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Register of the Penn Chemical Works (Campo Seco, Calif.)
Assay Records,
1912-1919
Mss14
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Title: Penn Chemical Works (Campo Seco, Calif.) Assay
Records,
Date (inclusive): 1912-1919
Collection number: Mss14
Creator:
Extent: 0.5 linear ft.
Repository:
University of the Pacific. Library. Holt-Atherton Department of
Special Collections
Stockton, CA 95211
Shelf location: For current information on the location of
these materials, please consult the library's online catalog.
Language: English.
Collection is open for research.
[Identification of item], Penn Chemical Works (Campo Seco, Calif.) Assay
Records, Mss14, Holt-Atherton Department of Special Collections, University of
the Pacific Library
Campo Seco, eight miles southwest of Mokelumne Hill in Calaveras County
prospered briefly as a gold mining camp (1850-1860), but in later years was
known principally for its production of copper and zinc, most notably from the
Penn Mine. In 1887 the Penn Chemical Co. acquired a mining site and erected a
smelter (1899) which served the Penn mines through 1919. The smelter was
equipped with a crushing and grinding plant, eight roasting furnaces and a
blast furnace. The smelter was shut down and dismantled when the price of
copper declined following World War I. Gross returns from the smelting
operation exceeded $7 million.
This collection consists of pages of unbound printed forms on which
daily assay samples are recorded, giving the percentages of copper, iron, etc.
in each sample. Since the period covered by these records includes the World
War I years, the data displayed may show an increase in mining activity in
response to war needs.