FOR IMMEDIATE RELEASE
February 9, 2026
South32 Hermosa – an advanced mine development project in the United States that could produce five federally designated critical minerals, including zinc and manganese – today announced that the Arizona Department of Environmental Quality (ADEQ) has issued the project’s updated Class I Air Quality Control Permit following a review by the U.S. Environmental Protection Agency.
The review confirmed that South32’s design for Hermosa remains protective of public health and the environment and meets all applicable federal and state regulatory air requirements.
The approval follows ADEQ’s limited reopening of the permit to consider additional information submitted by South32 in response to EPA seeking more clarity on issues largely related to recordkeeping and reporting. South32 proactively submitted supplemental details to assist ADEQ in updating the permit.
“We worked diligently with ADEQ to provide timely and complete information in response to the procedural request while keeping the permit process on schedule,” said Pat Risner, South32 Hermosa President. “ADEQ’s decision confirms South32 Hermosa meets all substantive state and federal air requirements, and the minor revisions under review did not affect the strong health and environmental protections that were already included in the final permit.”
ADEQ’s evaluation confirms the air quality permit’s enforceable emissions limits, monitoring, and compliance requirements are protective of air quality and public health. In its decision last year, the EPA rejected 15 of the 20 claims raised by petitioners and confirmed the permit met all substantive requirements under the Clean Air Act. The five claims upheld were procedural, focused on improving recordkeeping and reporting clarity.
“Because South32 is building Hermosa from the ground up, we are using advanced technology, world-class engineering and industry best-practices to enhance air quality safety for the surrounding community,” Risner added.
In addition to regulatory compliance commitments, South32 offers a publicly accessible air quality monitoring dashboard – a transparency tool that provides near-real-time data on local air quality and supports ongoing community awareness.
Additionally, South32 will deploy industry best-practice systems to measure baseline dust and manganese levels in surrounding communities prior to operations. That data will help the project better understand any potential changes as well as provide a baseline assessment of existing community exposure.
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About the South32 Hermosa
Located in a historic mining district in the Patagonia Mountains of Southern Arizona, South32’s Hermosa project is currently the only advanced mine development project in the United States that could produce up to five federally designated critical minerals — including zinc and manganese — both of which are essential minerals for powering the nation’s clean energy future. Learn more at www.south32hermosa.com.
Hermosa is a polymetallic development comprised of a zinc-lead-silver sulfide deposit, a battery-grade manganese deposit and an extensive, highly prospective land package with the potential for further polymetallic and copper mineralization.
Media relations
Lina Betancourt
M +1 514-210-1822
E Lina.Betancourt@south32.net