Action Date |
Action |
Description |
DEC Staff |
8/26/1993 |
Update or Other Action |
Treadwell Mine Complex was entered on the CS Database as a result of a DEC investigation by E&E that documented the presence of elevated levels of lead, zinc, arsenic and mercury in soil and surface water. |
Bruce Wanstall |
11/10/1994 |
Update or Other Action |
Ranked with the Alaska Hazard Ranking Module (AHRM) resulting in high priority site. |
Bruce Wanstall |
11/1/1999 |
Update or Other Action |
Re-ranked. Changed Air Exposure index from 0.2 to 1.0; Release Information Value from 0.2 to 1.0; and Quantity Value to 2.1. The unknown quantity value is based on the elevated arsenic levels at the cyanide tailings area. Volume or areal extent unknown. |
Bill Janes |
11/12/1999 |
Update or Other Action |
Re-ranked. Changed the Value for Environmental/Recreation Area from 0 to 3 based on the fact that the entire complex is probably about a mile long. At one end is the Sandy Beach recreation area, a City park. Sandy Beach is comprised of old Treadwell mine tailings. At the other end is the cyanide mill tailings area. Obvious stress to vegetation because no vegetation is growing there. |
Bruce Wanstall |
1/18/2001 |
Update or Other Action |
CERCLIS ID # AKD981767387. History: state-lead Discovery 3/1/87, PA 6/23/89, SI 6/30/91. Site Reassessment federal lead 6/30/99 thru 9/18/00. |
Bruce Wanstall |
2/15/2002 |
Update or Other Action |
Project tickler update - Reviewed SI data. Conferred with department risk assessor regarding potential health risks. Sent email to Program Manager recommending that we move on further investigation and probable cleanup. |
Bill Janes |
12/15/2003 |
Update or Other Action |
GW values changed to minimals. GW not used in the area. |
Bill Janes |
12/17/2010 |
Site Added to Database |
A new site has been added to the database for the 240, 300 and 700 mill processing sites in the Treadwell Mine historical mine district site. The former database record for the Treadwell Mine Complex is the record for the Mexican Mine cyanide tailings site. |
Mitzi Read |
7/1/2011 |
Site Visit |
DEC Juneau staff conducted a site visit to the intertidal lands offshore from the Treadwell Mine 240 and 300 mill sites where ore processing waste tailings are located. The tide was slack to minus four feet below mean low tide. DEC was accompanied by members of the Douglas Indian Assn Tribal Response Program to collect samples of buried sediment and interstitial (pore) water from discrete locations in Gastineau Channel. The clams and worms observed at sample collection sites appeared to be healthy. Samples will be laboratory analyzed for mercury and arsenic that were identified as contaminants of concern in previous site investigations. |
Bruce Wanstall |
11/9/2011 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79095 name: 240 and 300 Ore Processing Stamp Mills |
Bruce Wanstall |
11/21/2011 |
Meeting or Teleconference Held |
A meeting was held at City Hall in Juneau with deputy City Manager Kim Keifer and staff, Douglas Indian Assoc Tribal Response Program manager Eric Morrison and DEC/CS Manager Schlichting and staff to discuss the results of pre-Phase I environmental sampling conducted in July 2011, the scope of recommended additional sampling, and funding opportunities in the Brownfield competitive grant program. |
Bruce Wanstall |
11/22/2011 |
Update or Other Action |
DEC is requesting assessment of waste rock (tailings) on the Treadwell Mine Complex property for water, sediment and soil contamination stemming from historical processing of hard rock mining ore to extract precious metals. The targets of the assessment are the mineral processing chemicals mercury and cyanide and naturally occurring arsenic. If these chemicals are mixed with the waste rock tailings in sufficient concentration and are exposed by erosion or by excavation they may present an exposure risk to human health and ecological life at each trophic level. |
Bruce Wanstall |
9/18/2013 |
Document, Report, or Work plan Review - other |
DEC reviewed and approved by letter sent today Addendum to Site Assessment Report - Savikko Park by Nortech Environmental Engineering Inc submitted for the CBJ as an assessment of the western portion of the course sandy mine tailings on the shoreline of Savikko Park. Laboratory results confirmed that levels of RCRA 8 Metals are below DEC Method Two cleanup levels, with the exception of Arsenic. Arsenic was detected in samples at levels ranging between 3.59 and 6.79 mg/kg. As noted in the previously submitted Site Assessment Report (January 2013) by Nortech for the CBJ, the level of arsenic detected is within historical background levels for the Juneau area.
Based on information in the Report, DEC requested that CBJ continue the site assessment of course sandy mine tailings at the Treadwell Mine Complex site using the same sampling methodology and analysis plan for the remaining shoreline of Sandy Beach in Savikko Park eastward to the cave-in site. The shoreline is extensively used by the residents of Juneau and Douglas and deserves the same level of attention. |
Bruce Wanstall |
11/18/2013 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79095 Milled Ore Tailings. Source Area includes the Gastineau Channel Sandy Beach shoreline between the Savikko Park parking lot and the cave-in site next to the Mexican Mine. Extends into the channel as far as the pump house on the intertidal mud flats. |
Bruce Wanstall |
7/16/2014 |
Site Characterization Report Approved |
Douglas Indian Association Tribal Response Program "Sandy Beach Sampling Data Report" by Ridolfi Environmental approved by B. Wanstall. Sampling took place from April 29 to April 30, 2014. |
Julie Fix |
9/1/2016 |
Site Characterization Report Approved |
Douglas Indian Association Tribal Response Program "Sandy Beach Sampling Data Report" by Ridolfi Environmental approved by B. Wanstall. This sampling event was performed on behalf of the Douglas Indian Association. Sampling took place from June 7-8, 2016. |
Julie Fix |
2/15/2017 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79095 Milled Ore Tailings . |
Bruce Wanstall |
3/21/2022 |
Update or Other Action |
ADNR places Leaseholder Location Order (LLO) on state tide and submerged lands including this site. LLO #45 applies to this site; contact information for the affected mining claim has been added to the affiliates tab. |
Julie Fix |
4/10/2024 |
Document, Report, or Work plan Review - other |
The Centers for Disease Control released a draft Public Health Assessment for a 90-day public comment. DEC reviewed the report and did not have substantial comments. The primary findings of the PHA were that metals in beach sediments and shellfish at the site do pose some risk, but that the levels found were not above backgrounds in similar, unimpacted beaches nearby. The report recommended further characterization of sediments deeper than 3 feet on the beach, as well as further upland characterization around the Treadwell Mine ruins. |
Nick Waldo |