The processing of the copper oxide ore involved large quantities of sulfuric acid, made in an on-site sulfuric acid manufacturing plant.
Anaconda mining operations generated approximately 360 million tons of ore and debris from the open pit and 15 million tons of overburden resulting in 400 acres of waste rock placed south of the Pit, 900 acres of contaminated tailings, and 300 acres of disposal ponds.
In 1977, Atlantic Richfield Company (ARC) bought Anaconda.
The threats EPA is investigating at the site include contaminated groundwater and contaminated fugitive dust that could impact human health and surface water.
Additional concerns include on-site contaminated surface water (which could impact wildlife), and physical hazards associated with abandoned buildings, debris, and unstable materials such as the waste rock, heap leach and tailings piles, and pit lake slopes.
Portions of the site are owned by Arimetco (in bankruptcy) and portions are BLM managed public lands.