Patagonia – The Hermosa silver mine proposed inside Patagonia, Arizona’s Municipal Supply Watershed could deplete the town’s drinking water and perpetually contaminate area groundwater with acid mine drainage, according to a new peer-reviewed report. Reviewed* by a USGS scientist and released by the Patagonia Area Resource Alliance and Earthworks, the study also concludes that drinking water wells of surrounding residents are also threatened.
“A mine that threatens our town’s drinking water is a mine that shouldn’t be built,” said Wendy Russell of the Patagonia Area Resource Alliance. She continued, “In Arizona, water is more precious than silver, and especially so after more than a decade of drought.”
Proposed by Canadian exploration company Wildcat Silver – a company with no experience operating a mine – Hermosa is proposed at a time when Patagonia is already concerned with dropping groundwater levels and increasing concern about future water supplies.
The 4,000 foot wide and 1,500 foot deep Hermosa silver and manganese mine would consume 670 million to 1.2 billion gallons of groundwater per year – up to 53 times the amount of water the town uses today — to run the mine within the upper reaches of Harshaw Creek, a portion of Patagonia’s Municipal Supply Watershed. This water consumption will lower the recharge rates for the aquifer on which the town depends, and is also likely to produce acidic runoff, requiring ongoing treatment in perpetuity.
“If the U.S. Forest Service were to permit the Hermosa mine, this report shows it would jeopardize our community’s drinking water. And for what? For foreign shareholders’ silver,” said Wendy Russell. She continued, “This is a mine proposal that just doesn’t make sense for our community who would actually have to live with it.”
The mine is proposed within the Coronado National Forest, and therefore subject to the 1872 Mining Law. Federal land managers interpret the 1872 Mining Law to require them to permit mines, no matter if the land is better used for other purposes – like protecting a town’s drinking water supply watershed.
“Because the Hermosa mine proposal threatens area water supplies, it obviously should not be permitted,” said report author Pete Dronkers of Earthworks. He continued, “That it’s being considered at all is a strong argument for reforming the 1872 Mining Law to allow the consideration of other potential land uses.”
The report also evaluates the nature of groundwater depletion that is likely under the proposed mine plan, characterizes the impacts of such, and also analyses other known adverse impacts, such as air pollution, endangered species, and other cumulative impacts.
The report, including an executive summary, can be found at hermosareport.earthworks.org.