The Arrowhead district is in eastern San Bernardino County, 20 miles north-northwest of Danby in the southwest end of the Providence Mountains. The Hidden Hill mine was located in 1882. For several years following, Mexican miners recovered rich surface ores concentrated in arrastras. The Big Horn mine was worked on a large scale in 1918-19, and there was some activity during the 1920s and 1930s.
The principal rock in the district is quartz monzonite, which is cut by numerous diorite dikes, and in smaller amounts, quartzite and andesite. The ore deposits occur in north-trending quartz veins that are closely associated with the dikes. The ore contains free gold, pyrite, and chalcopyrite. Among the high-grade pockets found here, one 300-pound lot of ore recovered at the Hidden Hill mine in 1915 yielded $13,000. The chief sources of gold have been the Coarse Gold, Big Horn, and Hidden Hill mines.
Cloudman, H.C., et al, 1919, San Bernardino County, Arrowhead district: California Min. Bur. Rept. 15, pp. 800-801.
DeGroot, Henry, 1890, Arrowhead district: California Min. Bur. Rept.
Tucker, W. B., and Sampson, R. J., 1943, San Bernardino County, Big Horn mine: California Div. Mines Rept. 39, pp. 441-442.