It has been known for decades that there are about four billion tons of copper and nickel ore, "one of the world's largest undeveloped mineral deposits", in the Duluth Complex, which underlies part of northeastern Minnesota. Resource companies have proposed mines south and west of the BWCAW upstream of the wilderness and within its watershed, leading to concerns that surface runoff could damage the wilderness. In December 2016 the federal government proposed banning mining for 20 years while the subject was studied. The Trump Administration cancelled the study in September 2018, clearing the way for mining leases in the national forest. The Antofagasta PLC subsidiary Twin Metals Minnesota would operate the proposed mine. The proposed mine is approximately 2 miles from the BWCAW in an area which drains into the BWCA.