Oregon decided to outlaw “suction dredging,” the only profitable method of mining gold from streambed deposits. Suction dredging uses a small, lawn mower-sized motor and an underwater vacuum hose to suck up and filter gold out of streambed sediment. The federal Mining Act, however, encourages free and open exploration for valuable minerals on federal lands. The Constitution’s Supremacy Clause means that when the federal government authorizes you to do something, a state can’t prohibit you from doing it. Miners challenged the Oregon law as preempted by the federal Mining Act, which reigns supreme under our Constitution.
For nearly 150 years, federal law has expressly encouraged the “free and open” exploration for and extraction of valuable minerals from federal lands. Although states may regulate the environmental side-effects of mining on federal land within their boundaries, states cannot ban mining on federal land or pass laws significantly obstructing the objectives of federal mining laws. Nonetheless, Oregon passed a law prohibiting the use of all motorized mining equipment in its rivers and streams. Federal law allows it—encourages it, even. Congress can prevent the states from adding another layer of potentially costly and repetitive regulation onto the backs of individuals and businesses toiling in a regulated industry.
Several miners sued the state in the federal district court, but the court held that so long as the miners could dig with their hands and shovels, the mining ban is not preempted by federal mining law. The court characterized anything short of a complete ban as an environmental law that may not be categorically preempted. The court never considered whether the ban conflicts with federal objectives. Now on appeal to the Ninth Circuit, PLF and the Western Mining Alliance filed an amicus brief that explains how the district court badly misread the law on federal preemption, and that Oregon’s law does, in fact, significantly conflict with the federal objective of keeping mining “free and open.” When a state law conflicts with federal law, as Oregon’s does, the state law is preempted and must yield.