Hardrock Mining in Grass Valley

Empire Mine

Empire Mine State Historic Park in Grass Valley sits above one of the largest and richest gold mines in California. A 367-mile labyrinth of abandoned and flooded tunnels snakes below the park’s historical mining buildings and equipment.

In June and October 1850, gold was found within a mile radius of the Empire Mine’s site. A new gold rush began when hundreds of miners staked claims in the area. However, most of the gold was buried deep in the earth, veined in quartz. Extracting that gold required more sophisticated mining techniques than the panning and sluice-box methods used in nearby Coloma.

After many separate, smaller claims were bought and consolidated, the site officially became known as the Empire Quartz Hill Company in 1852. William Bourn, a major stakeholder in the company, gained a controlling interest in the mine in 1869 but died suddenly in 1874. His son, William Bourn Jr., began to run the mine in 1878 after the gold was thought to be played out at 1,200 feet. Empire Hill then entered its most fruitful period. Together with his cousin, mining engineer George W. Starr, the younger Bourn created a successful and modern mine that became one of the most productive in the United States.

Miners lunch

Mining gold from the hard rock deep in the earth proved tricky. Experienced miners from Cornwall, England, immigrated by the hundreds. Well-versed in hard-rock tin and copper mining, the Cornish miners brought such advancements as the “Cornish pump” that helped empty underground tunnels of water that flooded into mine passages from underground springs. With Cornish miners’ supervision and labor, tunnels became as deep as a vertical mile.

More than 5 million ounces of gold (worth well over seven billion dollars today) were taken from the Empire Mine—estimated to be only 20% of the total gold deposits still buried under the park (and underwater).

In 1929 Bourn sold the mine to the Newmont Mining Corporation, which controlled the Empire Mine until its closure in 1957. Static gold prices after World War II prompted the closure. In 1975, the State of California purchased the mine.

Bourn Mansion


Today, visitors can tour the entrance to the main mineshaft and the mining shops, buildings and equipment as well as the mansion, clubhouse and expansive garden that William Bourn Jr. built. The historical buildings are encircled by miles of lovely trails and woodlands accessible to the public. Empire Mine State Historic Park is a treasure, where generations of Californians were able to truly shout, “Eureka!”