The Barton and Lange Mine operated on the Klamath River in Siskiyou Valley, some four miles west of Oak Bar in the Oak Bar Mining District. Discovered in 1890 by owners J.A. Barton and company, the mine covered 60 acres at an elevation of 1,855 feet.
It primarily mined cinnabar, the source ore of mercury. Cinnabar resembles quartz and is most often found near areas of volcanic activity. The Barton and Lange vein stretched 160 feet wide and reached depths of 2,000 feet. Two tunnels driven in a bed of gray-green sandstone found the mineral, which was obtained by sluicing it.
Cinnabar is usually bright scarlet to brick red in color. It can be used to recover gold from river sediment and crushed ore, and the Chinese frequently bought the translucent red crystals for paint and medicinal purposes. They paid between $2 and $4 per pound, and sold its crystals for between $10 and $12 a pound.
Miners found cinnabar at several other sites, including along Horse Creek, 10 miles northwest of Oak Bar, and on the headwaters of the West Fork of Beaver Creek above Oak Bar.