California Gold and Nevada Silver Rush
One of the common images of the California Gold Rush is that of the miner panning for gold—maybe standing in a river, or kneeling by the side of a stream, with a large round pan in hand, often with gravel and water shown spilling out of the pan. Panning is a method of recovering gold that has settled in a stream bed after being eroded from rock and carried some distance from its point of origin. Gold, being very heavy, will sink faster than the light rock sands, and thus gold will drop to the bottom of a pan while water and rock sands will spill out. On a geological scale, this same behavior means that deposits will form in streams and rivers where slow-moving waters allow the gold to settle. These deposits are known as “placer deposits.”
The find that sparked the California Gold Rush was a placer deposit. It was gold sparkling in the bed of the South Fork of the American River that caught the eye of James Marshall, the foreman in charge of construction of a planned water-powered sawmill for the landowner John Sutter.
Placer deposits were found through a large area of the western Sierra Nevada, and they formed the initial mining opportunities of the Gold Rush in what is now known as California’s “gold country”—the western slopes of the Sierra Nevada in north-central California, including Placer County (named for the deposits), El Dorado County (where Marshall first found gold at Sutter’s Mill), and several others.
Panning is a good method for small-scale mining as it requires few tools and little skill. It processes only small amounts of ore sand, however. By using more water to process more ore-bearing sands and gravel, more gold can be extracted. As the most accessible sand and gravel deposits were worked quickly, and mining operations looked to increasing scale to move more and more sand and gravel, commercial mining operations quickly developed methods to process larger and larger amounts of ore, not just from stream beds, but from the surrounding sedimentary soils and rock.
In the early 1850s, miners started using directed streams of water to move soil, and by the 1860s these hydraulic mining operations were running large scale. Hydraulic mining uses powerful jets of water that wash soils and rock into a slurry that runs through a sluice that separates out the heavy ore sands and gravel.
Done large-scale, high-pressure jets of water stripped entire hillsides of their sedimentary sands and soft rocks (with occasional use of explosives to break hard rock). The canyons themselves were devastated. The scars of the state’s largest hydraulic mine—the North Bloomfield Mining and Gravel Company’s mine—can be seen at the Malakoff-Diggins State Historic Park in California’s Nevada County (just north of Placer County). The canyon that was carved by the mine is over a mile long, half a mile wide, and a quarter mile deep.
Debris from the mine (and others) poured downstream, filling the watershed with sand and gravel that affected the watershed as far as the San Francisco Bay. Upstream the debris caused erosion and damaged the environmental habitats on which native peoples relied for food (those native peoples who had not already been driven out by gold hunters). As the streams and rivers exited the foothills and entered the flatter valley, the debris piled up and caused massive problems with flooding.
The city of Sacramento and towns in the watersheds of the Sacramento and its tributaries experienced repeated floods in the 1860s and 1870s, despite continued levee building and other attempts at flood control. So much sediment was settling in the river beds, that river levels kept rising, forcing the need for more and larger levees and flood control. Ultimately, these mines were sued for the damages done by their debris. In Woodruff v. North Bloomfield Mining and Gravel Company, presiding judge Lorenzo Sawyer ruled that the North Bloomfield hydraulic mining operation was creating a public nuisance, noting that an estimated 100,000,000 cubic yards of material had been removed from hillsides and washed into the Yuba River, and citing as one example the case of a farmer whose 1,200 acres were all buried three to five feet deep in sand and gravel. Sawyer’s ruling 1884 ruling against the North Bloomfield Mining and Gravel Company led to the end of hydraulic mining in California.
By that time, navigation on the rivers—which had been a primary source of transportation—had become increasingly difficult, or impossible. Many Forty-Niners traveled up the Feather River from Sacramento to Marysville, but the debris of hydraulic mining rendered the river nearly unnavigable.
The mine tailings that settled in the Yuba River upstream from Marysville were so extensive that, starting the in the early 20th century, these tailings were dredged for gold—over 5 million ounces were recovered—becoming known as the Yuba goldfields.
About 10 years after the discovery of gold in California, prospectors found an extremely rich source of silver and gold in the rock of the mountains of the eastern Sierra Nevada, about 100 miles east of Sutter’s Mill. The gold at Sutter’s Mill, which drove the California Gold Rush, was a placer deposit—gold in a river bed that had been washed from eroding rock and settled as sediment—and such deposits were distributed across a fairly large range of the Sierra Nevada, as well as other gold fields in the north of the state. By contrast, the vast silver find in Nevada was all buried within about a six-mile stretch of land on the eastern side of Mount Davidson. It became known as the Comstock Lode, and its rich silver deposits (along with a good amount of gold) are largely responsible for Nevada’s nickname as “The Silver State.”
The story of the discovery of the Comstock Lode might be told starting with a caravan of immigrants to California seeking gold—either in 1849 or 1850 (sources differ). They arrived on the eastern front of the Sierra Nevada too early in the year to keep moving west: the passes were still deep with snow. They stopped to camp in Gold Canyon on the Carson River, near present-day Dayton, NV (about 10 miles south of Reno) and, while waiting for the passes to clear, panned for gold in the local streams. They did find some gold, but all the same, they moved on to California, perhaps anticipating greater finds, or perhaps leaving the valley when its streams dried in the summer, leaving the canyons without water.
Within a few years, however, permanent mining settlements had been formed in the vicinity, and in the late 1850s, several miners found different deposits of rich ore. In 1857 or 1859 (sources differ), placer miners digging a pit to process more ore sands found a rich black sand at the bottom of the pit. It was a sulfide of silver. Their find was at the head of Six-Mile Canyon, about 5 miles north of Gold Canyon, where, in early 1859, miners found gold in a ten-foot deep trench. These two finds marked the two ends of the immensely rich deposits of silver and gold under the eastern slopes of Mt. Davidson in Nevada. Mining to dig these ores out of the earth began.
As opposed to the placer mines of the California Gold Rush, the Comstock Lode mines delved deep into the earth, spurring the development of new underground mining techniques. The ore was in globular deposits—some so soft it required only a shovel to remove. But the deposits were large and deep, and the surrounding rock would cave in when too much ore was removed—a problem solved by the invention of square-set timbering. And as they mined deeper, there were problems with water within the rock, which was eventually addressed by the Sutro tunnel, named for Adolph Sutro, who would later become mayor of San Francisco.
The riches of the Comstock Lode were carried both east - financing the Union Army during the Civil War - and west over the mountains into California, and down to San Francisco, contributing to the wealth and growth of that city. Reno, Nevada, grew out of a settlement built around a bridge across the Truckee River, that connected the riches of the Comstock Lode with the California Trail, and then, in the 1860s, to the railroad, which had a station in Reno connecting to Sacramento, and which lay on the route of the first transcontinental railroad, which opened in 1869.
The first two decades of production on the Comstock Lode were the richest, and most work had stopped by the end of the nineteenth century, but new technologies and rising gold prices led to continued mining during the early decades of the twentieth century.