A draft environmental impact statement for the South32 Hermosa project issued by the U.S. Forest Service on Friday is now available for public review and comment and will be the subject of public meetings on May 27 at Patagonia Union High School and May 28 at Nogales High School. Both meetings will be from 4:30 to 6:30 p.m.

As part of its review, the Forest Service identified its preferred alternative for Hermosa’s plan of operations after weighing the benefits and environmental impacts of the mine’s proposed plan. Preferred alternatives include the construction of an overhead 138kv power line, a new primary access road, a dry-stack tailings facility and direct water discharge in the Patagonia Mountains.

The draft environmental impact statement and supporting documents are available under the “Project Documents” section on the Coronado National Forest website. The statement is divided into four chapters, totaling 750 pages, and 11 appendices totaling 435 pages.

The preferred alternative is outlined in Chapter 2. The preferred alternative does not represent a commitment on the part of the Forest Service but is intended to solicit written feedback from community members, participating agencies, consulting parties, tribal nations, and other stakeholders. 

Key components of the preferred alternative include:

  • A preferred access route of approximately 7.6 miles constructed on National Forest Service land, incorporating 2.7 miles of Flux Canyon Road, 0.2 miles of Forest Service Road 4654 and 4.7 miles of new construction that would parallel Forest Service Road 4653 (Barriles Tank Road). The route would include a new bridge over Flux Canyon and smoothing and widening existing roads. Primary access would continue to use the Cross Creek Connector and Harshaw Road until the Primary Access Road is complete.
  • Construction of approximately 225.6 acres of tailings storage facilities on Forest Service Land for placement of sulfide tailings, potentially acid-generating waste rock, wastewater treatment solids and sediment from stormwater basins.
  • Construction of a 138-kV overhead electric power transmission line, ranging in height from 58 to 128 feet. 
  • Discharge of treated water directly into Goldbaum Canyon and Mowry Wash in addition to the current discharge onto private land into Harshaw Creek.

Public comments must be received by June 23. They can be submitted electronically using the public comment form, by email with the subject line “Hermosa Critical Minerals Project,” or by mail to:

Kerwin S. Dewberry
Forest Supervisor, Coronado National Forest
ATTN: Hermosa Critical Minerals Project
300 West Congress Street
Tucson, AZ 85701

At the close of public comment period, the Forest Service will review the comments and make revisions as necessary in its final environmental impact statement, which is anticipated by February 2026.

“As USFS finalizes its review, we look forward to continue working with our federal, state, local and Tribal stakeholders to deliver on our aim of setting a new standard for sustainable mining and developing a project that benefits the region now and for generations to come,” said Brent Musslewhite, Hermosa Project Director of Environment and Permitting.