The Empire Mine
The Empire Mine operated for over a century from 1850 to 1956 making it one of the longest running gold mines of the Gold Rush Era in California, pulling more gold out of the ground than any other and is said to still contain millions of dollars of gold.
Located in Grass Valley, this mine was discovered by accident by George Roberts who was a lumberman, and that while he was surveying some trees in the area, he happened to glance at his boots and noticed tiny gold flakes on them, but this gold he couldn’t pan it out for it was imbedded in quartz.. The only way to get at it was dig it up and crush the rock. But this was very difficult for the time and a new and efficient method of extracting the gold from the quartz was in dire need. Seen the difficult task George sold his rights to the land for a mere $350 in 1851. Little did he know he was quite literally standing on a gold mine . George couldn't have known that in a mere 13 years, by 1864, the mine would already have produced one million dollars worth of gold.
Help came with the arrival of Cornish immigrants from the Cornish Peninsula of southwest England. For the past 1000 years, they pulled tin and copper from their native soil. They brought with them their knowledge of mining, their work ethic, and their customs. The Empire Mine labor force soon was made up of 90% Cornish miners.
The Cornish miners used the method known as Hard Rock Mining, which consists in first digging a hole into solid rock. Then the rock you dig up, you have to crush it. Then somehow extract the gold from the crushed rock using a Stamp mill. As the mining progressed to a feverish pace, the depth of the mine soon fell below the water table. The solution was the Cornish plunging pump capable of pulling 18,000 gallons of water out of the mine per hour. After 40 years of use, Cornish pumps were finally replaced with electrical hydraulic equipment around 1900.
Despite the efficient removal of water from the mine, timbers used to hold fast the ceiling of the mine would rot in the damp mine in turn producing methane- a colorless, odorless gas that killed when breathed. While birds such as canaries were carried into the mine to warn of an increase in methane gas, an unusual relationship also developed with rodents. Miners were known to feed the rats that lived inside the depths of the mine. A dead rat also gave quick warning to the buildup of the deadly methane gas. Mules were also used within the depths of the mine. At one year old, they were taken down into the maze of tunnels and spent the rest of their life there.
Responsible for the immense success of the mine were the owner William Bourn, Jr. and his mine superintendent George Starr. Bourn inherited the mine at age 21 in 1877 from his millionaire father. But it was Starr to whom the Miners called a "Mining Genius" and the "Shining Starr of the Empire". Geologists and engineers from around the world ventured to view the latest technologies being used at the Empire.
As the mine grew larger, the tunnels extended to over 367 Miles of labyrinthian pursuit of the veins of gold. Sadly in 1956 when the cost of operation outweighed the cost of extracting the ore the mining came to a close. It's said that only 20% of the gold from the Empire has been removed- enough to create a 7 foot square block of pure gold.