Holden Mine Water Treatment Plant

IMCO constructed a new mine water treatment plant at the site of an abandoned copper mine in remote central Washington, near Lake Chelan. IMCO’s client, global mining giant Rio Tinto, is responsible for the clean up of the mine that was acquired in 2007. Holden Mine has not been operational since the late 1950s. The water treatment plant project is part of a larger $200 million effort to remediate past environmental problems at the mine.  

This project was completed in just nine months, less than half the typical duration for a project of this size and scope. The work included excavation and backfill, footings and foundation, underground piping and utilities, an equalization pond, outfall pipeline, storm water ponds, basins, pump stations, a generation facility, and chemical storage building. All equipment and materials were barged up the lake from Chelan to the very remote site near Holden Village, where project personnel stayed during construction.   

Upon completion of construction, IMCO was hired to operate and maintain the WTP on an on-going basis. The plant operates 24 hours a day, seven days a week and has produced two billion gallons of clean effluent with zero unplanned downtime or environmental spills since completion in 2016.