[3] Between 1850 and its closure in 1956, the Empire Mine produced 5.8 million ounces (165 tons) of gold, extracted from 367 miles (591 km) of underground passages.

[4] In October 1850, George Roberts discovered gold in a quartz outcrop on Ophir Hill,[5] but sold the claim in 1851 to Woodbury, Parks and Co. for $350 (or about $13,000 today, adjusted for inflation).

The Woodbury Company consolidated several local claims into the Ophir Hill Mine, but they mismanaged their finances and in 1852 were forced to sell the business at auction.

Starting in 1895, Lester Allan Pelton's water wheel provided electric power for the mine and stamp mill.

[6]: 16  The Cornish provided the bulk of the labor force from the late 1870s until the mine's closure eighty years later.

[6]: 31  Bourn died in 1874, and his estate ran the mine, abandoning the Ophir vein for the Rich Hill in 1878.

[6]: 36 [7]: 87  Bourn purchased the North Star Mine in 1884, turning it into a major producer, and then sold it to James Duncan Hague in 1887, along with controlling interest in the Empire a year later.

[6]: 39 The Empire Mine installed a cyanide plant in 1910, which was an easier gold recovery process than chlorination.

[6]: 77  Ellsworth Bennett, a 1910 graduate of the Mackay School of Mines in Reno was the last "Cap'n" (Superintendent) of the Empire, and the only person from management allowed across the picket line (the miners' lives depended on his engineering skills and they worked as a team).