News release from Santa Cruz County:
Dec. 30, 2025 – The Santa Cruz County Board of Supervisors has invited South32, the Arizona Department of Environmental Quality (ADEQ), and local Hydrogeologist Chris Gardner, RG, to provide information regarding the recent water sampling results from the South32 Hermosa Mine. The sampling, conducted to meet the conditions of the mine’s Arizona Department of Environmental Quality Individual Aquifer Protection Permit, revealed an elevated presence of antimony, a regulated pollutant.
The detection of elevated antimony triggered a mandatory ADEQ review under state environmental regulations. These meetings will be an opportunity for stakeholders to update the community and respond to questions.
Meeting Schedule
- South32 Jan 7, 2026 9:30 am 2150 N. Congress Drive, RM120, Nogales
- ADEQ Jan 21, 2026 9:30 am 2150 N. Congress Drive, RM120, Nogales
- Chris Gardner, RG Feb 4, 2026 9:30 am 2150 N. Congress Drive, RM 120, Nogales
Submit Questions
We encourage all attendees to participate respectfully during the sessions. To support a timely and organized discussion, questions may be submitted in advance to clerkoftheboard@santacruzcountyaz.gov.
Members of the community will also have an opportunity to ask questions during the meeting; however, time will be limited. The sessions will also be available on the Santa Cruz County YouTube channel: https://www.youtube.com/@santacruzcountyarizona.
For more information about the South32 Hermosa Project water quality permitting, visit the ADEQ website: https://azdeq.gov/wqd/hermosa-south32.
Water Quality Permits Governing South32 Hermosa Operations
South32 Hermosa’s water quality is regulated under two separate permits: Arizona’s Aquifer Protection Permit (APP) and the Arizona Pollutant Discharge Elimination System (AZPDES). The APP is a state program intended to protect groundwater, which Arizona law considers to be clean drinking water. AZPDES is a federally required program administered by the state that limits pollutants from entering surface waters, such as rivers and streams.
South32 Hermosa operates under the Individual Arizona Aquifer Protection Permit No. P-512235 and AZPDES Permit No. AZ0026387. Water quality monitoring data reported by the company are publicly available through the U.S. Environmental Protection Agency’s ECHO database and can be accessed using the permit number at: https://echo.epa.gov/trends/loading-tool/get-data/monitoring-data-download.
About the Arizona Department of Environmental Quality
The Arizona Department of Environmental Quality (ADEQ) is the state agency responsible for administering Arizona’s environmental laws and delegated federal programs to protect public health and the environment. Established in 1987 under the Environmental Quality Act of 1986, ADEQ serves as Arizona’s cabinet-level environmental agency. The department is organized into three primary programs: Air Quality, Water Quality, and Waste. It carries out core functions including planning, permitting, compliance management, monitoring, environmental assessment, cleanup activities, and public outreach.