About the Project

The Holden Mine Cleanup Project cleanup project was divided into two phases. The first phase was completed in 2018 and a second, smaller phase is planned to begin construction in the next few years. Water, soil and biological monitoring and water treatment are ongoing and will continue for several years to ensure the cleanup meets federal and state standards.

Phase 1

Rio Tinto started construction on the Holden Mine Cleanup project in 2012 and the first phase was completed in 2018. The lead agency for the cleanup, the U.S. Forest Service, has confirmed that Rio Tinto has completed the first phase of the project in compliance with the approved design. Rio Tinto spent over half a million dollars and more than 2.2 million worker hours on phase one.

Phase 2

Phase two is slated to begin construction in 2023. During phase one, Rio Tinto constructed an 4,756-foot barrier wall and water collection system to capture water coming out of the old mine workings and off of the tailings piles and transport it to the water treatment plant. The wall constructed during phase one ran most of the length of the tailings pile, and the goal of phase two will be to complete that wall to ensure that all the contaminated water is collected and treated before returning to Railroad Creek.

The Future

Rio Tinto is committed to the Holden Mine Cleanup Project for the long term. Decades of environmental monitoring and water treatment will follow the cleanup activities. An operations and maintenance team remains at the site year-round to manage water treatment and take care of facilities. Shipments of supplies and materials for the water treatment plant will be barged up Lake Chelan for many years to come.