Idaho-Maryland Mine Reopening: What’s the Fuss About?

Staff Reporting

We at the Mountain Messenger would like to remind our readers that we have no dog in this fight, and as such would ask that both factions of public opinion please not deface our poor newsstands in Nevada City – they’re in rough enough shape as is.

If you live in Nevada County or have been anywhere within a 30-mile radius of Grass Valley, chances are that you’ve probably already heard the big story: the Idaho-Maryland Mine may be reopening soon, thanks to the miracles of modern mining techniques and the rising price of gold (see our commodity prices table near the back of the paper if you want to know just how much it has risen).  However, with all the public debate raging back and forth between the pro- and anti-mining factions locally and regionally, you may have missed some or most details of what’s being proposed, who is behind it, and what the fuss is all about.  That’s what we at the Mountain Messenger are here for, which is why we’re publishing this article.

Once upon a time, in the not-too distant past, the Idaho-Maryland Mine was the second-largest underground gold mining operation anywhere in California, only surpassed by the nearby Empire Mine, also on the outskirts of Grass Valley.  From its original location in 1865 by the Idaho Quartz Mining Company until its eventual closure in 1957, the mine was operated over six different periods by five different operators and remained consistently one of the most productive mines in the state.  The final owners, Idaho-Maryland Industries, closed the mine during World War II in compliance with Order L-208, which specifically closed gold mines nationally to redirect their labor force to aid with the war effort.

Though it reopened after the war, the price of gold was fixed at $35 an ounce by the Bretton Woods Agreement, which aimed to prevent the conditions that caused the Great Depression from happening again in Europe by stabilizing international monetary policies and exchange rates.  This rendered further underground gold mining uneconomical in the United States, and the mine closed in 1957.  Over its 92-year lifespan, the Idaho-Maryland Mine produced 2.414 million ounces of gold, worth about $4.76 billion in 2022 currency.

Rise Gold, a Vancouver-based Canadian mining company incorporated in 2007, purchased the two Idaho-Maryland mine properties and the mineral rights associated with those claims in their entirety.  The property consists of two sites – the 119-acre Brunswick Mine site, which is where mining activities will principally take place, and the 56-acre Centennial Industrial site, which the company intends to reclaim as developable real estate.  The Brunswick site is located off of Brunswick Road, downhill from the Nevada County Airport and next to a Christmas tree farm, while the Centennial site is located downhill from a garden supply store, between Idaho-Maryland and Bennett Roads.  The mineral rights for the property cover 2,585 acres in or east of Grass Valley.

The company is optimistic about both the likelihood of their project being approved and having a positive effect on the local economy.  Rise estimates that the mine reopening will add 312 jobs directly – 213 of which are expected to be recruited locally and 99 of which would be from out of the area – and another 300 indirect jobs as a result of employee expenditures in the local community.  The company expects it would overall pay out just over $138 million in payroll locally, which would be a noticeable positive inflow into the local economy.

With all that in mind, the proposal isn’t all sunshine and gold nuggets.  Local environmental groups and concerned citizens have been skeptical about the proposed project, principally from an environmental standpoint, and it’s not difficult to see why – this part of the Sierra Nevada is still, over a century and a half after the Gold Rush began, still dealing with the aftereffects of mine waste in the local environment.  While it may not be as bad as the days when mercury amalgamation methods were used to extract gold, which polluted dozens of waterways in the Yuba River watershed, modern mining techniques are still risky in the way of acid mine drainage and heavy metal leaching.

The mine itself has a bit of a history of causing trouble.  The aforementioned Centennial site, which was the mine’s principal tailings dump for decades, is riddled with enough heavy metal pollution to warrant consideration as a federal Superfund site under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (also known as CERCLA).  It would likely have ended up as just that if not for Rise Gold’s purchase of the Idaho-Maryland assets and agreement to clean the site up privately.  Still, that is just the waste from the old mine operations – what about the proposed project?

Rise Gold has defended their proposal by highlighting their planned use of cemented-paste backfilling, or CPB, to reduce their aboveground footprint and overall mine waste while preventing the risk of tunnel collapses affecting the aboveground environment after the mine eventually shuts its doors once more.  According to a 2020 doctoral thesis defended at the University of Adelaide, CPB is a method of refilling closed mine drifts and shafts with a high-pressure mixture of dewatered mine tailings, processed wastewater, and a cement binding agent.  The aim of this method is to fill mine cavities with tailings in a manner that prevents the leaching of toxic waste products into the surrounding water table.  The method is generally well-accepted, though critics have noted that the efficacy of the binding agent depends on the chemical composition of both the tailings and the binder, with some byproduct-binder combinations resulting in a quicker breakdown of the cemented matrix.

Local skepticism in response to the project has chiefly been due to the environmental effects the mine would have.  Groups such as the Community Environmental Advocates Foundation (CEAF) through its MineWatch community action campaign, and the Wolf Creek Community Alliance each have their own issues with the project, and are certainly willing to make their qualms known.

The Wolf Creek Community Alliance (WCCA) is a small local 501(c)(3) nonprofit that is entirely concerned with the health and streamflows of Wolf Creek, a tributary of the Bear River that drains the Grass Valley-Nevada city metro area.  Rise estimates that the reopening proposal would produce around 1,200 acre-feet of dredged wastewater per year, which would be heavily treated before being discharged into the South Fork of Wolf Creek.  The mine has attempted to assuage fears of riparian damage by highlighting the quality of the treated water, but the WCCA is also concerned with possible damage to aquatic invertebrate populations and stream erosion from the wastewater discharges.  Rise, for their part, claims a maximum discharge of 5.6 cubic feet per second – which doesn’t seem like much until you consider that the average baseflows on the South Fork are 15 cubic feet per second, meaning that the creek would swell by a full third at peak discharge.

MineWatch and the CEAF have been very outspoken and have encouraged community members who have issues with the proposal to join them in making their worries well known.  Their concerns span everything from noise increases and reduced property values to the project’s estimated 42 gigawatt-hours of annual energy consumption and the aforementioned mine waste issue.  The group has held community protests, including an upcoming one on March 20th, and has provided ample feedback on the project through written comments on the Draft Environmental Impact Report (DEIR).

There have also been financial concerns expressed in some circles about the project.  One commentor on social media noted that Rise Gold (OTCQX: RYES/CSE: RISE) is a penny stock that trades for 50 cents per share on average and has somewhere in the vicinity of $4-7 million USD in equity.  This is their first major operation, and if their approval is denied on environmental concerns, the bottom will fall out on this company in much the same way that it did on Northern Dynasty Minerals (another Canadian junior mining company) after their Pebble Mine project was denied.  The commentor postulated that it is entirely possible that the company will likely sell all its assets and permissions off to be handled by a larger, more experienced mining company if the project is approved, shifting the calculus of power and trust in this debate massively.

Regardless of your views on the proposal, the Mountain Messenger encourages all readers to make their stance heard at Nevada County’s DEIR meeting in the Eric W. Rood Administrative Building in Nevada City at 9:30 AM on Thursday, March 24th.

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