Sustainability

We view Hermosa as a next-generation mine, presenting an opportunity to deliver transformational safety and productivity outcomes while redefining the relationship between mining and the environment.

Setting a new standard

Next-generation mining

Dry-Stack Tailings

As part of voluntary cleanup of bygone-era mining waste left by a prior miner in this historic mining district, South32 built one of the nation’s first new dry-stack tailings facilities, limiting the surface disturbance and achieving the highest standard of safety and water conservation. Watch this video to learn more.

Water Management

In the interest of protecting and conserving natural resources, South32 closely monitors and measures water activities at Hermosa. Hermosa will use 90% less water than other mines in the region, and South32 is working with the community to explore beneficial reuse of the groundwater that needs to be relocated away from the orebody for safety. The project is being designed to eliminate the need for perpetual water treatment beyond the life of the mine.

Limited Footprint

Hermosa’s surface footprint is just 750 acres. That’s a fraction of the footprint of other mining projects, which often stretch for thousands of acres.

Wildlife & Biodiversity

South32 works hard to manage our environmental impact, and we are committed to protecting wildlife and biodiversity in the areas surrounding Hermosa. Wildlife and biodiversity monitoring has been ongoing at Hermosa since 2013, and we regularly conduct surveys for plants and aquatic species.

Cultural Preservation

South32 is working to build strong relationships with local tribes that have historic affiliation to the project area and neighboring lands., Establishing transparency and building trust are our top priorities, so we host site tours with local tribes, have discussed with them our project plans to understand any historic connections to the project area and surrounding region, and voluntarily conduct cultural resource surveys on 30,000 acres, including private lands, in the accompaniment of tribal monitors.

Underground Mining Method

We are developing Hermosa with an underground mining method that will also involve backfilling the stopes as we progress. The backfill materials will be the post-mining native rock that has no mineral value, treated to a consistency that allows it to be placed like a paste and dried to a cement-like state. Called “cement paste backfill,” this advanced method greatly reduces the volume of stored tailings on the surface while all but eliminating subsidence of earth at the surface.

Operating Remotely

South32 is developing Hermosa to use extensive automation technology and, in part, be run remotely from an office-like remote operating center in Nogales, Arizona. The remote operating center will further enhance productivity and safety for workers while reducing commuter traffic to and from the Hermosa project site in the Patagonia Mountains.

Reducing Impact

We will use automation and technology to minimize our impact on the environment and increase employee safety.

Renewable Energy

South32 is developing Hermosa to enable power supply from renewable energy, which could underpin new renewable energy capacity and infrastructure across the local region.

Electrified Transport

South32’s design principles include planning for an all-electric vehicle fleet at Hermosa powered by renewable energy to reduce noise, improve working conditions, safety and health, and support delivery of South32’s operational greenhouse gas reduction targets and goals.

Sustainable Development Report

Our 2025 Sustainable Development Report shares how we’re working toward our sustainability goals and managing key priorities. For more detail, view our full 2025 Annual Report, which includes both our Sustainable Development Report and Corporate Governance Statement.

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Our commitment to United Nations Sustainable Development Goals

South32’s commitment to advancing the UN Sustainable Development Goals (SDGs), including the 19 primary SDG targets which our activities contribute to.

Remediation

Building the foundation for next-generation mining

In early 2020, South32 completed a $40 million voluntary cleanup of mine waste left by a previous miner at the Hermosa project in the last century. This helped to: