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Red Devil Mine, Alaska Mercury Remediation/Aquatic Environments Sept. 26, 2013 R.M. Wilkening
Approximately 1400 t of mercury have been produced from the region, which is ~99% of all mercury produced from Alaska. • Red Devil Mine produced nearly 87% of all mercury produced from Alaska. (1330 Tons) • Mercury ore is predominantly cinnabar.
Red Devil Mine - History • 1933 – 1971 Active mining • Red Devil Mine Site - 190 Acres: • Process area-10 Acres • Surface area-39 Acres • 1989 BLM begins investigation of Mine • 2010 EPA/ADEC begins formal oversight of BLM’s investigation.
Physical Areas of the Mine
BLM Fish Study Results • BLM has been performing a large scale study of fish and mercury in the Kuskokwim River and its tributaries. • This area of the investigation includes Red Devil Creek that bisects the Red Devil Mine processing area and is eroding the contaminated material.
Watershed Health Assessments Using Aquatic Insects • Analysis of the aquatic insect data involved the use specific standardized measures or “metrics”. • These metrics range from the simply counting the number of species in a sample (richness) to more complicated measures which include pollution tolerance values for a given insect species. • BLM examined a variety of these metrics to determine if differences existed between streams that had a history of mining vs. those that are considered to be in pristine condition (reference streams)
Watershed Health Assessments Using Aquatic Insects cont: • Richness metrics summarize all unique taxa in a sample. Typically richness decreases with decreasing water quality • EPT taxa is based upon the number of mayflies, stoneflies, and caddisflies within a sample. Generally these species decrease with decreasing water quality. • Intolerant taxa are those species that have been found to be extremely sensitive to pollution. These species typically are absent from polluted sites.
Watershed Health Assessments Using Aquatic Insects cont: • Summary • Research has demonstrated that aquatic insects are sensitive to pollution, including metal contaminants. • Based on this study, aquatic insects at Red Devil Crk appear to be relatively insensitive to mercury, arsenic, and antimony, in spite of the elevated tissues concentrations. • A couple recent publications support BLM’s findings. • BLM’s studies are continuing
Tributary Sampling Results Total mercury(µg/g, ww) in whole fish samples of slimy sculpin and macroinvertebrates (stream bugs) from the small tributaries of the middle Kuskokwim, Alaska, 2010-11.
River Sampling ResultsPredatory Fish Tissue Results Total mercury(µg/g, ww) in muscle of northern pike from the middle Kuskokwim River and its large tributaries, Alaska, 2010-12.
Red Devil Mine Remedial Investigation Human Risk Assessment – Cumulative Arsenic Risk
Timeline for CERCLA Cleanup Projected Schedule: • 2013 Remedial Investigation Rpt finalized • 2014 Feasibility Study finalized • Summer 2014 - Early Action @ Processing Area • 2014-15 Propose Plan/Record of Decision • 2015-16 Remedial Design/Remedial Action
Contact Information • Matt Wilkening 208/378-5760 • firstname.lastname@example.org • BLM Fish Study Contact • Matt Varner 907/271-3348 • email@example.com • Questions about the project? Call Matthew Varner @ 271-3348, email at firstname.lastname@example.org, or go to the website: http://www.blm.gov/ak/st/en/prog/fisheries/rdm_fish.html