Investigation of West Belt Copper-Zinc Mines, El Dorado, Amador, Calaveras, and Mariposa Counties, California Page: 1
62 p. : ill., maps ; 27 cm.View a full description of this report.
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INTRODUCTION AIND SUMMARY
As a result of the examination of many copper-zinc properties in the
West Belt area of California, nine were chosen for exploration projects by
the Bureau of Mines. This was part of the Bureau's wartime mineral-
development program aimed at maintaining production of essential metals and
increasing ore reserves.
The properties explored were the El Dorado, El Dorado County; Copper
Hill, Newton, and Gray House, Amador County; Constellation, North Keystone,
and Collier, Calaveras County; and American Eagle and Akoz, Mariposa County.
In addition to surface sampling and mapping, 41 holes, aggregating
18,134 linear feet, were diamond-drilled. Detailed results of the work done
on all properties except the El Dorado and Akoz are given in this report.
The El Dorado and Akoz were discussed in Reports of Investigations 3896 and
4144, respectively. Figure 1 is an index map showing the location of the
mines covered in this publication.
In this report, the general features of the West Belt are summarized,
and mineral composition, characteristic types, and modes of occurrences of
ore deposits are described. The work performed by the Bureau of Mines is
reported in separate sections under the names of seven mines; each mine is
described separately, with a concluding section covering the work performed
by the Bureau of Mines.
Development and milling costs are reported in detail for the Keystone
mine. The Appendix embraces diamond drill-hole logs for the Newton, Copper
Hill, Gray House, and Constellation mines and contains other pertinent
information of drill holes, samples, and analyses of samples. Analyses of
drill-hole samples are shown in figures 3, 5, 6, 9, 9,11, and 13.
AC E0OWLJ)iX4I\NTS
Special acknowledgment is made to George Heyl of the Federal Geological
Survey, for his aid on many of the geologic problems. A. C. Rice, of the
Reno Rare and Precious Metals Experiment Station, Metallurgical Branch,
supervised the analytical work.
The Bureau is indebted to the late Otto Schiffner, general manager of
the Keystone Corp., for furnishing detailed cost data at the North Keystone
during the difficult war years of 1943 and 1944.
GENERAL FEATURES
The West Belt. copper-.zinc-bearing pone- t-raverses" the western slope of the
Sierra Nevada with unusual persistene from Butte Couity to Kern County, a
distance of more than 300 miles. It ranks among the important producing areas4033
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Wiebelt, Frank J.; Sanborn, W. C.; Trengove, R. R. & Ricker, Spangler. Investigation of West Belt Copper-Zinc Mines, El Dorado, Amador, Calaveras, and Mariposa Counties, California, report, February 1951; [Washington D.C.]. (https://digital.library.unt.edu/ark:/67531/metadc38555/m1/7/: accessed July 16, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.