The Midnite Mine cleanup continues on the Spokane Indian Reservation, with a host of major milestones completed in 2025.
After receiving partial clean-up funds from the federal government, Newmont Corporation, a gold mining company, began reclamation efforts in 2016 under direct oversight of the Environmental Protection Agency (EPA). Recent accomplishments include the final capping of Pit 4 with liners and nearby clean borrow material. Other than the water collected from the bottom of the filled pit, water from the upper half of the site will now be shed off without treatment. Palouse farmers also finished seeding slopes surrounding the site, which will enable native vegetation to take hold.
Pit 3, the largest on the site, started filling up with mine waste this fall. Before this could happen, the stored water had to be pumped out and treated, and a liner installed to protect the drain rock from filling in with sediment. The new water treatment plant is complete but undergoing one modification after the multimedia filtration step that didn’t operate as planned. By the end of 2026, the new plant should be treating water and discharging down to the Blue Creek Delta.
In 2026, Newmont expects to complete the landslide stabilization project in the Blue Creek Cove, and mine waste will be placed in Pit 3. They also expect that most of the work on waste rock will be completed in four years, which will include demolishing the old water treatment plant after the new one becomes operational. The discharge currently flows to a tributary of Blue Creek, whereas the new water treatment plant will discharge via a pipeline ending at the confluence of Blue Creek and the Spokane River. After passing through a “mixing zone” of a few hundred feet, the discharge is expected to meet Spokane Tribal water quality standards.
