The Office of Arizona Attorney General Kris Mayes has acknowledged community concerns about groundwater dewatering and water-quality impacts tied to the South32 Hermosa project in Santa Cruz County, according to a statement released by the Calabasas Alliance. The statement, transmitted in a letter dated October 26, 2026, from Chief Deputy Attorney General William Mundell, was expressly authorized for public distribution and follows the submission of background information, data, and letters from community members.
The Attorney General's Office said it is "closely monitoring community concerns regarding groundwater dewatering and water-quality impacts associated with the South32 Hermosa project" and that it supports "a careful, independent examination of all impacts on the water resources of Southern Arizonans so that the appropriate and necessary protections can be achieved." The acknowledgment matters because it elevates a local dispute over a major mining project to the state level, signaling that regulators may scrutinize project-sponsored modeling rather than accept it at face value.
The Calabasas Alliance has argued that conclusions about groundwater drawdown, aquifer connectivity, and water quality must be transparent, independently verified, and capable of withstanding rigorous technical and public scrutiny. The group points to analyses by community members, technical professionals, and university and independent researchers that identified gaps in the evaluation of long-term dewatering effects, potential contaminant pathways, and cumulative impacts on local aquifers and surface waters. The organization maintains that findings on dewatering rates, the resulting cone of depression, aquifer impacts, and water quality—including reported antimony and arsenic findings—should be cross-checked against regulatory datasets, peer-reviewed research, and transparent public data sources.
Ernie Edwards, a Lake Patagonia resident and president of the "B" Property Owners Association, said the pending cone of depression from dewatering is a direct threat to residents around Patagonia Lake. He warned that high-volume pumping will lower groundwater levels across a wide area, affecting wells, surface flows into the lake, and the connected aquifers that supply the community and the Santa Cruz Active Management Area. Edwards called for independent hydrologic analysis now, rather than reliance solely on South32 consultant models, to understand the full extent of impacts and ensure protections are in place before irreversible drawdown or ground subsidence occurs.
Robin Lucky, president of the Calabasas Alliance, said the group appreciates the Attorney General's recognition that community concerns warrant independent examination. Lucky noted that massive dewatering will alter aquifer levels for decades and that questions remain about arsenic and other heavy metals in wells. Lucky added that these concerns compound Santa Cruz County's longstanding pollution challenges, including some of the highest PFAS levels detected in Arizona drinking water, according to EPA and ADEQ reports, and poor air quality in Nogales. The Attorney General's support for an independent examination could therefore shape how state agencies weigh permits and protections for water resources and public health in Southern Arizona.
