The Patagonia Area Resource Alliance and Earthworks are working together to analyze Wildcat Silver’s open pit mine plans so that our community can better understand its likely impacts. Here are some of the outcomes we can expect if this proposal moves forward.
By reading reports that Wildcat Silver has recently released, which contain detailed information about its mining plans in the Patagonia Mountains, one can understand the purposes behind its current drilling proposal, which describes “drilling 24 geotechnical boreholes, 10 exploration boreholes and 12 hydrogeologic boreholes/monitoring wells, and excavating 16 test pits.”
One purpose of the monitoring wells, as described in a January 2014 Wildcat report, is to help “determine the quantity, location and pumping rates required to dewater the pit.” By the second year of mining, Wildcat’s open pit would go below the water table, and water would be seeping into the pit. In order to mine, Wildcat would have to continuously pump out this groundwater. The study says, “This creates a cone of depression around the pit allowing mining to take place.” What the report does not say is that this “cone of depression” will lower groundwater levels of the broader landscape. A rough calculation of groundwater pumping required by the mine would be 670 million gallons of water annually. To put this in perspective, the groundwater level for the town of Patagonia has already dropped nearly 18 feet since 2008, and the town uses approximately 42 million gallons per year. Wildcat’s drilling would require 15 times that amount.
Drilling is slated to occur primarily in Corral Canyon and Goldbaum Canyon. Corral Canyon is described in Wildcat’s report as “an optimal location for siting the TSF [Tailings Storage Facility]. Tailings typically contain dangerous chemicals, including arsenic, lead, mercury, and processing chemicals like acids and cyanide. Wildcat notes that Corral Canyon is at the top of the watershed. It is also the top of the Patagonia Municipal Supply Watershed, the sole source of drinking water for the town of Patagonia and an additional 300 area wells.
Goldbaum Canyon is the planned location for Wildcat Silver’s Waste Rock Storage Facility. Waste rock is rock that does not contain desired minerals. It often contains iron, which can transform to produce acid runoff when exposed to air and water. This phenomenon is known as acid drainage. Acid drainage is irreversible and is already an ongoing issue from historic mines in the Patagonia Mountains.
The ten exploration boreholes proposed in the current drilling plan, whose purpose is to prove the extent of the silver deposits, are essentially the same exploration holes Wildcat proposed in 2011 but withdrew when PARA, Defenders of Wildlife, and Sky Island Alliance sued the Forest Service over its approval of Wildcat’s plans.
By reading Wildcat Silver’s reports to investors, it becomes clear that the purpose of its current drilling proposal is to advance its open pit mine plan. A peer reviewed study of Wildcat Silver’s mine plan being prepared by PARA will provide further information on anticipated risks to our groundwater, the potential for acid drainage contamination, and heavy metals pollution, as well as the range of issues associated with air pollution, light and noise pollution.
Wildcat Silver reports can be found at: www.wildcatsilver.com/hermosa-project/overview/.