Mining proposal threatens Arizona town's water supply

Report outlines risks that mine will deplete aquifer and contaminate groundwater.


Just eighteen miles north of the Mexican border, the town of Patagonia, Arizona sits cradled by 4,000 foot high mountains– a high desert oasis of oak and piñon pines, home to the rare ocelot and jaguar. But scattered throughout those mountains are abandoned mine shafts and tailings from the town’s not-too-distant past.

Small-scale miners arrived here in the 1860s, eager to sink their picks and shovels into the mineral deposits that lace the surrounding peaks and valleys. A century later, mining came to an end and the town “moved on,” says long-time Patagonia resident Wendy Russell. Its main drag - all of two blocks long – is lined with small businesses, which rely mostly on tourists who come to bike on quiet mountain roads, birdwatch, and hike the nearby Arizona Trail.

Still, more than 145 million ounces of silver and 7.2 billion pounds of manganese lie buried beneath the hills, and plans are underway that could re-start Patagonia’s old industry on an even larger scale: an open pit mine 4,000 feet wide and 1,500 feet deep, just six miles southeast of town. Wildcat Silver, a Canadian mining company, is behind the proposed Hermosa Mine, which supporters says will bring 300 jobs and a boost to the local economy.

Plans are underway for a large open pit silver mine in the Patagonia Mountains of southeast Arizona. Photograph from Flickr user Patrick Alexander
But the site also lies within the watershed that supplies Patagonia’s drinking water, and that has Russell and many other locals worried. In 2011 she helped found the Patagonia Area Resource Alliance, a group devoted to stopping Hermosa, which opponents fear will deplete the town’s water supply and contaminate the groundwater with acid mine drainage. From her house, Russell can see the town’s municipal water wells, which have dropped 18 feet since 2008, hammered by drought that has lasted more than a decade. Last year, with water levels at an all time low, the town manager recommended residents begin restricting their water use.

Russell pointed out that Hermosa would eclipse those efforts. “We could save all the water in the world and it would still just be a drop in the bucket compared to what this huge mine would consume,” she says.

 Those fears were confirmed in a recent report released by Earthworks, an environmental nonprofit, which found that the mine would use between 670 million and 1.2 billion gallons of water every year – 28 to 53 times more water than the entire town of Patagonia currently consumes. Even after the mine closes, a lake containing billions of gallons of groundwater will form in the abandoned pit, increasing depletion further as water evaporates off the surface. “You’re creating perpetual water loss that will persist well beyond the mine,” says Pete Dronkers an Earthworks staffer who helped prepare the report.

Greg Lucero, Wildcat’s vice-president of sustainable development, criticized the report for “misusing data to distort the truth.” In an op-ed published in the Weekly Bulletin, a local paper, he claims there is no connection between the source of Patagonia’s water supply and Hermosa’s since they are two separate aquifers

But during a March 2014 Forest Service public meeting, Greg Olsen, a Forest Service hydrologist, was asked if it were true that there is no connection between the aquifer that would supply water to the mine and the aquifer that supplies Patagonia’s water.

“The whole watershed is connected one way or another,” Olsen said. “There is no ‘steel wall’ between the two.” 

Lucero said the company is committed to developing a long-term water conservation plan, though it will not be in charge of implementing those promises. Wildcat is a mining junior – which means it won’t actually operate Hermosa.  Such companies generally prove the reserves exist, get a plan for the mine permitted, and then sell the asset to a major mining firm, whose business it is to build and run mines.

Currently the company is in the process of securing more permits for exploratory drilling before submitting a plan of operations for approval. Since the proposed mine site is within the Coronado National Forest, the Forest Service evaluates the project under the 1872 Hardrock Mining Law. But the way the law was written  – 142 years ago – makes it hard for land managers to say no to a mining project, even if the land is already used for other purposes such as protecting a town’s water supply.

Approval from the Forest Service will trigger environmental review under the National Environmental Policy Act but for Dronkers, such review is basically just a disclaimer – a way to perhaps reduce the impacts, but not eliminate them. “At the end of the day, you still have a massive water-sucking pit,” he said.

A number of agencies could stop the project from getting off the ground. The EPA, for instance has veto power under the Clean Water Act,  if it believes the mine would unleash extraordinary impacts, but it rarely uses that authority.

Meanwhile, more than 50 years after the last mining operation shut down, heavy metals continue to leach into streams and groundwater in the mountains above Patagonia. And at least six other mining companies are eyeing the area’s mineral riches. 

Sarah Tory is an editorial intern at HCN. She tweets @tory_sarah

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