Editor’s note: This story was originally published by The Union on June 22, 2002.
For more than 90 years, between 1850 and the United States entry into World War II, the rich quartz mines of Western Nevada County shipped an annual average of $8 million in gold bullion to the San Francisco mint.
The Empire, Pennsylvania, Champion, North Star, Golden Center and Idaho-Maryland, among others, were the richest and deepest gold mines in the world.
In Grass Valley, the North Star’s central shaft descended vertically 3,000 feet into the earth.
Incline shaft extensions and other passages reached a depth of 10,500 feet from the surface.
Hard-rock gold mining began here and experienced far-reaching innovations, allowing years of sustained and profitable production.
In 1942, by order of the federal government, all gold mining was curtailed for the duration of World War II as being “nonessential” to the war effort.
Many of the miners went into military service, some took employment in San Francisco Bay Area shipyards, and still others worked at mining metals vital to the war effort in other locales.
Peace returned in 1945, and some of the mines reopened anticipating a return their pre-war output. However, the cost to rehabilitate the mines, coupled with inflated costs of production — especially wages and new machinery — rapidly approached and then exceeded the value of gold produced, leaving no profit or reinvestment capital.
In 1934, the federal government had fixed the price of monetary gold (bullion) at $35 per troy ounce and became the only legal purchaser. The mines were forced to sell only to the U.S. mint, thereby binding them to an artificially static price. There were no restrictions on specimen gold and nuggets for jewelry.
In 1956, an era came to a close when the mighty Empire, the area’s largest mine and greatest producer, “pulled the pumps” and stopped pumping ground water, which allowed some 300-plus miles of underground workings to flood.
Within two years, all machinery, tools and equipment from the Empire, Pennsylvania and other mines had been or was in the process of being auctioned.
Today, except at the Empire, which has become the Empire Mine State Historic Park, all that remains is a foundation or two and an occasional corrugated building to mark the location of the gold mines that were once the economic base of Nevada County.
Records show that more than half of all gold produced in California came out of the ground in this county.
An interesting experiment in gold mining technology took place at the big-producing Idaho-Maryland mine in Grass Valley in 1935-36.
At a location on the mine property close to Brunswick Road, the company’s engineer J.B. Newsom bored an experimental vertical shaft 5 feet in diameter some 1,125 feet into the earth through solid rock.
The traditional method to sink vertical or incline shafts called for drilling, blasting and then “mucking out” the loose rock.
Timbering followed to provide support for pipes, power cables and other necessary equipment. Timbering was expensive and required constant and costly maintenance.
The vertical bore required no maintenance and the necessary cables could be bolted to the shaft walls. Also, steel cage guides for underground transport to and from the surface were easier to attach to the smooth surface of the shaft than to an uneven one caused by blasting.
The experimental shaft passed near the 500, 750 and 1,100-foot working levels of the original Idaho-Maryland workings.
Newsom designed and built special equipment for the drilling experiment.
A rotating, vertical core barrel drill and a core puller both drilled and removed sections of rock which were usually 7 feet in length, weighing approximately 11 tons each.
According to records kept by Errol MacBoyle, the mine’s general manager, the greatest footage drilled during the experiment was 21 feet through solid rock in three days. Evidently, the experiment did not produce the expected results and the shaft was never utilized.
Two of the shaft core sections were saved and placed locally on public display. One is at the Nevada County Fairgrounds; the other is in Calanan Park in Nevada City.
Bob Wyckoff, was a former newspaper editor, author of local history, a lifetime student of California history and a longtime resident of Nevada County. Visit TheUnion.com for more of his stories and photography on western Nevada County history.