This "alternative use" proposal would use the existing mine tunnels as an emergency water source and reflects on the complex geology that could affect wells beyond the predicted area.
This opinion piece was originally published in The Union.
It is likely our community would survive another 80 years without a gold mine. We won’t survive that long without water, which is rapidly becoming the world’s new gold. Current climate trends and over-development increase the likelihood we will face water rationing, higher rates and increased pressure to build a new dam. Are there alternatives?
According to Nevada County documents, the Idaho-Maryland Mine contains between 576 to 815 million gallons of water as well as ongoing mine inflows — all to be pumped and dumped by mine operators into a local creek after improving to “drinking water standards.”
The inflow is “pass through” water from natural sources. Outflow would be less than inflow due to mine operations, I believe reducing Nevada Irrigation District’s currently available downstream draw and likely leading to higher water rates for NID customers.
As the mine is part of the currently stable water table system, a severe drop in mine water levels is expected to affect local wells and may, as critics point out, affect wells far beyond the areas predicted by incomplete modeling and old records.
The problem is our complex geology. Where influx water comes from is an open question. Well owners and the mine get water from cracks in bedrock that collect and transfer water — but it is only guesswork as to how far and wide these cracks extend, leading to questions as to how far well dewatering could occur.
Here are a few more thoughts for consideration:
∎ A Sierra College geology teacher once said that Nevada County’s geology is some of the most complicated in the state, noting that the water outflow on the public spring on Bitney Springs Road likely originates at much higher elevations.
∎ Local fracturing includes an earthquake fault three miles west of Grass Valley, running from Lake Oroville to beyond Auburn.
∎ Opening up gold-containing fractures raises more water movement questions. While the North San Juan Siskon disaster involved different geology, the principle is the same.
∎ At a city of Grass Valley-hosted forum on water issues for the previous (Emgold) proposal, mine proponents maintained that mining operations would be below existing ground water tables, so wells would not be affected. When then asked about where mine water came from, the vague response referenced uncertain geology around Wolf Creek, raising the possibility of partial creek dewatering if the mine were drained.
There may be a higher and better use for the mine. As we face the prospect of extended and possibly worsening drought for the foreseeable future, new water sources will have to be found.
The mine could potentially serve as a supplemental or emergency water source. In some ways, mine water storage is little different than a new dam but without eminent domain, massive construction costs, ecological negatives, etc.
Effects on local stream levels would be comparable to a dam’s varying stream flow impacts but on a smaller scale. As a supplement to existing supplies, this could offset the need for a new dam for years.
Estimates of the mine’s water volume range from 1,767 to 2,501 acre/feet. At California’s typical annual household usage of one half to one acre feet, the mine holds enough water to serve 2,500 or more homes for one year, making it a potential alternative revenue source for mine owners.
Drawn down in drought years and recharged in wet years, the mine water would be continually renewed at no cost beyond providing water to affected well owners. Even seasonal use is possible, as summer drawdowns would be eventually restored to Wolf Creek through our sewer system (minus evaporation from garden use, etc.).
Truckee just bought water from PG&E for about $38/acre foot and urban users pay as much as $1,500 to $2,000/acre foot; some farm districts pay much more. Sale of mine water could generate anywhere from $67,000 to several million dollars and becomes a sustainable local water — and revenue and job — source beyond the mine’s predicted lifespan.
Add in another profitable, clean, renewable and local job-producing opportunity for mine owners: a biomass plant. The Brunswick site was identified by Nevada County’s biomass research group as a possible biomass (logs, branches and brush) energy plant location. This is the place that recently had mountains of storm damage biomass — free energy — hauled away to a distant biomass plant.
It’s time for local leadership to take climate change seriously. The mine site offers better — sustainable — options than extracting sort-sighted profit.
Terry Lamphier lives in Grass Valley.