The Office of Arizona Attorney General Kris Mayes has acknowledged community concerns about groundwater dewatering and water-quality impacts linked 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 marks a significant step toward independent scrutiny of the mining project's environmental effects.
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 in Santa Cruz County” and 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 follows sustained, science-driven work by community members, technical professionals, and university and independent researchers who conduct ongoing water and air monitoring in the region.
The significance of the Attorney General's statement lies in its potential to shift the burden of proof. The Calabasas Alliance has consistently 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—rather than relying solely on project-sponsored modeling. The group maintains that scientific findings regarding 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 university research, and transparent public data sources.
Community leaders warn that high-volume pumping could lower groundwater levels across a wide area. 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, affecting wells, surface flows into the lake, and the connected aquifers that supply the community and the Santa Cruz Active Management Area. He called for independent hydrologic analysis now, rather than relying solely on South32 consultant models, to understand the full extent of these impacts and ensure effective protections are in place before irreversible drawdown or ground subsidence occurs.
Robin Lucky, president of Calabasas Alliance, said the group greatly appreciates the Attorney General's recognition that community concerns warrant independent examination. Lucky noted that massive dewatering will alter aquifer levels for decades, and questions remain regarding arsenic and other heavy metals in wells and the broader impacts in the county. 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 review could therefore have implications beyond the Hermosa project, reinforcing the principle that decisions about Southern Arizona's water and public health must rest on the best available science and transparent verification.
