Understanding proposed Key Mill expansion

Key Mill, located about six miles east of Republic in Ferry County, is a facility that processes rocks and sediment from nearby underground gold mining operations and stores the leftover materials called tailings.

The plant is operated by Echo Bay Minerals Co., also known as Kinross Kettle River Operations. Echo Bay Minerals is proposing to increase the mill's tailings capacity by approximately 5.5 million tons.

The expansion is intended to extend the life of the mill by another nine to 12 years. To accommodate additional tailings, the company has proposed raising the height of its storage facility by 75 feet.

Understanding potential environmental impacts

The proposed expansion substantially changes the mill's existing operations, and the change could result in environmental impacts. Because of this, we are carefully evaluating the proposed expansion and prepared a draft Supplemental Environmental Impact Statement (SEIS) under the State Environmental Policy Act. This assessment will help us better understand:

• Stability and safety of a raised tailings storage facility
• Potential impacts to water quality and aquatic life
• Effects on visual landscapes and communities
• Impacts related to climate change, environmental justice and potential cumulative effects on the region

Our draft SEIS is designed to update earlier environmental reviews with new information about the potential stability of a larger tailings storage facility, how the proposed changes could affect water quality, and how factors such as climate change and environmental justice are being considered.

This will help us determine what future permits may be needed for the expansion and ensure the project is responsibly managed to protect people and the environment.

Join us at a public meeting to better understand what's included in the draft SEIS, ask Ecology and the company questions, and provide feedback.

In-person public meeting
Wednesday, June 17, 2026, 5:30 p.m.
Ferry County Fairgrounds, Carousel building, 12 Fairgrounds Road, Republic, WA 99166

Virtual public meeting
Tuesday, June 16, 2026, 5:30 p.m.
The link to join the virtual public meeting will be added to the Key Mill webpage.

Submit comments

Ecology will consider all comments received during this public comment period and will include a response to comment summary in the Final SEIS. Comments can be submitted online or by mail to:

Karl Rains
Department of Ecology Eastern Region Office
4601 N. Monroe St.
Spokane, WA 99205