Butter Clam Shells in Hawk Inlet and Young Bay

Greens Creek Mine

The Greens Creek Mine has been in operation since 1989 in Southeast Alaska, in the Tongass National Forest near Hawk Inlet on Admiralty Island National Monument, approximately 18 miles southwest of Juneau. The State of Alaska has had a key role in overseeing Greens Creek Mine discharges to protect human health and the environment through various regulatory programs including the management of wastewater, solid waste, receiving water quality, air quality, and onsite use of oil and hazardous substances.

DEC's Role

A spill of ore concentrate at the Greens Creek Mine loading dock occurred in 1989 under the ownership of Kennecott Minerals Co. Greens Creek Mine is currently owned by Hecla Mining Co. Despite the previous owner’s many cleanup attempts, the Alaska Department of Environmental Conservation (DEC) listed 1.12 acres as impaired. In 2017, with assistance from EPA, DEC prepared a Total Maximum Daily Load (TMDL) for Hawk Inlet which involved an extensive collection of all known metal data within the Hawk Inlet area to identify potential sources to the inlet, evaluate spatial or temporal trends, and recommend additional data collection and analyses warranted. This exhaustive data evaluation confirmed there are no water quality impairments. Analyses of recent fish and shellfish tissue are similar to pre-mining conditions. Sediment within localized areas of the historic ore concentrate spill is the only impairment in Hawk Inlet. The TMDL identified point and non-point sources of lead into Hawk Inlet including the 1989 ore spill concentrate, the historic fish cannery, Greens Creek Mine, fugitive dust, and internal cycling of metals. Another source identified is the abandoned Empire Mine across Hawk Inlet from Greens Creek Mine; Empire Creek flows along the toe of the historic Empire Mine tailings pile transporting tailings to Hawk Inlet.

In the 2022 DEC listed 0.83 stream miles of Tributary Creek as impaired for lead. Best management practices, enforceable through the DEC Waste Management Permit, are anticipated to result in attainment of Water Quality Standards for lead within a 10-year timeframe (by 2030), or two permit cycles. Air and water quality monitoring analysis suggest that the deposition of fugitive dust₁ from the mine tailings disposal facility is a potential source contributing to the dissolved lead concentrations. However, the potential contribution from other anthropogenic and/or natural sources has not been thoroughly investigated and cannot be ruled out.

View full-screen map. DEC's Water Quality Standards, Assessment and Restoration Program created this map to provide information on impaired surface waters and water quality monitoring data to the public. Learn more: Alaska's Water Quality Map

Friends of Admiralty Study

“We have been proactive in adapting our management strategies as we gather new information, and Greens Creek Mine has been more than willing to meet our expectations throughout the years. DEC has and will continue to take a strong role regulating Greens Creek Mine to protect the health of Alaskans and the environment.” - Director of Water Randy Bates, April 14, 2023

In March 2023, Friends of Admiralty released a report comparing lead concentrations in butter clam shells taken from Hawk Inlet and Young Bay. Although the clam shell data from the Friends of Admiralty’s study are generally consistent with the over 30 years of environmental data DEC reviewed, the study’s conclusions are vastly overstated.   

The Friends of Admiralty’s report compares lead concentrations in butter clam shells taken from Hawk Inlet and Young Bay. The report’s conclusion suggests lead concentrations have increased over time and attributes recent lead concentration spikes around Hawk Inlet to the Greens Creek Mine. Friends of Admiralty also assert the mine is causing irreparable harm to the Admiralty Island National Monument.

Greens Creek Mine is required, through the State of Alaska permitting process, to monitor the Hawk Inlet ecosystem to evaluate the effect the mine has on the nearby environment, including lead concentration in marine sediment₂, and sea worm and mussel tissue. Data from these intensive State monitoring programs indicate that the vast majority of Hawk Inlet meets the Alaska water quality standards. The area near the historic ore spill in 1989 is currently listed as impaired and data from State monitoring programs and new data reviewed from Friends of Admiralty confirm this area is the only impairment in Hawk Inlet.

Figure 1: Lead Concentration (mg/Kg/dry weight) in Seaworm Tissue 1984-2022 (Click image to enlarge). Graph displaying the progression of lead concentration (mg/Kg/dry weight) in seaworm tissue from 1984 to 2022 and across the inlet.

DEC compared the clam shell lead data presented in the report to historic Hawk Inlet metal concentrations in sea worm and mussel tissue data that have been collected annually since 1984. A spike in sea worm and mussel tissue metal concentrations was observed after the historic ore concentrate spill (see Figure 1). After more than a decade of steady decline, metal concentrations in sea worm and mussel tissue have returned to pre-mining levels. The Friends of Admiralty report notes a similar increase in lead concentrations in clam shells in response to the ore spill as DEC observed in annual sea worm and mussel tissue metal concentration data. However, the clam shell samples only provide a composite concentration record of lead exposure over the life of the clam which may be as long as 20 years. The report fails to provide incremental, real-time, annual tissue data.

The State monitoring programs at Greens Creek Mine have been well received and sustained for decades as an adaptable management system to evaluate and address the effects of the permitted discharges from the mine and the health of Hawk Inlet. Citizen-provided environmental information, like the clam shell study, provides additional data for the department to consider when evaluating the efficacy and completeness of permitting and monitoring programs. DEC reviews this information, considers its quality and application, and uses it as appropriate to ensure the protection of human health and the environment.

DEC contact: Director of Water Randy Bates, 907-465-5307, randy.bates@alaska.gov

Related Documents:

• https://dec.alaska.gov/water/water-quality/integrated-report/, search for Hawk Inlet or Tributary Creek
• https://dnr.alaska.gov/mlw/mining/large-mines/greens-creek/, Greens Creek environmental data can be found near the bottom of this page
• Alaska's Water Quality Map

₁Fugitive dust is regulated and monitored through Hecla’s Waste Management Plan and Integrated Monitoring Plan.  Air monitoring data from the mill, mine, or adjacent infrastructure do not indicate violations of the National Ambient Air Quality Standards or Alaskan Ambient Air Quality Standards attributable to permitted activities. To address fugitive dust issues, the Draft Supplement Environmental Impact Statement for the Greens Creek North Expansion project proposes that Hecla develops a fugitive dust mitigation and monitoring plan, approved by the Forest Service in consultation with DEC and EPA, and finalized within 6 months following an approval.  DEC will perform a review of future air quality permit applications submitted by Hecla of the proposed tailings disposal facility expansion effort as its received. This review process will address both current regulation and public information relevant to the proposed project.

₂Fresh water sediment data was voluntarily collected, never required; all the fresh water sediment and fish data collected by the Alaska Department of Fish and Game since 2001 is summarized in Technical Report No. 19-01.