South Dakota Mining Ass'n, Inc. v. Lawrence Cnty.

Lawrence County, South Dakota (defendant) voters approved an ordinance banning new or amended surface metal-mining permits in the Spearfish Canyon Area, 90 percent of which was federal national forest land where surface mining was the only practical method of extracting minerals located at the earth's surface. Mining companies (plaintiffs) challenged the ordinance, and the district court found it preempted by the federal Mining Act of 1872, which encourages mineral exploration and extraction on federal land; a citizen (defendant) intervened and appealed, arguing the ordinance was a reasonable, narrowly targeted environmental regulation that didn't actually prevent the Act's broader purposes.