HISTORY OF MINING AND MILLING METHODS IN CALIFORNIA LOGAN 



33 



made principally by bucket dredges. They have been increased in size 

 and capacity until the largest, now operating in the Yuba River field, 

 all have 18-cubic foot buckets and dig more than 100 feet below the level 

 of the ponds on which they float. The weekly capacity of a large modern 

 dredge may reach 125,000 cubic yards. The largest and latest, Yuba No. 

 20, weighs 3700 tons, has a total length of 540 feet ; carries 135 buckets 

 of 18 cubic feet capacity each, and digs 124 feet below water level. Most 

 of the gold recovered in dredging is saved on Hungarian type riffles 

 arranged in rows crosswise of the dredge. These receive the fine material, 

 under \ inch, which passes through the perforations in the large trommel 

 or screen into which the digging buckets dump the gravel. The average 

 gold content of gravel (10^ to 15^ a cubic yard) handled by dredgers 

 and the cost of operation (5^ to 10^ a cubic yard) are quite close to those 

 realized years ago in hydraulic mining. But because of the small crew 

 (three or four men per shift) required to handle a large yardage, the 

 dredge operator is nearly independent of the cost of labor, which now 

 hampers other forms of gold mining. 



The dragline dredge, which generally is operated to supply gravel 

 to a barge carrying a gravel washing plant, was widely used in Cali- 

 fornia in the decade prior to the last war to work shallow gravel deposits 

 too small to justify a bucket dredge. About 200 such outfits, each employ- 

 ing about 10 men and digging about 2000 to 2500 cubic yards of gravel 

 a day, were in operation on small streams in this state in 1940-41. Their 

 operating cost is about double that of a bucket dredge and they are 

 limited usually to gravel not over 20 feet deep. The dragline is of the 

 type in wide use by earth-moving contractors, using Diesel power and 

 having a bucket preferably of two cubic yards capacity or more. The 

 washing plant, floating on a pond dug by the dragline, is a lighter, 

 cheaper and simpler version of those used on bucket dredges. 



QUARTZ MINING 

 First Gold-Quartz Discoveries 



The Mariposa mine, at the south side of the town of Mariposa, was 

 discovered in the spring of 1849 by Kit Carson, the famous scout, and two 

 associates. In July 1849, a stamp mill, probably the first in the State, 

 was crushing ore from this mine. The outcrop of the vein yielded rich 

 specimen ore, and the first mining was nothing more than the digging of 

 shallow holes to remove this ore, which was broken by hand before crush- 

 ing in the mill. The latter had no means of amalgamating the gold, which 

 had to be saved by washing the pulp in a rocker. Soon after, an arrastre 

 was built to handle the stamp mill pulp. 



Gold-bearing quartz was found on Gold Hill at Grass Valley in June 

 1850 and was so rich and plentiful for a time that the miners feared 

 gold would lose its value. The first gold quartz claims, limited to 60 feet 

 by 120 feet, were located on the Mother Lode in Amador County in 1850, 



and probably during the same year in the other mining counties. At the 

 time there were many Mexican placer miners in the region from El 

 Dorado County southward, and they introduced the arrastre for crush- 

 ing the ore and amalgamating the gold. Soon there were hundreds of 

 these slow but efficient machines in operation, notably at Nashville, El 

 Dorado County and Carson Hill, Calaveras County, crushing selected ore 

 taken from the surface or shallow holes that required only hand tools. 



The Stamp Mill Replaces the Arrastre 



The arrastre was too slow for the Americans. The stamp mill, pre- 

 viously used in Europe, had been introduced into the southern Appa- 

 lachian gold mines years before the California discovery, and men who 

 had seen it there before coming west are credited with designing the 

 first crude mills of the kind. These mills had square wooden stems and 

 square iron shoes. There was no provision for rotation, a point which 

 the travellers had forgotten, as rotation had been provided in the 

 Appalachian mill. Ore had to be broken by hand and shoveled into 

 the mill. 



Early Struggles of the Quartz Miners 



The quartz mining industry had many ups and downs in the first 

 15 years after these early discoveries. In a private report made in 1864, 

 Professor William Ashburner stated that "in 1858 there were upwards 

 of 280 quartz mills in California, each one of which was supplied with 

 quartz from one or more veins. The number of stamps in these mills was 

 2610 and the total cost of the whole mill property of this nature in the 

 state exceeded $3,000,000. In the summer of 1861 ... I made a careful 

 and thorough examination of all the quartz mills and mines of the state, 

 and could only find between 40 and 50 in successful operation, several 

 of which were at that time leading a very precarious existence." The 

 discovery of the Comstock Lode in Nevada in 1859 had attracted great 

 numbers of California miners. Actual progress in sinking on the veins 

 was slow. The Hayward, now the Old Eureka mine, being worked by 

 Central Eureka Mining Company at Sutter Creek, had reached an 

 inclined depth of 1230 feet, and was the deepest mine in the state in 

 1867, having been in continuous operation since 1852. The Eureka mine, 

 now part of the Idaho-Maryland at Grass Valley, was only 100 feet deep 

 in 1863. The North Star mine shaft at Grass Valley, probably the 

 deepest in that district at that time, had reached an inclined depth of 750 

 feet in 1867, and the vein had been explored underground for a length 

 of 1000 feet. At last, quartz mining was becoming firmly established. 



Innovations and Improvements 



The early-day shafts were sunk as inclines following the veins on 

 the dip. Steam engines were used mostly for power. Hand drills and 

 black powder were used entirely until 1868, when the first air drills and 

 dynamite were introduced, although the widespread use of air drills for 



