GoldGoldThe Saga of the Empire Mine 1850-1956
For centuries, the search for gold has driven humanity across all boundaries and cultures. When gold was first discovered in the United States in North Carolina in 1801, many methods of extraction were developed prior to the California Gold Rush of 1848.
The Empire Mine opened in the 1850s in Grass Valley, California, and its preservation is a small but significant example of the development of mining techniques and equipment, hard rock and deep-shaft mining, stamp mills, and the furtherance of geological knowledge in the West.
The early years of the Empire’s existence saw a number of ownership changes, yet produced 28,100 tons of gold-quartz ore in its first 9 years of operation. The Saga of the Empire Mine is a detailed historical pilgrimage back to the early days of mining and looks at the science of mining, for example, the chlorination of sulfides and the use of cyanide plants, and to its decisive turning point—new owners with sufficient financial backing to introduce the best mining equipment and the best available engineers to manage operations.
The Empire vein of gold was remarkably persistent and has been followed down into the earth 7000 feet using vertical shafts, and along the strike for over 5000 feet. The yearly financial reports were carefully preserved and attest to the mine’s growing wealth over the century in which it operated.
|
Endorsements |
“This book is a must for any researcher or explorer’s library and gives valuable insights into the real ‘work’ of mining the earth’s most preciousmineral—gold.”
|
Table of Contents |
Preface
1 Gold from Antiquity
Historical Background
History of Gold Metallurgy
Gold Discovered in the United States
The World's Greatest Gold Discovery
Early Treatment of Gold Ore in the United States
Discovery of Cyanidation
2 Historical Review of California Mining
First Discovery of Gold (Placer Gold)
Discovery of Lode Gold and the Empire Mine
Mining Equipment Development
3 Geology
Grass Valley Area Veins
Description of Veins
4 Mining of the Empire Veins
5 Early History of the Empire Mine
Owners and Stamp Mill Problems
The Grass Valley Process
Production Data, Ownership Change, Frue Vanner Developed
Chlorination of Sulfides
6 A New Owner and A New Approach to Mining
7 The Empire Under William Bowers Bourn, Sr.
Empire Production 1865-1878
8 The Empire Under William Bowers Bourn, Jr.
Critical Years for the Empire
Cousin George Starr
Years of Change and Growth—Empire Sold
New Business Horizons
Starr Goes to Africa—Bourn Reacquires the Empire
George Starr Returns to the Empire
North Star Mine Historical Background
Pennsylvania Mine Acquired by Empire
The Empire Cyanide Plant
Litigation, Plant Expansion, and Remodeling 1913-1929
9 End of an Era
Twenty-Eighth Annual Report
Sale of the Empire
10 Newmont and the Empire Star Mining Company
Brief Background of Fred Searls, Jr.
Newmont Acquires the Empire Mine
Newmont Acquires the North Star Mine
North Star Production Data
11 The Empire Star Under Newmont Control
Acquisition of the Murchie Mine
Federal Regulations Permit Higher Gold Prices
Acquisition of Zeibright Mine
Murchie Mine Closes Production, 1938
New Milling Method Installed
Summary of Empire Star Mines, 1939 to 1941
Banner Year for Production, 1941
Closure of Gold Mines for War Support
Gold Mines Reopen, June 1945
12 The Closing of the Empire Star Mines
13 Empire Mine Purchased by California State Department of Parks and Recreation
Addendum
Historic Gold Production of Grass Valley and Nevada City Mining Districts
Historical Price of Gold
Gold Theft—Security a Major Problem
Bibliography
Glossary of Terms
About the Author
|
Excerpt |
The first discovery of gold in the Sierra Nevada is credited to J. W. Marshall, who in January 1848 found nuggets in the millrace while constructing a saw mill at Coloma, El Dorado County. Placer gold was first found in Wolf Creek, Grass Valley, in 1848, shortly after Marshall’s discovery, and the discovery of rich placers in 1850 in Deer Creek, near the site of Nevada City, brought the first gold rush to that area.
Very soon, however, the older Tertiary Hill gravels were discovered; these deposits were far richer and more abundant in Nevada City than in Grass Valley. The term “Tertiary Hill gravels” identifies the rich, gold-bearing river beds which were thrust upwards in the course of the mountain forming activity of the Tertiary Period, a period in the Earth’s geologic time scale running from approximately 70 million to 25 million years ago. It was the period that saw the formation of the Cascade, the Sierra, and the Rocky Mountain ranges.
Hydraulic mining was successfully introduced in the huge Tertiary gravel banks of the ancient river beds, but was abandoned in 1884 when the courts ruled that this method of mining could be used only if a positive means could be established to prevent the resultant debris from entering the rivers and streams.
Discovery of Lode Gold and the Empire Mine
The first find of gold-bearing quartz was the discovery of the Gold Hill ledge in June 1850 by George McKnight. The quartz in this outcropping was literally filled with gold, demonstrating clearly the source of the rich nearby stream deposits.
The richness of the find caused a flurry of intense prospecting which, in October 1850, led to the discovery of gold-bearing ledges on Massachusetts Hill, Ophir Hill, Rich Hill, and other strikes. It was the Ophir Hill claim, located by George Roberts, which subsequently became the Empire Mine. So many of these early claims contained gold ore so rich and plentiful that, for a time, the mine owners feared gold would lose its value.
Because of the richness of the ore and the fact that a satisfactory method for recovering the gold still needed to be developed, the early claims were only 30 by 40 feet.
These discoveries marked the advent of new mining techniques for the California miners, at least new and strange to the majority of the men working the placer deposits of the northern rivers. Hard rock mining presented totally different problems. No individual, or even several men, could make a go of it with muscle alone. Pick, shovel, and gold pan—the usual equipment—were inadequate. Mining quartz veins required heavy machinery, explosives, the building of superstructures, an understanding of pumps, and methods of shoring up underground excavations. The capital this required demanded pooling of resources by groups, not only of miners but of outside investors.
It was a learning process for the miners with respect to new mining methods and equipment, and for the investors to reach awareness of the profit possibilities in properly equipped, well-managed operations. The risks were great, and there were trial, error, and disappointment which account, to some degree, for the frequency with which many early claims changed hands.
Empire Mine Park Association, reprint 2012