The Hermosa Mine is proposed in the Sonoran Desert, six miles southeast of Patagonia and just over an hour’s drive south of Tucson. If built it will mill about 13,000 tons of silver and manganese ore per day, ultimately digging a pit more than 1,500 feet deep.
The proposal lies within Patagonia’s Municipal Supply Watershed – its drinking water source – inside the Coronado National Forest.
AZ Mining Inc (Wildcat Silver), the junior Canadian company behind the proposal, has never operated a mine before.
Water consumption threats
- Even without a mine, the Patagonia area already faces a water crisis after a decade of drought.
- The mine would consume between 670 million and 1.2 billion gallons of water each year.
- The mine would consume water equivalent to 25,000 to 46,000 Arizonans.
- After the mine is closed, the pit lake will increase groundwater depletion in adjacent aquifers as it forms.
- Even after closure, evaporation from the pit lake will consume groundwater at a rate comparable to the operating mine.
- Wildlife is likely to be negatively affected as area springs run dry to due groundwater depletion.
Water pollution threats
- The geology of the deposit virtually guarantees that the mine’s waste will cause acid drainage and metals leaching to contaminate water in perpetuity.
- Studies show that groundwater flows down the drainage in which the mine is proposed, meaning wells below the mine site – including Patagonia’s drinking water supply – could be contaminated by sulfuric acid, heavy metals and sulfate.
- Most mines in the Patagonia Mountains – though operations ceased over 50 years ago — continue to leach acid today.
Other threats
- The mine may consume as much electricity as over 35,000 Arizonans, burn 9.3 million gallons of diesel fuel each year, and emit 591 million pounds of carbon dioxide pollution annually – equivalent to 71,000 cars.
- Light and noise pollution would be a constant reality for the 18 years the mine is projected to operate.
- The widening of Forest Service roads and numerous other types of infrastructure development will affect existing recreational uses and residences near and beyond the mine site.
- Because it’s proposed within the Coronado National Forest, Hermosa is 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 drinking water watershed.
