Location and History
This district is in the San Gabriel Mountains in eastern Los Angeles County. It is just west of Mount San Antonio, which is also known as Mount Baldy or Old Baldy. It is both a lode and placer-mining district.
Placer mining was originally done here in the San Gabriel River in the 1840s, and for several periods following that time, this district was quite productive. Production was obtained from both the stream beds and from terrace gravels, which were mined by hydraulicking. In 1874 it was reported that more than $2 million had been produced in the previous 18 years. The principal period of lode-gold mining was 1903- 1908, but there was some activity again in the 1930s. The estimated output from the lode mines is 50,000 ounces. There has been minor work in recent years, chiefly by weekend prospectors.
The gold-quartz veins occur in schist and gneiss. The ore deposits are rich in places. The ore bodies usually are three feet or less in thickness and do not extend to any great depth. The oxidized zones near the surface yielded the richest ore.
Allison $50,000, Baldora, Big Horn $40,000+, Eagle, Gold Dollar, Holly, Heaton, Native Son, Stanley, Zanteson.
Gay, T. E., Jr., and Hoffman, S. R., 1954, Gold-Los Angeles County: California Jour. Mines and Geology, vol. 50, pp. 493-502.
Sampson, R. J., 1937, Gold-Los Angeles County: California Div. Mines Rept. 33, pp. 177-196.
Tucker, W. B., 1927, Gold-Los Angeles County: California Min. Bur. Rept. 23, pp. 291-295.