South32 Hermosa project closer to US federal approval

Key Milestone for Hermosa Project

South32 (ASX: S32) has achieved a significant milestone in the advancement of its Hermosa zinc-silver project located in Arizona. The US Forest Service has released a Final Environmental Impact Statement and a Draft Record of Decision, indicating its intent to authorize development on National Forest land. This decision is pivotal as it potentially allows South32 to extend its operations beyond privately held land and construct essential infrastructure on federal property.

The Draft Record of Decision initiates a formal review period for stakeholders who have previously submitted public comments. Following this review, the Forest Service may issue a final decision, paving the way for the construction of various project components. This development marks a crucial step forward for the Hermosa project, which aims to tap into significant zinc and silver deposits.

Environmental Considerations and Mitigation

The Final Environmental Impact Statement underscores the agency’s preferred development approach, incorporating technical analysis derived from years of thorough environmental assessments. According to the plan, South32 will be permitted to construct a primary access road, a secondary dry-stack tailings facility, and a segment of a 138 kV transmission line on National Forest land. UniSource Energy Services will be responsible for the construction of the power line.

Notably, Hermosa was the inaugural mining project to be included in the federal FAST-41 permitting program, designed to expedite reviews for major infrastructure projects deemed vital to the US economy.

"This Draft Record of Decision reflects years of listening, collaboration and real changes shaped by community input," said Pat Risner, president of South32 Hermosa. "The draft decision affirms our design and development approach, including mitigation measures described in the Final Environmental Impact Statement that were informed through agency and public consultation."

The Forest Service conducted an independent analysis of Hermosa’s Mine Plan of Operations, which was released in 2024, alongside baseline environmental data collected over several years and feedback from the National Environmental Policy Act comment period. The agency determined that the selected development alternative optimally aligns with the project’s objectives while minimizing environmental impacts. The plan includes a primary access road designed to divert traffic away from Patagonia, a section of the 138 kV transmission line, an updated dry-stack tailings facility, and a direct water discharge system situated high in the Patagonia Mountains to replenish the aquifer and support local wildlife.

Project Timeline and Community Benefits

South32 has already obtained the necessary state permits from the Arizona Department of Environmental Quality for initial surface infrastructure located on private land. Beyond regulatory compliance, the company has pledged to implement nearly 140 additional conservation, mitigation, and monitoring measures developed in collaboration with federal agencies, Indigenous Nations, and community stakeholders. South32 intends to operate the project under an adaptive management framework and a no-net-loss biodiversity standard, enhancing environmental protections as scientific understanding advances.

The Draft Record of Decision initiates a 45-day objection period, followed by a potential 45-day resolution process before the Forest Service issues a final decision. South32 anticipates the Final Record of Decision in July and will continue to engage with regulators and communities during the review period. The Hermosa project, designed with a surface footprint of approximately 750 acres, is expected to use roughly 90% less water than many regional mining operations and could support up to 900 jobs at peak production, fostering long-term investment in surrounding communities. These jobs would provide a substantial economic boost to the region.