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Site Report: Alaska Treasure Mine


Site Name: Alaska Treasure Mine
Address: 4.41 Miles SE of Downtown Douglas; Douglas Island Near Juneau, Douglas, AK 99824
File Number: 1538.38.010
Hazard ID: 26217
Status: Active
Staff: Danielle Duncan, 9074655207 danielle.duncan@alaska.gov
Latitude: 58.226111
Longitude: -134.315000
Horizontal Datum:WGS84

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

Alaska Treasure Mine, along Nevada Creek on Douglas Island, was operated between 1903 and 1916. There were originally 4 adits to the mine; two of these have collapsed. The remaining adits on site are the Main Adit/Middle Mine Area and the Hudson Adit/Upper Mine Area. The Main Adit/Middle Mine Area has no evidence of milling but there is a pile of waste rock which has been terraced (35 terraces) as part of a mitigation plan to prevent waste rock from entering adjacent Nevada Creek. The terraces have been planted with native trees and shrubs. There was a 20 stamp mill located at the Hudson adit. In a November 2013 Corrective Action Plan, the Nevada Creek Mitigation Partners proposed steps to stabilize and/or remove mineral concentrates that are potential contaminant sources. Concentrations of lead and zinc in mineral concentrates were >1%. The affected area surrounding the concentrates is approximately 12 X 18 feet. Mineral Survey # MS575, 724, 1526 ARDF # JU228 MRDS# A012026

Action Information

Action Date Action Description DEC Staff
3/5/2014 Cleanup Plan Approved Cleanup Plan submitted by Nortech to remove metals concentrates located outside mine adit, sample underlying and surrounding soils for RCRA 8 metals plus zinc. Concentrates exceed TCLP for lead and possibly zinc; silver found at elevated levels. Sally Schlichting
3/5/2014 Cleanup Level(s) Approved Cleanup levels approved are Method 2 Migration to Groundwater for metals. Sally Schlichting
3/7/2014 Site Added to Database A new site has been added to the database Mitzi Read
3/12/2014 Potentially Responsible Party/State Interest Letter PRP Letter sent to Nevada Creek Mitigation Partners. Courtesy call was made to Steve Sego of NCMP. Sally Schlichting
4/4/2014 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 79615 name: Hudson Adit - Upper Mine Area - Metals. Remediation work anticipated to start May 2014. Danielle Duncan
9/12/2014 Update or Other Action Consultant did some site sampling and will provide report soon, pending lab data. Danielle Duncan
5/14/2015 Meeting or Teleconference Held Met with J. Ginter of Nortech and discussed cleanup progress at the site ahead of final reporting. Nevada Creek Mitigation Partners hand excavated and removed ore concentrates that were stored in burlap sacks. The concentrate was gray in color, quite heavy, and high in Au, Ag, and Pb. The lead concentration in soil at this time ranges from 395-825 mg/kg. The site is on Douglas Island, there is no trail leading to it, it's at about 900 ft., and about 1.5 hours from the beach. The site is close to Nevada Creek and the site is sloped sharply. Nevada Creek Mitigation Partners sealed the historic adit by welding a metal grate to the entry. The lead contamination is as a result of mining operations from 1884-1913. There was a 20-stamp mill and it appears as though only ore crushing occurred - no processing. Currently waiting for final data. Danielle Duncan
7/7/2015 Site Characterization Report Approved Approved the Corrective Action Report dated May 2015 and submitted by Nortech. Although the CAR is approved, the ADEC requests that further action be taken to characterize the Site. The known contaminant of concern for the Site is lead, however other metals concentrations have not been determined. In the ADEC letter dated May 14, 2015, titled “RE: Corrective Action Plan Approval”, the ADEC requested that confirmation soil samples be analyzed for all RCRA 8 metals plus zinc. In addition, the ADEC requests that the samples be analyzed for copper and mercury. Please also provide information about the terracing work completed at the waste rock pile located at the main adit/middle mine area. Furthermore, under 18 AAC 75 regulations for contaminated sites, analytical data is needed to characterize the waste rock material. Please submit a work plan to address this data gap in order to manage the site and exposure risk. Danielle Duncan
8/5/2015 Update or Other Action Spoke to Nortech today and verbally over the phone approved a work plan to take 3 analytical samples and a duplicate from the rock dump and have them tested for RCRA 8 metals plus mercury and copper. Also requested that the previous sampling areas from the tailings area be tested for RCRA 8 plus mercury and copper to address the data gap. pH values and approximate volume and other characteristics including photographs of the rock dump and terracing will also be provided. Danielle Duncan
10/5/2015 Report or Workplan Review - Other Rec'd Nortech's RE: AK Treasure Mine / Nevada Creek on 10/1/15. Samples previously collected and a few new samples were analyzed for RCRA 8 Metals plus Hg and Cu with the following results in mg/kg: As 8.9-942, Cr 0.22-109, Pb 5.6-1,060, Hg 0.99-3.2, Se 0.90-4.5, Cd 0.23-3.7, Cu 68-180. One sample was also analyzed for Cr 6+ and had 0% matrix spike recovery due to a reducing matrix. I requested that the Redox Potential and pH values be reported. Danielle Duncan
10/20/2015 Site Characterization Report Approved Sent approval letter for recent work on this date and plan to conduct a site visit to evaluate the efficacy of the terracing work to prevent metals migration into Nevada Creek and to identify potential ecological receptors and public access. The pH of the sample tested was 4.2. Danielle Duncan
3/8/2016 Site Visit Site visit to the middle mine/adit area where the waste rock pile was stabilized. The terracing appears to be preventing waste rock migration to Nevada Creek. The slope is super steep. The site is accessed by boat as no trail from town exists. Once ashore, there is an original corduroy road (< 1/4 mile) that leads to the site. There are motion detection cameras on the trail to record wildlife and trespassers. The adit is sealed and secured. There are various mining equipment (boilers, stamps etc.) in the woods nearby. We did not visit the upper mine tailings area but have plans to do so this summer. Danielle Duncan

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details

Requirements

Description Details

There are no documents for this site report.

Missing Location Data

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