California • Tuolumne • Techniques
Gold has been used as a universal standard of value and the common medium of exchange in the world of commerce. It still is the “noblest of metals” and most praised commodity in the world for many people. The saga of gold has touched many nations; here in California the Gold Rush was the basis of much of our local history and heritage.
This documentation about gold is a compilation (1579 – 2010) of events in a timeline starting from the beginning of the formation of the United States economy.
Sir Isaac Newton, master of the British Mint, established a fixed price for gold equivalent to about $20 per ounce (Troy.)
Between the end of the American Revolution War and 1823, the U.S. purchased gold at $15 per ounce and accumulated $20 million in gold. Much of the gold went to England after the end of the War of 1812.
Alexander Hamilton, first U.S. Secretary of Treasury under President George Washington, priced the American dollar at 24 ¾ grains of gold (not quite 1/20 of an ounce, making its price $19.39.) This set the “gold standard.” The price of gold remained approximately $20 per ounce until February 1934, a period of 142 years.
Other reports of gold during the governorship of Jose Argello during the Spanish regime were down played as a result of local Indian hostility in California.
Gold was being used by Spanish soldiers for barter in California.
U.S. raised its buying price for gold to $16 to again accumulate gold for coinage, which reached a reserve value of $250 million.
The earliest beginning of the rush to gold was in Southern California after Francisco Lopez, majordomo of San Fernando Rancho, stopped to rest in San Feliciano Canyon and dug up wild onions to eat. He found particles of gold in the roots, and found alluvial gold deposits nearby. Locals from the area, within 35 miles, from the Pueblo of Los Angeles initially came in search of gold. Within the year, men experienced in gold mining came from Sonora, Mexico. The miners used “dry washing” to extract the gold which was inefficient and hard work
Don Abel Stearns, a miner from Los Angeles, sent 18 ounces of placer gold dust to the U.S. Mint in Philadelphia by messenger. The mint paid $19 per ounce and recorded the first discovery of placer gold from California. Very little excitement was generated because of the small amounts of gold that was recorded
In an official communication in March, Thomas Larkin, Vice-Counsel at Monterey, notified Secretary of State James Buchanan of the fact that gold was found. There was still very little publicity of the gold. Mexican authorities were not inclined to increase immigration into California. At the time, California was still under the control of Mexico.
1846-48 The Mexican-American War started over the control of Texas and California. By 1848 the U.S. had won the war, taking over both states. This happened about the same time gold was discovered in Coloma, California.
January 24th, James Marshall party discovered gold on the South Fork of the American River at the sawmill (Coloma) constructed for John Sutter. Marshall and Sutter attempted to keep the gold discovery a secret, but by March 15, 1848, the San Francisco newspaper The Californian, published an article. The discovery of gold became known worldwide, starting the beginning of the major Gold Rush in California.
During the summer, gold was found at Woods Creek in what is now Jamestown by Benjamin Woods and James Savage party. This discovery was the beginning of the Southern Mines and what is now Tuolumne County
In December, President James K. Polk reported to Congress the samples of gold dust from California indicate a rich discovery of gold in the far west reaches of the continent. This official report created a major migration of the 49ers to California. The number of people engaged in mining skyrocketed from 4,000 in 1848 to about 100,000 by 1852, staying at that level until the late 1850s
In 1849, Californians sought statehood and, after heated debate in the U.S. Congress arising out of the slavery issue, California entered the Union as a free, non-slavery state by the Compromise of 1850. California became the 31st state on September 9, 1850.
The Gold Rush made up of mostly placer gold mining, reached a peak. The price of gold was still $19.39 per ounce. Mining technology during the placer mining period, 1848-1860, consisted of “dry washing,” panning using Indian “batea” or metal gold pans, rockers or cradles, and “long toms” or sluice boxes of various sizes. Later came the use of leveraging water to do more work using a method called “booming” or “hushing” for clearing away sediment using dams and employing ground sluicing to recover gold from the gold laden river bed
Hydraulic mining used water under pressure with nozzles termed “giants” to cut down the outcrops on hillsides of alluvial gravel. The water flowing downhill washed the soil into large long sluices strung along the base. Hydraulic mining was stopped by farmers in 1884 by legal injunctions concerning its negative environmental effects
Hardrock quartz mining was explored in the early placer mining days, with little success. Tunnel mining, drift and pocket mining was used to drill into the ancient river beds covered by volcanic rock at Table Mountain in Jamestown. The concept of dredging was tried unsuccessfully, until 1898, when a dredge floated and worked river beds below the surface on the Feather River, near Oroville. This concept continued in to the late 1960s.
The population of California was 380,000.
1860-1880 Many California miners went to Comstock, Nevada to follow the gold and silver mining strikes. This depleted the manpower available to California hardrock mining, which still was experimenting with various techniques. Renewed interest in California deep shaft quartz mining in the 1880s was a result of these new technique
During the Civil War, most of the $250 million U.S. gold reserve was sold to England for $16 ounce.
The population of California was 560,000.
The first 100 years of California’s statehood, the population doubled about every 25 years. In 1880, the population was 865,000.
1880-1905 The Second Gold Rush in California was realized when many miners returned from the Comstock after learning and developing new techniques necessary for drilling deeper mines and applying electricity, including chemical extractions of gold from poor grade ores. Environmental law limited the use of chemical (cyanide) in California.
The stock market crashes and investments dwindle; meantime, people are seeking out gold and hording it.
During the Great Depression, President Franklin D. Roosevelt was elected and moved quickly to end the outflow of gold from banks. With a proclamation, he closed all banks in the U.S. for a three day moratorium. This stopped citizens from removing and hording gold. He then required all citizens holding gold return it to the banks under threat of imprisonment and a fine of $10,000. This stimulated the domestic economy by encouraging people to spend their money instead of holding it in gold bars. In addition, only those U.S. citizens who dealt with gold for “customary industrial, professional, or artistic” use could own refined gold by obtaining a special license.
Roosevelt signed the Gold Reserve Act, which gave the government authority to demand physical possession of gold, to prevent its export, to reduce the amount of physical gold in coined dollars, to set aside the gold clauses in private and public contracts, and to fix the price of gold.
1934-1960 The U.S. attempted to maintain the price of gold at $35 per ounce by selling to the free market when the price increased, bringing the price back down.
The increased price of gold, combined with lower wages and material costs prevailing during the Depression, caused gold mining to become attractive again. Old mines reopened and currently operating mines expanded.
The U.S. government closed down the gold mining industry as a non-essential, war-related industry (War Production Board’s Order No. L-208.) This was an attempt to move the mining labor force into mining metals needed for the war effort.
A “foreign-exchange gold standard” was adapted to regulate international trade. Currencies of many countries were valued in terms of the U.S. dollar. At that time, the U.S. was the most powerful nation in the world, both politically and economically, having the most stable currency in the world. In theory, the U.S. would redeem its paper money for gold on the international market.
At the end of WW2, U.S. gold mining was reinstalled. Many California gold mines had flooded, caved in and were in a general deteriorated condition, requiring prohibitive capital needs to reopen.
The U.S. spearheaded an ill-fated attempt to change the world’s thinking about gold, weaning it away from gold as a medium of exchange, and setting the worldwide value of gold at $35 per ounce. This was known as the London Gold Pool, made up of eight major European countries. The pool agreed to sell off their gold, if the international price rose above $35 per ounce, and continued until the price dropped. When implemented, the pool lost $991 million of gold reserves. The U.S. lost $3.2 billion in gold reserves using this concept.
One-fifth of the U.S. gold reserves were gone. President Lyndon Johnson asked the Bank of England to discontinue the London Gold Pool.
In March, a two-tier market was established by the U.S. government. One tier required the U.S. Central banks to continue to transact business at the gold standard of $35 per ounce. The second tier allowed gold to fluctuate at what price supply and demand dictated.
In August, to prevent further leakage of gold, President Richard M. Nixon issued an Executive Order which ended the U.S. redemption of gold at $35 an ounce, and raised the price of gold to $38 per ounce. In December, the U.S. dollar was devalued
The gold standard price of gold was raised to $42.22 per ounce. With the announcement by the major U.S. Central banks that they would buy and sell gold at the free market price, the two-tier market perished. The concept of government regulation of the price of gold ended and was now based on supply and demand. This marked the end of the 180-year-old gold exchange standard and ushered in the current monetary system of floating exchange rates. Now, currencies are backed by a nation’s economic net worth rather than by gold.
President Gerald Ford repealed all sanctions against U.S. citizens owning or selling gold to anyone they wished. Gold essentially became a commodity and was now listed on the New York Commodity Stock Exchange.
The international gold market was dominated by the Union of South Africa, Soviet Union, China, and other foreign countries, including Canada. The largest and best known gold trading center was the London Gold Market.
The price of gold reached an all time high of $850 per ounce and an average of $615 per ounce. This again raised interest in some California gold mining districts. Large corporate interests with major capital and access to newer mining technologies and high volume open pit mining techniques. Many new mining enterprises sprung into action.
The large Sonora Mining Company in Jamestown owned primarily by Canadians, with a small share of California ownership, started high volume open pit gold mining. It was an operation near the Harvard Mining conglomerate, the Trio. Gold had risen to $368-$447 per ounce over that period. The ore was transported to Nevada for gold extraction due to California environmental restrictions.
California’s annual gold production exceeded $320 million; most of the gold came from about 15 large open pit mines. The most productive California revitalized mines were not in the Sierran gold counties, but in the Coast Ranges of Napa, Lake and Yolo Counties, north of San Francisco. These areas had been previously mined for mercury, not gold.
After eight years of gold mining, the Sonora Mining Company closed operation because the average price of gold had fallen to $384 per ounce. The overall cost of doing business, with the new environmental laws, made mining an unattractive investment. This basically ended major gold mining operations in Tuolumne County and the Southern Mines in California
In May, the average price of gold went up to $603 per ounce with a high of $725 per ounce, the highest price since 1980 when the average price was $615 with a high of $850 per ounce.
The yearly average price of gold was $695, with a high of $833 per ounce.
In December, the U. S. government officially recognized the country was in a technical recession. Unemployment rate rose beyond 8.5%, the highest in 26 years.
In March, gold reached its all time high, with average price of $968 and a high of $1,011 per ounce; the yearly average was $871 per ounce.
The Dow averages in the stock market went from a strong value of $13,000+, dropping in September to new lows, finishing in December at $8,700 for a loss of about 34% in value.
In December, gold reached its all time high, with an average price of $1,134 and a high of $1,212 per ounce; the yearly average was $972 per ounce.
Gold reached an all time high price of $1431. The average Dow was $11,578, an 11% gain over 2009 at the close of the year.
Discovery of Gold in California
James Marshall, after traveling to Oregon by wagon train in early 1840s, wandered down the coast to California and started working for John Sutter. Sutter was building a farming empire, which became known as Sutter’s Fort. In August 1847, Marshall became Sutter’s partner and agreed to build a sawmill to support many of Sutter’s activities. In January 1848, Marshall discovered gold in the raceway of the sawmill in a valley called “Coloma” by the local Native Americans on the south fork of the American River. When Marshall and Sutter realized they had found gold, they attempted to keep the discovery a secret for fear the farming lands would be overrun by gold seekers.
Sam Brannan had come to Sutter’s Fort earlier and opened a general store there. Brannan was one of the first to hear the news of gold as it leaked out. He also was first to see an opportunity to make his fortune by supplying shovels, picks and other simple mining supplies to the gold seekers. Brannan purchased enough gold dust to fill a jar and traveled to San Francisco and walked the streets shouting and showing the gold.
These events started the gold fever and the race for gold began in California in early 1848. But back east, people were not sure that this was the real thing until President Polk verified the gold discovery on December 5, 1848, when he made his official annual message to Congress. He reported that gold was being found daily in California, worth large sums of money, and displayed a small box filled with gold dust that had been sent to him by courier from California.
Americans came from the east, both north and south and from everywhere in between. They came by the thousands in sailing ships, steamships, by horse, mules, ox and wagons and on foot. Some were ordinary workingmen, farmers, professionals and many were deserting soldiers and sailors. They had one thing in common—they sought gold, which was free to anyone. When they stuck it rich, they would return home. Many died, many went back empty handed and many stayed to work for years in poverty, but some did strike it very rich. They were the lucky ones. Placer gold mining reached its peak in 1852. Soon the easy placer gold was gone and they had to join forces and use new technology to extract the gold. By the end of the 1850s some estimates put the total amount of gold yield at about 600 million dollars. The future of mining now belonged to people who were willing to pay for the building of commercial water and flumes for hydraulic mining and stamp mills, equipment needed to extract gold from quartz deposits recovered deep below the earth’s surface.
The Gold Rush changed the Native American cultures that had been in existence for hundreds of years. In the 1840s, the Native American population was estimated at 150,000. By 1880, the population was reduced to only 16,000. Virtually every Native American village on the coast of California was destroyed, during or shortly after the Gold Rush. Besides outright murder and displacement, settlers and miners brought diseases to the Native Americans that often proved fatal. Some of these diseases were cholera, typhoid, measles, malaria, small pox, whooping cough and tuberculosis. In just three years, the Gold Rush created a major population expansion consisting of over twenty different nationalities and accelerating California into statehood at the expense of the Native American cultures. By 1870 there were fewer than fifty thousand. It was the worst injustice to fall onto to the Native Americans in the United States history. The Gold Rush made major changes to the people who lived in California and impacted the entire Western cultural development.
Gold in Tuolumne County
This map of our county’s gold mines was created by the Tuolumne County History Research Center. The (*) next to the mine indicates that it was mapped during 1879 according the the J.P Dart map. Another source for this map was the Illustrated Historical Brochure of Tuolumne County California which shows the mines up to 1901. Locations of these mines may not be exact. They are however within the general area to which the marker was placed. Some markers indicated by the yellow shows groupings of mines around the area that may be even less accurate. Perhaps with time and useful input from those that know more about the area will give us a clearer and more holistic view of the the mining operations that is responsible for one of the most significant human migrations in U.S. history. Hope this information helps! If you have information regarding any of these mines and you would like it to be added to our map information, please go to our contact page and send us the information.
After gold was first discovered in January 1848 by James Marshall, that summer gold was found in streams and rivers draining the Sierra Nevada and the foothills in what is now called Tuolumne County. An Oregon prospector, Benjamin Wood, and his party which included James Savage, found gold on the banks of a branch of the Tuolumne River. They called their camp Wood’s Crossing and the creek, Wood’s Creek. By summer’s end 1848, Colonel George James from San Francisco started a mining camp above Wood’s Crossing and named it after himself—Jamestown. About the same time, a Judge Tuttle had found a rich site of gold on Mormon Creek and set up a log cabin and a camp known as Tuttletown. Other camps were springing up at Melones, Don Pedro’s Bar and Shaws Flat. Things slowed down when the winter cold set in.
In March 1849, Mexican and some Chilean’s were working claims a short distance upstream on Wood’s Creek at a camp known as Santiago. They secretly moved about four miles further up Wood’s Creek in the area of today’s Columbia Way in the northern portion of Sonora. The new gold diggings became know as Sonoranian Camp, named after the Mexican miners from the State of Sonora, Mexico. Shortly thereafter, waves of immigrants began arriving in Tuolumne County from the east and all parts of the world. Gold strikes were popping up again at places like Curtis Creek, Sullivan’s Creek and Savage Diggings. The town of Jacksonville sprung up where Wood’s Creek met Tuolumne River. Texas Bar and Indian Bar, and near Melones, Robinson’s Ferry and Soldier’s Gulch overnight became pockets of gold seeking miners. South of the River in Big Oak Flat, gold was discovered on Rattlesnake Creek. Chinese Camp was established with a rapid growth of up to 5000 Chinese immigrants living and working the gold diggings there.
The Tuolumne County foothills became covered with miners, gamblers and all sorts of people. Crime became a problem and the original friendly atmosphere changed dramatically. There was no California law or system of courts for settling disputes. Each settlement made up rules of their own, about claims, how to stake one and how to hold on to it. They used the old Mexican Alcalde system (similar to sheriffs and mayors), many times selecting men who were veterans of the Mexican War. Justice was questionable at best.
Originating out of the Hildreth Diggings, Columbia found major new rich gold strikes in 1850. Miners moved in from all the surrounding diggings and things grew and became more complicated. In Columbia, as was the case with most of the southern mines, the camp was comprised of an overwhelming number of foreigners. As mines played out, anti-foreign sentiment began to be voiced among American miners and they wanted help from the new legislature that was developing at the state level.
The population in the mining camps of Tuolumne County continued to grow rapidly. Conflict between miners over claims and lawlessness broke out, changing the earlier relationship between the people of various nationalities. In the spring of 1850, the Foreign Miners Act was made law, requiring all foreigners to pay $20 per month tax for the privilege of mining in California. At first many foreign miners left and many businesses fell on hard times. Some foreign miners struck back with violence and the gold mining fields became dangerous as robberies and killings became frequent. Vigilante groups formed to stop the crime. However, they exercised their own law and punished many by hanging suspected criminals without legal trials. Even after the repeal of the Foreign Miner’s Tax law, things were never the same and some trouble persisted up until 1858.
In 1853, other gold mining areas (the East Belt) above the Mother Lode mining camps were discovered up in hills near Soulsbyville and beyond. The Confidence, Independence, Mary Ellen, Payboy and Little Jessie mines sprung up. About 1855 Cherokee and Arastraville mines began just north of Tuolumne area and placer gold was found in Turnback Creek in 1856. That same year, Cornish men, creating many more mining sites in this area, discovered the Eureka Quartz Mine in Soulsbyville.
By 1853, estimates of gold seekers had passed the quarter million mark. Mining techniques changed from simple knives and panning to using special sluicing devices like rockers and long toms. It graduated to diverting of waterways, damming, re-routing complete segments of rivers, and dredging using a floating barge to scoop up the ore. The use of hydraulics’ mining started with simple washing down of small hillsides and graduated to the use of nozzles and monitors at extremely high pressures that could wash down portions of mountains. Hard rock mining where the gold was integral to the quartz and devices like arrastras and stamping machines were used to crush ore and separate the gold with water, mercury and cyanide. Each new concept increased the efficiency of mining and extracting the gold. However, large investments in lumber, machinery and access to commercial water required men to work together and become part of larger corporations. The era of the lone prospector was over; only corporations could afford the higher cost of extracting gold. Depending on the value of gold, the cost of mining became a major consideration, which was never a factor in early days of 1848. Major damage to the environment resulted from the mining and logging activities during the Gold Rush era. New environmental laws increased the cost of mining and logging by the turn of the century.
Summary of Gold Mining Techniques in Western United States 1842-1996
The first tools used to mine gold were extremely simple, knives, small wooden hand tools, such as picks and shovels. Extraction of gold from ore bearing gravel without water was termed “dry washing.” It was a crude and inefficient, but also inexpensive. After pay dirt was dug, it was sun dried on a large canvas and then pulverized into dust. It was then thrown by the pan full into the air in order to allow the wind to blow away lighter elements and to let the heavier gold dust fall back into the pan. This was originally an old agricultural procedure of “winnowing” and was first used by miners near the Pueblo of Los Angeles in the San Feliciano Canyon in 1842.
When water was available it was used to work away the lighter dirt and fine gravel concentrating the heavier gold in the bottom of the metal pan or a wooden basket call a “batea.” Panning was slow and hard. A good miner could barely handle 100 pans in a ten hour day. Introduction of the rocker or cradle, the “long tom,” and sluice boxes made of wood and some flat iron were the next improvements.
The rocker is a crude gold concentrating machine that combines shaking motion of the pan with some features of the sluice. Riffles or obstructions are placed across the bottom to catch the heavy flakes of gold. Dirt and gravel are washed over the tops of the riffles. Using the rocker both gravel and water were introduced by hand. Using a sluice, the water flows by gravity, but gravel is shoveled by hand.
The sluice box consisted of three boards nailed together to form a flume. It had slats or riffles to catch the gold. A number of these units could be fitted together, end to end, to make a long series of sluice boxes and men stationed at intervals along the line could shovel gravel into the swiftly flowing water inside the box.
The long tom (brought here by miners from Georgia) was simply a trough of boards usually about twelve feet long by eight inches deep. The opening at the head was 12 to 15 inches wide and the entire trough increased in width until it was about two feet wide at the lower end. A piece of sheet iron with holes punched in it was placed so that the fine sand would fall into a sluice box below, while the larger rocks would pass on by. It increased production so a man could work more gravel (even poorer gravel) in a day as he could with a pan or even with a rocker.
Placer gold mining peaked about 1852.
By 1860, gravel that would pay to work by these methods was now hard to find and gold production declined. Seeking increased mining efficiency the use of water in motion was further exploited. Ground sluicing used a stream of water which was brought to the top of a bank of gravel and allowed to flow down over the face. It softened the gravel and with a little help from the miner, carried it along to a natural sluice prepared on the bedrock below. This increased the volume of gravel one man could work.
Additional volume was achieved by taking advantage of water to also do the work of clearing away the sediment which was call “booming” or “hushing.” A dam was built and water diverted through the area being mined; the water carried the lighter elements downstream leaving the gold bearing ore easily accessible to be worked with some of the original placer methods. This water diversion depended on stream volume and time of the year. The dam structure was usually built by a team of men.
These later methods required a steady stream of water and resulted in the construction of the miners’ ditch. Many ditch companies were organized prior to 1853 for the sole purpose of delivering water to the placer miners at a price set by what the traffic would bear. Miners themselves organized their own companies and cooperatives to supply their own needs. This competition resulted in litigation and violence.
With the advent of hydraulic mining, water companies became big business and started a large effort to pursue dams, lakes, reservoirs, canals, and pipelines to supply water to miles of ditches, tunnels, and flumes. In 1860, an estimated 5,000 miles of artificial water courses were developed. This figure increased to about 8,000 miles at the height of the hydraulic mining.
Hydraulic Mining 1853-1884
Great jets of water under high pressure using nozzles called “giants” were directed against the banks of gravel hundreds of feet in height. After proper ditches and gravity fed pipe lines had been installed, thousands of cubic yards of gravel could be washed without hand labor. The gold was recovered in riffle-sluices and quicksilver (mercury) was usually added to aid in its recovery. However, the debris deposited in streams by hydraulic miners became so environmentally objectionable to agricultural interests this method was stopped by legal injunction in 1884. The Malakoff Mine at North Bloomfield was one of the largest hydraulic mine areas and is now a State Park.
Drift Mining/Tunnel Mining/Pocket Mining
Mining of buried ancient river channels by means of shafts and adits, was started very soon after the outcrops of gravel were noticed on the hillside. Drift mining developed at about the same time as hydraulic mining; it did not suffer from the same restrictions. However, they were more expensive and used on richer gold bearing gravels. These methods resembled coal mining. Much of the gravel was found to be cemented and had to be milled or washed several times after laying in the open air to aid disintegration. Stamp mills with coarse screens worked well for milling cemented gravel. The use of tunnels to mine Table Mountain in Jamestown was intense over the placer mining years. The Humbug Mine was one of the most successful reaching the ancient river bed capped by lava flow. In Sonora, the Bonanza Mine was one of the largest pocket mines in the Southern Mines.
The dredging idea was originally simple, an endless chain of buckets bringing up mud and gravel from the river bottom and depositing it in sluice boxes aboard a boat. The fine material was separated from the coarse material by screens and the free gold caught by the use of quicksilver. Both the propelling and dredging machinery would be operated by steam. This simple idea began early in 1850s but did not reach a practical implementation till as late as 1897, when the single lift bucket elevation type system was floated in California on the Yuba River. Throughout the history of dredging in California the Oroville district has floated more dredges and seen more dredging companies than any other areas in California. By 1909, gold dredging had become big business and although there were a number of small one-dredge operators, the bulk of the land was now controlled mainly by three large companies.
Modern dredging techniques included dredges held in position by shore line and a huge spud, vertical column at the boats stern, with the ladder and bucket line operator well below the water level. Rocks and gravel drop from the end of the tailings stacker and the muddy runoff from the riffles is discharged from chutes on both sides of the boat. Gold dredges not only work on river bottoms, but also operate well inland, taking their own ponds with them, by the simple expedient of cutting from the front and filling in at the back.
In 1927, as an example after various acquisition/mergers the Capital Dredging Company was working four dredges on 2200 acres of land on the American River near Folsom. This company ended dredging operations in 1968. Another large company whose name was synonymous with California gold dredging was the Natomas Company, which operated along the American River in the Folsom area, almost to the city limits of Sacramento which closed down dredging in 1962. Aerial views of dredge tailings near Folsom look like the tracks of a giant earthworm i.e. mounds of lumpy tailings that follow the boats path.
Dredging was the chief method of gold mining in California from 1900 to the 1960s. It continued into the 1970s in the Yuba goldfields north of Sacramento. Dredged property once considered virtually destroyed is now being leveled and made suitable for industrial sites and housing.
Quartz Hard Rock Mining 1850s-2000 – Early Days
It began in 1849, rose quickly between 1850 and 1852, collapsed, rising again later in the next decade and eventually dominating the industry. The path to commercial viability was tortuous, filled with geological, technological, economic pitfalls taking many years to overcome. Successful early quartz mining was relatively simple because only the shallow deposits were worked. Before 1860s, California mines rarely reached levels below three hundred feet, the basic maximum depth of ground water. Above three hundred feet gold deposits containing sulfides or “suplhurets” was subject to the natural process of oxidation, leaching and erosion leaving a zone of higher grade ore easier to mine and mill than deeper un-oxidized sulfide deposits.
Quartz Ore Crushing Methods
The arrastra was one of the first ore crushing devices. Mexican miners brought the method here in the very early hard rock mining activities. The arrastra was made up of a circle of stones arranged to hold the ore. In the center, a post driven into the ground was used to pivot a pole which was drawn by a mule pulling a heavy stone over the ore, crushing it into a powder. The mule would pull the stone for about three to four hours, quicksilver and water was added, creating a slurry. The water was drained off leaving quicksilver-gold amalgam, which was then panned out to remove the gold.
Modern crushing or milling processes was a technology that evolved from early importing of other European designs. By 1860s, newer approaches were based on Eli Whitney Blake’s design who had invented a crushing machine for road construction in Connecticut. Design modification resulted in the “California improved stamp mill” which became the standard design in the mining west. It was a single, five stamp battery manufactured in San Francisco foundries. Hand drills and black power were used entirely until 1868, when the first air drills and dynamite were introduced, but widespread use of these improvements did not come for another 30 years.
The 1860s through the 1880s became a period when many of the California miners went to the Comstock, Nevada to follow the gold and silver mine boom there. California miners brought their experiences and skills to the Comstock and learned and created many new techniques necessary to be successful in deep shaft mining there.
The early 1850s, quartz mining boom fell short of investor’s expectations. In 1855, there were only thirty-two quartz mines in California, but by 1857 there were as many as 150 and a larger number of stamp mills and arrastras for extracting the gold from the quartz. By 1870, quartz mining accounted for 31 percent of the dollars value of all gold mined in California.
In 1880-1905, a “Second Gold Rush” in California was based on industrialization and returning miners, new investors and improved deep shaft mining technology which was applied to older mines, pursuing new veins associated with the revised mines earlier abandoned. Electricity, steel stranded cables, square set timbering, water and ventilation pumps, use of steam and air powered drilling with diamond bits were some of the technology. New gold concentration and chemical extraction techniques all contributed to the recovery of gold quartz mining in California.
In 1880, the State Bureau of Mines was established by the California legislature, headed by a mineralogist appointed by the Governor. The Bureau was empowered to collect and preserve mineral specimens and detailed information on mining and milling, etc. and prepare detailed reports on mining operations in each mining district throughout the state.
Other chemical techniques, such as the chlorination process for recovery of gold from concentrate was brought to California from Europe, and improved to the point of being widely used. Chlorination was a process of dissolving gold ores, after crushing and roasting, by the use of chlorine gas.
In 1896, the cyanide process was introduced for the extraction of gold from finely crushed ores, concentrates and tailings by means of cyanide of potassium. The gold is dissolved by solutions and subsequently deposited upon metallic zinc or by other means. By 1900s, this process was most efficient since almost all California mines were deeper, working in lower-grade ore often higher in sulfides, which were ineffectually treated by using only gravity-separation technology. By 1936, there were an estimated 3,200 gold mines.
Open Air Mining
Large open air or “open pit” mining has become the leading method for new mining of precious metals in the last half of the 1900s. Major corporations with sophisticated mining methods require large capital investments, complex environmental licensing and scientific staffing. Much study and analysis is used to prepare detailed mapping, core drilling, and three dimensional computer modeling to define the mining operations.
Low grade ore can be processed with various modern cyanide processes which create special environmental restrictions. Open pit mining consists of developing a pit with concentric, circular cut rings or ledges. This allows excavation equipment to move along the cut, dislodging the ore, with pre-blasting, and using large loading shovels to load oversized hauling trucks. Removed from the pit, the gravel is hauled to concentration and extracting facilities. These may be nearby or transported in more conventional trucks to other states depending on environmental laws. The mines operate twenty-four hours a day removing thousands of tons of ore. Gold can be mined as a byproduct of a copper mine, such as the Kennocott Mine in Utah, where many additional metals and minerals are extracted.
Modern gold extraction techniques such as “heap leaching” is a new method of treating low grade gold ore by piling it into an outdoor heap, then sprinkling cyanide solution over it. Within a few weeks, the cyanide will have dissolved the gold and it runs down a sloping, impermeable pad into large sluices. The pad on which the ore is leached must be impermeable to prevent solution from leaking into the ground water, carrying not only the gold but poisons as well. An example is the McLaughlin Mine in northern California. Some ore can have a little as one ounce of gold per ton of ore and still is economically feasible to make it profitable. At the McLaughlin Mine the cost of installing the heap leaching equipment was $250 million.
Effects of U. S. Government on the Price Control of Gold and the Mining Industry
A number of economic constraints were put on gold mining by the U.S. government. The price of gold was controlled as a gold standard of $20 per ounce from 1792 until the 1930s during the Depression. President Franklin D. Roosevelt stopped the run on the banks and hording of gold in 1934, also raising for the first time the price of gold to $35 per ounce. In 1942, at the beginning of WW2, the gold mining industry was closed down with the intent to move the mining labor force into war related metals. At the end of the war, gold mining was re-instated, but many mines had caved in, were flooded, and in general disrepair. After the depression, some mines reopened when the price of labor and material were still low. It was not until 1971, that President Nixon tried to stop the flow of gold out of the U.S. and raised the price to $42 per ounce, but that was not the solution. Several other approaches were tried with the same negative result. Finally in 1972, the government gave up on controlling the price of gold in the U.S. and it became a commodity item on the N.Y. Stock Exchange.
This resulted in the price of gold rising rapidly in the next ten years, reaching $850 per ounce in 1980. The gold mining industry was now seen to be a good investment and large corporations started revitalizing old mines and using modern open air (open pit) mining technology and cyanide concentration and extraction techniques to recover gold. There was resistance later in the 1990s when the environmental laws were created to protect against poisoning ground water, air pollution, and loss of animal and plant life. These restrictions resulted in lower numbers of new mines but they became large and more environmentally controlled at major capital expense. As the price of gold rose (1980 gold peaked at $850 per ounce, averaging $594 per ounce), so did the mining investment. In the Mother Lode, the Carson Hill and the old Harvard mines, right on the quartz vein of the Lode had resurgence. More than two million ounces of gold in the ground were still available with ore containing only 0.073 ounce per ton. The Sixteen-To-One Mine and others in the Alleghany district mines in historic Grass Valley district (notable Idaho-Maryland Mine) and even some drift mines were cleared for working. Gold dredging shut down in 1967 and started up again in the Yuba Goldfield north of Sacramento.
Underground mines, dredging and small-scale placer mining accounted for much of the gold production in the 1970s.
In California, nearly all the gold output for the year 1986 (400,000 ounces) came from five large open pit mines using the new refining technique of heap leaching. By 1988, when California’s annual gold production exceeded 732,000 ounces ($320 million) most of the gold came from fifteen large open pit mines. The most productive of California’s revitalized mines were not in the Sierran gold country, but in the Coast Ranges in Napa and Yolo counties, north of San Francisco. This is an area long mined, not for gold, but for mercury. One of these, the McLaughlin Mine, had to get 327 different environmentally related permits before one gold bar was poured. By 1995, California was second in the nation in gold production, exceeded only by Nevada. In 1996, California mined 835,000 ounces ($326 million.)
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A Golden State, Mining & Economic Development in Gold Rush California, James J. Rawls and Richard J. Orsi, 1999.
Fabulous Gold, Donlu D. Thayer, 1975.
“Historical Gold Prices – 1833 to Present”, National Mining Association, Washington D. C., www.nma.org
“Gold 2006 & 2007 Historical London PM Fix – USD”, Kitco Bullion Dealers, www.220.127.116.11/scripts/hist_charts/yearly_graphs.plx