Site Report: Riverside Mine
| Site Name: | Riverside Mine |
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| Address: | 7 miles north of Hyder on, Salmon River Highway, Hyder, AK 99923 |
| File Number: | 1512.38.001 |
| Hazard ID: | 4071 |
| Status: | Active |
| Staff: | Brittani Mack, 9072628205 brittani.mack@alaska.gov |
| Latitude: | 56.003007 |
| Longitude: | -130.073030 |
| Horizontal Datum: | NAD83 |
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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
PASI Site Investigation has documented that elevated concentrations of cadmium, lead, arsenic, mercury, and zinc are present in sediments along the surface water path from the Mine Portal Adit to the Salmon River. Waste rock tailings adjacent to the inactive mill site along the state highway were characterized using multi-increment sampling. The concentration of lead in the waste rock tailings reached 123,800 milligrams per kilogram (mg/kg). Mine Adit sediment sample analysis found 12,800 mg/kg lead; a water sample from the stream flowing from the Adit and beneath the highway and entering the Salmon River had 348 milligrams per liter (mg/L) lead. The Water Quality action level is 0.018 mg/L (acute). Legal Description: SW1/2 SW1/4 NW1/4, Section 2, Township 68 S, Range 99 E, Copper River Meridian. Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) ID# AKN001002478
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 3/18/2005 | Site Added to Database | Elevated concentrations of metals with completed pathway to recreational surface water. | Bruce Wanstall |
| 3/21/2005 | Site Ranked Using the AHRM | 1,344 tons of waste rock were deposited near the mill site in 1942. Erosion of the waste rock during floods of the Salmon River have redistributed heavy metals into river sediments. | Bruce Wanstall |
| 3/21/2005 | GIS Position Updated | USGS 1:24K/25K Series topographic map interpolation of property latitude and longitude referenced to North American Datum (NAD) 27 using web-based service. | Bruce Wanstall |
| 8/2/2007 | Exposure Tracking Model Ranking | Surface water is the most significant off-site migration pathway for elevated metals contamination identified at the site. Primary land use identified by the EPA PA/SI is recreational hiking, fishing, hunting and bear watching. The controlling exposure route to human and ecological receptors at the site is wild foods; chronic exposure and bioaccumulation of contaminants has not been evaluated. | Bruce Wanstall |
| 1/14/2008 | Update or Other Action | ADEC letter was sent to the RP representative requesting additional characterization of contamination on the property and a site remedy to establish physical and chemical controls on the mine waste rock tailings currently stored on the property. | Bruce Wanstall |
| 2/5/2008 | Update or Other Action | ADEC letter to owner representative Walter Moa was rejected and returned unopened. | Bruce Wanstall |
| 2/6/2008 | Potentially Responsible Party/State Interest Letter | ADEC mailed a Notice of Cost Recovery and Data Request letter to the responsible party/owner/operator of the property. ADEC is requesting development of a site specific conceptual site model to identify receptors and evaluate exposure pathways. Environmental investigation data must meet ADEC quality assurance standards for use in determining the need for a site remedy to mitigate contamination. | Bruce Wanstall |
| 3/27/2008 | Meeting or Teleconference Held | ADEC held a meeting with the property owner representative Mr. Walter Moa to discuss the environmental problems with the Riverside Mine Contaminated Site that are documented in the Weston EPA START Team 2004 Preliminary Site Assessment/Site Inspection Report (heavy metals: dissolved lead). Two ADEC data request and notice of cost recovery letters, that were previously mailed and returned unclaimed by Mr. Moa, were hand delivered at this meeting. | Bruce Wanstall |
| 4/23/2008 | Update or Other Action | The Salmon River Highway collapse seven miles north of Hyder was repaired using mill tailings from the nearby Riverside Mine property. DEC discussed establishing control measures in the right-of-way with ADOT; installing a culvert will divert upland surface drainage away from ore tailings that line several hundred feet of the highway. Property owner representative Walter Moa confirmed capping and re-vegetating rather than mining is planned for the site. | Bruce Wanstall |
| 6/24/2015 | Update or Other Action | Project Manager updated the location to the north side of the Salmon River Road washout area. CS file record and Web Map NAD 83 coordinates. | Bruce Wanstall |
| 6/24/2015 | Exposure Tracking Model Ranking | A new updated ranking with ETM has been completed for source area 75045 Mine Mill tailings waste rock. The mining mill tailings waste rock and mill ruins are unlikely to be disturbed but controls on excavation are not in place for the property and the tailings are present within, and adjacent to, the Right of Way managed by ADOT&PF. An upland stream currently flows through exposed tailings lining the roadside ditch. The stream can be redirected by installing a culvert beneath the Salmon Highway discharging directly to the river thus mitigating the migration of high concentrations of metals from its current path to the Salmon River. | Bruce Wanstall |
| 11/9/2017 | Potentially Responsible Party/State Interest Letter | Sent today. | Danielle Duncan |
| 12/27/2017 | Update or Other Action | Mailed a request for a work plan this date. | Danielle Duncan |
| 1/18/2019 | Exposure Tracking Model Ranking | A new updated ranking with ETM has been completed for source area 75045 Mine Mill tailings waste rock. | Danielle Duncan |
| 1/30/2019 | Workplan Requested | Requested a work plan this date ahead of spring site visit. | Danielle Duncan |
Contaminant Information
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Control Type
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Requirements
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No associated sites were found.