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CEA Comments to Grass Valley Development Director

September 6, 2020


Thomas Last, Grass Valley Community Development Director

Grass Valley City Council

Grass Valley Planning Commission

Grass Valley Development Review Committee Tim Kiser, Grass Valley City Manager


Application Number 20PLN-24

Conceptual Development Review of Idaho-Maryland Mine Permit Application in the City’s Sphere of Influence

Dear Thomas Last, City Council Members, et al,

Please accept these comments regarding the Idaho-Maryland Mine Permit Application within the Grass Valley Sphere of Influence.

Community Environmental Advocates Foundation (CEA Foundation) is concerned that the reopening of the Idaho-Maryland Mine would create serious impacts to the people of Grass Valley, to the environment, and to the local economy. Whereas the county is processing the application, it is the City that, by far, has the most to gain or lose. It is for this reason that we implore City staff, Planning Commission, and elected City Council Members to apply due diligence towards addressing the many issues this project presents and assuring that the interests of Grass Valley are fully protected. Our City- specific concerns are detailed here.

An Economic Study is Essential

We implore the City to request an economic study. Numerous realtors have stated that the mine will have a significant negative impact on residential home prices throughout the region. Already, just the permit application for the mine has caused housing prices to slump in the area of the mine and several owners have stated that they will move out if the mine is approved. [1] This is not surprising. People have moved to the neighborhoods surrounding the Brunswick site for the serene rural residential atmosphere. Consider driving past a 30+ acre gravel dumping and grading operation up to 90 feet high and the proposed massive 122,000 sq ft industrial facility on the way to your home. Then you would get to listen to grading and compacting equipment run every day. Or perhaps you are considering buying a home in the new Loma Rica project where you will have to drive by the 44 acre gravel operation along Idaho-Maryland Rd.

Economic impacts may extend far beyond local residential housing prices. As in the case with the previous mine application, local high tech businesses may be forced to close or move out of the area due to several factors, including the impacts of vibration on sensitive equipment, the difficulty im recruiting and retaining highly trained employees from out of the area, a degradation of the aesthetic appeal of living in a quiet mountain community, and the impacts of worsening air quality due to emissions and fugitive dust from mining operations.

Health impacts from poor air quality will be exacerbated by the cumulative impacts of up to 100 daily truck round trips, grading equipment operating daily to spread and compact the two large “engineered fill” pads that are proposed, and other sources including chemical emissions from ammonium nitrate blasting operations, sulfide processing, etc.

The economic cost from the loss of wells can potentially include over 300 private business and residential wells that sit above the 2585 acres of mineral rights that Rise Gold may mine, and dewatering may affect wells well beyond the boundaries of the mineral rights.

And at some point, as always, the mine will close and we will be left with the pieces. There are financial risks to the City in terms of infrastructure costs, possible failure to perform mitigations or conditions on the part of the mine operators, emergency services, bond insufficiency, etc.

Will adequate safeguards be put in place to protect the City and its residents?

Granted, there may be new jobs. Unfortunately, most of the jobs require mining related skills, so there will have to be an influx of people to fill those needs initially. In the long run, will the number of jobs in our area actually increase, or will the other impacts and loss of small businesses create a net job loss?

There will be a lot of construction initially, but will the loss of construction in the housing market due to depressed prices result in a new long term loss of construction jobs and less new housing?

If an economic study shows that the mine would hurt the community, and the county decides to approve the project, what recourse would the city have?

These are all very important questions that should be answered. It is for that reason that we strongly urge the City to request an economic study as part of the Idaho-Maryland Mine permitting process so that decision makers and the public will be able to make an informed opinion.

The Centennial Cleanup Is A Significant Concern

The Department of Toxic Substances Control (DTSC) is the lead agency in a current cleanup project (referred to as the Centennial site) on the 56 acre former Idaho-Maryland Mine site on Idaho-Maryland Road and Centennial Drive. This is a separate project from Rise’s application to reopen the Idaho- Maryland Mine, which will be operating at a new location on Brunswick Road. Rise Gold entered into a “Voluntary Agreement” with the DTSC in order to avoid listing this property as a superfund site. [2] The Voluntary Agreement is a signed and sealed contract binding Rise Gold (aka Rise Grass Valley) to complete the cleanup under the DTSC supervision. [3] The Preliminary Endangerment Assessment (PEA) for the project has been completed and now the Remediation Action Plan (RAP) is being prepared.[4] A separate CEQA process will ensue. Soon, a Notice of Preparation will be posted and more project details will be available. It is important to note that cleanup of the former 56 acre site is required regardless of the decision on reopening the Idaho-Maryland Mine.

What is known: As stated in the PEA, there are approximately 270,000 cubic yards of legacy tailings covering the Centennial site at various levels of contamination. As stated in the staff report (pg 14, pg 16) these tailings must be removed before any “engineered fill” can be deposited. The suggested solution is that these tailings will be mixed with the 1000 tons/day imported waste rock and tailings from the Rise mine project and used as part of the engineered fill. Or, if they are too contaminated for that, they will be sequestered in a pile and capped, never again to be disturbed. More testing will be needed to determine the actual volume of highly contaminated material. Obviously, the 270,000 yards of old tailings materials cannot be mixed with imported new mine waste if the mine isn’t operating to produce that waste. Also, there is potentially additional contamination of the underlying original soils and bedrock. And would the imported mine waste also have contamination to levels of concern?

Clearly, the situation is complicated. The final phasing of the cleanup may significantly impact the proposed import of new mine waste to the Centennial site. It is critical that the cleanup operations be completed and that the Centennial site be left in an acceptable state regardless of whether the mine is approved or not, and regardless of whether the mine fails financially at some point along the way.

There is concern that Rise may end up depleting its funding to get the mining permit approved while delaying the cleanup process, possibly leading to corporate bankruptcy before the cleanup gets completed. The DTSC was only recently even made aware that the “engineered fill” that was proposed to be used for mixing with the legacy tailings is in fact mine waste. [5]

For each possible scenario of phasing with respect to the cleanup project, some provision should be made for the phase of the mining project. In other words, if the cleanup is taking place but the mine project isn’t approved, a reclamation plan that does not involve bringing in waste rock and tailings from the Rise mine project needs to be prescribed. Or if the mine is approved and producing waste rock but the cleanup project is delayed, a provision for transporting the mine waste to some other site needs to be prescribed. Impacts of each phase need to be addressed, as for example, transport of mine waste to another location will affect traffic, road conditions, dust and other associated impacts.

The City should be concerned about the location and profile of contaminated legacy tailings that are to be sequestered on site and capped. Is the location a suitable one when considering the long term usage scenarios of the site? What methods will be used to provide continuous monitoring and maintenance of the contaminants to prevent erosion or leaching, etc?

Will the new mine waste create a new problem for future use? Is it acceptable to have a 33% slope on the fill area? The City should be concerned about the details of the engineered fill profile and future land use scenarios.

Centennial Zoning Issues

The DTSC and Nevada County Planning are designating the 56 acre Centennial site “Industrial zoning” because the County has it shown that way. However, the LAFCo designation and City of GV have pre- designated the Centennial site as Business Park (BP) and Urban Medium Density Residential (UMD). If the cleanup is done to industrial standards as currently proposed, it may be unsuitable for use as BP and UMD usage. Therefore, if the city ever wants to use any portion of this land for BP or UMD, the level of cleanup that is done now needs to be up to the standards for BP and UMD. Otherwise, the higher level of contamination that is acceptable in industrial land will limit the City’s ability to use the land as planned.

A change to the stricter criteria for acceptable BP and UMD contamination levels should be immediately requested to preserve the ability to use the land as planned. Otherwise, a defacto zoning change will take place outside of normal zoning change processes.

Note that the Nevada County General Plan Policy 1.8 allows Grass Valley to determine the designation. Someone representing the City just has to raise the point.

Is the City going to request the change to BP and UMD?

Annexation for the 56 acre Centennial site is long overdue. City annexation would provide the city with the appropriate full control of all aspects of the land use.

Has the decision to not annex been formally made?

If so, what was the basis of the decision to not require annexation at this time?


Cement, explosives, diesel, and various other chemicals will be regularly transported to the site and stored. Cement will be mixed with tailings and pumped back underground and used to backfill mining voids. By one estimate, the backfill paste will use approximately 25 tons of cement daily. Explosives will include ANFO (Ammonium Nitrate and Fuel Oil), and Ammonium Nitrate Emulsion. These explosives will be transported on local highways and roads to the site. Up to 28,000 lbs. of explosives will be stored onsite underground. Diesel fuel storage will consist of a 30,000 gallon above ground storage tank. A number of other chemicals will be utilized for processing the gold using the sulfide flotation system and other activities. Emergency responders will need MSDS sheets and information on locations and manner of storage of all chemicals on site, including those used in drilling, water treatment, gold extraction and so on. Additional first responder training and support systems will be needed.


To move mine waste to the Centennial site, the plans indicate that haul trucks would be making an average of 50 round trips daily (up to 100 max), exiting the Brunswick site with a left turn onto Brunswick Rd, passing the East Bennett Rd intersection, and then turning left on the steep downhill stretch of Brunswick to enter Whispering Pines. Is this acceptable?

Only 11 years are allocated to haul via Whispering Pines to the Centennial site or to be dumped onsite at the Brunswick site. For the remaining 69 years, trucks would haul via Highway 49 by entering Glenbrook Basin. Is this acceptable? How will this impact traffic on Brunswick Road at the proposed intersection for the Loma Rica SDA and the Sutton Way intersection, for example?

A full traffic study should be conducted under the guidelines of the City’s current needs and long term planning, not the County’s.


The City is currently in the design and engineering phase of construction of the Wolf Creek Trail. Wolf Creek and the proposed trail pass through the Centennial Site. The proposed project must indicate how it will enable and enhance the City’s plan to create a public trail, with an improved riparian habitat, along the Wolf Creek/Idaho Maryland Road corridor.


Additional concerns are listed in the CEA Foundation NOP comments which were submitted to the County and are provided as a supplement to this document.

As guardians of the health and well-being of Grass Valley, we implore you to seriously consider each concern listed in this document and its ultimate impact on the community which you represent.

Thank you,

Ralph Silberstein, on behalf of CEA Foundation

A local resident conducted an informal survey of well known and large volume realtors in the area and asked for their professional opinion as to the impact. He contacted multiple local realtors with multiple firms. 100% of them agreed it would have a negative impact on values.

A well know realtor at Century 21 said that in her professional opinion “reopening the mine depending on the property, could reduce values near the mine by from $50,000 to $100,000 or more”. Others estimated the reduction in terms of 20% to 25% or more. A realtor at Coldwell Banker said “While it would impact the properties close to the mine the most, it would negatively impact all property values in the area. I’ve had multiple potential buyers decide not to purchase here at all when they learned the mine could reopen”.

“The same home in a nice area compared to one next to a railroad track would have far different values. No one wants to live next to a mine” said another agent. “The most important factors in values are “location, location, location. Next to a mine is not a good location”, several others stated. Another realtor told us “We had a property in escrow recently, but the sale fell through when the buyer found

out that the mine could reopen”. (Contact names available upon request.)

  • US EPA Transmittal of Preliminary Assessment Report,Sept 26, 2019;

  • Cleanup Agreement, Signed by RISE Aug 13, 2019;

  • Link to PEA: https://www.envirostor.dtsc.

  • Per email correspondance with Dean Wright, Aug 17, he states “I am not aware of any plans for new tailings or waste rock to be added to the Site. Several of the remedies being looked at include a “cap” of clean soil but it’s not yet known where that material will originate. Regardless of it’s origin, any material brought on site will be sampled to ensure it meets required standards.


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