The Golden Gate Mine was first discovered in 1898, expanded by further discoveries of veins of minimal bearing quartz, and in 1900 J.E. Canter claimed 1500 linear feet by 600 feet of lode and named it Golden Gate. Purchased between 1900 and 1902 by Ed F. Donovan and Joe A. Brown, the mine was developed with tunnels, trails, chutes, and a reworked wagon road, and Brown and Donovan owned and operated it from 1902 to 1927, though it was idle through much of the later years. Miners hand drilled ore from quartz veins in five adit tunnels ranging from 300 to 1800 feet and shipped it by a 2300 foot aerial tramway to a ten-stamp, water-powered mill, where the ore was pulverized and gold was extracted with mercury. The mine produced the only gold in the West Walker River Mining District, and in 1908 it reportedly netted more than $12 a ton; between September 1912 and April 1913, 6,848 tons of ore were crushed, yielding $33,646. Avalanches repeatedly damaged the operation: one four years before 1911 destroyed the mill and buildings, and two major slides in March 1911 destroyed the bunk house, stable, water plant intake, and boarding house, causing minor injuries, a horse’s broken leg, and $759 in damage after rebuilding had been moved 200 feet from the slope miners thought was the only avalanche-prone hill. The same 1911 storms also brought deadly avalanches elsewhere, killing nine miners, including the owner of the Masonic mine, at Copper Mountain, Masonic, and Lundy, and an estimated 4,000,000 tons of snow slid off Copper Mountain. Stamp mills had become popular in the Sierra after the Sawyer Act of 1883 outlawed hydraulic mining; at Golden Gate, heavy stamps weighing 850 to 2,000 pounds were lifted by cams and dropped to crush ore, after which the crushed material was washed over mercury-coated sheets or mixed with mercury in a battery box so the gold could be recovered as an amalgam and then separated by heating. The surviving Golden Gate Mill is the last standing stamp mill on public land administered by the Bureau of Land Management’s Bishop Field Office, and in October 2005 stabilization began with a National Park Service historic structure stabilization crew, which spent three months removing ninety years of rock-slide rubble and addressing severe deterioration of the post-and-beam superstructure.