Cover Photos: Woman Miner at the Kendon Pit, Mono County, 1930;
African American Miners at the Andrade Dredge Mine, California;
Cornish Miners on Skip at the Empire Mine, Grass Valley, 1900
( used with permission, California State Department of Conservation, California Geological Survey).
Cite as: California Department of Transportation.
Historical Context and Archaeological Research Design for Mining Properties in California.
Division of Environmental Analysis, California Department of Transportation, Sacramento, CA. 2008.
For individuals with sensory disabilities, this document is available in alternate formats upon request.
Please call:
( 916) 653- 0647 Voice, or use the CA Relay Service TTY number 1- 800- 735- 2929
or write:
Chief, Cultural and Community Studies Office
Caltrans Division of Environmental Analysis
P. O. Box 942874, MS- 27
Sacramento, CA 94274- 0001
i
MANAGEMENT SUMMARY
The California Department of Transportation ( Caltrans), in cooperation with the Federal
Highway Administration, California Division, and the California State Historic Preservation
Officer ( SHPO), prepared this thematic study to assist with evaluating the information potential
of mining properties in California, that is, for their eligibility for the National Register of
Historic Places under Criterion D. To be eligible under Criterion D, National Register guidance
states that a property must have, or have had, information to contribute to our understanding of
human history or prehistory, and the information must be considered important. An integral part
of this study is the development of a research design. The archaeological research design
explicitly demonstrates the connection between the information a property contains and
important research issues or questions associated with a particular property.
While this document provides a framework for evaluating most types of mining properties found
in California, it is not a comprehensive history of mining in the state nor does it satisfy the
requirements of site- specific research. This study is intended to serve as both an analytical tool
and a methodological framework to interpret and evaluate properties associated with the theme
of mining in terms of their ability to yield important information. Researchers should also
consider carefully whether additional National Register criteria may apply to individual sites,
although those other possible values are not discussed in this study.
The historic context presented here is a broad overview that addresses the major themes in
California’s mining history during the period from statehood in 1850 to circa America’s entrance
into World War II. Future researchers are encouraged to use this context as a starting point when
assessing the National Register values of a mining property.
Archaeological evidence collected during previous studies suggests that mining properties have
the potential to address the following research themes within a contextual or interpretive
approach: technology, historical ethnography/ cultural history, ethnicity and culture, women and
family, economy, and policy. Research is not necessarily limited to these themes, however, and
individual researchers may follow other theoretical approaches or find alternative research
themes relevant to specific sites. In addition, this document includes an implementation plan that
advocates specific methods to follow when assessing the information value of mining properties,
in an effort to improve consistency and thereby facilitate better inter- site comparisons.
Any questions or comments on this study should be directed to the Chief, Cultural and
Community Studies Office, Division of Environmental Analysis, MS 27, P. O. Box 942874,
Sacramento, CA 94274- 0001.
ii
ACKNOWLEDGEMENTS
An interdisciplinary team of consultants prepared the initial draft of this document. The
Anthropological Studies Center ( ASC) at Sonoma State University was the coordinating
institution, with Mary Praetzellis acting as the project manager. The team consisted of Julia G.
Costello of Foothill Resources, Ltd., Rand F. Herbert of JRP Historical Consulting Services,
LLC ( JRP), and Mark D. Selverston of the ASC, with contributions by Judith D. Tordoff of
Caltrans. Shawn Reim of JRP also provided valuable assistance in preparing the initial draft of
the review of recent articles on mining related topics. The study was prepared under the overall
direction of Greg King, Chief of the Caltrans Cultural and Community Studies Office, with
Anmarie Medin acting as the Project Manager assisted by Kimberly Wooten.
Because the contracted scope of work limited the breadth of the study, Caltrans staff augmented
the consultant- prepared report. Primary authors for Caltrans included Dana Supernowicz,
Richard Levy, and Anmarie Medin, with assistance from Julia Huddleson, Thad Van Bueren,
and Kimberly Wooten. Ed Carroll and Tory Swim, Sacramento State Public History program
graduate students, contributed to the second draft of this document.
The Secretary of the Interior's Standards and Guidelines for Archeology and Historic
Preservation ( 48 FR 44716) state that historic contexts should be constructed by an
interdisciplinary process that considers the comments of the interested public and scholars. To
facilitate public comment and peer input, the authors presented their approach in symposia at the
2006 annual conference of the California Council for the Promotion of History. A similar
presentation was made at the Society for California Archaeology's 2006 northern data- sharing
meeting. A review draft was posted online and comments were received from professionals in
the cultural resources field. The Mining HARD was also discussed in a session on thematic
studies at the 2008 Society for Historical Archaeology conference.
Caltrans facilitated peer review by historians and historical archaeologists for both drafts, which
included reviews by Steven Mulqueen of the California State Lands Commission and Margaret
Hangan of the Cleveland National Forest. Caltrans staff reviewing this study included Dicken
Everson, Blossom Hamusek, Julia Huddleson, Greg King, Richard Levy, Anmarie Medin, Steve
Ptomey, Dana Supernowicz, Karen Swope, Judy Tordoff, Thad Van Bueren, Tom Wheeler, and
Kimberly Wooten.
This mining study is the second in the Caltrans historical archaeology thematic studies series. At
FHWA, Stephanie Stoermer oversaw the first efforts to establish this thematic studies series and
Gary Sweeten continued to provide management perspective. At the OHP, Deputy SHPO Steve
Mikesell has been involved from the project’s inception and project review unit staff members
have provided valuable input throughout the process of compiling this set of thematic studies.
We would also like to thank geologist and educator George Wheeldon, for the use of his digital
images of mining in California, and Gary Taylor, California Department of Conservation,
California Geological Survey, for the use of digital images from the department’s “ California
Gold Mines: A Sesquicentennial Photograph Collection.”
iii
TABLE OF CONTENTS
Chapter 1. Introduction .............................................................................................................. 1
Research Design Series.................................................................................................. 2
The National Register Evaluation Process under Criterion D ....................................... 3
The California Register of Historical Resources ........................................................... 4
Using this Document for Section 106 Consultation ...................................................... 5
Index to Studies.............................................................................................................. 5
Chapter 2. Historic Context ...................................................................................................... 9
Introduction................................................................................................................... 9
Geomorphic Regions of California.............................................................................. 12
Klamath Mountains................................................................................................ 14
Cascade Range....................................................................................................... 14
Modoc Plateau ....................................................................................................... 14
Coast Ranges.......................................................................................................... 15
Great Valley ........................................................................................................... 15
Sierra Nevada......................................................................................................... 16
Great Basin............................................................................................................. 16
Transverse Ranges ................................................................................................. 16
Mojave Desert........................................................................................................ 17
Peninsular Ranges.................................................................................................. 17
Colorado Desert ..................................................................................................... 18
Summary ................................................................................................................ 18
Major Metal or Mineral Commodities in California.................................................... 19
Barite ( Barium) ...................................................................................................... 19
Borates ................................................................................................................... 20
Chromite ................................................................................................................ 22
Coal........................................................................................................................ 22
Copper.................................................................................................................... 23
Feldspar.................................................................................................................. 25
Gold........................................................................................................................ 25
Lead........................................................................................................................ 26
Limestone............................................................................................................... 27
Manganese ............................................................................................................. 28
Magnesite............................................................................................................... 28
Mercury.................................................................................................................. 29
Pyrite...................................................................................................................... 32
Silver...................................................................................................................... 32
Strontium................................................................................................................ 33
Sulfur...................................................................................................................... 34
Talc and Soapstone ................................................................................................ 35
Tungsten................................................................................................................. 36
Zinc ........................................................................................................................ 37
The Gold Rush ............................................................................................................. 38
Mining Technology...................................................................................................... 45
Placer Mining......................................................................................................... 48
iv
Hydraulic and Drift Mining ................................................................................... 50
Dredge Mining....................................................................................................... 52
Lode Mining........................................................................................................... 53
Improved Technologies and Diversification of California’s Mining Industry ............ 57
Mining Law, Regulations, and Government................................................................ 60
Water Rights .......................................................................................................... 62
Culture, Race, and Ethnicity ........................................................................................ 63
Women and Families in the Mines .............................................................................. 68
Economics, Labor, and Unionization........................................................................... 74
Summary ...................................................................................................................... 79
Chapter 3. Property Types ....................................................................................................... 81
Introduction to Property Type Categories.................................................................... 81
Prospecting and Extraction Property Types................................................................. 82
Tailings Piles.......................................................................................................... 83
Cut Banks, Channels, and Placer Tailings............................................................. 87
River Diversion...................................................................................................... 88
Dredge Tailings...................................................................................................... 89
Drift Mining Remains ............................................................................................ 91
Hard Rock ( Lode) Mining Property Types.................................................................. 92
Small Pits and Surface Vein Workings.................................................................. 93
Waste Rock Piles ................................................................................................... 94
Shafts, Adits, and Facilities in their Vicinity......................................................... 95
Underground Workings ......................................................................................... 97
Open Pit Mines ...................................................................................................... 97
Ore Processing ( Beneficiation) Property Types .......................................................... 97
Arrastras................................................................................................................. 98
Mills: Industrial Foundations, Pads, and Machine Mounts ................................... 99
Mill Tailings......................................................................................................... 102
Ancillary Mining Property Types .............................................................................. 103
Structural Remains............................................................................................... 103
Site- Specific Transportation Features.................................................................. 104
Site- Specific Water Conveyance Systems ........................................................... 105
Mining Community Property Types .......................................................................... 105
Domestic Structural Remains .............................................................................. 106
Domestic Artifact Deposits.................................................................................. 109
Domestic Landscape Features.............................................................................. 110
Inter- Site, Mining Support Property Types ............................................................... 110
Inter- site Linear Transportation Features....................................................... 111
Inter- site Water Conveyance Systems ........................................................... 111
Inter- site Utilities ........................................................................................... 112
Chapter 4. Research Design................................................................................................... 113
Introduction to Mining Research ............................................................................... 113
Significant Source Material ....................................................................................... 113
Selected Archaeological Literature............................................................................ 116
Theme 1: Technology ................................................................................................ 118
Theme 2: Historical Ethnography / Cultural History................................................. 121
v
Theme 3: Ethnic and Cultural Groups in the Mines .................................................. 162
Theme 4: Women, Families, and Gender .................................................................. 140
Theme 5: Economy.................................................................................................... 144
Theme 6: Policy ......................................................................................................... 149
Chapter 5. Implementation Plan ............................................................................................ 155
Phase 1: Identification and Recording of Mining Sites ............................................. 155
Phase 2: Evaluation of Mining Sites under Criterion D ............................................ 157
Integrity...................................................................................................................... 158
Significance Evaluations............................................................................................ 161
Methodological Consistency...................................................................................... 163
Steps for Assessing the Research Potential of Mining Sites...................................... 169
Simple Mining Sites................................................................................................... 170
Simple Mining Sites with Domestic Deposits ........................................................... 173
Industrial Mining Sites............................................................................................... 174
Industrial Mining Sites with Domestic Deposits ....................................................... 175
Safety Concerns ......................................................................................................... 176
Conclusions................................................................................................................ 177
Chapter 6. Bibliography......................................................................................................... 179
TABLES
1 Index to Property Types in Thematic Studies................................................................ 7
2 Important Copper Mines in California......................................................................... 23
3 Placer Gold Mining, Number of Mines in Selected Years .......................................... 25
4 Cost of Living Comparison: 1850 and 2007................................................................ 43
5 Volume of Placer Gravels Processed by Mining Technique ....................................... 50
6 Important Gold/ Precious Metals Mining Counties, 1850- 1940................................... 57
7 Gold Production in California, 1850- 1940 .................................................................. 58
8 Comparative Growth of the Male and Female Population in California, 1850- 1890.. 69
FIGURES
1 Golden Crown Mine, Imperial County, 1900 ............................................................... 9
2 Gold bars and Mexican guards at La Grange Mine, n. d. ............................................. 10
3 Hydraulic Mining at La Grange Mine, Trinity County, 1940...................................... 11
4 Typical Gold Rush era Mother Lode Town, circa late 1920s...................................... 12
5 Map of Geomorphic Provinces in California............................................................... 13
6 Hydraulic Mining, Junction City, Trinity County, n. d. ............................................... 14
7 Dixie Queen ( Big Four) Mine, Modoc County, n. d..................................................... 15
8 Lower Gold Bluff Mine, Humboldt County, 1895 ...................................................... 15
9 Tailings Wheels at Kennedy Mine, Amador County, n. d............................................ 16
10 Keane Wonder Mine, Inyo County, 1916.................................................................... 17
11 Banks Wash San Bernardino County, 1895................................................................. 18
12 New Almaden Quicksilver Mine, 1877 ....................................................................... 30
13 View of New Almaden Quicksilver Mine, Reduction Works ..................................... 31
vi
14 Sutter’s Mill soon after Abandonment, Coloma, 1853 ................................................ 38
15 Gold Miners Running a Long Tom Sluice at Spanish Flat, El Dorado County........... 39
16 Wing Dams along the Middle Fork American River 1859.......................................... 40
17 Miners Cabin near Bidwell Bar, Butte County, 1906................................................... 41
18 View of Buildings at Randsburg, 1896........................................................................ 42
19 Sunday Morning in the Mines...................................................................................... 44
20 Working Gold Placers with a Long Tom or Sluice near Murphy’s,
Calaveras County, early 1850s .................................................................................... 45
21 Placer Mining on the American River, 1852 ............................................................... 46
22 Low Level Hydraulic Mining at the Hocumac Mine, San Bernardino County........... 47
23 Using a Rocker or Sluice, 1935 ................................................................................... 48
24 Hydraulic Mining at Michigan Bar, Sacramento County, 1860. ................................. 49
25 North Bloomfield Mine ( Malakoff Diggins), Nevada County, 1890 .......................... 51
26 Men Astride Giants ( monitors) at the La Grange Mine, Trinity County, n. d. ............. 51
27 American Gold Dredging Company, Shasta County, 1922......................................... 52
28 Dredge Tailings, Lava Beds Dredging, Butte County, 1901 ....................................... 53
29 Arrastra in the High Sierra, circa 1900 ........................................................................ 54
30 A Crew of Miners ( Cornish) Ascends in Skips, Empire Mine, Grass Valley, 1900 ... 55
31 Yellow Aster Mine Stamps, Kern County, 1912 ......................................................... 56
32 Trinity Dredge, Trinity County, 1922.......................................................................... 59
33 Cornish Miner, 1900, Empire Mine, Grass Valley ...................................................... 63
34 Mexican Miner Panning for Gold, La Grande, Trinity County ................................... 65
35 Andrada Dredge Mine, Black Crew with new lip applied to clam shell bucket,
circa 1930s ................................................................................................................... 66
36 Chinese and White Miners Sluicing at Auburn Ravine, Placer County, ca. 1852....... 67
37 Woman Miner along the North Fork American River near Rocky Bar or
Estey, Placer County, 1915.......................................................................................... 72
38 Woman using a Rocker, Kendon Pit, Mono County, 1930 ......................................... 73
39 Blasting at Empire Mine, Nevada County, 190 ........................................................... 75
40 Air Drill Operators, Empire Mine, Nevada County, ca. 1900 ..................................... 77
41 Rocker Clean- out Pile, Prairie Diggings Placer Mining District ( PDPMD),
Locus 20, Sacramento County ..................................................................................... 84
42 Ground Sluice Tailings, Alder Creek Corridor Placer Mining District
( ACCPMD), Sacramento County ................................................................................ 85
43 Sluice Tailings, PDPMD, Locus 20, Sacramento County ........................................... 85
44 Sluice- mining landscape created in the 1850s- 1860s, McCabe Creek,
Butte County ................................................................................................................ 86
45 Bedrock Drains in Ground Sluice System, PDPMD, Locus 19, Sacramento County .87
46 Stewart Hydraulic Mine Cut, Dutch Flat, Placer County ............................................ 88
47 Remains of a wing dam along the Stanislaus River..................................................... 89
48 Bucket- line Dredge Tailings, Yuba River ................................................................... 90
49 Bucket- line Dredge Landscape along the Feather River, Oroville, Butte County....... 90
50 Dry- land Dredge Tailings, PDPMD, Locus 3, Sacramento County ............................ 91
51 Tractor- boiler that Supplied Power to Two- stamp Mill at Defiance Claim ................ 94
52 Waste rock Pile in Canyon, San Bernardino County................................................... 95
53 Small Head Frame with Chute, Inyo County............................................................... 96
vii
54 Isolated Shaft Collar, Inyo County .............................................................................. 97
55 Remains of Twentieth- century Arrastras, Inyo County............................................... 98
56 Remains of Arrastra Floor, Amador County................................................................ 99
57 Remains of the Royal Consolidated Mill................................................................... 100
58 Hendy Ball Mill at Mountain King Mine .................................................................. 101
59 Tailings at New Melones Reservoir, Stanislaus River Drainage............................... 102
60 Tramway Header, Star of the West Mine, Inyo County ............................................ 105
61 Star of the West Mine, Inyo County: Partially Standing Stone Cabin....................... 107
62 Remains of a Masonry- lined Dugout, Butte County ................................................. 108
63 Large Stone Oven, Chili Junction, Calaveras County ............................................... 109
64 Decision Tree for Evaluation of Isolated Tailings Piles and Waste Rock................. 172
APPENDICIES
Appendix A. Major Mines by Focus Commodity
Appendix B. Mineral Commodities of California
viii
Mining Thematic Study
Chapter 1. Introduction
1
CHAPTER 1. INTRODUCTION
The purpose of this research design is to provide general guidance for evaluating historic- era
mining sites, specifically their data potential. It includes a historic context outlining important
periods of mining history in California, identification of property types, and important research
themes and questions relevant to mining sites. Due to the range of natural resources in
California, the scope of this document is necessarily limited to the mining of metals and related
archaeological sites. Mining sites are defined here as those sites containing evidence of metals-mining
activities.
The period of study is 1848 to circa 1940. The minor and spatially limited mining that took place
during the pre- gold rush period in California is not the subject of this context. While this study is
intended to help evaluate properties up to 1940, the historic context discusses minerals mining
into the mid- century to provide some additional perspective. Examples of site types this study
may help evaluate include, but are not limited to, mines, mills, shafts, adits, prospects, and
placer- mining sites. These sites may include processing equipment, ruins of mine buildings
and/ or miners’ habitations, scatters of equipment or mining debris, trash associated with the
miners’ occupation of the site, and other related items. Where standing structures are extant
( mills, headframes, support buildings), they should be considered for both their potential
contributions to research and for their eligibility under other criteria. These are properly
considered as historic architectural resources that, in addition to being addressed as features of
the mining operation, also need to be evaluated on Department of Parks and Recreation ( DPR)
Building/ Structure/ Object forms by a qualified architectural historian. These architectural
resources may also have a historical archaeological component.
The property types addressed in this report are related to the processes associated with extraction
and beneficiation of precious and non- precious minerals or metals. The focus of this study,
however, is on those minerals whose properties were such that they were industrially mined and
either individually or collectively assumed an important role in local, state, regional, or national
economies. Mineral Commodities of California ( Wright 1957b) lists a total of seventy- seven
commodities which are present in California. Of the seventy- seven commodities, nineteen are the
focus of this report. 1 They include barium ( barite), borates, chromite, coal, copper, feldspar,
gold, lead, limestone, manganese, magnesite, mercury, pyrites, silver, strontium, sulfur, talc and
soapstone, tungsten, and zinc. Appendix A lists major mines in the state for focus commodities
while Appendix B provides information on all 77 commodities.
1 The following commodities occur in California, but their production was limited: aluminum, antimony, arsenic, asbestos,
beryllium, bismuth, black sands, calcite, cobalt, fluorspar, graphite, iron industries, kyanite and andalusite, mica, nickel, nitrogen
compounds, phosphate, thorium, tin, titanium, and vanadium. In addition, other mineral commodities were excluded because they
were not produced commercially prior to 1940 and thus fall outside the scope of this study. These include uranium, pyrophyllite,
quartz crystal ( electronic grade), rare earth elements and molybdenum. Also excluded were commodities used primarily in the
construction industry including asphalt and bituminous rock, cement, clay, gypsum, pumice, pumicite, perlite, volcanic cinders,
quartzite and quartz, sand and gravel, expansible shale, crushed and broken stone, and dimension stone. Other commodities were
excluded because they were recovered from salts and bittern, such as bromine, iodine, lithium compounds, salines, salt, sodium
sulfate, sodium carbonate, and calcium chloride. Still others were excluded because they are byproducts of the refinement
process, including cadmium and platinum. Some commodities were excluded because the processes by which they are recovered
bear little resemblance to mining, such as peat, gem stones, natural gas, petroleum, abrasives, diatomite, and specialty sands.
Mining Thematic Study
Chapter 1. Introduction
2
This document is divided into five chapters:
• Chapter 1 consists of this introduction, which outlines the document’s purpose, authorship,
structure, and theoretical orientation.
• Chapter 2 contains the historic context, a synthetic narrative describing the significant
broad patterns of mining development in California that may be represented by historic
properties.
• Chapter 3 describes archaeological property types created by the processes presented in
Chapter. These are the features that archaeologists encounter in the field.
• Chapter 4 consists of a review of current scholarship to identify scholarly themes and
develop specific research questions that information from mining sites might be able to
address.
• Chapter 5 offers an implementation plan that presents standardized methods that will
enhance comparative research and guide evaluation under Criterion D. Data requirements
and issues of integrity are addressed here.
RESEARCH DESIGN SERIES
This study is one of a series of statewide, thematic archaeological research designs developed by
the California Department of Transportation ( Caltrans). Its purpose is to help archaeologists
assess the importance of historic- era archaeological sites commonly encountered on Caltrans
projects. Caltrans has produced, or is producing, other volumes in this series, cited throughout
this study as Agriculture, Townsites, and Work Camps thematic studies. The Agriculture study
was finalized in 2007 and is posted on the Caltrans Division of Environmental Analysis web
page ( www. dot. ca. gov/ ser/ guidance. htm# agstudy). The Town Sites and Work Camps studies are
currently in draft form and are being finalized by Caltrans. Table 1 contains a list of historic- era
archaeological features and indicates in which volume each is addressed.
The series grew out of Caltrans’ long- term efforts to improve the process of site- specific research
and evaluation as well as the California State Historic Preservation Officer’s recommendation
that the agency improve how historical archaeology is conducted in the context of Section 106 of
the National Historic Preservation Act. This statute requires that federal agencies take into
account the effects of their undertakings on properties listed on or eligible to the National
Register of Historic Places ( NRHP).
It is important to note that this Mining Sites Research Design is concerned with NRHP Criterion
D, under which properties may be eligible for listing if they have “ yielded, or may be likely to
yield, information important in prehistory or history” ( 36 CFR 60.4[ d]). The historic context
approach to site identification and recommended procedures for recording mining sites should be
useful to both historians and archaeologists.
Mining Thematic Study
Chapter 1. Introduction
3
THE NATIONAL REGISTER EVALUATION PROCESS UNDER CRITERION D
To be eligible for listing in the NRHP, a mining property must be significant in American
history, architecture, engineering, or culture and possess integrity of location, design, materials,
workmanship, feeling, setting, and association. In addition, the mining property must meet one or
more of the four National Register criteria:
A. be associated with events that have made a significant contribution to the broad patterns
of our history; or
B. be associated with the lives of persons significant in our past; or
C. embody the distinctive characteristics of a type, period, or method of construction, or that
represent the work of a master, or that possesses high artistic values, or that represent a
significant and distinguishable entity whose components may lack individual distinction;
or
D. have yielded, or may be likely to yield, information important in prehistory or history.
All researchers should carefully consider which of the other NRHP criteria in addition to D
might also be applicable to the property they are evaluating. This document specifically
addresses how to evaluate mining sites under Criterion D, incorporating five basic steps defined
by Little and Seibert ( 2000: 14):
1. Determine site structure, content, and classes of data it may contain.
2. Identify the appropriate historic context by which to evaluate it.
3. Identify important research themes and questions that the data it contains may be able to
address.
4. Considering the property’s integrity, structure, and content, assess whether the data it
contains are of sufficient quality to address these important research issues.
5. Identify the important information that the property is likely to contain.
Archaeological properties are evaluated within an appropriate historic context defined by theme,
place, and time period. Chapter 2 of this document presents a historic context for mining sites in
California between 1848 and 1940, beginning at the gold rush and ending just before America’s
entry into World War II. It can provide the basis of a context statement for evaluation, but must
be supplemented by property- specific research to provide the relevant focus. The National Park
Service’s Revised Thematic Framework, History in the National Park Service: Themes and
Concepts, offers eight themes and many sub- themes that are useful for developing historic
contexts for specific properties ( NPS 1996). The historic context is linked to an individual
property by property types— groupings of individual properties that have shared physical
characteristics or associations. Property types are discussed in Chapter 3. To make the
connection between specific archaeological resources and the property types identified in the
historic context, Donald Hardesty ( 1988) developed the concept of “ feature system:” a cluster of
archaeological features that are the products of an identifiable process or activity. This approach
focuses the evaluation effort onto historically significant units.
Mining Thematic Study
Chapter 1. Introduction
4
To be eligible to NRHP under Criterion D, a property must both contain information that can
contribute to our understanding of some aspect of human history and the information must be
considered important. Research themes and associated questions that can be applied to specific
property types are specified in Chapter 4.
Archaeological facts are not intrinsically valuable; they achieve importance in relation to their
ability to advance our understanding of human history. We can define what constitutes important
information by reviewing current scholarship in disciplines such as history, geography,
anthropology, and archaeology. As change in research orientation is a normal part of social
science, important issues are moving targets that must be frequently reassessed. We recommend
that historical archaeologists consider both the scientific and humanistic contributions of the
discipline as they design and conduct their work. Some questions have definitive answers, such
as those designed to gather base- line information about the structure, content, and integrity of a
property. Some questions will have less conclusive or quantifiable answers, as they are designed
to help incrementally reveal large- scale historical and cultural processes significant or important
in our history. Individual properties often contribute by illustrating how a diversity of processes
played out in specific contexts, deepening our understanding of their effects on Californians in
the past.
To be eligible to the NRHP an archaeological site must be able to convey its significance to
those for whom it has value. In the case of Criterion D, these are scholars and others who may
seek to use the information the site contains. The ability of a property to convey this information
is measured by assessing its integrity. The appraisal of integrity accompanies an assessment of
significance: significance + integrity = eligibility. This topic is discussed in Chapter 4.
Applying the NRHP criteria for evaluation is a complex undertaking. It requires that researchers
follow a set process and understand certain professional standards and practices. The NRHP
Bulletin series is an essential reference. Of particular importance are Bulletin 15 How to Apply
the National Register Criteria for Evaluation ( NPS 1991) and Bulletin 36 Guidelines for
Evaluating and Registering Archeological Properties ( Little and Siebert 2000). Bulletin 42
Guidelines for Identifying, Evaluating, and Registering Historic Mining Properties offers
essential information as well ( Noble and Spude 1997). All are available online at
http:// www. cr. nps. gov/ nr. Donald Hardesty and Barbara Little’s book Assessing Site
Significance: A Guide for Archaeologists and Historians ( 2000) offers practical advice and many
informative case studies.
THE CALIFORNIA REGISTER OF HISTORICAL RESOURCES
The eligibility criteria for the California Register of Historical Resources ( CRHR) closely follow
those of the NRHP, although some properties that are ineligible to the latter may qualify for the
CRHR ( Office of Historic Preservation 2001: ii). The Caltrans series of research designs may be
used to help evaluate properties’ eligibility to the CRHR for the purposes of CEQA within the
requirements of the Register’s implementing regulations at CCR Section 4850 et seq.
Mining Thematic Study
Chapter 1. Introduction
5
USING THIS DOCUMENT FOR SECTION 106 CONSULTATION
Caltrans’ ultimate goal in producing this document is to streamline eligibility determination
consultations with the SHPO under Section 106. To that end, researchers are encouraged to cite
relevant sections of this document and apply specific research questions that relate to the mining
property being evaluated.
California SHPO staff reviewed early drafts of this study, commented on its fundamental scope,
and find it provides useful guidance when assessing information values of mining- oriented
historical archaeological sites. However, as with all guidance, the SHPO staff will review
individual submittals for appropriate application of research questions contained herein as well
as for appropriate application of the recommended methods. The individual researcher must
explain how the selected research questions apply to the site being evaluated; that is, what
information is contained within the individual site and why it is important. As stated elsewhere in
this document, other theoretical orientations, research issues, or individual research questions not
discussed herein may be identified as relevant to the site under study. If so, those other items
would require an appropriate level of development for SHPO consultation.
INDEX TO STUDIES
As an aid in using these documents, Table 1: Index to Property Types in Thematic Studies
provides an index to many of the property types that appear in the thematic studies series
Caltrans is producing. A number one in the table indicates the thematic study or studies where
this property type is primarily discussed and the appropriate volume to turn to for research. A
number two indicates a secondary discourse, where a property type is discussed, but perhaps to a
lesser degree. As of the publishing of this mining study, both the Townsite and Work Camps
thematic studies are in draft form.
Mining Thematic Study
Chapter 1. Introduction
6
Mining Thematic Study
Chapter 1. Introduction
7
Table 1: Index to Property Types in Thematic Studies
( Note: 1 indicates the highest applicability of a study to a property type; 2 indicates secondary applicability of a
study to a property type).
Property Type Category Property Type
Agriculture
Mining
Townsites
Work Camps
Residential structure House ( e. g. basement,
cellar)
1 2 1 2
Boardinghouse - 2 1 -
Hotel - 2 1 -
Bunkhouse 1 2 - 1
Lean- to/ tent - 2 - 1
Improvised ( e. g. boxcar,
dug- out)
- 2 - 1
Vertical interfaces, hollow- filled features: Artifact caches
( domestic, business, industrial)
Privy, pit, well 1 2 1 2
Horizontal interfaces, fill layers: Artifact accumulation ( domestic,
business, industrial)
Sheet refuse 1 2 1 1
Gardens, yards, landscapes ( private) 1 1 1 2
Activity buildings/ structures Line camp - - - 1
Shed 1 2 - 1
Blacksmith shop 1 2 1 2
Barn 1 - 2 1
Corral 1 2 2 1
Stable 1 2 2 -
Bake oven/ outdoor kitchen 1 1 - 2
Placer tailing piles - 1 - -
Cut banks, channels, tailings - 1 - -
River diversions - 1 - -
Dredge tailings - 1 - -
Equipment mounts/ foundations - 1 - 2
Headframes ( collapsed) - 1 - -
Adits and tailings - 1 - -
Retaining walls/ platforms - 1 2 2
Tramways/ tracks - 1 - 2
Mining Thematic Study
Chapter 1. Introduction
8
Table 1: Index to Property Types in Thematic Studies ( continued)
Property Type Category Property Type
Agriculture
Mining
Townsites
Work Camps
Prospect pits and surface vein working - 1 - -
Waste rock piles - 1 - -
Shafts and adits - 1 - -
Underground workings - 1 - -
Open pit mines - 1 - -
Ore processing industrial structures/ buildings Arrastra, foundation, pad, machine mount - 1 - -
Ore processing tailings - 1 - -
Transportation, private ( activity specific) Road, trail, railway - 2 2 2
Transportation, intrasite Road, trail, railway - 2 2 2
Transportation, extrasite - 2 2 2
Water- conveyance systems, intrasite Ditch, drain - 1 - 2
Electrical utilities Generation and transmission feature - 2 - 2
Public infrastructure building School, church, hospital - - 1 2
Office, dining hall, cookhouse, showers,
bunkhouse
2 2 2 1
Refuse dumps ( municipal, not household/ activity
specific)
- - 1 1
Townsite creation features Fill, levee, terrace, waterway - - 1 -
Townsite infrastructure features Sewer, water, - - 1 -
Industrial buildings/ structures Forge, casting floor - 1 1 2
Industrial processes byproducts Waster, raw materials, refuse - 2 1 2
Mercantile building Shop, warehouse - 2 1 -
Mercantile activities Merchandise/ stock - 2 1 -
Service business building/ structure Laundry boiler/ drying rack - - 1 -
Service business byproducts Laundry boiler waste, food waste - - 1 -
Mining Thematic Study
Chapter 2. Historic Context
9
CHAPTER 2. HISTORICAL CONTEXT
INTRODUCTION
Metals mining fundamentally shaped California’s early economy, culture, and politics. Gold and
silver mines pumped millions of dollars into the state during the mid- to late- nineteenth century
in a manner that was unique in the American west and central to the state’s development. Later
industries such as agriculture provided additional development of the state and its economy, but
it was the gold rush and influx of people that transformed California from a Mexican province to
a state important in the world economy. While it is recognized that mining was foremost an
extractive industry that had disastrous effects on the environment, the remains of this industry
provide archaeological data on a wide array of important research questions as well as providing
a physical reminder of the state’s history. Notwithstanding the negative effects created by
California’s mining industry, the state’s mining history had a profound influence on immigration
and emigration, and fostered the creation of numerous towns and communities.
The American mining frontier represents a mosaic of cultural and technological landscapes
reflecting a diverse range of economic influences, from local to international. As historical
archaeologist and mining historian Donald Hardesty explains:
Mining colonies were financed, manned, and supplied from the urban centers of
America and Europe. Despite their geographical remoteness and small size, the
Figure 1: Golden Crown Mine, Imperial County, 1900 ( used with permission, California
Department of Conservation, California Geological Survey).
Mining Thematic Study
Chapter 2. Historic Context
10
colonies were
linked into a vast
transportation,
communications,
demographic, and
economic
network on a
national and
international scale
( Hardesty
1988: 1).
Not only did California’s
mining industry shape the
character of the state, it
also had a significant
effect upon the nation,
increasing its wealth and
sustaining economic
growth. Virtually every county in California witnessed some degree of minerals exploration.
This was in large part due to the state’s diverse geological history. Oddly enough, serpentine, the
metamorphosed remains of magnesium- rich igneous rock that contains asbestos and that holds
little monetary value, is the official “ state rock.” Gold, rightly so, is the official “ state mineral”
( California Geological Survey 2007).
The state’s mining history, and perhaps that of the western United States, is based upon the
romanticized notion of “ get rich quick” mineral discoveries. The reality of the industry was
another thing, and the cyclical nature of the mining industry resulted in “ boom and bust” periods,
some of which were created through artificial means or, even worse, unscrupulous investment,
and, in other cases, by depletion of the mineral reserves themselves. As John Muir aptly stated
“ mining discoveries and progress, retrogression and decay seem to have been crowded more
closely against each other here [ in California] than on any other portion of the globe” ( Muir
1992: 944).
The cyclical nature of mining was influenced by economic conditions both in California and the
nation, as evidenced multiple times. The “ Panics” of 1873, 1893, and 1907 had ramifications for
the state’s mining industry by deflating interest in mining investments and stocks. Too, the 1906
San Francisco earthquake shook the financial markets of the West Coast and briefly shut down
the Pacific Stock Exchange. And the rise in the price of gold in 1934 resulted in a flurry of
speculation, the reopening of hundreds of gold mines, and the migration of thousands of would-be
small- scale placer miners to the gold regions of the state.
The mineral history of California spans nearly the entire state. However, when discussing the
production of gold, there are two geomorphic provinces that deserve special attention: the
Mother Lode region and the Klamath and Trinity river basins. Both of these geomorphic
provinces witnessed unprecedented growth following the discovery of gold at Sutter’s Mill in
Figure 2: Gold Bars and Mexican Guards at La Grange Mine ( used with
permission, California Department of Conservation, California Geological
Survey).
Mining Thematic Study
Chapter 2. Historic Context
11
January of 1848. Mining had a significant impact in both regions, particularly on indigenous
peoples, but also on the regions’ future economic development, including the expansion of other
industries, such as agriculture.
Prior to 1848, gold was reportedly mined in the San Gabriel Mountains near Los Angeles, within
Castaic, Paloma, Placerita, Santa Feliciana, and San Francisquito canyons. Additional
discoveries of gold were made in the La Panza District located about 40 miles east of San Luis
Obispo ( Irelan 1888: 531; Clark 1970: 179, 1985: 254). Other precious metals mined in California
besides gold include silver and platinum. Non- precious metals or commodity minerals, such as
aluminum, antimony, arsenic, asphalt, black sands, bromine, boron, cadmium, cement, gypsum,
mica, nickel, petroleum, pumice, salt, shale, titanium, to name just a few, were also mined in the
state. The focus of this study, however, is on those minerals whose properties were such that they
were industrially mined and either individually or collectively assumed an important role in
local, state, or regional economies, including barium ( barite), borates, chromite, coal, copper,
feldspar, gold, lead, limestone, manganese, magnesite, mercury, pyrites, silver, strontium, sulfur,
talc and soapstone, tungsten, and zinc. Each of these commodity minerals and/ or metals was
exploited for its economic value; each provided employment, and to different degrees, fostered
the development of communities and transportation systems.
In his seminal book California Gold: The Beginning of Mining in the Far West ( 1947), historian
Rodman Paul noted that the gold rush period spanned the years 1848 through the 1870s. Other
scholars suggest that the gold rush era declined or perhaps ended in the mid- 1850s, when the
recovery rate of placer gold began to diminish ( Clark 1970, Holliday 1981, Johnson 2000). In
either scenario, by the end of the 1850s the character of the mining industry in California was
quite different then it had been in the early 1850s.
Between 1849 and 1854,
California’s cultural landscape
was transformed by population
expansion, the creation of
mining camps, and the
development of associated
industries. This transformation
had devastating consequences
for the state’s indigenous
peoples, as well as Californios
whose lands were preempted
by settlers. What followed the
gold rush were sporadic
discoveries of new placer gold
deposits throughout the Mother
Lode, expansion of hydraulic
mining, the development of the
hardrock or quartz gold mining
industry, discoveries of new
Figure 3: Hydraulic Mining at La Grange Mine, Trinity County, ca.
1940 ( used with permission, California Department of Conservation,
California Geological Survey).
Mining Thematic Study
Chapter 2. Historic Context
12
minerals, and a surge
in new mining- related
technologies.
Improved techniques
for hydraulic mining
resulted in more
capital- intensive
forms of mining that
required significant
amounts of labor.
While hydraulic
mining was
dramatically curtailed
following the Sawyer
Decision in 1884, it
continued throughout
portions of
California, although at a much smaller scale ( Kelley 1959). Mining other metals, such as lead,
copper, and mercury, gained in importance throughout the late nineteenth century due to
changing economic conditions and demand for products made from these minerals.
During the late 1890s, new technologies led to the invention of dredge mining, which spread
throughout portions of California, particularly along the American, Sacramento, Feather, and
Trinity rivers, where placer gold was still plentiful. Small drag line or “ doodle- bug” dredges
were used in the 1930s, allowing mining companies or miners to access and dredge remote
locations. Dredge mining was cost- effective largely because of the scale on which the operations
were conducted, but they nearly obliterated the natural landscape and left piles of tailings, some
over 100 feet tall.
During the Great Depression ( 1929– 1941), after a period of limited production or after sitting
idle, a number of gold mines resumed their operations and unemployed workers, many from the
state’s metropolitan areas, staked out claims throughout California. Many of the “ small scale
placer miners” moved into areas previously mined and reworked old diggings, sometimes
adjacent to abandoned mining camps and gold rush era communities, or to isolated areas to take
advantage of public lands such as national forests ( Averill 1946).
GEOMORPHIC REGIONS OF CALIFORNIA
Mining for precious and non- precious commodity metals or minerals occurred in California in
almost all areas of the state, as California’s diverse geomorphology lent itself to a wide variety of
mineral resources. The following is a brief description of each geomorphic province in
relationship to minerals extraction and several of the principal mines in each province. The
following descriptions draw heavily on Norris and Webb ( 1976).
Figure 4: Typical Gold Rush era Mother Lode Mining Town, circa late 1920s.
Note the abandoned storefronts ( used with permission, California Department of
Conservation, California Geological Survey).
Mining Thematic Study
Chapter 2. Historic Context
13
Figure 5: Map of Geomorphic Provinces in California ( compiled by Caltrans from Beck and Haase 1974;
Schoenherr 1992; and Johnson 1997)
Mining Thematic Study
Chapter 2. Historic Context
14
KLAMATH MOUNTAINS
The Klamath Mountains
cover an area of some
11,800 square miles in
southwestern Oregon and
northwestern California.
Constituent ranges in
California include the
South Fork, Trinity,
Trinity Alps, Salmon,
Scott, Scott Bar, and
Siskiyou mountains. The
Klamath Mountains
adjoin the Cascade Range
on the east and the Coast
Ranges on the west and
south. Elevations range
from sea level to the top of Thompson Peak in the Trinity Alps at 9,002 feet. Many upland
summits range between 5,000 and 7,000 feet. The principal metals mined in the province include
gold, barium- barite, chromium, copper, and to a lesser degree, silver, zinc, lead, pyrites, and
coal. Most of the gold mining occurred in Trinity, Shasta, and Siskiyou counties. Chromium
mines were located largely in Del Norte County, and copper mines mainly in Shasta County.
CASCADE RANGE
East of the Klamath Mountains rise the volcanic peaks and lava rims of the Cascade Range.
These mountains extend southward from British Columbia through Washington and Oregon,
reaching 150 miles into California. The exposed rocks of the California Cascades are
predominately volcanics of great variety and form. The principal metals extracted in the Cascade
Range were sulfur and coal. The Supan Sulfur Works was the main producer in Shasta County,
while the Rogue River District produced a considerable amount of coal.
MODOC PLATEAU
The separation between the Modoc Plateau and the eastern border of the Cascade Range is
indefinite in northern California because the fault systems and rocks characteristic of the two
regions are intermingled. The Modoc volcanic platform is actually the southwestern tip of the
Columbia Plateau that covers much of eastern Oregon, Washington, and southern Idaho.
Topographically, the Modoc Plateau is a jumble of lava flows and fissures, ridges, small cinder
cones, and basalt plains averaging more than 4,500 feet above sea level. Most of the mining in
this region was concentrated along the Oregon border, comprised of small, shallow gold
prospects and placer mines.
Figure 6: Hydraulic Mining, Junction City, Trinity County, n. d. ( used with
permission, California Department of Conservation, California Geological
Survey).
Mining Thematic Study
Chapter 2. Historic Context
15
COAST RANGES
The Coast Ranges,
formed by a variety of
ranges, mountains, and
valleys, extend north-northwesterly
along the
Pacific Ocean, west of
the Central Valley and
Klamath Mountains,
almost into Oregon.
The Coast Ranges
stretch some 550 miles
from the Oregon border
south to the Santa Ynez
River. San Francisco
Bay marks the division
between the North and
South Coast Ranges.
Hills and ridges tend to
be rounded in this range due to erosion, but some spectacular highland topography appears to the
north. Peaks seldom rise above 6,000 feet. Where the mountains meet the sea is a dramatic and
extremely rugged environment, much of which is marked by vertical sea cliffs and steep
mountains at the seashore. The primary metals mined in the Coast Ranges include barium- barite,
chromium, magnesite, manganese, mercury, coal, and to a lesser degree tin, sulfur, and pyrite.
GREAT VALLEY
The Great Valley, drained by the
Sacramento and San Joaquin rivers,
extends almost 500 miles from north
to south and averages about 40 miles
in width. Much of the Great Valley
is a level plain with elevations
ranging from 30 feet above mean sea
level near Sacramento to 400 feet
near Bakersfield. The Sutter
( Marysville) Buttes rise above this
plain more than 2000 feet in
elevation and constitute the only
major igneous outcrop in the valley.
Mining in the Central Valley has
focused on clay, sand and gravel,
and dredge mining for gold in gravel
deposits. In addition, coal was mined
in Placer and Amador counties.
Figure 8: Lower Gold Bluff Mine, Humboldt County, 1895.
Oregon tom ( long tom) saving gold on bare boards ( used with
permission, California Department of Conservation, California
Geological Survey).
Figure 7: Dixie Queen ( Big Four) Mine, Modoc County, n. d. ( used with
permission, California Department of Conservation, California Geological
Survey).
Mining Thematic Study
Chapter 2. Historic Context
16
SIERRA NEVADA
The Sierra Nevada mountains
extend approximately 400
miles from near Mount Lassen
in the Cascade Range to the
north to Garlock fault in the
south. The Garlock fault forms
the separation between the
Sierra and the Tehachapi
Mountains on the one hand and
the Mojave Desert on the other.
The Sierra vary between 40
and 100 miles in width.
Elevations range from 400 feet
above mean sea level on the
west where it abuts the Great
Valley to more than 14,000
feet in the southern Sierra.
Extensive vertical movement
on the Sierra Nevada fault
system produced a precipitous
eastern escarpment in the
southern part of the range. On the west the Sierran basement terminates beneath the western
margin of the Great Valley in contact with the Franciscan formation of the Coast Ranges. The
rich mineral resources of the Sierra Nevada lie near the surface because ancient rocks have been
exposed by erosion in deep canyons and on steep slopes. The ancient river channels are elevated
above their original surroundings and provided many opportunities for drift mining of gold.
Besides gold, silver and copper were mined in considerable quantities within this province. Other
metals such as tungsten were also mined, but to a lesser degree.
GREAT BASIN
The Great Basin province covers an immense area south of the Columbia Plateau, between the
Cascade, Sierra Nevada, Cordillera, and Rocky mountains. Parallel north- trending fault block
ranges ( horsts) and intervening basins ( grabens) give the region its particular relief. Surprise
Valley in northeastern California and Owens Valley east of the Sierra Nevada are typical Great
Basin valleys. The principal metal mined in this province was boron or borates, primarily in Inyo
County. Other metals mining included gold, barium- barite, tungsten, molybdenum, copper,
bismuth, silver, copper, sulfur, magnesite, talc- soapstone, feldspar, and lead.
TRANSVERSE RANGES
The Transverse Ranges consist of many overlapping mountain blocks. The Transverse Ranges
trend east- west in contrast to the northwest- southeast orientation of the Sierra Nevada and the
Figure 9: Tailings Wheels at Kennedy Mine, Amador County, n. d.
Tailings wheels ( 68 ft. tall) used to transport wastes for storage ( used
with permission, California Department of Conservation, California
Geological Survey).
Mining Thematic Study
Chapter 2. Historic Context
17
Coast Ranges. The major mountain ranges of the Transverse Ranges are the Santa Ynez, Santa
Susana, Santa Monica, San Gabriel, and San Bernardino. Sediment- filled basins between these
ranges are the Santa Ynez, Ventura, Ojai, Santa Clara, Simi, San Fernando, and San Gabriel
valleys and the Santa Barbara Channel. Rising from the Mojave Desert in the east, near the
Colorado River, the Transverse Ranges extend westward in a band towards the ocean, forming
the islands of Santa Rosa, San Miguel, and Santa Cruz. Mining in the Tranverse Ranges focused
primarily on boron or borates. The Lang Mine in Los Angeles County was one of the biggest
producers of boron.
MOJAVE DESERT
The Mojave Desert consists of about 25,000 square miles bounded by the San Andreas Fault and
the Transverse Ranges, the Garlock Fault, the Tehachapi Mountains, and the Great Basin. It
extends into southern Nevada and western Arizona. The Mojave is dominated by broad alluvial
basins that receive erosional debris from the adjacent uplands. These aggrading basins are
burying topography that was once more mountainous. Prominent ranges include Granite, Bristol,
Providence, Bullion, Turtle, Maria, and Chocolate mountains. Mining has and continues to play
an important role in the overall economy of the Mojave Desert. The principal metals mined
include gold, barium, barite, borates, copper, feldspar, lead, and magnesite. Silver, manganese,
strontium, and tungsten were also mined to a lesser extent.
PENINSULAR RANGES
The Peninsular Ranges extend 125 miles from the Los Angeles Basin and the Transverse Ranges
to the Mexican border, and beyond another 775 miles to the tip of Baja California. The width of
the ranges varies between 30 and 100 miles. The ranges contain minor amounts of Jurassic rocks
Figure 10: Keane Wonder Mine, Inyo County, 1916. Said to have produced $ 1,100,000 before closing in
1916 when ore was depleted ( used with permission, California Department of Conservation, California
Geological Survey).
Mining Thematic Study
Chapter 2. Historic Context
18
but are primarily composed of
igneous rocks of Cretaceous age
and plutonic origin. Typical
igneous rocks of these ranges
include gabbro, quartz diorite, and
granodiorite. Mining in the
Peninsular Ranges focused on
barium- barite ( Orange and Los
Angeles counties), feldspar
( Riverside and San Diego
counties), lead ( Los Angeles and
Orange counties), strontium ( San
Diego County), sulfur ( Imperial
County), and tin ( Riverside
County).
COLORADO DESERT
The floor of the Colorado Desert
lies at a low elevation, from 350
feet near the Colorado River on its
northern edge, to 130 feet at Winterhaven near Yuma. The bulk of the Colorado Desert drains
into the Salton Sea, an inadvertent artificial lake. The Salton Sea occupies the lowest parts of the
Salton Trough, a large depression extending from Palm Springs to the Gulf of California. The
basin occupied by the Salton Sea last received marine deposits in the Miocene and Pliocene.
There are no major mines in the Colorado Desert region, although small mines operated along
fringes of the desert floor.
SUMMARY
Gold mining, by far the most widespread and ubiquitous mining property type, was undertaken
in the Sierra Nevada, Cascades, Siskiyous, Tehachapis, San Gabriels, the mountains east of San
Diego, and in wide areas of the Mojave Desert and its surrounding ranges. There was also a
small, isolated gold- mining area within the coastal mountains of the Big Sur region in Santa Cruz
County. The reason for this broad distribution is that gold and other precious metal ores are
typically found in or near hilly or mountainous terrain; exceptions are limited to deposits or
placers found in alluvial areas at the edge of the Great Central Valley, or along the northern coast
of California in the form of black sands.
The Central Valley and coastal strip from San Diego to the Oregon border has experienced
extensive mining activity, but almost all of it is based around construction materials and
industrial minerals rather than precious or semi- precious metals. Industrial metals, such as
manganese and chromite, were mined in the Coast Ranges and elsewhere. The most notable
exception, mercury mining, was undertaken primarily in the coastal ranges west of the San
Joaquin and Sacramento Valley, but for the most part relatively distant from the coast. A
simplified visual representation of the location of mining areas in California can be found on
Figure 11: Banks Wash San Bernardino County, 1895. The road
behind the cabins is now Lytle Creek Road ( used with permission,
California Department of Conservation, California Geological
Survey).
Mining Thematic Study
Chapter 2. Historic Context
19
Maps 90 and 91 of the Historical Atlas of California ( Beck and Haase 1974). A map showing
“ Locations of past- producing gold and mercury mines in California” is available through
Minerals Availability System/ Mineral Information Location System ( MAS/ MILS) database
compiled by the former U. S. Department of the Interior Bureau of Mines ( USBM), now archived
by the USGS ( Causey 1998). While there are many individual reports documenting specific
minerals or metals, perhaps the most comprehensive report was the California Department of
Natural Resources, Division of Mines and Geology’s Bulletin 176: Mineral Commodities of
California ( Wright 1957b).
MAJOR METAL OR MINERAL COMMODITIES IN CALIFORNIA
Scholars examining the history of mining in California have focused, perhaps not surprisingly,
on mining of precious metals, such as gold and silver. These metals represented the greatest
economic value and generated the most excitement. It was the lure of riches that drew the
Argonauts during the gold rush, and it was the search for gold and silver that led prospectors to
fan out across the state and the American West, in search of new mining discoveries. In a way,
the search for gold, and to a lesser extent silver, captured the collective imagination of historians
as well as miners. Of course, a wide variety of metals were mined in California between 1848
and 1940; some, like mercury ( quicksilver), were used at first primarily in the gold- mining
industry. Others, like lead, copper, zinc, tungsten, manganese, molybdenum, and antimony, were
industrial metals and used for industrial processes or for industrial purposes, especially those that
developed in the late- nineteenth and early- twentieth century. For example, tungsten became the
metal of choice for use in electric light bulbs in the twentieth century; its high melting point also
made it valuable in producing hard and sharp steel tools for machining steel and other metals
( Jenkins 1950: 355– 361). These metals were often found in association with gold and silver.
During the 1910s through the 1930s, gold and silver mining, and to some extent copper, lead,
and zinc mining, followed a patterns expansion and contraction. Other than state and federal
mineralogist reports, relatively few published works focus on this period. The United States
Bureau of Mines ( USBM), for example, tracked production from placer and lode mines
producing all five metals and provided statistics for the years 1903 through 1940; a chapter in the
Minerals Yearbook, Review of 1940 focused on gold, silver, copper, lead, and zinc in California.
The following summaries of the metals or minerals do not cover the entire spectrum of the
history of each; instead the purpose is to provide a broad overview and document some of the
most pertinent source material.
BARITE ( BARIUM)
Barite, the main ore of barium, is important in the manufacture of paper, glass, and rubber. A
rich, white pigment is made from crushed barite. In more recent years barite has also been used
in radiology for x- rays of the digestive system, and when crushed, it is added to mud to form
barium mud, which is poured into oil wells during drilling. Barite is also a very popular mineral
among mineral collectors, and fine specimens are greatly sought after. California’s barite, which
is quite common throughout the state, is almost completely obtained from bodies that have
Mining Thematic Study
Chapter 2. Historic Context
20
replaced limestone or filled fractures ( Kundert 1957: 71). California’s most significant source of
barite is in the El Portal area of Mariposa County west of Yosemite. Barite mining began in this
region around 1910 ( Boalich 1913: 191; Bradley 1930: 45).
In addition to Merced County, barite of differing qualities and quantities is also found in
limestone replacement deposits throughout the state including Nevada, San Bernadino, Orange,
Shasta, Los Angeles, Tulare, and Monterey counties. Notable mines include Nevada County’s
Democrat Mine, active during the 1920s, that was at one time California’s leading barite
producer. This 200- foot open- cut mine operated until 1930, when the mine’s deposit of high-grade
barite was depleted. The Spanish Mine, also located in Nevada County, operated from
around 1930 until 1955 and produced over 35,000 tons of barite. Here the ore was crushed and
trucked nearly 50 miles to Colfax’s rail depot. Similar to the Democrat Mine, the Spanish Mine
was mined by way of the open pit method until its final closure in 1955. Synthetic Iron Color
Mine, another leading barite producer located in Plumas County, was mined with both open pit
and underground methods ( Kundert 1957: 71- 73). The nearby Savercool Mine was mined strictly
with the underground method.
The principal barite mines of Plumas and Nevada counties were generally known as small
quantity but high- grade mines, producing ore that, despite the high costs of excavation due to
difficult accessibility and shipping, remained profitable ventures. The products of these mines
and other lower- grade deposits were used largely in the petroleum, chemical, and glass
manufacturing industries ( Kundert 1957: 73- 74).
Further readings on the history of excavation and usage of barite in California include Walter W.
Bradley’s ( 1930) Barite in California, Charles V. Averill’s ( 1937) Mineral Resources of Plumas
County California and ( 1939) Mineral Resources of Shasta County: California, and W. B.
Winston’s ( 1949) Barium.
BORATES
Borax ( tincal), colemanite, and ulexite are among the derivatives of boron with commercial uses.
Boron itself does not occur naturally as a free element and has limited industrial applications.
Commercial uses range from porcelain enamels and ceramic glazes, soil nutrients for agriculture,
to well- known household cleansers ( Ingalls 1897). In desert regions, borate rich playas will form
borate “ crusts” a few inches thick that can be mined, reform over time, and be mined again. This
discussion focuses primarily on early borate mining in Lake County, and later, more- developed
mining in Kern, Inyo, and San Bernardino counties. These southeastern counties, which by 1950
contained the largest boron deposits in the world, supplied “ over nine- tenths of the world’s
requirements” ( Ver Planck 1957a: 87).
The first commercial borax mine in the United States was California’s Borax Lake Mine,
operating from 1864 to 1868 at Clear Lake, Lake County. That operation, run by the California
Borax Company, shifted its focus to the Little Borax Lake Mine from 1867 to 1873. Along with
gold and mercury mining, the borax industry employed large numbers of Chinese. Chinese labor
was critical to these early boron mining operations: “ The operations caused a terrible stench,
endured largely by Chinese Americans, who had been driven out of the gold mining areas and
Mining Thematic Study
Chapter 2. Historic Context
21
could not find other employment because of racial discrimination” ( NPS 2004). Working as mine
laborers, labor bosses, and support staff for both labor and company owners, the Chinese
remained connected to borax mining before and after the passage of the 1882 Chinese Exclusion
Act. Chinese labor figured prominently in not only Death Valley borax operations, in particular
the gathering of dry borax, but also in many early surface operations.
Borate mining started in southern California and southern Nevada’s desert valleys
contemporaneously in the early 1870s, ending the financial profitability of the operations in Lake
County. Francis “ Borax” Smith initiated the region’s “ Borax Rush” with his discovery of a
deposit at Teal’s Marsh in Nevada in 1872 ( Ingalls 1897). Similarly, Death Valley’s saline lakes,
marshes, and playas proved an ideal source of borates. Crustal mining operations, a process of
scraping and refining surface borates, began at Searles Lake ( or Marsh), San Bernardino County,
in 1874. John and Dennis Searles formed San Bernardino Borax Mining Company, and produced
100 tons of borax per month. The company operated until 1895 ( Ver Planck 1957a: 89- 90).
The opening of these new deposits in the 1870s caused the price of borax to decline from 32
cents per pound in 1873 to a decade low of 8.5 cents per pound in 1878. In the early 1880s
international prices began rising, encouraging new ventures ( Ingalls 1897: 60). In the 1880s and
1890s borax mining was viewed as “ one of the most promising industries” in California
( Lindenmeyer 2000: 185). Eagle Borax Works, founded by Frenchmen Isadore Daunet, began
operations in Death Valley in 1882. Prominent Californian businessman William Coleman
purchased Daunet’s works in 1883, letting it fail. That same year, Coleman also started one of
the most significant operations, the Harmony Borax Works ( California Historical Landmark
No. 773) in Death Valley, near Furnace Creek. The company employed 40 men, primarily
Chinese, and produced three tons of borax daily. The “ cottonball” ore ( ulexite) was scraped from
the playa and hauled by the now- famous twenty- mule teams 165 miles to the railhead in Mojave.
Coleman’s operations near Shoshone, Amargosa Borax Works, also employed Chinese labor
( NPS 2004).
The colemanite deposits near Calico, San Bernardino County, were discovered in 1882, and
proved to be a cheaper source of borax than playa deposits ( Ingalls 1897: 60). Colemanite
deposits also required a different mining technology than used on playas, employing incline
shafts and open pits ( Ingalls 1897: 57- 58). The development of borax mines had close ties to
development of smaller railroad lines, such as the Tonopah & Tidewater Railroad and the Death
Valley Narrow Gauge Railroad ( Vredenburgh 2005). In 1890, Francis “ Borax” Smith purchased
Coleman’s borax holdings— Coleman having gone bankrupt in 1888— and combined these with
his own Nevada deposits into the newly founded Pacific Coast Borax Company. Smith followed
up by developing other deposits in Borate, near Calico ( 1890), and Furnace Creek Ranch, Death
Valley ( 1904). The site at Furnace Creek included waste tailings, a company town, 20- mule team
wagons for transportation, rectangular iron- dissolving tanks, boilers, “ machine rooms,”
“ skimming piles,” ore carts/ track/ transportation infrastructure and “ several long rows of
crystallizing vats with truncated cone shapes” ( Ver Planck 1957a: 88).
Mining of playa borates peaked around 1890, and with the financial panic of 1907, playa mining
ceased in the state. In 1913, John Suckow discovered the largest borate deposit in the world— the
Kramer deposits, near what is now Boron. In 1927, Francis “ Borax” Smith began processing of
Mining Thematic Study
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22
the Kramer district sodium borates, making processing of colemanite deposits less economical
( Ver Planck 1957a: 89- 90). That same year, the Borax Company built the Furnace Creek Inn with
an aim towards attracting tourists to Death Valley. Many of Death Valley’s old borax mines were
closed and incorporated into Death Valley National Park in 1933, turning them into tourist
destinations.
CHROMITE
Chromite is an oxide of chromium and iron, which is utilized in furnaces as a refractory lining
for smelting copper and steel. Chromite was discovered by gold rush miners, although its
importance at that time was considered minimal. Today chromite’s principal role is in the
manufacture of hardened steel alloys. Use of this metal increased dramatically during the
twentieth century with the introduction of automobiles, and in war- related technologies such as
armor plating and armor piercing projectiles. ( Browne 1867: 224,198; Palmer 1992: 29).
It was first mined in 1868, and between 1869 and 1889 1,500 to 2,000 tons of ore were obtained
each year from mines in Del Norte County, as well as from smaller deposits in San Luis Obispo,
Placer, Sonoma, and Lake counties. In 1950 the California Division of Mines reported that there
were 1,200 deposits in the state, of which 46 mines had shipped at least 1,000 tons of ore each.
At that time the mines were in the Sierra foothills and the Klamath Mountains, with a scattering
in the Coast Range from San Luis Obispo to Tehama counties. Between 1921 and 1941, the state
averaged only 500 tons of ore per year ( Jenkins 1950: 297– 298).
COAL
In 1858, W. C. Israel discovered coal deposits in Contra Costa County about six miles south of
Antioch. A year later Francis Somers and James T. Cruikshank discovered a source of coal
known as the Black Diamond Vein. Coal so close to San Francisco was vital to the growth of the
California economy, providing a cheap, readily available source of energy needed to fuel
foundries, mills, ferries, steamers, and other developing industries.
Because of the demand for coal by commercial and residential markets, several mining
companies were formed, attracting a large number of miners to Contra Costa County. English
and Welsh miners, as well as Americans who had gained experience in Pennsylvania coal mines,
found their way to the Black Diamond Mines. Italians, Germans, and Chinese opened businesses
in the burgeoning towns. Initially, single men came for work, later bringing their families when
they were sure the mines would be operating on a long- term basis. Noah Norton opened the
Black Diamond Mine and founded the town of Nortonville in 1861. While Welsh miners
accounted for a majority of the populace, it soon evolved into a melting pot of diverse cultures
( Clayton Historical Society 2002).
By 1860, there were six miles of mines stretching between the towns of Somersville and
Nortonville and Judsonville and Stewartville. Clayton, only a few miles from the activity of the
Mt. Diablo Coalfield, responded immediately to the demand for services and supplies. By 1861
Clayton had become the hub of activities in the area. Four million tons of coal were extracted
during the brief history of coal mining in the Mt. Diablo Coalfield. The soft bituminous coal was
Mining Thematic Study
Chapter 2. Historic Context
23
of low quality. By 1902, the mining costs, competition from high quality Washington coal, and
the advent of oil as an industrial power source drove most of the mines out of business. Many of
the miners departed for Washington and Oregon where the hard coal, or anthracite, was being
mined. Nortonville and Somersville ultimately became ghost towns and Clayton turned to
ranching.
COPPER
Copper is reddish with a bright metallic lustre. It is malleable, ductile, and a good conductor of
heat and electricity ( second only to silver in electrical conductivity). Its alloys, brass and bronze,
are very important. The most important compounds of copper are the oxide and sulphate or blue
vitriol ( Winter 1993- 2007). Table 2 lists major copper mines in the state and their county
locations. Not surprisingly, the counties listed are among the most active mining counties in the
state ( Jenkins 1950: 302).
Copper was first discovered in Southern California, but went largely unnoticed until 1855 when
a deposit was found in Amador County’s Hope Valley. Early on, copper, like many other
minerals, was ignored as a by- product of gold mining. It was not until accessible placer gold
deposits had largely played out toward the end of the 1850s that miners began to devote their
attentions to copper mining rather than discarding it as a nuisance. In 1860 silver prospector
Hiram Hughes accidentally discovered a large copper vein 35 miles southeast of Stockton in
Calaveras County, near what became known as Copperopolis. Hughes had it assayed and learned
its value was $ 120 per ton. Other miners rushed to this area in hope of establishing their own
successful copper mines, and in 1861 five mining companies, including the Union and Keystone,
controlled over 11,000 feet of lode. Hughes’s mine, known as the Napoleon Mine, was
incorporated as the Napoleon Copper Mining Company in 1862. Occupying over 2,700 feet of
the lode, it emerged as the most successful, producing over 4,000 tons of copper ore during the
next two years. While this
production was diminutive in
comparison to that of states with
major copper mines ( such as
Arizona and Montana), copper
ranked second only to gold in
terms of its value as a metal,
making even small operations
profitable ( Browne 1867: 13- 140,
St. Clair 1999: 204).
Those who failed in Calaveras
returned to their own mining
districts throughout the state in
search of their own copper
deposits. In 1861 prospectors
identified an immense belt of
copper reaching from just north
of Los Angeles and extending
Table 2: Important Copper Mines in California
Major Mine County
Iron Mountain Shasta
Walker, Engels Plumas
Penn, Keystone Calaveras
Other Significant Mines
Copper Hill, Newton Amador
Big Bend Butte
Napoleon, North Keystone, Quail Hill Calaveras
Copper King, Fresno Fresno
Pine Creek Inyo
Daulton Madera
Spenceville Nevada
Dairy Farm, Valley View Placer
Superior Plumas
Copper World San Bernardino
Afterthought, Balaklala, Bully Hill, Hornet,
Keystone, Rising Star, Shasta King, Sutro
Shasta
Blue Ledge, Gray Eagle Siskiyou
Island Mountain Trinity
Data Source: Jenkins 1950.
Mining Thematic Study
Chapter 2. Historic Context
24
through Mariposa, Merced, Tuolumne, Stanislaus, El Dorado, Placer, Nevada, Yuba, Trinity,
Plumas, and Shasta counties. Other major deposits were soon discovered at the base of Mount
Diablo and Del Norte County. These discoveries and the high price of copper spurred the
incorporation of numerous copper mining companies throughout California. Major mines during
this time included those of the Copperopolis Table Mountain, Hope Valley, Newton, Cosumnes,
Birdseye Mine, Buchanan, and Genesse Valley Mine ( Browne 1867: 141- 143; Table 2).
A smelter was constructed in Contra Costa County in 1862, and by 1868 nine smelters were
operating in the Sierra foothills. Falling copper prices led to a period of inactivity in the industry
until the mid- 1890s, when a slow recovery began. Iron Mountain Mine in Shasta County
resumed operations and erected a smelter near Keswick that operated until 1907 when the
company built its major smelter at Selby, near Martinez in Contra Costa County. During the first
years of the twentieth century, other mines, like the Afterthought, Balaklala, Bully Hill, and
Mammoth, built smaller smelters on site. Problems with high levels of zinc in the ores, combined
with lawsuits, led to the Shasta mines being idled by 1919 and in the years that followed there
was only sporadic activity. California’s copper deposits were mined with underground methods
and the ores required fine grinding and use of flotation to form concentrates suitable for sending
to the smelters ( Jenkins 1950: 305, 307).
The beginning of the twentieth century brought about a renewed demand for copper.
Development of new technologies, especially advancements in electrical mine machinery,
propelled copper to the top of the mining industry between 1900 and 1930, with the United
States manufacturing over 65 percent of the world’s copper supply during this period. With
improved transportation, copper companies were able to ship lower grade ore, helping to
transform copper mining from a selective to a more profitable non- selective endeavor.
Ultimately, western mines produced a much lower grade of ore than the massive copper mines in
Michigan’s Lake Superior region, making it difficult for California companies to compete
against their Michigan counterparts ( Hovis and Mouat 1996: 435- 436).
Between 1897 and 1930, an average yield of 16,000 tons of ore per year was produced. Output
dropped between 1931 and 1936, owing to a decline in the price of copper. Most of the
production came from Shasta, Plumas, and Sierra foothill counties. By the end of 1946, 54
percent of the state’s production came from Shasta county, while 26 percent came from Plumas
county, and 12 percent from the Sierra foothill counties ( of which Calaveras produced more than
80 percent of the total). The Iron Mountain Mine in Shasta County alone accounted for 42
percent of the state’s total production, while the Walker and Engels mines in Plumas County and
the Penn and Keystone- Union in Calaveras County produced 37 percent. All the other copper
mines in the state represented 21 percent of production. The California Division of Mines
reported that “ only eight counties in the state have no recorded copper production. Those
counties included Kings, San Francisco, San Joaquin, San Mateo, Santa Cruz, Solano, Sutter, and
Yolo” ( Jenkins 1950: 300– 307). The single best producer of copper at that time was the Walker
Mine in Plumas County, which milled 437,450 tons of ore and produced 10,524,345 pounds of
copper, along with 14,176 ounces of gold and 237,891 ounces of silver ( USBM 1941: 251). The
gold and silver found in conjunction with the copper often provided the profit for the mining
company, while the production and sale of copper simply met its mining expenses. Besides those
mentioned above, 26 other mines produced significant amounts of copper ( Jenkins 1950: 302).
Mining Thematic Study
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25
FELDSPAR
Feldspar is mostly buff to cream- colored with local bluish- gray spots and streaks due to minute
inclusions. As is usual in all feldspar quarries, most of the material marketed under the
commercial name " feldspar" is an intergrowth of feldspar and quartz. The standard or No. 2
grade obtained at quarries consists principally of graphic granite with a subordinate amount of
pure feldspar. Some No. 1 grade nearly free from quartz is also obtained ( Bastin 1911).
One of the largest feldspar mines was the Mount Apatite, operated by Maine Feldspar Company
in the early 1900s near Auburn. The workings consisted of a number of small pits 75 to 150 feet
long, 50 feet in average width, and 10 to 20 feet in depth. These were either close together or
partly connected and were located in a single mass of pegmatite ( Sampson and Tucker 1931).
GOLD
The history of gold in California is well documented in published books, journals, and
photographs. Prior to 1848, gold’s presence in California was known to its few settlers and
natives, but the extent and quantity of gold in the state was unknown. While exact figures may
never be known, from James Marshall’s 1848 discovery in Coloma until 1954, California yielded
over 106 million troy ounces of gold. Gold remained California’s most valuable mineral
commodity until 1942, when it was surpassed by tungsten, iron, and quicksilver over the
following decade. Over time, high mining costs and difficult access to deposits contributed to
gold’s decline as a commodity ( Clark 1957: 215).
Gold can be found throughout the state, but is heavily concentrated in a few areas. The primary
area of concentration, the western slope of the Sierra Nevada, is home to the famous Mother
Lode and the Grass Valley- Nevada City gold district. The most productive area of the Mother
Lode, a twelve mile stretch between the towns of Plymouth and Jackson in Amador County,
encompasses many large deposits, including the Kennedy and Argonaut mines. The Mother Lode
contains two main types of gold. The first, gold- quartz veins are generally found in its northern
region, while the second, bodies of mineralized country rock, are found to the south ( Knopf
1929: 23, cited in Clark 1957: 215).
Gold mining methods varied, but there are four basic types of extraction: placer, hydraulic, lode
( underground), and dredging ( Table 3). Eventually, lode mining replaced placer and hydraulic
mining as the primary method of recovering gold. Besides providing the foundation for world
currency systems,
gold has many uses.
It is widely used for
gilding, plating,
jewelry making and
dozens of other
industrial and
domestic
Table 3: Placer Gold Mining, Number of Mines in Selected Years
Type of Mine 1910 1920 1930 1935 1940
Placer / dredging 41 / 72 25 / 41 21 / 31 99 / 114 363 / 259
Hydraulic 168 51 79 93 92
Small surface placers ( wet) 184 61 688 1,132 282
Small surface placers ( dry) 1 1 6 21 17
Drift 139 45 88 143 96
Data Source: US Bureau of Mines 1941: 219- 222.
Mining Thematic Study
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26
applications ( Clark 1957: 221).
Gold mining is discussed extensively elsewhere in this document ( refer to Gold Rush in this
chapter). Additional sources include J. E. Doolittle’s ( 1905) Gold Dredging in California, A.
Knopf’s ( 1929) The Mother Lode System of California, G. A. Joslin’s ( 1945) Gold, Olaf Jenkins’
( 1948) Geologic Guidebook along Highway 4, and William Clark’s ( 1970) Gold Districts of
California.
LEAD
Lead is a rare and malleable mineral of hydrothermal origin. California’s lead ore is mainly
recovered through typical underground mining methods. Once brought to the surface, the ore is
shipped immediately or milled and then shipped, depending on its quality. It is further
concentrated through flotation and then smelted for refinement ( Stewart 1957a: 285). Lead’s
malleability, high resistance to corrosion, and high specific gravity made it a useful component
of alloys and chemical compounds.
Over 450 million pounds of lead have been recovered in California, with most of it coming from
Inyo County. Lead was reportedly first produced by Mormon miners working silver deposits in
the Panamint Range in 1859. The mines at Cerro Gordo were discovered and worked on a small
scale by Mexican miners starting in 1862. The California Division of Mines reported that
“ American interests” took over these mines in 1869, and increased production. They erected a
smelter at Cerro Gordo and another at Swansea, on the eastern shore of Owens Lake. The mill
and smelter site at Swansea, California Historical Landmark No. 752, produced silver bars. Cerro
Gordo’s lead mines were substantially worked out by 1877, but interest revived after a railroad
reached Keeler, just south of Swansea, and the mines were worked intermittently until the 1940s.
Mines of the Cerro Gordo district produced more than $ 17 million in lead, silver, and zinc. Silver
and lead mining peaked in the 1880s but there was a second boom for zinc in the 1910s ( Stewart
1957a: 281).
Inyo County has three major lead districts. The Cerro Gordo produced over 150,000 tons of ore
from its 15 miles of underground workings ( Stewart 1957a: 281). The Darwin District, which
first opened in 1874, was the principal source of California lead through the 1950s, with most of
the ore being found in Pennsylvania limestone. The third lead district of Inyo County, the Tecopa
District, operated from 1912 to 1928. In 1947 the several small mines that comprised the district
included the Columbia which produced over 93,000 tons of ore from 1912 to 1928 ( Stewart
1957a).
Other notable lead mines included the 1865 Gunsight Mine, which produced over 55,000 tons of
ore between its peak years of 1912 and 1928, and the Santa Rosa Mine, a producer of lead,
silver, zinc, and copper. Both were located at the southern end of the Inyo Range. Rich lead
deposits, generally by- products of copper and gold mining operations, were found at the northern
edge of Inyo County’s Argus Range, the Sierra Nevada foothills, and the Klamath Mountains.
Smaller deposits were worked in San Bernadino and Orange counties ( Stewart 1957a: 283- 284).
Mining Thematic Study
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27
Further suggested reading includes A. Knopf’s ( 1918a) A Geologic Reconnaissance of the Inyo
Range and the Eastern Slope of the Sierra Nevada, California, D. L. Davis and E. C. Peterson’s
( 1949) Anaconda’s Operation at Darwin Mines, Inyo County, California, L. A. Norman’s ( 1951)
Mines and Mineral Resources of Inyo County, and E. M. MacKevett’s ( 1953) Geology of the
Santa Rosa Lead Mine, Inyo County, California.
LIMESTONE
Limestone is composed of sedimentary rocks that are made from the mineral calcite which came
from the beds of evaporated seas and lakes and from marine shellfish remains. Limestone is the
most abundant of the non- clastic sedimentary rocks. The main source of limestone is the limy
ooze formed in the ocean. The calcium carbonate can be precipitated from ocean water or it can
be formed from sea creatures that secrete lime such as algae and coral. Chalk is another type of
limestone that is made up of very small, single- celled organisms.
While lime production in California predated the gold rush, the rush created an increased
demand for building materials, ushering in the era of mass production of lime. Essential for
producing mortar, plaster, and later cement, lime became indispensable to the construction of
brick buildings and other structures. The flammable canvas and timber buildings of gold camps
and cities were soon replaced with stone and brick materials, significantly increasing the demand
for lime. Kilns in Olema in Marin County in 1850 and Santa Cruz in 1851 provide the earliest
evidence of this period of limestone production. The forested areas of Santa Cruz County were
soon dotted with kilns whose operators relied heavily on the local, slow- burning redwood for
their fuel. Santa Cruz combined a readily available fuel source with abundant capital and labor
along with water access for transportation and shipping, causing it to emerge by 1868 as the
center of California lime production. The lime industry soon spread throughout the county to
towns such as Davenport and Felton ( Bowen 1948; Piwarzyk 1996: 20).
The demand for lime for making mortar and other purposes, including plastering stone and adobe
structures, resulted in significant production in the towns of Cool, El Dorado County, and Ione,
Amador County ( Jenkins 1949), to name two. In El Dorado County the owners of limestone
quarries and kilns produced and shipped their product to locations along the Sacramento and
Placerville and Central Pacific railroads in order to accommodate diverse markets. Kilns near
present- day Cameron Park were employed to supply the region with lime and Marble Valley,
situated near the railroad, shipped much of its lime to Sacramento ( Sioli 1883).
The growing popularity of Portland cement in the early 1890s spurred further limestone
quarrying with production in California peaking in 1904. Portland cement, which used limestone
in conjunction with other added minerals, was a much stronger building material than traditional
lime. As Portland cement gained popularity, large manufacturing companies systematically
replaced the smaller concerns of the Santa Cruz area and the last of those kilns ceased operating
in 1946 ( Bowen 1948).
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28
MANGANESE
Manganese is a gray- white metal resembling iron, and while it is harder, it is very brittle. The
metal reacts chemically and decomposes slowly in cold water. It is an important component of
steel. Mining manganese varied in accordance with the size and shape of the deposit. Generally,
wider deposits were mined by an open cut method, while narrower ore bodies were recovered
through underground mining methods. The manganese ore was then hand sorted for milling
purposes and separation. Separation techniques included flotation, fine grinding, spiral
concentration, and magnetic separation. Used heavily in steel- making, manganese and its
derivative chemicals, such as manganese sulfate, manganese acetate, and manganese chloride,
were major components of many industrial products such as paint and varnish. Manganese
sulfate, for example, was used with great success as a manganese spray supplement for walnut,
apricot, peach, and citrus trees ( Davis 1957: 332- 333, 337).
Manganese ore, first mined in California in 1867, can be found throughout the state. Some
leading manganese producing counties include Humboldt, San Joaquin, Stanislaus, Imperial,
Riverside, Trinity, Mendocino and San Bernadino. The largest percentage of ore is extracted
from four areas within the Coast Ranges: the Diablo Range, spanning San Joaquin, Stanislaus,
Santa Clara, and Alameda counties; the Mad River Valley in southern Humboldt and Trinity
counties; Mendocino and Lake county ranges; and the western portion of San Luis Obispo
County. California’s desert region contained several productive manganese districts including
Imperial, Riverside, and San Bernadino counties ( Davis 1957: 325, 329).
One of California’s earliest and largest manganese mines, the Ladd- Buckeye in San Joaquin
County, opened in 1867. At its peak, the Ladd- Buckeye Mine accounted for over 60 percent of
the Coast Range’s total production and one- third of California’s entire manganese production.
As with many of the state’s mineral industries, wartime demand led to heightened production
from California’s manganese mines. Both world wars necessitated increased production for a
variety of military uses. During World War I, the Ladd Buckeye produced 10,000 tons of
manganese ore ( Davis 1957: 329- 333).
Further information on manganese can be found in J. B. Hadley’s ( 1942) Manganese Deposits of
the Paymaster Mining District, Imperial County, California, and Olaf Jenkins’ ( 1943)
Manganese in California.
MAGNESITE
Magnesite occurs as veins in ultramafic rocks, serpentine, and other magnesium- rich rock types
in both contact and regional metamorphic terranes. It varies in color from white to gray, yellow,
brown, or even clear. It is used in refractory bricks and cement. Most of California’s magnesite
deposits are associated with serpentine and are found in the Coast Ranges and the western
foothills of the Sierra Nevada. Recovery is generally performed using underground techniques
and some open cut procedures. To avoid dilution and a subsequent reduction of quality, the ore is
generally hand- sorted ( Ver Planck 1957b: 313- 316).
Mining Thematic Study
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29
Magnesite was first recognized in Porterville in 1853, but the first large- scale mining operations
began in Alameda County in 1886. Other early magnesite mining occurred in Napa County in
1886 and at Santa Clara County’s Red Mountain Mine located on the border of Santa Clara and
Stanislaus counties in 1899. These small operations marked the beginning of a large, statewide
industry. Until 1917, the Porterville District produced all of America’s domestic magnesium,
accounting for nearly all of California’s pre- 1930 production ( Ver Planck 1957b: 313, 321).
Necessary for the manufacture of military equipment, magnesite production increased during the
two world wars as dormant mines were reopened or production increased at working mines.
Between the wars, magnesite production mainly occurred in the Porterville District as the Sierra
Magnesite Company had established a large plant there in 1920 to produce oxy- chloride cement.
Porterville’s resources dwindled and by 1931 had all but played out, prompting the Sierra
Magnesite Company to invest in Stanislaus County’s Bald Eagle Mine. Other prominent mines
included the Western Mine ( 1919- 1931), Tulare County’s Harker Mine ( 1923- 1926); and the
state’s largest magnesite mine, the Red Mountain Mine ( 1922- 1932). World War II created a
huge demand for lightweight aircraft materials, prompting magnate Henry J. Kaiser to construct
thermal reaction plants in San Mateo and San Joaquin counties. These operated between 1941
and 1953, with some temporary suspensions after WWII ( Ver Planck 1957b: 313, 321).
California had separate industries reliant upon different forms of magnesite, although they
produced similar products. One type of operation was the commercial production of bitterns, a
concentrated solution of magnesium chlorides and other chemicals extracted from evaporated
seawater. This commercial refinement and production of magnesium began in 1880, when it was
utilized by the dynamite industry as an absorbent. World War I brought about a world wide
shortage in magnesium, prompting the opening of plants in Los Angeles, Alameda, San Diego,
and San Mateo counties for the duration of the war. Uses of the finished product included rubber
manufacturing, as well as high magnesium alloys for kiln linings and other high temperature
furnaces ( Ver Planck 1957b: 319- 322).
Suggested additional reading on magnesite includes the Lewis E. Aubury’s ( 1906) Magnesite.
The Structural and Industrial Minerals of California; F. L. Hess’ ( 1908) Magnesite Deposits of
California and J. B. Perry and G. M. Kirwan’s ( 1942) The Bald Eagle Magnesite Mine.
MERCURY
Historically, what we now commonly refer to as mercury was, in its raw form, called cinnabar, a
composite mineral containing sulfur and mercury. The finished product was commonly referred
to as “ quicksilver.” Although mercury mining in California predates the gold rush, the
emergence of the industry was nevertheless closely tied to the discovery of gold. Spanish settlers
near San Jose were aware of mercury sulfide deposits in the local hills in the 1820s. Large- scale
mining for the ore in the area, however, did not begin until 1846. The New Almaden Mine
opened that year, and from 1850 to 1870 it was the principal producer of mercury for both the
state and the nation. New Almaden yielded 535,437 flasks ( the flask being the standard unit of
mercury measurement, roughly equal to 76 pounds) over this twenty- year period ( Ransome and
Kellogg 1939: 359, 361).
Mining Thematic Study
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30
In 1851, the mine’s
first full year of large-scale
production, it
produced over 27,000
flasks at an estimated
value of over
$ 2,000,000. As with
all mining techniques
the process of
producing quicksilver
would undergo
several changes and
improvements over
time due to
advancements in
transportation,
engineering, and
scientific knowledge.
During the mine’s
early years, little
machinery was used
as workers hand drilled and blasted the ore from the tunnels of the mine ( Schneider 1992: 20- 21).
Eventually the mine expanded to over 7,800 acres as it accommodated new equipment and a
large labor force ( Browne 1867: 173).
Initially, the New Almaden Mine relied on Native American and Mexican labor. Cornish miners,
who were already well known for their hard rock mining expertise, also constituted a large
portion of New Almaden’s labor force ( Schneider 1992: 52). As mining activity increased, so did
the site’s infrastructure. By 1867, over 400 stores, workshops, and barracks served New
Almaden’s workers as the mine took on the appearance of a small town ( Browne 1867: 173).
During the nineteenth century mercury was shipped to China for use in paints. It was also used in
preserving wood, developing daguerreotypes, silvering mirrors, and in hat making. Prior to the
early- twentieth century, mercury was crucial to the extraction of gold in the United States. Most
metals adhere to mercury through a process known as “ amalgamation.” Employing this physical
principle, miners would pass gold ore down a trough coated with mercury, or otherwise mix the
gold- bearing “ pulp” with mercury. Any gold in the ore would then bind with the mercury,
forming a gold- mercury amalgam. Miners would scrape off the mercury and separate it from the
amalgam, usually through a retort to distill off the mercury, yielding higher- purity gold
concentrates. Residual mercury from this process was often released into the environment,
deposited in the earth, in streams, rivers, or lakes, contributing to a significant amount of
environmental pollution that only worsened with the onset of hydraulic mining. Mercury
pollution from the gold rush persists into the present ( Alpers and Hunerlach 2000: 1– 6).
The shift to hydraulic mining and the discovery of the Comstock Lode in the late 1850s further
stimulated mercury production in the state as gold and silver mining companies sought to
Figure 12: New Almaden Quicksilver Mine, 1877 ( Photo courtesy Library of
Congress, Washington, D. C.)
Mining Thematic Study
Chapter 2. Historic Context
31
maximize the extraction of gold ore. From roughly 1860 to 1870, a number of mines rich in
mercury opened. The Knoxville and Manhattan mines both began production, as did the
Manzanita Mine and a number of other smaller properties in and around Sulphur Creek and
Wilbur Springs in Lake and Colusa counties. Cinnabar was discovered near Santa Barbara and
San Luis Obispo as well, deposits that prompted the opening of the Oceanic and Klau mines
( Ransome and Kellogg 1939: 359– 360).
Other mercury discoveries occurred between 1857 and 1875 in Napa, Sonoma, Colusa, and Lake
counties, within areas of volcanic activity in which mercury commonly proliferates ( Davis 1957:
348). The St. Johns, Aetna, and Guadalupe mines were all opened in this period; however, only
the latter produced any mercury prior to the 1860s ( Ransome and Kellogg 1939: 359). Other
mercury or cinnabar mines were located in Death Valley ( Swope 1999).
The 1870s was the most significant era for mercury mining in California history. During this
decade, the state produced a third of the world’s mercury ( Isenberg 2005: 48). Of all California’s
mercury regions, the Mayacmas district— an area that encompasses much of the mountainous
and volcanic areas of Lake, Napa, and Sonoma counties— was the single most important locale.
Within the Mayacmas District, several new mines joined those already in production, including
the Great Western, the Culver- Baer, the Cloverdale, and the Oat Hill. Existing district properties,
such as the Knoxville, the Guadalupe, St. Johns, Aetna, and the Altoona mines, all reached
record highs of production ( Ransome and Kellogg 1939: 359– 360).
While mercury production remained an important component of California’s geological
economy into the mid- twentieth century- particularly with the onset of World War II- the industry
as a whole largely stagnated from the 1880s onward. Gold beneficiation processes in the United
States moved away from amalgamation, and although mercury remained important to a number
of technological and medical devices, demand was easily met by existing reserves and by
overseas production
( Jenkins 1950: 335;
American Institute of
Mining and Metallurgical
Engineers 1953: 325– 332).
After 1878, only two
notable mercury
discoveries were made in
the state: the Mirabel Mine
in 1887 and the Corona
Mine in 1895 ( Ransome
and Kellogg 1939: 360).
The demand for mercury
during World War II
increased both its value and
production level until 1944,
when production tapered
off dramatically ( Davis
1957: 348).
Figure 13: View of New Almaden Quicksilver Mine Reduction Works ( Photo
courtesy HABS photograph, Library of Congress, Washington, D. C.).
Mining Thematic Study
Chapter 2. Historic Context
32
PYRITE
Pyrite, also known as marcasite by jewelers, is a brass- yellow mineral with metallic luster,
employed to some extent for the purposes of ornament. It is widely distributed in the earth’s
crust and often mistaken for gold, hence its name “ fools gold.” The name pyrite is derived from
the Greek word for fire, an allusion to the fact that, owing to its hardness, it will strike fire with
steel. Brittle and heavy for its size, in large quantities it forms an ore of sulfur ( Farrington
1903: 212).
The mining of pyrite began in Nevada County’s Spenceville Copper Mine in 1860, where it was
derived as a by- product of copper mining. Since 1900, most of California’s pyrites have been
recovered from Shasta County’s West Shasta Copper- Zinc District. Operated by the Mountain
Copper Company, the Iron Mountain Mine and others located in this district account for
California’s chief source of pyrite production. At the Iron Mountain Mine, pyrite is extracted
using open pit methods then crushed at an on- site mill before being shipped to manufacturers of
sulfuric acid. Aside from Shasta County, Alameda County is the only other known producer of
commercial pyrites. Alameda’s principal mines, the Alma ( 1891- 1920) and Leona ( 1895- 1934),
produced over 250,000 tons of pyrite during their years of operation ( Chesterman 1957: 419, 449-
451).
Reports and Bulletins concerning pyrite in California include F. F. Davis’ ( 1950) Mines and
Mineral Resources of Alameda County, California, and A. R. Kinkel’s ( 1951) Geology of the
Massive Sulfide Deposits at Iron Mountain, Shasta County, California.
SILVER
Pure silver has a brilliant white metallic lustre. It is a little harder than gold and is very ductile
and malleable. Pure silver has the highest electrical and thermal conductivity of all metals, and
possesses the lowest contact resistance. Silver is stable in pure air and water, but tarnishes when
exposed to ozone, hydrogen sulfide, or air containing sulfur. It occurs in ores including argentite,
lead, lead- zinc, copper, and gold found in Mexico, Peru, and the United States.
The history of silver production in pre- gold rush California is sparsely documented in
comparison to other minerals. The materials and skills necessary to separate silver from its host
rock were not fully developed in California until the late 1850s, when surface gold became
scarce and attention turned to underground mineral resources. The 1856 discovery of silver at
Shasta County’s South Fork Mining District created a new awareness of potential silver deposits
in California. The discovery of Nevada’s Comstock Lode three years later resulted in extensive
prospecting in Alpine, Mono, and Inyo counties. The success of these early operations,
particularly in Alpine County, was limited due to the lack of advanced processing equipment
needed to separate the silver from other elements. Notable mines during the beginning of
California silver mining include Mono County’s Blind Spring Hill ( 1862- 1890) and two Inyo
county districts, the Cerro Gordo founded in the 1860s, and the Darwin dating to the early 1870s
( Stewart 1957b: 529- 532).
Mining Thematic Study
Chapter 2. Historic Context
33
Statistics on silver mining in California were not collected by the state until 1888, but in the
years between 1888 and 1950, 100 million ounces of the metal were produced, which
represented 2.8 percent of the national total to that time. As noted, silver was most often found
with other metals; only a few mines, such as those at Calico ( 1881– 1896) and Randsburg ( 1895),
had silver as the principal ore ( Jenkins 1950: 343– 347).
Most of California’ silver has been recovered from base metal ores, primarily in Inyo and San
Bernadino counties. Two of California’s principal silver districts, Calico and Randsburg in San
Bernadino County, were developed at different times. Calico, a series of small mines founded in
1881, enjoyed its peak years from 1882 to 1896 and was mined sporadically thereafter. This
mine, because of its unusual quantity of high- grade ore, was worked in an unsystematic fashion
that left much of the lower grade ore untouched. In Randsburg, the Kelly Mine opened in 1919
and produced the largest silver output of any mine in California until its closure in 1942. Shasta,
Calaveras, Kern, Mono, Nevada and Plumas counties also produced significant quantities of
silver ( Stewart 1957b: 529- 531).
Silver is mined with typical underground methods, and depending upon the purity and quality of
the ore, undergoes several types of treatment. The pure ore, or silver chloride, in the Calico Mine
District, is handled differently than base metal ores from other mines in which the silver must be
extracted and separated. Silver is derived from these base metal ores the same way as copper,
zinc, and lead; it is further separated by means of mercury amalgamation or smelting. Cyanide
leaching, introduced in the 1890s, was another popular form of derivation. Smelting and
cyanidation became common practices and were often preceded by concentration ( Stewart
1957b: 533- 534).
For additional information on silver mining refer to H. G. Hanks’ ( 1884) Silver in California, J. L.
DeLeen’s ( 1950) Geology and Mineral Deposits of the Calico Mining District, and Donald
Carlisle’s ( 1954) Base Metal and Iron Deposits of Southern California.
STRONTIUM
Strontium is a soft silver- white or yellowish metallic element of the alkali metal group that turns
yellow in air; it occurs in celestite and strontianite. Strontium and its compounds have but a few
commercial uses. Some compounds are added to glass and ceramics to give them a beautiful red
color. Compounds of strontium are also used to provide the red colors seen in a fireworks
display. Celestite is the major source of strontium. Although celestite deposits occur in Arizona
and California, domestic production of celestite has been small and sporadic. Much of the
strontium demand is satisfied by imported ores from England and Mexico. Strontium nitrate is
used in pyrotechnics, railroad flares, and tracer bullet formulations. Strontium hydroxide forms
soaps and greases with a number of organic acids which are structurally stable, resistant to
oxidation and breakdown over a wide temperature range.
First mined in San Bernadino County’s Avawatz Mountains in 1911, strontium was a minor
product of California’s mining industry. Most California deposits of strontium are found in the
southern part of the state, specifically in San Bernadino County, where two of California’s three
largest deposits are located. Strontium mining in California generally occurred during World
Mining Thematic Study
Chapter 2. Historic Context
34
War I and II, when it was needed for flares, tracer bullets, signal rockets, and other related
products ( Ver Plank 1957c: 607). It is also used heavily in the pyrotechnics industry. Several
strontium- producing plants were constructed in California during these periods.
The largest known deposit of strontium is the Cady Mountain deposit, located on the southern
slope of San Bernadino County. Work began on this low- grade deposit in 1916 at the onset of
World War I when imported strontium from Germany and Britain became unavailable due to
shipping and importing restrictions. With a few exceptions, the reintroduction of cheaper British
and German strontium nitrate after the wars terminated strontium production in California.
During World War II, the deposits of San Diego County’s Fish Creek Mountain provided nearly
20 percent of the national strontium output. A third major deposit in the Mud Hill area near
Barstow in San Bernadino County also contributed to war- time production ( Ver Plank
1957c: 607- 611).
Studies of strontium in California include Adolf Knopf’s ( 1918b) Strontianite Deposit Near
Barstow, California, and Cordell Durrell’s ( 1953) Geologic Investigations of the Strontium
Deposits of Southern California.
SULFUR
Sulfur is found in meteorites, volcanoes, hot springs, and as galena, gypsum, Epsom salts, and
barite. Uses of sulfur are varied. Sulfuric acid is used widely for industrial explosives, petroleum
refinement and chemical production. Industries that make use of non- acid sulfur include fertilizer
producers and pulp and paper manufacturers. Sulfur production in California was ultimately
hindered by low- grade product, high transportation costs and out of state competition ( Lydon
1957: 618, 622).
Sulfur has been mined in several California counties, including Alpine, Lake, Shasta, Colusa,
Kern, Inyo, and Imperial. The Leviathan Mine, California’s largest sulfur mine and located nine
miles from Markleeville in Alpine County, was opened in 1863 for the purposes of mining
copper and gold. It was abandoned shortly thereafter and reopened in 1894 for copper mining.
The mine was opened again for sulfur production in the early 1930s by the Leviathan Sulphur
Company. This mine was excavated using open pit and underground methods, in which the ore
was drilled, crushed, and then sorted according to grade. The ore was often transported
elsewhere for further refinement and treatment ( Lydon 1957: 613- 614).
In 1906 the Leona Heights sulfur mines opened east of Laundry Farm Canyon in the Oakland
hills. A bunker was built at the Car Barn site in Laundry Farm Canyon, which connected aerial
cable tramways to the sulfur mines, and later rock quarries, in the hills above. The mines were
the project of Franics Marion “ Borax” Smith, who made a fortune in Oakland, but fell into
bankruptcy in 1913. The sulfur mines frequently caught fire and had to be abandoned. With
miles of tunnels, they were played out by 1929 ( Mix 1999).
Inyo County’s Last Chance Mine produced over one- third of the native sulfur in California.
These deposits were accessed mainly by underground methods, although open cut methods were
used on limited occasions. The region’s peak period of production, 1928- 1943, was curtailed due
Mining Thematic Study
Chapter 2. Historic Context
35
to lack of water near the mines along with difficult and expensive transportation methods to
bring the mined product to refineries and markets ( Lydon 1957: 614- 615).
Other significant California mines and deposits feature the Full Moon ( 1928) and the Coyote
Mountain deposits in Imperial County. Both of these deposits were mined using underground
and open pit techniques. Kern County experienced minor production in 1893 in the Sunset Oil
District. Lake County’s Sulphur Bank Mine, operated by the California Borax Company,
experienced a brief period of production from 1865 to 1868, until high amounts of cinnabar
complicated the refining process and hastened the demise of the operation. The Sulphur Bank
Mine reopened in 1873 for the purpose of mining quicksilver ( Lydon 1957: 614- 616).
For more information on sulfur, refer to E. D. Lynton’s ( 1938) Sulphur Deposits of Inyo County,
California, W. B. Tucker and R. J. Sampson’s ( 1938) Mineral Resources of Inyo County, W. B.
Tucker’s ( 1942) Mineral Resources of Imperial County, and D. L. Everhart’s ( 1946) Quicksilver
Deposits a the Sulphur Bank Mine, Lake County, California.
TALC AND SOAPSTONE
Talc or soapstone ( also known as steatite) usually occurs in flaky, foliated or massive forms, and
in plates that appear to be tabular crystals. It also forms with chlorite and a few other substances,
and varies in color from white to greenish yellowish, red, and brown. All varieties are soft and all
have a soapy feeling. Early California settlers used soapstone found in the Sierra Nevada for
construction materials, furnace foundations and linings, and other domestic purposes. Ground
talc or soapstone was also used for stoves, headstones for cemeteries, and in rare instances for
building construction. In the twentieth century it was used extensively as a lubricant to line acid
vats and laundry tubs as well as for table tops and sinks.
Talc mining techniques are primarily underground methods in which the rock, after being
blasted, is fed into ore cars by gravity then crushed and ground. Talc is easily accessed to around
200 feet, and with increasing difficulty, and expense to around 500 feet. A variety of industries
including ceramics, rubber and paper manufacturing, textiles, pharmaceuticals, and asphalt were
reliant upon talc ( Wright 1957a: 631- 633).
Most of California’s talc is found in the southeastern part of Death Valley’s Kingston Range,
including parts of Inyo and San Bernadino counties. Smaller deposits have been found and
mined on the western slopes of the Sierra Nevada range and Los Angeles County ( Wright
1957a: 623).
Mining of soapstone and talc was sporadic until 1912 when several mines, including the Talc
City, Western, and Silver Lake, were opened in southeastern California. When foreign talc
supplies were severed during World War I, these mines became essential sources of talc. In the
1930s, increased use of talc in tile and paint production and high frequency electrical insulators
helped propel the industry to higher levels of production. Important mines during the 1930s and
1940s were the Alliance, Florence, White Eagle, and White Mountain Mines in the Inyo
Mountain area; the Ibex, Monarch and Superior within the Death Valley Kingston Range; and
Mining Thematic Study
Chapter 2. Historic Context
36
several small, active mines in the Yucca Grove area. World War II helped sustain domestic need
for talc which carried over into the post war era’s construction boom ( Wright 1957a: 633).
For additional information on talc see L. A. Wright’s ( 1950) California Talcs, R. S. Lamar’s
( 1952) California Talc in the Paint Industry, T. E. Gay and L. A. Wright’s ( 1953) Geology of the
Talc City Area, Inyo County, California, and J. W. Lennon’s ( 1955) Investigation of California
Talc Use in Wall Tile.
TUNGSTEN
Pure tungsten is a light gray or whitish metal that is soft enough to be cut with a hacksaw and
ductile enough to be drawn into wire or extruded into various forms. If contaminated with other
materials, tungsten becomes brittle and is difficult to