CHEYENNE, Wyo. (AP) — Environmental groups hailed the U.S. Supreme Court’s rejection of an appeal challenging a federal rule that bars development on 50 million acres of roadless areas in national forests, ending one of the main legal battles that had left the rule in doubt for more than a decade.

“The Supreme Court action validates arguably one of most important public land conservation polices in a generation,” said Jane Danowitz, a director of the Pew Environment Group, which has worked on the rulemaking since 1998. “Without the roadless rule and its national standard of protection these millions of acres of pristine forest land could be opened to a variety of development, including logging, mining and drilling.”