Archive for January, 2020

Jan 21, 2020, Press Release
Facing EPA Superfund Designation, RISE Gold Compelled To Cleanup Existing
Idaho-Maryland Mine Tailings

While Canadian mining company RISE Gold Corp was promoting the gold mine potential and alluring prospects of gaining permits to reopen the Idaho-Maryland Mine (IM Mine) in Grass Valley, CA, federal and state regulatory agencies were focusing on the polluted tailings that cover most of the 56.4 acre site and taking steps leading towards a Superfund Designation.

There has been little public disclosure of the contaminated legacy IM Mine tailings, but correspondence from the EPA dated Sept 26, 2019 indicates that IM Mine’s potential designation as a Superfund site was conditionally deferred because RISE entered into a cleanup contract with the California Department of Toxic Substance Control (DTSC).[1] OnAugust 13, 2019, RISE Gold Corp CEO Ben Mossman signed agreements to cleanup the site, also known as the Centennial site.[2] According to the DTSC records, RISE has been dealing with this issue from at least as early as March 13, 2019, when the first Scoping Meetings with the DTSC took place.[3]

Tests conducted in 1993 by Vector Engineering showed elevated levels of arsenic, chromium, copper, mercury, lead, and nickel over two large areas of the legacy tailings, one area originating from the Mercury gold extraction processing that took place prior to 1926, and a second area being from the Cyanide extraction processing that took place from 1936 until the mine closed around 1956.[4] More recent reports from the DTSC determined thatlead, arsenic, nickel, and mercury are present at hazardous levels.[5] Contaminated tailings cover roughly 2/3 of the 56.4 acres with depths ranging from 2 to 20 feet.

As an additional complication, RISE Gold’s recent bid to re-open the mine includes plans to use the site for disposal of 1.6 million tons of mine waste rock and tailings as “engineered fill” over the course of 5 years, covering 44 acres and creating a built-up area 30 to 70 feet above current grade. However, a recently posted geotechnical report indicates that the legacy tailings are not structurally adequate for use underneath the engineered fill, so theyhave to be completely excavated before the dumping can take place.[6] The full extent of the contamination within the tailings is not yet clear, but even if some of the tailings are clean they will all have to be extracted and then remixed with other aggregates before they would be stable enough to be built upon as planned.[7]

Rise Gold has not yet revealed what procedures will be used to get the legacy tailings off the bedrock and safely dealt with before the new waste rock and tailings from mine operations can be deposited. Nor is it clear whether the contaminated tailings will need to be sequestered separately on site, whether they can be integrated into the engineered fill, or whether they need to be trucked to a waste disposal facility.

According to the agreement, the entire remediation process will be overseen by the DTSC. However, Nevada County and other government agencies will be overseeing all operations with respect to the IM Mine’s re-opening permits, which is independent of the DTSC permitting and is a separate project with a separate time frame.

[1] US EPA Transmittal of Preliminary Assessment Report, Sept 26, 2019;

[2] Cleanup Agreement, Signed by RISE Aug 13, 2019;

[3] Ibid., Exhibit E

[4] “Contaminant Assessment of the Bouma-Erickson-Toms Property”, Vector Engineering,
Nov 1993.

[5] Centennial Geotechnical Report, NV5

[6] Centennial Site History, DTSC,

[7] Idaho-Maryland Mine Project Description, Nov 2019, pg 16;

Content provided by Community Environmental Advocates Foundation (CEA Foundation)
*** Visit the CEA website at http://www.cea-nc.org *** Contact via info@cea-nc.org ***

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Community Environmental Advocates, Press Release, January 14, 2020

A Canadian company, Rise Gold Corporation, aka Rise Grass Valley, has filed an application for a permit to reopen the Idaho Maryland mine. These are some key points from the initial application:
  • The operation will remove 1000 tons of ore and 500 tons of non-gold bearing rock a day with mining continuous 24 hours a day, 7 days a week.
  • The headframe, rock conveyors, ore crushers/grinders, water treatment plant, paste backfill plant, and truck loading area will all be located at the Brunswick Industrial Site at the corner of East Bennet and Brunswick Road. 122,000 square feet of industrial buildings will be constructed at this site.
  • Haul trucks—50 to 100 round trips per day, running from 6 AM to 10 PM, 7 days a week—will dump a mixture of barren rock and processed tailing sand at two sites: the southern end of the Brunswick site, near to and behind homes on Mink Court, Elk Lane, Brunswick Drive, and Cedar Ridge Drive; and at the Centennial site, off Idaho Maryland Rd, along the edge of Wolf Creek.
  • The trucks will be loaded with rock with a front-end loader from 7 AM until 7 PM, 7 days a week. After the rock is dumped, it will be compacted beginning at 7 AM using bulldozers, graders, and rolling compactors. This operation will create a large amount of noise and dust. Dust from these operations is likely to contain asbestos as well as lead and arsenic from massive tailings that must be remediated first.
  • In addition to four industrial-size backup diesel generators, the exhaust from the daily use of diesel trucks, bulldozers, graders, and compactors, will greatly increase greenhouse gas emissions.
  • The paste backfill plant will create 500 tons of backfill every day, 7 days a week. The production of the cement used to make the backfill paste will release an estimated 55,000 pounds of CO2 daily. Thus, the CO2 generated in one day—just by the backfill plant—will be roughly equivalent to the CO2 generated by over 1600 cars.

The project description, noise study, and other documents related to Rise Gold’s application can be obtained at:


If you object to having an industrial-scale gold mine in our community, voice your objections to Matt Kelley, who is the Project Planner for the County, and your Nevada County District Supervisor. Mr. Kelley can be reached by phone at 530-265-1423 or by email to matt.kelley@co.nevada.ca.us. Your district supervisor can be found at:


Demand an open, public process, full disclosure of the current physical and chemical hazards on the properties in question, and the negative impacts the mine will have on our community.

CEA Foundation is committed to being fully engaged to protect our community from the impacts of this massive project. Subscribe to our newsletter for further information.

*** Visit the CEA website at www.cea-nc.org *** Contact via info@cea-nc.org ***










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