Donnelly, Maurice (1934) Geology and mineral deposits of the Julian District, San Diego County, California. California Journal of Mines and Geology, 30 (4). pp. 331-370. ISSN 0096-1558. https://resolver.caltech.edu/CaltechAUTHORS:20200131-111820477
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Abstract
The Julian region, in the central part of San Diego County, California, includes the Julian, Banner, several other less important mining districts, and the Stonewall Mine on the Cuyamaca land grant. In addition to being one of the few areas in the Peninsular Range of southern and Baja California that have yielded notable amounts of gold, it constitutes geologically a diagnostic part of the range because of the land forms, structures, and rock formations exposed. Discovered in 1870, the Julian and Banner districts produced in the next several years $2,500,000 in gold from oxidized ore, having an average tenor of $50 a ton. This came from narrow veins which were only in a few instances mined below the water-table. The Stonewall Mine, worked continually from 1870 until shut down in 1893, produced $2,000,000 from a large ore body extracted to a depth of 600 feet. The Julian and Banner districts had a brief mining revival during the '90s.
Item Type: | Article | ||||||
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Additional Information: | © 1934 California State Mining Bureau. Report submitted as part of a doctor's thesis to the Balch Graduate School of Geological Sciences, California Institute of Technology. | ||||||
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Issue or Number: | 4 | ||||||
Record Number: | CaltechAUTHORS:20200131-111820477 | ||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20200131-111820477 | ||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||
ID Code: | 101032 | ||||||
Collection: | CaltechAUTHORS | ||||||
Deposited By: | Tony Diaz | ||||||
Deposited On: | 31 Jan 2020 21:11 | ||||||
Last Modified: | 31 Jan 2020 21:11 |
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