 The Bureau of Land Management ( <unk> ) administers most land in the <unk> Creek Mountains , but there are also some private lands and some roads in the area . The private lands are mainly used for <unk> along mountain streams , while the <unk> lands include large grazing <unk> for local ranchers ' cattle . At least 100 mining claims in the mountains have been recorded since 1892 , some of which were staked for gold exploration . Commercial mining has occurred in some areas , mostly near the <unk> <unk> , where uranium and large amounts of mercury have been extracted . <unk> in what was called the <unk> <unk> District produced 270 @,@ 000 <unk> of mercury — " the richest supply of mercury in the western hemisphere " — from <unk> extracted from the <unk> in the 20th century . The two leading mercury @-@ producing mines in North America were the <unk> and <unk> mines on the edge of the <unk> in Nevada . Together , they operated from 1933 to 1989 . The <unk> Mine , the last mercury mine in the United States , closed three years later , in 1992 . However , mineral exploration has continued at the <unk> Mine in the 21st century , and waste containing mercury and arsenic was returned there from the community of <unk> as part of a U.S. Environmental Protection Agency <unk> project . 
