Red Devil Mine, Alaska

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.

Surface Features, 1974

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.

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

Watershed Health Assessments Using Aquatic Insects cont:

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

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 ResultsRiver Sampling ResultsPredatory Fish Tissue 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.

Fish Consumption Advisory

17

Timeline for CERCLA CleanupProjected 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

▫wilkening.matt@epa.gov

• BLM Fish Study Contact▫Matt Varner 907/271-3348▫mvarner@blm.gov

• Questions about the project? Call Matthew Varner @ 271-3348, email at mvarner@blm.gov,or go to the website: http://www.blm.gov/ak/st/en/prog/fisheries/rdm_fish.html