News Release
In December 2022, the Patagonia Area Resource Alliance (PARA) filed legal objections to two permits issued by Arizona state agencies for the Hermosa Project in the Patagonia Mountains: an Aquifer Protection Permit (groundwater impacts) and an Arizona Pollutant Discharge Elimination System Permit (surface water impacts).
Aquifer protection permit
In 2018, the AZ Department of Environmental Quality (ADEQ) issued an Aquifer Protection Permit to the mining company South32, which is developing the Hermosa Project. This permit allowed for discharge of 120 gallons per minute of treated water into the Alum Gulch aquifer. In
August 2020, the mining company filed a significant amendment to add the discharge of 4,500 gallons per minute (6,652,000 gallons per day) from a newly constructed second water treatment plant into Harshaw Creek.
One week after filing a Motion to Stay requesting that the mining company not be allowed to discharge any water into Harshaw Creek until PARA’s appeal is decided by the State Court Judge, PARA filed an Opening Brief on Dec. 12 requesting that the State Court Judge return the permit back to the ADEQ with instructions to modify the permit; to require the installation of at least one monitoring well in Harshaw Creek; to require that the mining company demonstrate that the piping that will transport untreated tailings across the mining property complies with Arizona statutes; and to rule that as a matter of law the ADEQ has the authority to include narrative aquifer water quality standards in this permit.
AZ pollutant discharge elimination system permit
In 2018, the ADEQ issued an AZ Pollutant Discharge Elimination System Permit to the mining company. South32 has filed a request to renew the permit, which expires on Jan. 7, 2023. This permit is required for municipal, domestic, and non-domestic (industrial) discharges of pollutants to a surface water that fits the definition of “waters of the U.S.” as described in the Federal Clean Water Act.
On Dec. 14, 2022, PARA, along with several other environmental groups, submitted comments objecting to the renewal. The comments assert that the permit renewal cannot be issued primarily because the Hermosa Project is a “new source” of discharge as defined in the Federal Clean Water Act and because the ADEQ cannot renew the Permit until ADEQ updates the Total Maximum Daily Load (TMDL is the calculation of the maximum amount of a pollutant allowed to enter a waterbody so that the waterbody will meet and continue to meet the water quality standards for that particular pollutant).
PARA also asked the agency to address issues related to the sampling process; changing the water hardness calculation from influent to effluent water; and additional reporting requirements, stating that there are ongoing concerns about dewatering the aquifer.
Given the importance of the Patagonia Mountains and the existence of immense biodiversity in this region, the depletion of the aquifer will almost certainly harm or even destroy the numerous springs and seeps, and other surface water features, at a time when the existence of these critical water resources and the habitat they support are already under pressure from drought and climate change. The water that would be permanently removed from these aquifers by South32 is an important part of the function and health of the biodiversity of the Patagonia Mountains and the Sonoita Creek Watershed.
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