The U.S. Forest Service will resume cleanup work on six abandoned mines on the Prescott National Forest in Yavapai County.
The site primarily produced gold and silver, but operations likely ceased before the 1940s.
Officials say since then mine waste has polluted the surrounding environment impacting local watersheds and threatening human health and wildlife.
Last year the Forest Service began an effort to clean up the mines but split the construction into two phases to avoid working during Mexican spotted owl breeding season.
Phase one was completed last February and the next phase will begin in December.
Crews will consolidate mine waste, close entrances to the mines and install erosion control measures. Residents and visitors should expect heavy construction near the town of Cherry.