLM’s contractor made numerous soil borings and sampled groundwater to find the extent of remaining fuel contamination. The findings of this investigation show that no further excavation is necessary at the AST #5 site.