South32 Submits Information to Assist ADEQ with Hermosa Air Permit Non-Substantive Claim Amendments

FOR IMMEDIATE RELEASE

August 25, 2025

Additional record-keeping and reporting details provided in limited ADEQ permit reopening

South32 Hermosa – the only advanced mine development project in the United States that could produce two federally designated critical minerals, manganese and zinc – has submitted information to the Arizona Department of Environmental Quality (ADEQ) in response to its limited reopening of the Hermosa air quality permit. This action was taken to address the five non-substantive petitioner claims upheld in the Environmental Protection Agency (EPA)’s May 30^th, 2025, decision.

“We worked diligently with ADEQ to respond to the EPA’s ask while keeping the permit amendment process on schedule,” said Pat Risner, President of South32 Hermosa. “Our day-to-day did not change with this request, and we have continued to safely construct and work on site under the currently approved air permit, which meets all substantive Clean Air Act requirements.”

In its decision, the EPA rejected 15 of the 20 claims raised by petitioners, confirming the permit met all substantive requirements under the Clean Air Act. The five claims upheld were procedural, focusing on improving recordkeeping and reporting clarity.

Public comments can be made only on the specific sections of the permit that were revised in response to EPA’s request.

Public Comment Period:
August 26 – September 25, 2025

Public Hearing:

Thursday, September 25, 2025 | 6:00 PM
Patagonia Elementary and High School Multipurpose Room
200 Naugle Avenue
Patagonia, Arizona 85624

The draft permit and related documentation are available for public review at azdeq.gov/publicnotices.

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