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DEAL KILLERS - MineWatch June 2022 Meeting

Three major, significant and unresolved impacts of the mine.

The MineWatch June Community Meeting brought together three of the most significant learnings from the Draft Environmental Impact Report (DEIR) comment period that ended in April 2022. Watch the recorded presentation below to get the full story. Download the PDF for a quick overview. Or, read the script below to find specific information.

01:55 – Project Update - CEA Foundation President Ralph Silberstein gives an update on project status.

8:17 – Wells & Groundwater – CEA volunteer, Mike Shea, reviews what the DEIR said about wells and groundwater, then summarizes the flaws found by experts at Baseline Environmental Consulting

19:34 – Mine Waste Disposal and risks to air & water – CEA volunteer, Greg Thrush, explains how the the byproducts of mining are a critical concern for the quality of air and water in our area.

36:11 – Greenhouse Gas Emissions – The host of KVMR's Climate Report radio show, Martin Webb tells us how the DEIR yardstick is outdated and key emissions are missing, which leads to dangerous conclusions.

50:40 – Questions and Answers

1:18:09 – Take Action


June 2022 MineWatch Community Meeting
Download PDF • 5.69MB


Script for Project Update

Planning Commission Meeting Good evening. I’m just going to do a quick report on recent events.

In case you missed it, this picture is from the March 24 Planning Commission meeting for the Idaho-Maryland Mine Draft Environmental Impact Report or DEIR.

We counted 482 people who showed up, and only one person of the 100 speakers spoke in favor of the mine.

Of note, we were well received. The Planning Commission was very impressed with how civil and on topic everyone was and thanked us.


The Draft EIR comment period officially ended on April 4, but to me it seems like April 1 was more appropriate because Rise Gold continued to claim that the project basically had “No Impacts”.

I kept imagining "April Fools, Investors! The project has numerous additional significant impacts that the DEIR missed."

Nevada County Planner Matt Kelley said it looks like there were over 1000 comments .

We submitted a letter on behalf of our coalition of 20 organizations, CEA submitted extensive Legal comments as well as addition general comments, and we had a number of comments from experts.

The Draft EIR needs to be recirculated

County has ot yet made a determination on recirculation. And reportedly they are still processing the comments.

Under CA law, a Draft EIR must be recirculated if (1) there is significant information that was not included initially, or (2) the Draft EIR is so fundamentally and basically inadequate and conclusory in nature that meaningful public review and comment are precluded.

This Draft EIR fails on both points.

What Draft EIR Recirculation Means

A number of additional studies will have to be done, the impacts will need to be adequately identified, and appropriate mitigations detailed in a new Draft EIR.

It starts with gathering adequate data. For example:

The Centennial Cleanup Project current conditions (baseline) needs to be detailed, and impacts from the cleanup assessed.

Well monitoring to get a groundwater baseline has to be done BEFORE the project is started as part of the Draft EIR

Extensive mine rock testing is needed to evaluate the potential toxic hazards

There needs to be a realistic construction schedule instead of the ridiculous 1 year listed. It will be more like 7 years before any gold could be produced.

Many other items need additional information

THEN a revised Draft EIR needs to be published, and then we’d have a repeat of the public comment period and hearings.

Centennial Cleanup status

For those of you who are just learning about the mine, What is the Centennial project?

Not to be confused with the Centennial Dam, the historic IM Mine site on Idaho-Maryland Road and Centennial Drive is covered with old mine waste that is toxic and needs to be cleaned up. Rise Gold plans to dump more tailings on the site, so they need to clean up the 44 acres of mine waste first. This is being done under the supervision of the Dept of Toxic Substances Control, or DTSC.

The DTSC is a separate agency, and the cleanup plan (Remedial Action Plan, or RAP) is not even approved, but the Mine Draft EIR pretends that it is already done.

The Final Remedial Action Plan and response to public comments is now expected late this month with a proposed Final RAP, and final approval of that would follow at some later date.

Our view:

The cleanup and all of it’s impacts must be included in the Draft EIR. The DEIR should describe the current conditions of the site and assess all of the impacts of the cleanup and the mine together instead of breaking the mine project into pieces and thereby disguising the true impacts.

Economic Study Status

Nevada County contracted to have an independent Economic Study done on the proposed mine’s economic impact.

The consultant is apparently waiting for some evaluation of the Draft EIR comments due to the high possibility that the project description will change.

Our take: The study will likely be less favorable to the Mine than the study provided by Rise Gold, which has a number of defects.


Script for Wells & Groundwater

My section of the presentation will focus on the mine's potential impacts on groundwater and wells.

- First a little background - Numerical Model

Rise hired two firms to look at the effects the mine will have on hydrology – EMKO Environmental, Inc. and Itasco, Denver Inc. (Eye tas ka)

Itasca developed a 3-D numerical groundwater flow model of the Mine and the surrounding area. Using this numerical model and other analytical methods, historical data was used to simulate and evaluate the effects of mine dewatering on domestic wells above the underground mine works.

- Modeling

And based on their simulations and evaluations, the firms made estimates, predictions, and assumptions on how the mine will affect wells. According to the Idaho Maryland Well Mitigation Plan that accompanied the draft EIR:

“All potentially impacted wells are located in the E. Bennett Road area. Domestic water wells outside this area will not be impacted.”

- What me worry

And, as you may have heard, Rise says it will provide NID hookups for up to 30 properties using well water along East Bennett Rd.

So it sounds like Rise has everything covered. What can possibly go wrong?

We have consulted with other experts, ones that weren't paid to prepare reports for Rise Gold. And here is what our experts found:

Flawed Groundwater Model – Fracture patterns

The Draft EIR does not accurately evaluate the project’s impacts on wells because it relies on a flawed groundwater model. There are several reasons for this. Let’s take a look at them:

Baseline Environmental Consulting, a consulting firm hired by CEA's attorneys, points out that accurate prediction of groundwater behavior in fractured bedrock using groundwater models rarely occur because there are different, unknowable, fracture patterns in the bedrock.

Flawed Groundwater Model – Baseline groundwater

The DEIR acknowledges that baseline groundwater levels have not been established and wants to defer the collection of additional data to the future using a Groundwater Monitoring Plan. But by then it would be too late because the mine would already be approved and dewatering will have started.

And this Groundwater Monitoring Plan seeks to establish pre‐dewatering baseline levels but not until after dewatering begins. Do you get how crazy that is?

Flawed Groundwater Model – wide enough area

Also, the DEIR states that “drawdowns of the water table are generally within the mineral rights boundary” but provides no explanation as to how it determined that water table drawdowns would be limited to the area within the Rise mineral rights boundary. According to Baseline Environmental, since the area surrounding the Project site contains a fractured bedrock system it is possible for water table drawdowns to extend beyond the mineral rights boundary.

Flawed Groundwater Model – data limited and not current

Rather than using current data, the groundwater model was calibrated based on historical pumping rates and a single water level measurement from 64 years ago.

Data used about the private wells was old and limited to just a few years.

Flawed Groundwater Model – new mine features

Also, the groundwater model did not include the proposed access shaft Rise wants to put in or other proposed mine features, all of which would contribute to the downward transmission of ground water.

Flawed Groundwater Model - faults

Plus, there are three major faults and numerous minor faults in the mineral rights area. These impact the transmission of water and introduce a high level of uncertainty in the accuracy of a model which assumes the geology is uniform.

Flawed Groundwater Model end

These are all elements that are critical for constructing a reliable groundwater model. And, before the impacts of the mine dewatering can be accurately identified, a reliable ground water model is needed.

It is our position that the groundwater model is seriously deficient with respect to data reliability, initial conditions, and modeling assumptions, and does not accurately depict the projects impacts.

Significant to who

And here’s another thing, the DEIR holds that a well isn’t considered significantly impacted unless there is a 10 percent reduction of water. Nowhere in the DEIR is it explained how this arbitrary 10 percent reduction figure was chosen, nor is it justified. What about low volume wells that barely supply enough water now? Any reduction may be too much for them. Keep in mind Rise has made no plans to provide water to well owners other than those on East Bennet.

Monitoring Wells

As I previously mentioned, the Groundwater monitoring plan acknowledges that more groundwater level data is needed to assess the potential impacts of the project to groundwater levels.

The DEIR and associated Groundwater Monitoring Plan does not propose to monitor water levels in the actual domestic wells that may be affected by the project, but proposes to install 15 monitoring wells.

No explanation has been given on how it was decided 15 wells would adequately represent the hundreds of other wells in the area, nor was information provided on how they arrived at the locations of the monitoring wells. This shows the locations of the monitoring wells, represented by a red dot with crosshairs, with the mineral rights boundary shown by a double doted line. I think you can see that there are large areas within the mineral rights area that do not have a monitoring well, nor are there any monitoring wells outside of the mineral rights boundary.

Do these 15 wells make you feel comfortable that your well won’t go dry?

The bottom line is that the DEIR incorrectly concludes that the impacts to wells are less than significant and any possible impact is fully mitigated. We disagree.

–Protection for Well Owners

This leads us to what we believe what needs to be done to insure well owners are protected from any impact the mine could have on their wells.

• Completion of a detailed water supply well inventory for all wells within the Mineral Rights Boundary, plus a substantial buffer zone;

This would include the details about each potentially affected well such as the construction design, type and use of the well (e.g., domestic, irrigation, industrial, etc.); water demand; recharge rates; and seasonal variations in water levels; and

• Development of a plan for each well to ensure that an immediate alternate water supply can be provided should a well be impacted. This plan must ensure alternate water supplies will be provided throughout the 80‐yearlife of the mine and beyond.

The question is, will the county protect its residents by requiring Rise to pay whatever is necessary to ensure well owners are not without water.

Things do go wrong

I'd like to end with two examples of how models and simulations can go wrong.

First, you no doubt are already aware of what happened when an underground gold mine was opened in San Juan Ridge. After a bedrock fault was encountered the water flowing into the mine greatly increased. A dewatering well was drilled to capture this excess water, but when the water was pumped out of the well it caused “significant water level declines in water supply wells north of the mine.” What I want to point out is, before the mine was approved a groundwater study was also done, and if you read it, you will see the same words used in the EMKO and Itasco studies – Modeling, Simulation, Predicted, Estimated, Assumed. And the prediction was, that dewatering would have a minimal impact on neighboring wells. So as you can see, models are not perfect.

The second example concerns the Stillwell aggregate mine operated by Cemex in Lemon Cove, California. Without getting into the specifics of the problems faced by well owners, a water consulting firm hired to review the data and previous groundwater evaluations was able to demonstrate numerous contradictions and inconsistencies within the Hydrological report previously prepared by EMKO. That name sound familiar? The problems in Lemon Cove further illustrate the issues that arise in hydrologic studies.

The bottom line here, is that reopening a mine under the feet of an established residential and business area is a huge risk. History tells us that things do go wrong. The analysis and proposed mitigations presented in the DEIR are wildly inadequate and completely fail to address the significant disruption and financial consequences that would befall local residents and businesses when things fail.



Script for Mine waste and the impact on water and air quality

1. Introduce topic of mine waste

a. Hardrock mining creates large amounts of mine waste. Mine waste includes the barren rock excavated in search of the mineralized ore rock and the tailings that are created as the ore rock is processed to extract gold.

b. The Draft Environmental Report (DEIR) describes three ways to deal with the mine waste. 1) Dump it on a suitable disposal site, 2) sell the waste rock as a product (which has to meet certain standards before it can be sold to assure that it is not a source of contamination), or 3) return the material back into the mine. I’m going to focus on surface disposal because it bears upon the impacts to water and air quality in our area.

c. Of the 1500 tons of rock excavated each day, 500 tons are returned back into the mine as backfill and the rest ends up somewhere on the surface.

d. That “somewhere” happens to be near the residential neighborhoods that border the New Brunswick Mine site and the Centennial Site that adjoins the industrial / business park area off Whispering Pines Drive near downtown Grass Valley.

2. Mine Waste Storage

a. Under the current mine proposal, each day 500 tons of barren rock and 1000 tons of mineralized ore rock are excavated and crushed underground to a size of about 6 inches.

b. The freshly broken rock is brought to the surface. The mineralized ore is processed which results in fine sand tailings, and rest is 6 inched-sized, unprocessed barren waste rock.

3. Water quality impacts

a. It’s easy to think of rocks as unchanging, but they are actually composed of mineral elements that interact with what’s around them. Mine waste piles are actually dynamic physical and chemical systems.

b. Surface disposal exposes waste rock to conditions different than what exist underground. Weathering, the exposure to water and oxygen, causes waste rock to undergo changes that leach metals into the fluids flowing through it. Depending on the chemical composition of the rock, these effluents can be hazardous.

c. Arsenic, Iron and Manganese are three principal minerals of concern because they are abundant and naturally occurring elements in our region. All are readily leachable metals. If not properly managed, hazardous substances contaminate public waterways, get deposited on land where they dry and can become airborne. Water and dust are the primary exposure pathways to humans and other animals.

d. The State’s Central Regional Water Quality Board is tasked with assuring that discharges into public waters do not exceed established standards. Under Title 27 of the California Codes and Regulations, effluent water quality data are used to classify mining waste in order to determine whether containment will be required, based on that data. Containment means making sure that toxic substances don’t get into public waterways.

4. What does the DEIR say about mine waste?

a. The short answer is practically nothing, beyond where to put the stuff. According to the DEIR, there are no significant concerns about mine waste that would be produced by the mine’s operations.

b. Rise Gold collected drill core samples and hired a consulting firm to analyze the samples and characterize the geochemistry of the waste rock. The analyses concluded that the mine’s tailings would not generate acid. Acid Rock Drainage is one common environmental hazard that accelerates heavy metal leachates. This is all that the DEIR says about effluents coming from mine waste.

c. Waste rock and mill tailings that produce near neutral to alkaline pH effluents with elements such as arsenic are not mentioned at all. This is a significant omission given that both the historic Idaho-Maryland mine and the neighboring Empire mine contain documented high levels of arsenic in the mine waste piles produced by prior mining activities in this area.

d. A paper published in 2014 about arsenic associated with historical gold mining in the Sierra Nevada foothills found that waste piles at the Empire Mine Historical State Park contain high levels of arsenic. [Explain figures]

i) This map of Empire Mine State Historic Park shows the locations of mining features. Waste-rock piles are shown in light green. It shows data points for arsenic concentrations on trails prior to remediation determined by field X-ray fluorescence.

ii) This table presents the levels of heavy metals found in the various waste rock piles in the park. The final two columns titled “Total Metals Exceeding Criteria” and “As Exposure Point Concentration” show which elements exceeded CA Health Screening levels in each waste pile and levels of arsenic concentrations at each place. For reference, natural concentrations of arsenic in soil typically range from 0.1 to 40 mg/kg.

5. Air quality impacts

a. In terms of air quality, in addition to the above mentioned metals, silica and asbestos are substances of concern in mine-waste because they are released when rocks are crushed, transported and disposed of.

b. Silica is essentially pulverized crystalline silica or quartz. The size of the airborne silica particles determines the amount of risk. Larger particles, such as beach sand, are not as great a concern because they are too large to inhale. Smaller particles can be inhaled deep into the lungs where they cause health impacts like silicosis.

c. Serpentine rock often co-exists with gold bearing quartz and it does exist within the mineral boundary area of the proposed mine. Serpentine rock commonly contains asbestos. The crushing, hauling and deposal of waste rock liberates the materials within it – including asbestos. This possibility is acknowledged and discussed in the DEIR.

6. Review some of the expert comments to the DEIR related to mine waste

a. The DEIR does not contain any data that would serve as a basis for classifying waste rock or mill tailings. Given what is known about historic waste rock and mill tailings contamination from past mines in the area and its potential to generate poor quality effluent that threatens water quality, the DEIR is negligent not to address this.

b. The sampling that was submitted for analysis appears to be selective and, given the DEIR’s lack of documentation about how the samples were chosen, it is not possible to determine if this sample is representative of the ore body that would be mined. Rise Gold completed 19 drill exploration drill core holes, totaling 67,500 linear feet, from 2017-2019. From this drill core, Benchmark Resources collected six drill core samples that it used to characterize the geochemistry of the waste rock. The geochemical predictions for approximately 96% of the waste rock to be produced comes from one 10-foot interval of drill core, and one 1-foot sample. The sampling is inadequate at best and possibly deceptive.

7. What does the DEIR say about mitigating asbestos and silica?

a. The DEIR makes no mention of silica, most likely because it is so pervasive, but it does talk about asbestos.

b. The Asbestos Management Plan would ensure that average mined material and engineered fill contains less than 0.01% asbestos. Testing the asbestos content, however, does not control the amount of asbestos in the actual material mined. To control the average amount of asbestos in output materials (and to avoid significant impacts related to asbestos exposure) you have to test and potentially stockpile asbestos-rich material to mix it down to an acceptable level with other mine waste. Currently, the DEIR does not include any evidence that asbestos levels will not exceed this threshold.

c. The testing process can require up to two weeks before the results are known, yet the Project calls for daily mining activity to continue during this time. The DEIR does not address how this would happen given that daily mined material might have to be stockpiled while awaiting the test results. Otherwise, the mine waste could get trucked out and dumped with knowing what levels of asbestos it contained.

d. Incidentally, Rise Gold’s business plan counts on eventually selling and trucking mine waste as a construction material. The ability to do this is also regulated by the State and thus would have to conform to the same contamination standards as local surface storage.

8. Conclusion

a. As I’ve briefly outlined, the DEIR has serious omissions related to mine waste.

b. While mining technology advances in terms of its efficiency and has made improvements by abandoning some dangerous processes like the use of mercury, the byproducts of mining are not different than they were 150 years ago and the environmental impacts of mine waste remain the same as well. Operating a mine again in our area would re-start many of the same issues that the initial exploitation of the gold rush introduced.

c. Over the past 15 years, about one million dollars in EPA Brownfields funding has been allocated for our area just to help figure out how to remedy the contamination resulting from past mining activities. Mine waste is a significant environmental issue that still needs to be addressed in our area and re-opening a mine would simply contribute to the complicated legacy problem of mine waste contamination.

d. The DEIR is supposed to describe what are the environmental impacts of opening a mine and how those impacts will be addressed should the mine application be approved. The DEIR clearly fails to do this with regards to mine waste.

e. Mine proponents talk about the benefits and the wealth created by mining gold but are mute about the social and environmental burdens that our community bears to in order allow them to achieve their objectives.

f. It is not within the DEIR’s scope to assess the social costs borne by our community to host an industrial mining operation, but they are real. So it is up to us to make sure that the issues are understood and communicated to the County’s decision makers. This concludes my presentation. Thank you for your time and attention.


Arsenic Associated with Historical Gold Mining in the Sierra Nevada Foothills: Case Study and Field Trip Guide for Empire Mine State Historic Park, California

Arsenic species in weathering mine tailings and biogenic solids at the Lava Cap Mine Superfund Site, Nevada City, CA


Script for

Greenhouse Gas Emissions:

DEIR yardstick is outdated, key emissions are missing, leading to dangerous conclusions



The DEIR must choose a GHG yardstick

Question: At what level do GHG emissions break into “significant” territory, requiring mitigation by CEQA?

A level of acceptable unmitigated GHG emissions is set

Project stays below that annual limit = GHG pollution is ignored by DEIR and considered “Less Than Significant”

Project goes above that limit = GHG mitigations must be taken that lower the GHG, and increase the project costs

DEIR uses the wrong GHG yardstick, for the wrong place, at the wrong time

Some CA Counties & AQMD’s came up with arbitrary 10,000 metric tons/year of “CO2 equivalent” = no worries

10,000 “MT of CO2e” = ~22 million pounds of CO2

That’s shredding a 6-million-pound solid block of carbon/yr

This number was arbitrary and does not represent the best climate science and GHG goals

DEIR uses the wrong GHG yardstick, for the wrong place, at the wrong time

Some CA Counties & AQMD’s came up with arbitrary 10,000 metric tons/year of “CO2 equivalent”

Our County & our AQMD (Northern Sierra) have never set any numerical GHG limits to use for this analysis

We are a different county/region than SoCal, the Bay Area, Sacramento Metropolitan area, and Placer County

This was lifted from SoCal AQMD, Bay Area AQMD, Sacramento Area AQMD, Placer Co

DEIR uses the wrong GHG yardstick, for the wrong place, at the wrong time

2015 = International Paris Climate Accord set new global GHG reduction goals

2016 = CA SB32 updated state GHG reduction goals, triggering statewide review

2017 = CA Air Resources Board Scoping Plan says “Achieving no net additional increase in GHG emissions, resulting in no contribution to GHG impacts, is an appropriate overall objective for new development.”

Old limits that don’t apply here, in a time of urgent GHG reductions, allow emissions to spoil our environment unchecked.

Four chronological parts for GHG analysis:

Year 1: “Construction & Dewatering” = 3,444 MT/yr … Limit set at 1,100/yr

5 Yrs: “Mining/Dumping @Centennial” = 7,222 MT/yr … Limit set at 10,000/yr

6 Yrs: “Mining/Dumping @Brunswick” = 7,000 MT/yr … Limit set at 10,000/yr

70 Yrs: “Mining/Dumping @Elsewhere” = 9,041 MT/yr … Limit set at 10,000/yr

The DEIR abandons all efforts to mitigate, eliminate, or offset 1.5B lbs of CO2 emissions for the entire 80 years of operation.

DEIR MITIGATION GOAL: ONLY OFFSET 2,344 METRIC TONS 1 YEAR, ALLOW 7,000-9,000 METRIC TONS FOR 80+ YRS (approves of releasing >1.5 billion pounds of CO2 = burning ~800,000,000 pounds of coal, according to EPA)



Ignore GHG emissions from Centennial cleanup…but donate its GHG benefits:

5 Yrs: Mining/Dumping @Centennial = 7,222 MT/yr … Limit set at 10,000/yr

70 Yrs: Mining/Dumping @Elsewhere = 9,041 MT/yr … Limit set at 10,000/yr

Centennial toxic cleanup is not part of “existing starting environmental conditions.” The GHG section wasn’t supposed to assume a cleanup was done. It does anyway.

This allows the mine’s environmental report to capture GHG benefits of a cleanup that may never happen, while ignoring all negative impacts of that same cleanup.

The DEIR must either fully ignore, or fully include, GHG impacts of the Centennial toxic cleanup as part of the mine report.

Ignores GHG emissions from using cement

Cement Paste Backfill use is constant = DEIR says 468 cement truck trips/yr

Based on payload size of trucks = 3,884 MT of CO2e released every year to produce the cement…not included anywhere in DEIR GHG analysis

This number would blow GHG emissions past the 10,000 limit used in the DEIR, for the entire 80 years of operation, triggering necessary mitigations

Per CEQA, the DEIR can’t include the project’s GHG emissions from cement production as part of the mine’s analysis, but the impact will happen, regardless

Ignore GHG emissions from ore processing

After some initial on-site ore processing, gold concentrate is shipped away because refining is a chemically intensive process w/ environmental issues

The gold-to-be-refined could be transported to Nevada, other US states, or even overseas for refining

The GHG emissions from this final transportation step (especially if via ship), as well as GHG released during the final gold refining process, are ignored

Final decisions should take into account the project’s GHG emissions from off-site ore transportation/ refinement regardless of the DEIR analysis.



Outdated limits (set too high)

Multiple GHG sources ignored =



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