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diff --git a/29926.txt b/29926.txt new file mode 100644 index 0000000..dd6f179 --- /dev/null +++ b/29926.txt @@ -0,0 +1,2481 @@ +Project Gutenberg's Hittel on Gold Mines and Mining, by John S. Hittell + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Hittel on Gold Mines and Mining + +Author: John S. Hittell + +Release Date: September 7, 2009 [EBook #29926] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK HITTEL ON GOLD MINES AND MINING *** + + + + +Produced by The Online Distributed Proofreading Team at +http://www.pgdp.net (This file was produced from images +generously made available by The Internet Archive/American +Libraries.) + + + + + + +HITTEL + +ON + +GOLD MINES + +AND + +MINING. + + + +QUEBEC: +PRINTED BY G. & G. E. DESBARATS. + +1864. + + + + +HITTEL +ON +GOLD MINES +AND +MINING. + + +_Chief Industry._--Mining is the chief industry of California. It +employs more men and pays larger average wages than any other branch of +physical labor. Although it has been gradually decreasing in the amount +of its production, in the profits to the individuals engaged in it, and +in its relative importance in the business of the state, it is yet and +will long continue to be the largest source of our wealth, and the +basis to support the other kinds of occupation. + +_Metals obtained._--Our mines now wrought are of gold, silver, +quicksilver, copper and coal. Ores of tin, lead, and antimony in large +veins, beds of sulphur, alum and asphaltum; lakes of borax and springs +of sulphate of magnesia, are also found in the state, but they are not +wrought at the present time, though they will probably all become +valuable in a few years. Platinum, iridium, and osmium are obtained +with the gold in some of the placer mines, but are never found alone, +nor are they ever the main object sought by the miner. The annual yield +of our gold mines is about forty millions of dollars, of our quicksilver +two millions of dollars. Our silver, copper and coal mines have been +opened within a year, and their value is yet unknown. All our other +mining is of little importance as compared with the gold. + +_Gold Mines._--Our gold mines are divided into placer and quartz. In +the former, the metal is found imbedded in layers of earthy matter, +such as clay, sand and gravel; in the latter it is incased in veins of +rock. The methods of mining must be adapted to the size of the +particles of gold, and the nature of the material in which they are +found. In placer mining, the earthy matter containing the gold, called +the "pay-dirt," is washed in water, which dissolves the clay and +carries it off in solution, and the current sweeps away the sand, +gravel and stones, while the gold, by reason of the higher specific +gravity, remains in the channel or is caught with quicksilver. In +quartz mining the auriferous rock is ground to a very fine powder, the +gold in which is caught in quicksilver, or on the rough surface of a +blanket, over which the fine material is borne by a stream of water. +About two-thirds of our gold is obtained from the placers, and +one-third from the quartz. + +A mine is defined and generally understood to mean "a subterraneous +work or excavation for obtaining metals, metallic ores or mineral +substances;" but this definition does not apply to our placer mines, +which are places where gold is taken from diluvial or alluvial +deposits. Most of the work is not subterraneous; it is done in the full +light of day. In some of the claims the pay-dirt lies within two feet +of the surface; in others it lies much deeper, but all the +superincumbent matter is swept away. + +Water is the great agent of the placer miner; it is the element of his +power; its amount is the measure of his work, and its cost is the +measure of his profit. With an abundance of water he can wash every +thing; without water he can do little or nothing. Placer mining is +almost entirely mechanical, and of such a kind that no accuracy of +workmanship or scientific or literary education is necessary to mastery +in it. Amalgamation is a chemical process it is true, but it is so +simple that after a few days' experience, the rudest laborer will +manage it as well as the most thorough chemist. + +It is impossible to ascertain the amount of gold which has been taken +from the mines of California. Records have been kept of the sums +manifested at the San Francisco Custom House, for exportation, and +deposited for coinage in the mints of the United States; and there is +also some knowledge of the amounts sent in bars and dust to England; +but we have no account of the sums carried by passengers to foreign +countries and coined elsewhere than at London, or used as jewelry, or +of the amount now in circulation in this state. According to the books +of the Custom House of San Francisco, the sums manifested for export +were as follows: + +In 1849, $4,921,250; in 1850, $27,676,346; in 1851, $42,582,695; in +1852, $46,586,134; in 1853, $57,331,034; in 1854, $51,328,653; in 1855, +$45,182,631; in 1856, $48,887,543; in 1857, $48,976,697; in 1858, +$47,548,025; in 1859, $47,640,462; in 1860, $42,303,345; in 1861, +$40,639,089; a total of $551,603,904 in twelve years. + +The exportation of gold commenced in 1848, but we have no record of the +sums sent away in that year. Previous to 1854 very large sums were +carried away by passengers, who gave no statement at the Custom House; +since that year, the manifests show the exportation correctly within a +few millions. I am entirely satisfied that the total gold yield of +California has been not less than seven hundred millions of dollars; +but I have not room here to state the reasons for this opinion. My +estimate is considerably less than that of most business men of the +state, and less than that made by Hunt's _Merchants' Magazine_. There +was undoubtedly a regular increase in the annual yield of the mines +from 1848 to the end of 1853; and there has been a gradual decrease +since the beginning of 1854--a decrease perhaps not very regular but +still certain. Since 1854 considerable sums exported from San +Francisco, and included in our tables, came from mines beyond the +limits of California, such as the mines in Southern Oregon, in the +eastern part of Washington Territory, in British Columbia, and in +Nevada Territory; and while the California gold yield has been +decreasing, these extraneous supplies have been increasing. Several +millions must be deducted from the annual shipments since 1858, for +foreign gold. The gold yield will undoubtedly continue to fall, but to +what point and at what rate no one can know. I believe that in 1870, +the yield will not exceed thirty millions of dollars. + +_Placer Mines._--Placer mines are divided into many classifications. +The first and most important is into deep and shallow. In the former +the pay-dirt is found deep, twenty feet or more beneath the surface; in +the latter, near the surface. The shallow or surface diggings are +chiefly found in the beds of ravines and gullies, in the bars of +rivers, and in shallow flats; the deep diggings are in hills and deep +flats. The pay-dirt is usually covered by layers of barren dirt, which +is sometimes washed, and sometimes left undisturbed, while the pay-dirt +is taken out from beneath it through tunnels or shafts. So far as our +present information goes, we have reason to believe that no gold +country ever possessed so large an extent of paying placer mines, with +the pay-dirt so near the surface, and with so many facilities for +working them as California. In Australia the diggings are very deep and +spotted, that is, the gold is unevenly distributed, and the supply of +water for mining is scanty. In Siberia the winter is terribly cold +during six months of the year. In Brazil the diggings were not so +extensive nor so rich as in this state. Here we have numerous large +streams coming down through the mining districts, very large bodies of +pay-dirt, and a mild climate. + +After dividing placers into deep and shallow, the next classification +will be according to their topographical position, as into hill, flat, +bench, bar, river-bed, ancient river-bed, and gulch mines. Hill +diggings are those where the pay-dirt is in or under a hill. Flat +diggings are in a flat. Bench diggings are in a "bench" or narrow table +on the side of a hill above a river. Benches of this kind are not +uncommon in California, and they often indicate the place where the +stream ran in some very remote age. Bars are low collections of sand +and gravel at the side of a river and above its surface at low water. +River-bed claims are those beneath the surface of the river at low +water, and access is obtained to them only by removing the water from +the bed by flumes or ditches. Ancient river-bed claims are those of +which the gold was deposited by streams in places where no streams now +exist. Gulch claims are those in gullies which have no water, save +during a small part of the year. A "claim" is the mining land owned or +held by one man or a company. + +The placer mines are again classified according to the manner in which, +or the instruments with which they are wrought. There are sluice +claims, hydraulic claims, tunnel claims, dry washing, dry digging, and +knife claims. In 1849 and 1850, the main classification of the placers +was into wet diggings and dry diggings, the former meaning mines in the +bars and beds of rivers, and dry diggings were those in gullies and +flats where water could be obtained only part of the year or not at +all. That classification was made while nearly all the mining was done +near the surface, before the great deposits of pay-dirt in the hills +had been discovered, and before ditches, sluices, and the hydraulic +process had been introduced. The class of mines then known as the "dry +diggings," and which for several years furnished nearly half of the +gold yield of the state, are now, with a few unimportant exceptions, +exhausted, or left to the attention of the Chinamen. + +The purpose of all placer miners is not to catch all the gold in the +dirt which they wash, but to catch the greatest possible quantity +within a given time. It is not supposed that any process used in gold +mining catches all the metal. Part of it is lost; in some processes a +considerable proportion. The general estimate in California is, that +one-twentieth of the gold in the dirt which is washed is lost. Many of +the particles are so very small as to be invisible to the naked eye, +and so light that their specific gravity does not avail to prevent them +from being carried away by the water like sand. The larger pieces will +sink to the bottom and resist the force of the water; the smaller the +particles, the greater the danger that it will be borne away. Many +devices have been tried to catch all the gold, but none have succeeded +perfectly, and some which have caught a portion of what escaped from +the ordinary modes of mining, have been found to cost more than their +yield. The miner does not grieve about that which he cannot catch. He +is not careful to catch all that he could. His purpose is to draw the +largest possible revenue per day from his claim. He does not intend to +spend many years in mining, or if he does, he has become thriftless and +improvident. In either case, he wishes to derive the utmost immediate +profit from his mine. If his claim contain a dollar to the ton, and he +can save five dollars by slowly washing only six tons in a day, while +he might make ten dollars by rapidly washing fifteen tons in a day, he +will prefer the latter result, though he will loose twice as much of +the precious metal by the fast as by the slow mode of working. The +object of the miner is the practical dispatch of work, and his success +will depend to a great extent upon the amount of dirt which he can wash +within a given space of time. He regrets that any of the gold should be +wasted, but his regret is because it escapes from his sluice and his +pocket, rather than because it is lost to industry and commerce. + +_The Sluice._--The board-sluice is a long wooden trough, through which +a constant stream of water runs, and into which the auriferous dirt is +thrown. The water carries away the clay, sand, gravel and stones, and +leaves the gold in the bottom of the sluice, where it is caught by its +gravity and by quicksilver. The board-sluice is the great washing +machine, and the most important instrument used in the placer mining of +California. It washes nearly all the dirt and catches nearly all the +placer gold of the country. It was invented here, although it had +previously been used elsewhere; it has been more extensively employed +here than in any other country, and it can be used here to more +advantage than elsewhere. It is not less than fifty feet long, nor less +than a foot wide, made of boards. The width is usually sixteen or +eighteen inches; and never exceeds five feet. The length is ordinarily +several hundred and sometimes several thousand feet. It is made in +sections or "boxes" twelve or fourteen feet long. The boards are an +inch and a half thick, and are sawn for that special purpose, the +bottom boards being four inches wider at one end than the other. The +narrow end of one box therefore fits in the wide end of another, and in +that way the sluice is put together, a long succession of boxes, the +lower end of each resting in the upper end of another, and not fastened +together otherwise. These boxes stand upon trestles, with a descent +varying from eight to eighteen inches in twelve feet. It is therefore +an easy matter to put up or take down a sluice after the boxes are +made, and it is not uncommon for the miners to haul their boxes from +one claim to another. The descent of a sluice is usually the same +throughout its length, and is called its "grade." If there be a fall of +eight inches in twelve feet, the sluice has an "eight-inch grade," and +if the fall be twice as great, it is a "sixteen-inch grade." The grade +depends upon the character of the pay-dirt, the length of the sluice, +and its position. The steeper the descent, the more rapidly the dirt is +dissolved, but the greater the danger also that the fine particles of +gold will be carried away by the water. The tougher the dirt, that is, +the greater its resistance to the dissolving power of the water, the +steeper, other things being equal, should be the sluice. A slow current +does not dissolve tough clay, and that is the greater part of the +pay-dirt, so rapidly as a swift one. The shorter the sluice, other +things being equal, the smaller the grade should be. There is more +danger that the fine particles of gold will be lost by a short sluice +than by a longer one, and to diminish this danger, the rapidity of the +current must be reduced by a small grade. The greater the amount of +dirt to be washed, other things being equal, the steeper should be the +grade; for a swift current will wash more dirt than a slow one. In many +claims the pay-dirt is full of large stones and boulders, weighing from +one hundred to five hundred pounds each, all of which must be carried +away through the sluice. Some are sent down whole, and others are +broken into pieces with sledge hammers before they are thrown into the +box. These require a swift current and a large body of water. The +larger the supply of water, the steeper the sluice is made, other +things being equal. Of course economy and convenience of working +require that the sluice should be near the level of the ground, and as +that may be steep or level below the claim, the grade of the sluice +must to some extent conform to it. There are thus a multitude of points +to be taken into consideration in fixing the grade of a sluice; but a +fall of less than eight or more than twenty inches, in a box of twelve +feet, would be considered as unsuitable for the board-sluice. Sometimes +the upper part of the sluice is made steeper so as to dissolve the +dirt, and the lower part has a small grade to catch the gold. The +clayey matter of ordinary pay-dirt is fully dissolved in a sluice two +hundred feet long with a low grade, so the use of the boxes beyond that +length is merely to catch the gold. There are claims however in which +the clay is so extremely tough that it will roll in large balls more +than a quarter of a mile through a steep sluice with a large head of +water, and come out at the lower end scarcely diminished in size. + +The gold is caught in the sluice-boxes by false bottoms of various +kinds. It would not do to leave the smooth boards, for the water would +sweep all the gold away, and the boards themselves would soon be worn +through. The most common false bottom is the longitudinal riffle-bar, +which is from two to four inches thick, from three to seven inches +wide, and six feet long. Two sets of these riffle-bars go into each +sluice-box, the box being twice as long as the bar. A set of +riffle-bars is as many as fill one half of a box. They are wedged in, +from an inch to two inches apart; the wedging being used, because the +bars can more readily be fastened in their places, and more easily +taken up, than if nails were used. Before the work of sluicing +commences, all the boxes are fitted with riffle-bars, and the bottom of +the sluice is therefore full of holes from one to two inches wide, from +three to seven inches deep, and six feet long. These are the places in +which the gold, quicksilver, and amalgam are caught. Quicksilver is +used now in nearly all the sluices, and is the more necessary the +smaller the particles of gold. The large pieces of the metal would all +be caught by their specific gravity without the aid of amalgamation. + +The sluice-boxes having been made, and set up with the proper grade, +the water is turned in. The boxes are made of the rough boards as they +come from the saw, and the joints are not waterproof, but the leaks are +soon stopped by the swelling of the wood, or by the dirt. The stream of +water in the sluice is at least two inches deep over the bottom. The +height of the sides of the boxes is from eight inches to two feet. The +sluice usually runs through the claim, and the auriferous dirt is +thrown in with shovels, of which from four to twenty are constantly at +work. A man will throw in from two to five cubic yards of dirt in one +day. The water rushing over the dirt as it lies in the box, rapidly +dissolves the clay and loam, and then sweeps the sand, gravel and +stones down. The first dirt in the box goes to fill the spaces between +the riffle-bars. After the sluicing has been in progress a couple of +hours, some quicksilver is put in at the head of the sluice, and it +gradually finds its way downward, most of it stopping, however, near +where it is put in. + +_Amalgamation._--There are a few metals, including gold, silver, copper +and tin, which, with quicksilver, form a peculiar chemical union called +amalgamation, a process of great importance to the gold miner. When a +piece of gold or silver is placed in mercury, the latter metal +gradually penetrates through it, destroys the coherence of its +particles, and form with it a mass like dough. A lump of gold as large +as a bean will be soaked through in three or four days; with silver and +copper the process is slower, but they are affected in the same manner. +Amalgamation, though a union of a solid with a liquid, differs much +from a solution. In the latter the union is mechanical; in the former +it is chemical. In the latter the solid is reduced to particles of +impalpable fineness; in the former it is not. An ounce of salt will be +dissolved in, and nearly equally diffused through, a pint of water; but +if an ounce of gold be thrown into a pint of quicksilver, it will, +after forming an amalgam with the quicksilver, remain at the bottom. We +have no texture so fine that it will strain salt out of water; but the +particles of gold are so coarse in amalgam that they can easily be +strained out by means of buckskin or tight cloths. However, a little +gold will remain in the quicksilver--about the fiftieth part of an +ounce of gold in every pound of quicksilver; and the only method of +obtaining this gold is by retorting. + +Quicksilver is used in gold mining for catching the small particles of +metal; the large ones are caught by their weight. But many of the +particles are so small that they are almost invisible to the naked eye, +and when in moving water they float. Miners frequently show visitors +the fineness of their gold by putting some of the dust in a vial with +water, and upon shaking, the particles of metal can be seen floating +about in the clear water. Riffles, and all the devices to get the +benefit of specific gravity, are of little use to arrest this +"float-gold," so amalgamation is employed. If a bit of quicksilver is +put in the way of the fine gold, the two metals unite at once and make +a larger bulk, which can be caught. + +There is no such attraction between gold and quicksilver as there is +between the magnet and iron; but when the two former metals once touch, +an amalgam is immediately formed, and if the proportions of the metals +be about even, they in time make a hard mass. Some gold does not +amalgamate readily; in various diggings of Siskiyou county, the gold +has a reddish coating, which prevents amalgamation. Grease or resin in +the water used for washing, is also unfavorable. So is cold. Heat is +favorable, and therefore less gold is lost in summer than in winter. +Quicksilver that has been once used is considered better than that +fresh from the flask. + +No tinned iron or copper vessel should be used for holding or panning +out amalgam, or dirt containing amalgam; since quicksilver forms an +amalgam with tin and copper, and will stick to the sides of a tinned or +copper pan. + +In most sluices, the quicksilver is put in above the riffle-bars at +various places along in the boxes, with a confidence that the great +specific gravity of the metal will prevent it from being lost. The +greater the quantity and proportion of fine gold, the greater the +importance of the quicksilver. + +The best method of catching very fine gold by amalgamation is to cover +a large copper plate with mercury, and let the dirt and water, in a +thickness of not more than a quarter of an inch, pass over it slowly. +There are various methods of covering copper plates with quicksilver. +The first thing, in every case, is to wash the copper with diluted +nitric acid, so as to remove all dirt and grease. The quicksilver may +then be rubbed on with a rag; or, still better, it may be dissolved in +nitric acid, and the liquid nitrate of quicksilver may be applied with +a rag. The nitric acid will attack the copper, and leave the +quicksilver as an amalgam on the surface of the copper. This is the +most common process, but the nitrate of copper continues for a long +time to come up through the quicksilver and interfere with the catching +of the gold. When the nitrate of copper appears--it is a green +slime--it should be scraped off and the place rubbed over with +quicksilver. When a plate is once covered with mercury, the operation +need never be repeated; but more mercury must be sprinkled on as the +gold collects and forms a solid amalgam. The plate is usually three +feet wide and six feet long, and is set nearly level. In very large +sluices the stream should be divided so as to run over different +plates. The slowness of the current and the shallowness of the water +are important, for with a swift current or deep water many of the +particles of float-gold may escape without touching the quicksilver. +Wherever a speck of gold has fixed itself on the plate, there others +will collect about, evidently preferring to fix themselves in a +neighborhood rather than in a waste place. The more gold there is on a +plate, the better it is considered to be. The seasons for cleaning up +are usually determined by the danger of theft. Miners do not like to +leave their gold out in quantities so large as to attract thieves. The +amalgam is sometimes half an inch thick, and is usually, at cleaning-up +time, a hard mass, which must be loosened by heat. The plate is put on +a fire, and when it gets so warm that the hand can scarcely bear it, +the amalgam is softened and loosened, so that it can be scraped off +readily. The plate is then sprinkled anew with quicksilver, and is +ready for use again. Mercury does not amalgamate with copper so readily +as with gold or silver. A copper plate, the sixteenth of an inch thick, +may be used for at least five years, and perhaps for ten; whereas a +gold plate of equal thickness would, if exposed to the action of +quicksilver in the same manner, fall to pieces in a few weeks. After a +time the quicksilver pervades the copper, and gives it a silvery +whiteness all through on the under side. It is said that a solution of +cyanuret or prussiate of potash, is used instead of nitric acid in +applying mercury to copper plates, and that it is still better, there +being then no trouble with the green spots of nitrate of copper. + +A good amalgamated copper plate is considered as serviceable as a bed +of quicksilver of equal size, and it is very much cheaper and more +convenient to manage. + +The dirt and water should be admitted to the copper plate, by falling +first through a sheet-iron plate, pierced with holes half an inch long +and a sixteenth of an inch wide. Some miners place this sheet-iron +plate immediately over the copper. + +Very soon after the water and dirt commence to run in the sluice, all +the spaces between the riffle-bars are filled with sand, gravel and +dirt; which, however, present many little inequalities of surface, +sufficient to catch all the particles of gold larger than a pin-head. +The largest gold is caught near the head of the sluice; and the farther +down the sluice, the finer the gold. In some sluices, where the +pay-dirt contains much coarse gold, the quicksilver is introduced from +thirty to sixty yards below the head, so as to catch only the fine +particles of metal. + +_Cleaning up._--The separation of the gold, amalgam, and quicksilver, +from the dirt in the bottom of the sluice, is called "cleaning up;" and +the period between one "cleaning up" and another is called a "run." A +run in a common board-sluice usually lasts from six to ten days. +Ordinarily the sluice runs only during daylight, but in some claims the +work continues night and day. Cleaning up occupies from half a day to a +day, and therefore must not be repeated too often, because it consumes +too much time. In some sluices the cleaning up does not occur until the +riffle-bars have been worn out or much bruised by the wear of the +stones and gravel. Cleaning up is considered light and pleasant work as +compared with other sluicing, and is often reserved for Sunday. At the +time fixed, the throwing in of dirt ceases, and the water runs until it +becomes clear. Five or six sets of riffle-bars, a distance of thirty or +thirty-five feet, are taken up at the head of the sluice, and the dirt +between the bars is washed down, while the gold and amalgam lodge above +the first remaining set of riffle-bars, whence it is taken out with a +scoop or large spoon, and put into a pan. Five or six more sets of bars +are taken up, and so on down. Sometimes all the riffle-bars are taken +up at once, save one set in every thirty-six feet, and then the work of +cleaning up is dispatched much more rapidly. + +The quicksilver and amalgam taken from the sluice are put into a +buckskin or cloth, and pressed, so that the liquid metal passes +through, and the amalgam is retained. The amalgam is then heated, to +drive off the mercury. This may be done either in an open pan or in a +close retort. In the former, the quicksilver is lost; in the latter, it +is saved. The pan is generally preferred. Often a shovel or plate of +iron is used. Three pounds of amalgam, from which the liquid metal has +been carefully pressed out, will yield one pound of gold. The gold +remaining after the quicksilver has been driven off by heat from the +amalgam, is a porous mass, somewhat resembling sponge-cake in +appearance. + +_Riffle-Bars._--The riffle-bars are usually sawn longitudinally with +the grain of the wood, but "block riffle-bars" are considered +preferable; the latter are cut across the tree, and the grain stands +upright in the sluice-box. The block riffle-bars are three times more +durable than the longitudinal; and as the latter kind are worn out in a +week in some large sluices, there is a considerable saving in using the +former. The block riffle-bars are only two or three feet long. + +In some small sluices the riffle-bars are not placed in the boxes +longitudinally, nor in sets; but one bar near the head runs downward at +an angle of forty-five degrees to the course of the box, not touching +its lower end to the side of the box, but leaving an open space of an +inch there. Just below this open space another bar starts from the side +of the box and runs downward at right angles to the course of the first +bar, and an open space is again left at the end of this bar; and so on +down to near the lower end of the sluice, where there are longitudinal +riffle-bars in sets as described in the preceding paragraphs. The +consequence of using this kind of riffle-bar is, that though much of +the water and light dirt runs straight over the bars, the heavier +material runs down from side to side in a zigzag course. Near the head +of the sluice is a vessel, from which quicksilver falls by drops into +the box; and it follows the course of riffle-bars, overtaking the gold +which takes the same route. These zigzag riffle-bars are nailed down. +In all sluices, men must keep watch to see that the boxes do not choke; +that is, that the dirt and stones do not collect in one place, so as to +make a dam, and cause the water to run over the sides, and thus waste +the gold. + +There are small sluices, from which all stones as large as a doubled +fist are thrown out. For this purpose the miner uses a sluice-fork, +which is like a large manure-fork or garden-fork, but has tines which +are blunt and of equal width all the way down; the bluntness being +intended to prevent the tines from catching in the wood, and the +equality of width to prevent the stones from getting fast in the fork. + +In some sluices, the "block riffle-bars"--that is, bars cut across the +grain of the tree--are set transversely in the boxes, and about two +inches apart. + +Another device is, to fill the pores of such riffle-bars with +quicksilver. This is done by driving an iron cylinder with a sharp edge +into the surface of the bar, then putting mercury into the cylinder, +and pressing it into the wood. The quicksilver, thus fastened in the +wood, catches particles of gold, which must be scraped off when the +time for "cleaning up" comes. + +_Double Sluices._--Sluices are sometimes made double--that is, with a +longitudinal division through the middle, so that there are two +distinct sluice-boxes side by side. Two companies may be working side +by side, so that it will be cheaper for them to build their sluices +jointly. In some places the amount of water varies greatly; so that in +the winter there is enough to run two sluices, and in the summer only +one. And there are companies which wish to continue washing without +interruption; so they wash first on one side and then on the other, and +clean up without any interruption to the process of washing. + +Another device for saving gold in sluices is the "under-current box." +There is a grating of iron bars in the bottom of a box, near the lower +end of a sluice; and under this grating is another sluice, with an +additional supply of clean water, and with a lower grade. The grating +allows only the fine material to fall through; and the current of water +being moderate, many particles of gold, that would otherwise be lost, +are saved. Sometimes the matter from the under-current box is led back +to the main sluice. + +_Rock-Sluices._--Large sluices are frequently paved with stone, which +makes a more durable false bottom than wood, and catches fine gold +better than riffle-bars. The stone bottoms have another advantage--that +it is not so easy for thieves to come and clean up at night, as is +often done in riffle-bar sluices. But, on the other hand, cleaning up +is more difficult and tedious in a rock-sluice, and so is the putting +down of the false bottom after cleaning up. The stones used are +cobbles, six or eight inches through at the greatest diameter, and +usually flattish. A good workman will pave eight hundred square feet of +sluice-box with them in a day; and after the water and dirt have run +over them for an hour, they are fastened very tightly by the sand +collected between them. In large sluices, wooden riffle-bars are worn +away very rapidly--the expense amounting sometimes, in very large and +long sluices, to twenty or thirty dollars a day; and in this point +there is an important saving by using the stone bottoms. They are used +only in large sluices, and they generally have a grade of twelve or +fourteen inches to the box of twelve feet. + +_Hydraulic Mining._--After the board-sluice, with its various adjuncts +of riffle-bars, stone bottoms, copper plates, and so forth, the next +instrument of importance in the gold-mining of California, is the +hydraulic hose, used to let water down from a considerable height, and +throw it under the pressure of its own weight against the pay-dirt, +which is thus torn down, broken up, dissolved and carried into the +sluice below. The sluice is a necessary part of hydraulic mining. The +hose is used, not to wash the dirt, but to save digging with shovels, +and to carry it to the sluice. + +The hydraulic process is applied only in claims where the dirt is deep +and where the water is abundant. If the dirt were shallow in the claim +and its vicinity, the necessary head of water could not be obtained. +Hydraulic claims are usually in hills. The water is led along on the +hill at a height varying from fifty to two hundred feet above the +bed-rock, to the claim at the end or side of the hill, where the water, +playing against the dirt, soon cuts a large hole, with perpendicular or +at least steep banks. At the top of the bank is a little reservoir, +containing perhaps not more than a hundred gallons, into which the +water runs constantly, and from which the hose extends down to the +bottom of the claim. The hose is of heavy duck, sometimes double, sewn +by machine. This hose when full is from four to ten inches in diameter, +and will bear a perpendicular column of water fifty feet high; but a +greater height will burst it. Now, as the force of the stream increases +with the height of the water, it is a matter of great importance to +have the hose as strong as possible; and for this purpose, in some +claims, it is surrounded by iron bands, which are about two inches +wide, and are connected by four ropes which run perpendicularly down. +The rings are about three inches apart. The "crinoline hose," thus +made, is very flexible, and will support a column of water one hundred +and fifty or two hundred feet high. The pipe at the end of the hose is +like the pipe of a fire-engine hose, though usually larger. Sometimes +the pipe will be eight inches in diameter where it connects with the +hose, and not more than two inches at the mouth; and the force with +which the stream rushes from it is so great, that it will kill a man +instantaneously, and tear down a hill more rapidly than could a hundred +men with shovels. + +One or two men are required to hold the pipe. They usually turn the +stream upon the bank near its bottom until a large mass of dirt tumbles +down, and then they wash this all away into the sluice; when they +commence at the bottom of the bank again, and so on. If the bank is one +hundred and fifty feet high, the mass of earth that tumbles down is of +course immense, and the pipemen must stand far off, for fear that they +will be caught in the avalanche. Such accidents are of daily +occurrence, and the deaths from this cause probably are not less than +threescore every year in the state. Often legs are broken; still more +frequently the pipemen have warning, and escape in time. When men are +buried in the falling dirt, the water is used to wash them out. In some +claims, the pipe will tear down more dirt than the sluice can wash; in +other claims, the sluice always demands more dirt than the pipe can +bring down. In the latter case, blasting may be used to loosen the +dirt, or the miners may undermine the bank, leaving a few columns of +dirt for support; and then these being washed away by the pipe, the +whole bank comes tumbling down. + +In hydraulic claims, all the dirt is washed; in all other kinds of +claims, such dirt as contains no gold is thrown to one side, or +"stripped off." "Hydraulic mining" is the highest branch of placer +mining; it washes more dirt, and requires more water, and a larger +sluice, than any other kind of mining. The number of men employed in a +hydraulic claim, however, is usually small, from three to six, the +water doing nearly all the work. In some claims a man is constantly +employed with a heavy sledge-hammer in breaking up large stones, so +that the pieces may be sent down the sluice. One man attends to the +sluice, and sees that the dirt does not choke up in the sluice, or in +the claim above it. + +The quantity of dirt that can be washed with a hydraulic pipe depends +upon various circumstances--such as the supply of water, the height of +its fall, the toughness of the dirt, and the amount of moisture in it. +More can be washed in winter than in summer, because the dirt is then +moister, and requires less water to loosen and dissolve it. The +quantity of water used in a hydraulic claim is from forty to two +hundred inches. With one hundred inches, at least thirty cubic yards +can be washed in ten hours, on an average; and three men can do all the +work. If there were a cent's worth of gold in each cubic foot, the +thirty cubic yards would yield eight dollars and ten cents per day, or +two dollars and seventy cents to the man, exclusive of the cost of +water. But, as a matter of fact, nearly all the hydraulic claims pay +more than that, and they will average at least three cents to the cubic +foot, and many of them yield five cents. The water usually costs twenty +cents an inch per day, so that one hundred inches would cost twenty +dollars. Allowing for the water at that rate, a claim in which thirty +cubic yards could be washed in a day with one hundred inches of water, +and in which the dirt contained five cents to the cubic foot, would +leave a net pay of six dollars and sixty-six cents to each man per day. + +One hydraulic company, of whose labors I have a note, washed two +hundred and twenty-four thousand cubic feet of dirt in six days, using +two hundred inches of water, and employing ten men. The wages of the +men amounted, at four dollars per day each, to two hundred and forty +dollars; the water cost three hundred dollars; and the waste of +quicksilver, and wear of sluice, perhaps one hundred dollars more, +making a total expenditure of six hundred and forty dollars: and the +gold obtained was three thousand dollars, leaving a clear profit of +twenty-three hundred and fifty dollars. The dirt contained one cent and +a fifth of gold in a cubic foot. The greater the amount of water used, +the greater the proportionate amount of dirt that can be washed, and +the greater the proportionate profits. It is far more profitable to +have a large sluice than a little one, if the water and dirt can be +obtained in abundance. + +Usually, in a hydraulic claim, the dirt is washed down to the bed-rock; +but in some places the washing stops far above the bed-rock, because +there is no outlet for the water. + +_Blasting._--In some hydraulic claims, the dirt, in dry seasons, is +blasted, so as to loosen it. A drift or hole is cut into the bottom of +a hill, one or two hundred feet high, and a number of kegs of powder +(from twenty to two hundred) are introduced, and they are fired with a +slow match. The explosion makes an earthquake in the vicinity; and the +ground is loosened to such an extent that there is a great saving of +labor. The breaking up of the dirt and the exposure to the air are +supposed to facilitate the washing greatly. + +More water is required for piping down banks than for washing the dirt; +and often the sluice is almost idle for want of dirt, while the water, +after being thrown against the hillside, runs away without doing any +service at washing. Blasting, therefore, by loosening the earth, +enables the hydraulic miner to have an abundant and regular supply of +dirt in his sluice, at an expense much less than the cost of manual +labor to dig the bank down with pick and shovel. + +_Tail-Sluice._--The tail-sluice is a large sluice made for rewashing +the tailings or dirt which has previously passed through other sluices. +It is placed ordinarily in the bed of a ravine or creek through which +tailings run, and it receives no attention for weeks or months at a +time, save to keep it from choking. The sluices emptying into it +furnish both dirt and water, and in the dirt there is always a large +amount of fine gold, as is plainly proved by the fact that some of the +tail-sluices have paid large profits to their owners. Tail-sluices are +always large, long and paved with stones; and sometimes they are +double, so that one side may be cleaned up while the other continues +washing. In a branch of the Yuba there is, or was not long since, a +tail-sluice twenty feet wide. + +_Tunnel-Sluice._--A tunnel-sluice is a sluice in a tunnel. It sometimes +happens that a considerable body of water runs out through a tunnel; +and in such case, a sluice at the bottom of the tunnel offers the +easiest method of getting out and washing the dirt. The tunnels are +never cut level, but with a slightly ascending grade, so that the water +will always run out. The grade is so low, that transverse riffle-bars +must be used; for with longitudinal riffle-bars or stones, there would +be too much danger of choking. These tunnel-sluices, because of their +low grades, require much more attention than any other kind of sluices. + +_Ground Sluice._--All the sluices hitherto mentioned and described have +wooden boxes, but the ground-sluice has no box: the water runs on the +ground. The place selected for the ground-sluice is some spot where +there is a considerable supply of water, a steep descent for it, and +much poor dirt. The stream is turned through a little ditch, which the +miners labor to deepen and enlarge, and when it is deep they prize off +the high banks so that the dirt may fall down into the ditch. This is a +very cheap and expeditious way of washing, but it is not applied +extensively. It is used to the most advantage for washing where the +water is abundant for only a few weeks after heavy rains, and where it +would not pay to erect large sluices. A few cobble-stones should be +left or thrown at intervals in the bed of the ground-sluice to arrest +the gold, for if the bed were smooth clay, the precious metal might all +be carried off. Quicksilver is not used in the ground-sluice. After the +dirt has all been put through the ground-sluice, it is cleaned up in a +short board-sluice, or a tom. + +_Long Tom._--The tom or long tom, an instrument extensively used in the +Californian mines in 1851 and 1852, but now rarely seen, is a wooden +trough about twelve feet long, eighteen inches wide at the upper end, +and widening at the lower to thirty inches, with sides eight inches +high. It is used like a board-sluice, but has no riffle-bars, and at +the lower end its bottom is of sheet-iron, perforated with holes half +an inch in diameter. This sheet-iron is turned up at the lower end, so +that the water never runs over there, but always drops down through the +perforated sheet-iron or riddle, into a little riffle-box, containing +transverse riffle-bars. A stream of water of about ten inches makes a +"tom-head"--or the amount considered necessary for a tom--through the +tom, which has a grade similar to that of a board-sluice. The dirt is +thrown in at the head of the tom, and a man is constantly employed in +moving the dirt with a shovel, throwing back such pieces of clay as are +not dissolved, to the head of the tom, and throwing out stones. From +two to four men can work with a tom; but the amount of dirt that can be +washed is not half that of a sluice. The tom may be used to advantage +in diggings where the amount of pay-dirt is small and the gold coarse. +The riffle-box contains quicksilver, and as the dirt in it is kept +loose by the water falling down on it from the riddle above, a large +part of the gold is caught; but where the particles are fine, much must +be lost. + +_Cradle._--The rocker or cradle is still less than the tom and inferior +in capacity. It bears some resemblance in shape and size to a child's +cradle, and rests upon similar rockers. The cradle-box is about forty +inches long, twenty wide, and four high, and it stands with the upper +end about two feet higher than the lower end, which is open so that the +tailings can run out. On the upper end of the cradle-box stands a +hopper or riddle-box twenty inches square, with sides four inches high. +The bottom of this riddle box is of sheet-iron, perforated with holes +half an inch in diameter. The riddle-box is not nailed to the +cradle-box, but can be lifted off without difficulty. Under the riddle +is an "apron" of wood or cloth, fastened to the sides of the cradle-box +and sloping down to the upper end of it. Across the bottom of the +cradle-box are two riffle-bars about an inch square, one in the middle, +the other at the end of the box. The dirt is shovelled into the hopper, +the "cradler" sits down beside his machine, and while with one hand +with a ladle he pours water from a pool at his side upon the dirt, with +the other he rocks the cradle. With the water and the motion the dirt +is dissolved, and carried down through the riddle, falling upon the +apron which carries it to the head of the cradle-box, whence it runs +downward and out, leaving its gold, black sand, and heavier particles +of sand and gravel behind the riffle-bars. The man who rocks a cradle +learns to appreciate the fact, that the "golden sands" of California +are not pure sand, but are often extremely tough clay, a hopperful of +which must be shaken about for ten minutes before it will dissolve +under a constant pouring of water. Many large stones are found in the +pay-dirt. Such as give an unpleasant shock to the cradle, as they roll +from side to side of the riddle-box, are pitched out by hand, and after +a glance to see that no gold sticks to their sides, are thrown away; +but the smaller ones are left until the hopperful has been washed, so +that nothing but clean stones remain in the riddle, and then the +cradler rises from his seat, lifts up his hopper, and with a jerk +throws all the stones out. The water and the rocking are both +necessary. Without the water, the dirt could not be washed; and without +the rocking, the dirt would dissolve very slowly, and the gold would +most of it be lost. The rocking keeps the dirt in the bottom of the +cradle more or less loose, so that the particles of gold can sink down +in it, whereas if the cradle stood still, the sand there would almost +immediately pack down into a hard floor, over which the gold would run +almost as readily as over a board. The whole business of washing with a +cradle, is a repetition of the process already described--some dirt, +about one-third or one-fourth of what the hopper would hold, if full, +is put into the hopper, and while the cradle is rocked with one hand, +the other pours in the water. The cradle is cleaned up two or four +times in a day. The cleaning up is done by lifting the hopper, taking +out the apron, scraping up all the dirt in the bottom of the cradle +with an iron spoon, putting it into a pan and washing out the dirt, so +that only the gold will be left. This last process is called panning +out, and will be described in the next section. Most of the gold +collects above the upper riffle-bar, including all the larger lumps. If +the apron be of rough woollen cloth, some of the fine gold will be +caught there. In diggings where the gold is very fine, the hopper is +sometimes placed over the lower end of the cradle, and the apron is +made twice as long, and with a lower inclination than in the more +common form of the rocker. The water for the cradle should be supplied +by a little ditch, with a reservoir at the head of the cradle, to +contain five or six gallons. The dipper should be of tin, shaped like a +basin, hold about a gallon when full, and have a handle an inch and a +half in diameter, and eight inches long. The difference of height +between the upper and lower ends of the cradle should not be more than +two inches: a steeper inclination will make the current running through +it too strong, and the gold will be carried off; and, on the other +hand, if the cradle be nearer a level it will be hard to rock, and the +dirt in the bottom will pack more rapidly. The amount of dirt that can +be washed in a day with a cradle, varies from one to three cubic yards. +The dirt is usually shovelled into a pan or bucket, from which it is +thrown into the hopper. The miners usually measure the amount of dirt +washed by the number of "pans." One man working alone with a cradle +ought to wash from seventy-five to one hundred and fifty pans in a day, +and two men will wash twice as much. A pan may contain one-third or +one-half of a cubic foot. Two men can work more conveniently with the +rocker than one. There is enough work to give constant employment to a +cradler and a shoveller. The latter has a couple of buckets or pans, +which he fills alternately, always keeping one full and near the +cradler, so that without moving his feet he can pick it up and empty it +into the riddle-box. If the rocker have only one man, he must stop +rocking after washing every pan and get more dirt. This delay is +injurious to the process of washing, because it allows the dirt in the +bottom of the cradle to harden and pack, and some gold is always lost +as a consequence. If the dirt and water be convenient, not more than +two men can work to a profit with a rocker. But sometimes it happens +that water cannot be led to the claim, and in such case the dirt must +be carried to the water, a greater weight of which is used than of +dirt. At least three times as much water as dirt is required for +washing. If the distance from the hole to the water be not over ten or +twenty feet, the miners will usually carry the dirt in buckets; if +farther they will use wheelbarrows; and sometimes for greater distances +pack-mules or waggons. The greater the distance, the more the men +required for carrying the dirt. Sometimes, too, it happens that the +claim is troubled by water, and then one man may be constantly employed +in bailing. + +It is of great importance in mining with the cradle, to have the cradle +placed within four or five feet of the hole from which the pay-dirt is +obtained, and to have a good supply of water at the head of the cradle, +and then to have a good descent below the cradle, so that the tailings +may all be carried away by the water, so as not to accumulate. The +rocker washes about one-half the amount of dirt that can be washed by +an equal number of men with the tom, one-fourth of what can be washed +with the sluice, and one-hundredth of the amount that can be washed +with the hydraulic process; but it is peculiarly fitted for some kinds +of diggings. Many little gullies, containing coarse gold in their beds, +cannot obtain water for washing except during rains, and then only for +a few days at a time. In these gullies the cradle can be used to the +best advantage, for it can easily be transported, and it is very good +for saving coarse gold. While dirt that would pay from ten to +twenty-five cents, was abundant at the surface of the earth in the +Californian mines, the cradle was extensively used, but now it has been +abandoned by the whites, and is left to the Chinamen, who think +themselves doing well if they make seventy-five cents or one dollar per +day. + +The great difficulty in mining with the cradle is, that the sand will +"pack," or make a hard mass on a level with the top of the riffle-bars, +and the gold then is lost. So long as the cradle is in motion the dirt +does not pack, but when the rocking ceases, the mass hardens in a few +minutes. If the miner leaves his cradle standing for fifteen minutes, +he stirs up the dirt with his spoon before commencing again to wash. +One device to prevent packing is to put a little block under each end +of the rockers, so that at the end of every motion the cradle receives +a shock. Quicksilver is sometimes used in cradles, but not usually. + +_Pan._--The pan is used in all branches of gold mining, either as an +instrument for washing, or as a receptacle for gold, amalgam, or rich +dirt. It is made of stiff tin or sheet-iron, with a flat bottom about a +foot across, and with sides six inches high, rising at an angle of +forty-five degrees. A little variation in the size or shape of the pan +will not injure its value for washing. Sheet-iron is preferable to tin, +because it is usually stronger and does not amalgamate with mercury. +The pan is the simplest of all instruments used for washing auriferous +dirt. Some dirt, not enough to fill it full, is put in, and the pan is +then put under water. The water ought to be not more than a foot deep, +so that the pan may rest on the bottom, while the miner inserts his +fingers in and under the dirt and lifts it up a little, so that the +whole mass is wet. If the water be deep, the pan may be held in one +hand while the other is used to stir up the dirt, but it is more +convenient to take both. The dirt having been filled with water, the +miner catches the pan at the sides, raises that part toward his body, +and lowers the outer edge a little, and commences to shake the pan from +side to side, holding it so that all the dirt is under water, and so +that a little of the dirt can escape over the outer edge. The earthy +part of the dirt is rapidly dissolved by the water, assisted by the +shaking of the pan and the rolling of the gravel from side to side, and +forms a mud which runs out while clean water runs in. The light sand +flows out with the thin mud, while the lumps of tough clay and the +large stones remain. The stones collect on the top of the clay, and +they are scraped together with the fingers and thrown out. This process +continues, the pan being gradually raised in the water, and its outer +edge depressed, until all the earthy matter has been dissolved, and +that as well as the stones swept away by the water, while the gold +remains at the bottom. Panning is not difficult, but it requires +practice to learn the degree of shaking, which dissolves the dirt and +throws out the stones most rapidly without losing the gold. If the +shaking be too mild and slow, the process consumes too much time; +whereas if it be too rapid and violent, the gold is carried off with +the stones. Sometimes the pan is shaken so that the dirt receives a +rotary motion. This is the most rapid method of washing dirt, but also +the most dangerous. The pan must always be used in cleaning up the dirt +which collects in the cradle, in prospecting, and frequently in washing +small quantities of dirt collected in other kinds of placer mining. +Amalgam can be separated from dirt by washing, almost as well as gold. +In panning out, it frequently happens that considerable amounts of +black sand containing fine particles of gold are obtained, and this +sand is so heavy that it cannot be separated from the gold by washing, +while it is easily separated by that process from gravel, stones and +common dirt. The black sand is dried, and a small quantity of it is +placed in a "blower," a shallow tin dish open at one end. The miner +then holding the pan with the open end from him, blows out the sand, +leaving the particles of gold. He must blow gently, just strong enough +to blow out the sand, and no stronger. From time to time he must shake +the blower so as to change the position of the particles, and bring all +the sand in the range of his breath. The gold cannot be cleaned +perfectly in this manner, but the sand contains iron, and the little of +it remaining is easily removed by a magnet. The blower should be very +smooth, and made of either tin, brass or copper. + +_Dry Washing._--Dry washing is a method of winnowing gold from dirt. In +many parts of the mining districts of California, water cannot be +obtained during the summer for mining purposes. The miner therefore +manages to wash his dirt without water. He takes only rich dirt, and +putting it on a raw hide, he pulverizes all the lumps and picks out the +large stones. He then with a large flat basin throws the dirt up into +the air, catches it as it comes down, throws it up again, and repeats +this operation until nothing but the gold remains. Of course a pleasant +breeze, that will carry away the dust, is a great assistance to the +operation. Sometimes two men have a hide or a blanket, with which they +throw up the dirt. The process is very similar to the ancient method of +separating grain from chaff. The miner who devotes himself to dry +washing must be very particular to take only rich dirt, so he scrapes +the bed-rock carefully. He never digs very deep--not more than twenty +feet; and when he goes beyond seven or eight feet he "coyotes," or +burrows after the pay-dirt. He may coyote into the side of a hill, or +sink a shaft and coyote in all directions from it. This style of mining +is named from the resemblance of the holes to the burrows of the +coyote, or Californian wolf. Coyoting is not confined to the dry +washing, but is used also by miners washing with the pan and cradle. +One of the Congressmen elected some years ago to represent California +at Washington, was a miner at the time of his nomination, and was so +fond of coyoting, that he was generally known as "Coyote Joe." + +_Dry Digging._--Dry digging is that mining where the miner, after using +the shovel to strip off the barren dirt, scrapes the pay-dirt over with +a knife, picking out the particles of gold as he comes to them, and +throwing away the earthy matter. This is a slow process, but in rich +placers may be profitable. The miner is, of course, particular to +examine all the crevices in the bed-rock; and if the material be slate, +he digs up part of it, to see whether the gold has not found its way +into cracks scarcely perceptible on the surface. "Dry digging," as a +mode of mining, must not be confounded with "dry diggings," a kind of +mining ground which has been described near the beginning of this +chapter. + +Knife-mining differs a little from dry digging. In the latter, a shovel +is used to strip off the barren dirt; whereas the knife-mining is +practised in those places where the gold is deposited in crevices in +rocks along the banks of streams, without any covering of barren dirt, +so that the knife alone is used in scraping out the dirt; and afterward +the dirt, being placed in a pan, may be washed in water, which is never +used in dry digging. + +_Puddling-Box._--The puddling-box is a rough wooden box, about a foot +deep and six feet square, and is used for dissolving very tough clay. +The clay is thrown into the box, with water, and a miner stirs the +stuff with a hoe until the clay is all thoroughly dissolved, when he +takes a plug from an auger-hole about four inches from the bottom, and +lets the thin solution of the clay run off, while the heavier material, +including the gold, remains at the bottom. He then puts in the plug +again, fills up the box with water, throws in more clay, and repeats +the process again and again until night, when he cleans up with a +cradle or pan. The puddling-box is used only in small mining +operations, and never with the sluice, or in hydraulic claims. + +_Quicksilver-Machine._--The quicksilver-machine, or Burke rocker, is a +cradle about seven feet long, two feet wide, and two feet high. In the +bottom are a number of compartments, all containing quicksilver. One +man rocks the machine without cessation. A constant stream of water +pours into the machine at its head. The riddle extends the whole length +of the machine; and the stones, after being washed clean, fall off the +riddle at the lower end. One man is employed constantly working with a +shovel to keep the dirt on the riddle under the stream of water, and in +throwing off the big stones. If the pay-dirt is very convenient, two +men can shovel enough to keep the machine in operation. The Burke +rocker was extensively used in California eight and ten years ago, but +now it is a great rarity. + +_Tunnel-Mining._--A tunnel, in California mining, is an adit or drift +entering a hill-side, or running out from a shaft. Mining-tunnels are +usually nearly horizontal--those entering hill-sides having a slight +ascent, for the double purpose of draining the mine, and to facilitate +the removal of the pay-dirt. In a few hills the tunnels run downward at +an angle of twenty degrees or more, to avoid veins or ledges of rock, +which would have to be blasted through if the tunnel were cut +horizontally; but this can only be done with safety in hills which are +drained by older horizontal tunnels. + +The mining-tunnel does not run through a hill, but only into it. The +length of tunnels varies greatly; the longest are about a mile. The +usual height is seven feet, the width five feet. Ordinarily the top +must be supported by timbers, to prevent it from falling in, and not +unfrequently the sides must also be protected by boards. The cost of +cutting a tunnel varies from two to forty dollars a longitudinal foot, +according to the nature of the ground, the cost of getting timbers, &c. +Tunnels are usually made by companies of eight or ten men, of whom +one-half may be merchants, lawyers, physicians or office-holders, and +the remainder laboring miners. The latter class do the work; the former +furnish provisions and tools, and a certain amount of cash weekly until +the pay-dirt is reached. Two or three men work at a time cutting a +tunnel; one or two to dig the earth, and one or two to haul it out. The +dirt of the first fifty yards is hauled out in a wheelbarrow; beyond +that distance a little tram-way or railroad is laid down, and the dirt +is hauled out in cars, pushed by the miners. It is not customary to use +horses. It is common to have two relays of laborers--one set working +from noon to midnight, the other from midnight to noon. Work in a +tunnel is as pleasant at night as in the daytime. When a company is +rich, or has many laborers, it may have three relays, each to work +eight hours in the twenty-four. + +It is not uncommon for two companies, owning adjacent claims in a hill, +to unite and cut a tunnel on joint account along the dividing line. +They go in until they reach the pay-dirt, and then a surveyor is +employed to run the line between their claims, and the tunnel is +continued through the pay-dirt. The dirt from the tunnel is washed for +the joint account of the two companies. After the dividing line has +been established, each company keeps on its own side, and each has its +time to use the tram-way. They may also have a joint-stock sluice at +the mouth of the tunnel--one company having the privilege of using the +sluice one week, and the other the next. All the dirt brought out in a +week can readily be washed in a day. The work of taking out the +pay-dirt after the main tunnel has been cut, is called "drifting;" and +the holes made by the men engaged in it are termed "drifts." The drifts +are usually not so high as the tunnels. The large stones and barren +dirt obtained in the drifts are piled up here and there to sustain the +earth overhead. Sometimes wooden posts are likewise necessary. + +_Shafts._--Shafts are used in prospecting, and also in mining, where +the claims are deep and cannot be reached by either the hydraulic +process or the tunnel. The prospecting shaft is sometimes sunk into +hills supposed to be auriferous, where the shaft is far less expensive +than the tunnel. After the shaft demonstrates that the dirt is rich, +and precisely the altitude at which it lies, a tunnel is cut to strike +it. The shaft may be the cheaper for prospecting, but the tunnel is +usually the cheaper if any large amount of dirt is to be taken out. + +The shaft is dug by one man in the hole, and one or two are employed at +a windlass in hauling up the dirt. Mining-shafts in placer diggings are +rarely over one hundred feet deep; but one was dug in Trinity county to +the depth of six hundred feet, for the purpose of prospecting, but it +found neither pay-dirt nor the bed-rock. + +_River-Mining._--River-mining is mining for gold in the beds of rivers, +below low-water mark. The only practicable method of doing this is by +damming the stream, and taking the water out of its bed, in a ditch or +flume. It has been proposed by persons who never saw the mines, to get +the gold by dredging, or with a diving-bell; but such schemes are +absurd in the eyes of miners. The rivers in which the gold is found are +mountain-torrents, in which a canoe can scarcely float in summer, much +less a dredging machine; and any large scoop working under water would +miss the crevices and corners in the rocks, where most of the gold is +found. As the water is very seldom more than a couple of feet deep, a +diving-bell would be of little service. The flume, the ditch, and the +wing-dam, are the chief tasks of the river-miner. The ditch is rarely +used, because the banks of the mining-streams are usually so steep, +high, rocky and crooked, that a flume is cheaper. The wing-dam is not +often used, because the river-beds are in most places too narrow. The +flume is almost universally employed. + +The work of river-mining can be done only during the summer and fall, +while the water is low, and while the miner can have confidence that it +will not rise. It may be as low in January as in August, but the winter +is the season of rains; and when the flood comes, it sweeps dams, +flumes and every thing before it. If the dam and flume be commenced too +early in the season, they may be carried off before they are finished; +and it frequently happens that they are destroyed in the fall just when +the miners are commencing to reap the reward of their summer's labor. + +River-mining has many disadvantages, as compared with other branches of +mining. The miner cannot work at it more than half the year; he cannot +prospect the dirt which is hidden under water; he must erect expensive +dams and flumes, which can be used for only a few months; and then he +is exposed to floods which may come and destroy all his work before he +has commenced to wash. These disadvantages, and the exhaustion of most +of the river-diggings in the state, have almost put an end to +river-mining in California. In a few cases, extensive fluming +enterprises have proved profitable; but, as a general rule, +river-mining in this state has cost more than it has produced. A river +is seldom flumed for less than three hundred yards, and sometimes for a +mile; and the lumber and labor required to make so long a flume, and +one large enough to hold all the water of a river, are very expensive. +The dam will always leak, and water will run into the bed from the +adjacent hills and mountains, and this water must be lifted out by +pumps driven by wheels placed in the flume. The river-beds are full of +large rocks, weighing from one to ten tons, and these must be moved by +machinery, to allow the dirt to be taken out. + +River-mining is now never undertaken by an individual, but always by +large associations, generally called "fluming companies," sometimes +composed of miners exclusively, sometimes of miners and all the +principal business-men living near the place where the work is to be +done. The lawyers, doctors and office-holders, pay their assessments in +cash; the merchants furnish provisions, the lumbermen supply lumber, +and the miners make the dam, and help the carpenters build the flume. + +_Beach-Mining._--Beach-mining is the business of washing the sands of +the ocean-beach. Between Point Mendocino, in California, and the mouth +of the Umpqua River, in Oregon, the beach-sand contains gold, and in +some places it is very rich. The beach is narrow, and lies at the foot +of a bluff bank of auriferous sand. In times of storm, the waves wash +against this bank, undermine it, sweep away the pieces which tumble +down, leaving the gold on the beach. The gold is in very fine +particles, and it moves with the heavier sand, which alters its +position frequently under the influence of the waves and surf. One day, +the beach will have six feet depth of sand; the next, there will be +nothing save bare rocks. The sand differs greatly in richness at +various times: one day, it will be full of golden specks; a few days +later, at the same place it will be barren. The sand in the mean time +has been moved by the waves, and replaced by other sand. + +It is a very difficult matter to know where the sand is rich and where +it is not. The companies employed in mining on the beach number about +ten men; and there is a foreman who rides out early every morning, +following the beach about two miles to the northward and two miles to +the southward of the camp, for the purpose of finding where the sand is +the best. So changeable is the sand, that a new examination is made +every day; and only three or four men are supposed to be good judges of +the quality of sand, from its appearance. + +When the foreman has selected a place, he orders all the men to it, and +they go with twenty pack-mules, which carry the sand in _alforjas_, or +raw hide sacks, to the place of washing, which is up on the bluff, +probably a mile or more distant from the spot where the sand is +obtained. It happens occasionally that the foreman rides long distances +on the beach, and sometimes he will order the sand to be obtained ten +miles from the washing-place. The sand must, of course, be very rich, +to pay for such transportation, but the beach-sand at times in the +sunlight is said to be actually dazzling yellow with gold. The purpose +of going upon the bluff to wash it, is to get fresh water for washing; +for the sea-water is not so good, nor can it be obtained conveniently. +The richest dirt is that the farthest down on the beach, so still +weather and low tide are the best times for getting it. When a rich +place is discovered low down on the beach, great exertions are made to +get as much of the sand as possible before the tide rises. When high +tide and storm come together, little can be done. The sand, having been +separated from all clay and soluble matter by the action of the sea, is +very easily washed, and all collected in a month can be washed in two +days in a sluice. + +_Mining-Ditches._--The placer-mines of California would yield very +little gold, were it not for the numerous ditches which supply them +with water for washing. The auriferous districts are very dry in +summer, and in some places there is not a spring nor a brook within +many miles. The artificial ditch supplies the want. The ditches are +made by large companies, which sell the water by the "inch." An inch of +water is as much as will run out of an orifice an inch square, with the +water standing six or seven inches deep in the flume over the orifice. +The depth of water over the orifice is called the "head." The orifice +is usually two inches high, and as long as necessary to give the amount +of water desired. Nobody wants less than ten or twelve inches for +mining: a "sluice-head" is about eighteen inches; a "hydraulic-head" is +from forty to two hundred inches. The water, however, is not measured +accurately. Of course the amount which runs through the orifice will +depend to a considerable extent upon the "head," which is usually +greater in the morning than at night. At sunrise there may be fifteen +inches head, and at sunset only three. The water collects during the +night, and is exhausted during the day. The price of water is in no +place less than ten cents an inch per day; in some places it is forty +cents; the average is about twenty cents. + +Many of these ditches are extensive enterprises, and have cost hundreds +of thousands of dollars. When they cross ravines and valleys, large +flumes--wonders of carpentry--must be built. Some of these are two +hundred feet high and a mile long, and so large that a horse and waggon +can be driven through them. In all, save length and durability, they +are as wonderful as the great Roman aqueducts, whose tall ruins still +stand in the Campagna, near the Eternal City. In some cases iron tubes +have been used, and although they are very expensive, yet they may pay +for themselves, by preventing evaporation, leaking and soaking, which +take away much of the water from flumes and ditches. + +_Prospecting._--"Prospecting" is the search for gold. The instruments +used by the prospector for placer-mines are usually the pan, pick and +shovel. He should be familiar with the general laws of the distribution +of gold, and then try the dirt in the most favorable places. If there +is any gold in a district, he can scarcely fail to find specks of it by +washing dirt from the bed-rock in the ravines, and in bars. The +existence of gold in a district having been established, close +observation will suggest to the prospector where he may reasonably +expect to find the best diggings. It is usually found that placer-gold +is collected in those places where, if he had been familiar with the +ancient topography of the country, he should have had reason to suppose +that it would be. + +_Quartz Mining._--Quartz mining differs much from placer mining. For +the former, more capital, more experience, more complicated machinery +and richer material are required than for the latter. The placer miner +throws the dirt into the water, which then does the work; whereas the +pulverizing of rock is a nice operation, requiring constant attention. +Quartz requires a mill and water-power; placer dirt is washed in a +simple sluice. Dirt containing ten cents in the cubic yard may pay the +hydraulic miner, but the quartz miner must have a hundred times as much +in a cubic yard of vein stone, or he cannot work. The placer gold, when +freed from the baser material surrounding it, is much of it in coarse +particles, which are easily caught by their specific gravity; the +quartz gold must be reduced to a fine powder before it be set free from +its gangue, and with the fineness of the particles increases the +difficulty of catching them. + +Auriferous quartz lodes are often found by accident. Not unfrequently +it happens that a rich streak of pay-dirt in a placer claim is followed +up to the quartz vein from which it came. While miners are out walking +or hunting, they occasionally will come upon lodes in which the gold is +seen sparkling. Some good leads have been found by men employed in +making roads and cutting ditches. The quartz might be covered with +soil, but the pick and shovel revealed its position and wealth. In +Tuolumne county in 1858, a hunter shot a grizzly bear on the side of a +steep _canon_, and the animal tumbling down, was caught by a projecting +point of rock. The hunter followed his game, and while skinning the +animal, discovered that the point of rock was auriferous quartz. In +Mariposa county, in 1855, a robber attacked a miner, and the latter saw +the rock behind his assailant sparkle in the sunlight, at a spot where +a bullet struck a wall of rock. He killed the robber, and found that +the rock was gold-bearing quartz. In Nevada county, several years ago, +a couple of unfortunate miners who had prepared to leave California, +and were out on a drunken frolic, started a large boulder down a steep +hill. On its way down, it struck a brown rock and broke a portion of it +off--exposing a vein of white quartz which proved to be auriferous, +induced the disappointed miners to remain some months longer in the +state, and paid them well for remaining. Science and experience do not +appear to give much assistance in prospecting for quartz lodes. +Chemists, geologists, mineralogists and old miners, have not done +better than ignorant men and new-comers. Most of the best veins have +been discovered by poor and ignorant men. Not one has been found by a +man of high education as a miner or geologist. No doubt geological +knowledge is valuable to a miner, and it should assist him in +prospecting; but it has never yet enabled any body to find a valuable +claim. + +_Distribution of Gold in Quartz._--The rich quartz-veins of California +extend from Kern River to the Siskiyou, are found on hills, in _canons_ +and in vales. They are at least two thousand feet above the level of +the sea, and not more than ten thousand feet above it. Their course is +generally from north-north-west to south-south-east, and they dip +steeply to the eastward, sometimes being nearly perpendicular. They +differ in thickness from a line to sixty feet. Quartz veins are very +numerous in most of the mining districts, so the task is not to find +the veins, but rather to find those which are gold-bearing. It is +supposed that nearly all large veins come to the surface of the +bed-rock or "country;" but many of them are covered with soil and thus +are hidden. Hidden veins are called "blind;" those plainly visible on +the surface are called "croppings veins," because their position is +shown by the out-croppings. Experience has not ascertained whether +large or small veins are more likely to contain gold. It is found in +both. The porous quartz, or that containing many cavities, is more +frequently found auriferous and richly auriferous, than the very +compact quartz. The best gold-bearing veins are usually yellowish or +brownish in tinge, near the surface at least; but very rich specimens +are found in white and bluish-white rock. Most quartz veins in +California contain a little gold; the metal seems to have been +distributed most lavishly, but unfortunately in nine-tenths of the +veins, the proportion of metal is too small to pay. Most of the large +veins are supposed to run for miles upon miles, though they can rarely +be traced clearly on the surface for more than a furlong. The +auriferous veins vary much in richness. No vein is wrought for more +than a few hundred feet. Beyond that, it is either too poor to pay, or +the vein is hidden. Some persons have supposed that there is one great +gold-bearing quartz vein running along the side of the Sierra Nevada, +from Mariposa to Plumas county, and that many of the richest claims are +really in this one vein; but this a supposition which cannot be proved +now. Sometimes a vein seems to spread out and divide into a number of +smaller veins, all of which afterward unite again. These points of +junction, and the narrower places in the vein, are usually richer than +other parts of it. When two veins cross each other, one may be +auriferous on one side of the intersection and not on the other; but in +this case the other vein will be auriferous on both sides. It is as +though they were streams, one rich, the other barren, and that after +meeting, the wealth of the one was divided between them. It is a +general rule that metalliferous veins running parallel with the strata +of the bed-rock or country are not extensive. In fact they are rather +deposits than veins, and though often extremely rich are soon +exhausted, while the lodes which run across the stratification, run far +and deep, and have a regular and straight course and dip. Lodes lying +between two different kinds of rock, are usually richer than those +which have the same kind of rock on both sides. Thus it is said that +the richest veins of auriferous quartz in California, have been +discovered at the intersection of trap and serpentine, and the richest +places in veins are where they cross from one kind of bed-rock into +another. The richest part of a lode of auriferous quartz is almost +invariably on the lower side of the vein, near the foot-wall. All these +are facts to be remembered by the prospector as a guide, and an +assistance to him in his search for a rich gold-bearing vein. If the +lode is covered with earthy matter, he may sometimes trace its course +by the difference in the color of the dirt and stones over it from that +elsewhere. When the prospector finds dirt and stones on a vein, +evidently disintegrated portions of it, he should wash some of the dirt +in a pan, and if he finds no gold, there is a strong presumption that +the vein is barren. + +_Prospecting Quartz Rock._--After finding a gold-bearing vein, the +question arises whether it will pay. Great sums are lost in gold-mining +countries by injudicious investments in mills and machinery to work the +auriferous rock, and persons going into the business should be +particularly careful not to commit this great error. The business of +quartz mining has great profits, but also great pecuniary dangers +connected with it. It is rarely that all the rock of a vein will pay +for working. In some lodes, the vein-stone will average one hundred +dollars to the ton, for all the stone found in a certain part of the +lode, but beyond that the rock may be poor or worthless. Picked +specimens may be worth several thousand dollars to the ton, but perhaps +not more than a ton of such specimens has been obtained in the best +lode ever opened in the state. The most profitable lodes are those +which have a large supply of rock, easily to be obtained, and all of it +yielding something above the cost of working. The common method of +ascertaining whether rock will pay, is to pulverize a little of it and +wash it in a horn spoon. In taking out the quartz rock in large lodes, +it is important to take out only that which will pay, and to determine +this, the superintendent of the quarry-men must occasionally test the +vein-stone. He takes several little pieces of it, average specimens, +places them on a hard, smooth, flat stone, about a foot square, on +which he crushes them with a stone muller four inches square, and then +by rubbing with the muller he reduces them to a fine powder. He has a +horn spoon, made of a large ox-horn, with a bowl about three inches +wide, and eight inches long, being merely one-half of the horn in its +natural shape. With this spoon he washes out the powder in water, and +if he does not find a speck of gold or a "color," as it is called, in a +pound of the rock, he infers that it will not pay. The three principal +quartz mines in the state are those of Fremont in Mariposa county, of +the Allison company in Nevada county, and of the Sierra Butte company +in Sierra county. The first has produced $75,000 in a month, the second +$60,000, and the third $20,000, but the average is probably thirty per +cent. less, and the expenses about thirty per cent. of the total +product. The average yield of the Fremont rock is fourteen dollars to +the ton, of the Sierra Butte rock eighteen dollars, and that of the +Allison company, according to report, has for more than a year at a +time been one hundred dollars per ton. The cost of working quartz rock, +including quarrying, crushing and amalgamating, is in the best mills +from five to ten dollars per ton. The width of the vein, the softness +of the rock, the amount of work done, and the skill and industry of the +workmen, all are items of great importance in estimating the cost of +quartz-mining. It is a business which the owner of the mill ought to +understand. The cost of quarrying common quartz rock is about two +dollars per ton, that is, for mill-owners that understand the business +and superintend the labor themselves. When given out by the job, it +usually cost more. When quartz is crushed in a custom mill, that is, a +mill built to crush for all applicants, the cost is rarely less than +five dollars per ton, and in Washoe, the price was at one time thirty +dollars per ton; but in the large mills, where many tons are crushed +every day, is about two dollars per ton. + +_The Divining Rod._--In prospecting for auriferous quartz, use is +sometimes made of the divining rod, a practice not without credit with +some good miners. The rod is a fork of a green hazel-bush, shaped like +a V, with the arms about a foot long. The prospector holds the end of +an arm in each hand, with the point of the V directed forward +horizontally, and as he walks along, the point turns down whenever he +comes over a metalliferous vein, metallic body or water. It is supposed +that very few persons can use the divining rod effectually; for most +men it refuses to turn. It is used in nearly every civilized country, +especially by miners, and is generally considered superstitious, +because it is employed by ignorant people, and because there has been +no generally accepted scientific explanation of the manner in which a +stick could be influenced by a metal hidden under ground. A scientific +explanation of the principle of the divining rod has been offered to +the world, by Baron Reichenbach, (see page sixty of his _Odic-Magnetic +Letters_, translated by John S. Hittel). + +_Quarrying Quartz._--The quarrying of quartz rock differs little from +the quarrying of other metalliferous vein-stones. The lode descends +steeply, and the excavation must follow its course. Sometimes the +quartz is so soft that it may easily be loosened with the pick. The +harder rock is blasted. Soft quartz is that which is penetrated by +numerous cavities, though the lumps between the cavities may be very +hard. Some quartz on exposure to the air crumbles into sand, though +hard when first taken from the vein. In narrow lodes, some of the +wall-rock must be cut away to get room for the workmen. In wide lodes, +that part of the vein-stone which does not pay is left. Sometimes the +gold from the lode penetrates a little way into the foot-wall, and in +that case the quarrying must extend beyond the vein stone. The quartz +loosened in the vein, must either be hoisted perpendicularly in a +bucket with a windlass, or be hauled out through a tunnel. The common +method is to hoist the rock with a windlass. Most of the veins are in +such places that shafts are more easily dug than tunnels. After the +excavation has extended twenty or thirty feet below the surface, it is +usual to dig a perpendicular shaft, so as to strike the vein sixty or +seventy feet below the surface, and from this point the miner or +"drifter" works upward, and as he loosens the rock it falls to the +bottom of the shaft, where it is put in the bucket to be hoisted to the +surface. Our quartz mines are generally in dry hills, so that they are +not troubled much by water; but there are a few shafts where +steam-pumps are constantly at work to carry off the water. + +Occasionally the miners find small quantities of auriferous quartz +which are so easily broken up, and the pieces of gold in which are so +coarse, that after the rock has been pounded a little in a mortar, the +metal can easily be picked out with the fingers. + +_Arastra._--Quartz is pulverized either in an arastra, or Chilean mill, +or by stamps. + +The arastra is the simplest instrument for grinding auriferous quartz. +It is a circular bed of stone, from eight to twenty feet in diameter, +on which the quartz is ground by a large stone dragged round and round +by horse or mule-power. There are two kinds of arastras, the rude or +improved. The rude arastra is made with a pavement of unhewn flat +stones, which are usually laid down in clay. The pavement of the +improved arastra is made of hewn stone, cut very accurately and laid +down in cement. In the centre of the bed of the arastra is an upright +post which turns on a pivot, and running through the post is a +horizontal bar, projecting on each side to the outer edge of the +pavement. On each arm of this bar is attached by a chain a large flat +stone or muller, weighing from three hundred to five hundred pounds. It +is so hung that the forward end is about an inch above the bed, and the +hind end drags on the bed. A mule hitched to one arm will drag two such +mullers. In some arastras there are four mullers and two mules. Outside +of the pavement is a wall of stone a foot high to keep the quartz +within reach of the mullers. About four hundred pounds of quartz, +previously broken into pieces about the size of a pigeon's egg, are +called a "charge" for an arastra ten feet in diameter, and are put in +at a time. The mule is started, and in four or five hours the quartz is +pulverized. Water is now poured in until the powder is thoroughly mixed +with it, and the mass has the consistence of thick cream. Care is taken +that the mixture be not too thin, for the thickness of it is important +to the amalgamation. The paste being all right, some quicksilver (an +ounce and a quarter of it for every ounce of gold in the quartz, and +the amount of gold is guessed at from the appearance of the rock) is +scattered over the arastra. The grinding continues for about two hours +more, during which time it is supposed the quicksilver is divided up +into very fine globules and mixed all through the paste (which is so +stiff that the metal does not sink in it to the bottom), and that all +the particles of gold are caught and amalgamated. The amalgamation +having been completed, some water is let in three or four inches deep +over the paste, and the mule is made to move slowly. The paste is thus +dissolved in the water, and the gold, quicksilver and amalgam have an +opportunity to fall to the bottom. At the end of half an hour, or +sooner, the thin mud of the arastra is allowed to run off, leaving the +precious material at the bottom. Another charge of broken quartz is now +put in and the process is repeated, and so on. The length of a "run," +or the period from one cleaning up to another, varies much in different +places. In the rude arastra a run is seldom less than a week, and +sometimes three or four. The amalgam having settled down between the +paving stones, the bed must be dug up and all the dirt between them +carefully washed. In the improved arastra the paving fits so closely +together, that the quicksilver and amalgam do not get down between +them, but remain on the surface, and can readily be brushed up into a +little pan, and therefore cleaning up is much less troublesome and is +more frequently repeated than in the rude arastras; besides there is a +greater need of frequent cleaning up in the improved arastras, because +the amount of work done within a given time is usually greater. + +The arastra is a slow instrument, but in some important respects it is +superior to any other method of working auriferous quartz. It grinds +the quartz well, is unsurpassable as an amalgamator, is very cheap and +simple, requires no chemical knowledge or peculiar mechanical skill in +the work, requires but little power, and very little water--all of them +important considerations. In many places, the scarcity of water alone +is enough to enable the arastra to pay a larger profit than any other +method. Again, if a miner finds a rich spot in a lode, he may be +doubtful as to the amount of paying rock which he can obtain. Such +cases very frequently happen in California, and the arastra is just the +thing for the case; for then if the amount of paying rock is small, +nothing is lost, whereas the erection of a stamping-mill would cost +much time and money, and before it could get into smooth operation the +rich rock would be exhausted, and the mill perhaps become worthless. No +other simple process of amalgamation is equal to that of the arastra; +and it has on various occasions happened in California, that Mexicans +making from fifty to sixty dollars per ton from quartz, have sold out +to Americans who have erected large mills at great expense, with patent +amalgamators, and have not been able to get more than ten or fifteen +dollars from a ton. The arastra is sometimes used for amalgamating +tailings which have passed through stamping-mills. + +_Chilean Mill._--The Chilean mill has a circular bed like the arastra, +but much smaller, and the quartz is crushed by two large stone wheels +which roll round on their edges. In the centre of the bed is an upright +post, the top of which serves as a pivot for the axle on which both of +the stones revolve. A mule is usually hitched to the end of one of the +axles. The methods of managing the rock and amalgamating with the +Chilean mill, are very similar to those of the arastra. The Chilean +mill, however, is rarely used in California; the arastra being +considered far preferable. + +_Stamps._--Nine-tenths of the quartz crushed in California is +pulverized by stamps, of which there are two kinds, the square and +rotary. The square stamp has a perpendicular wooden shaft, six or eight +feet long, and six or eight inches square, with an iron shoe, weighing +from a hundred to a thousand pounds. The wooden shaft has a mortice in +front near the top, and a cam on a revolving horizontal shaft enters +this mortice at every revolution. When the cam slips out of the +mortice, the stamp falls with all its weight upon the quartz in the +"battery" or "stamping-box." The rotary stamp has a shaft of wrought +iron about two inches in diameter, and just before falling this shaft +receives a whirling motion, which is continued by the shoe as it +strikes the quartz. The rotary stamp is considered superior to the +square, its advantage being that it crushes more rock with the same +power, that it crushes more within the same space, and that it wears +away less of the shoe in proportion to the amount of rock crushed. +There are usually half a dozen square stamps or more, standing side by +side in a square-stamp mill, and these do not all fall at the same +moment, but successively, running from the head to the foot of the +"battery." The quartz is put in at the head of the battery, and is +gradually driven to the foot. The rotary stamps sometimes stand side by +side, and sometimes in a circle. The battery of both rotary and square +stamps is surrounded by wire gauze, or a perforated iron plate, +allowing the finely pulverized quartz to escape, and retaining the +coarser particles. Quartz is crushed wet and dry. In wet crushing a +little stream of water runs into the battery on one side and escapes on +the other, carrying all the fine quartz with it. + +_Separation._--After pulverization comes the separation of the gold +from the rocky portion of the powder. The means of separation are +mechanical or chemical. The chemical process is amalgamation; the +mechanical are those wherein the gold is caught on a rough surface with +the aid of its specific gravity. The chief reliance is upon +amalgamation, and in some large quartz-mills mechanical appliances are +not used at all for catching the particles of gold, but only for +catching amalgam. + +The mechanical appliances used in quartz-mills in separating the gold +from the pulverized rock, are the blanket, the sluice, and the raw +hide. + +The blanket is a coarse, rough, gray blanket, which is laid down in a +trough sixteen inches wide and six feet long. The pulverized quartz is +carried over this by a stream of water, and the particles of gold are +caught in the wool. The blanket is taken up and washed, at intervals +depending upon the amount of gold deposited. In some mills where a +large amount of rock is crushed, and where the powder is taken over the +blanket before trying any other process of separation, the washing +takes place every half hour. In mills where the pulverized quartz is +exposed to amalgamation first, the blanket may be washed three or four +times a day. The washing is done in a vat, kept for that especial +purpose. + +The sluice used in quartz-mills is similar to the placer board-sluice, +but the amount of matter to be washed is less, and there is no dirt to +be dissolved, and there are no larger stones, and therefore the sluice +is not so large, so strong, or so steep in grade, as the placer-sluice, +and the riffle-bars are not so deep. In some quartz-mill sluices there +are transverse riffle-bars. If the quartz has much iron or copper +pyrites, the sluice is used to collect this material and save it for +separation at some future time. The pyrites ordinarily contains, or is +accompanied by much gold, which it protects from amalgamation. This +separation of the pyrites from the pulverized rock is called +"concentrating the tailings," and the material collected is called +"concentrated tailings." In the sluices of some quartz-mills cast iron +riffle-bars are used; cast in sections about fifteen inches square, and +about an inch deep. Much study has been devoted to the subject of +making these riffle-bars in such a manner that the dirt will not pack +in them, but will always remain loose, and keep in constant motion +under the influence of the water running over them; but the object has +never been fully attained. Quicksilver is used in nearly all +quartz-mill sluices. + +The raw hide used in separating gold from the pulverized quartz is a +common cow hide, laid down in a trough with the hairy side up, and the +grain of the hair against the course of the water. The gold is then +caught in the hair. Sheep hides have been used in the same manner, +recalling to mind the Golden Fleece. The hides, however, are inferior +to the blankets for this purpose, and are never used in the best mills. + +The methods of amalgamating are numerous. Among them are amalgamation +in the battery, amalgamation with the copper plate, amalgamating bowls, +and patent amalgamation of many kinds. + +In many mills quicksilver is placed in the battery, two ounces of +quicksilver for one of gold; and about two-thirds of the gold is caught +thus. The copper plate in quartz-mills is made in the same manner as in +placer-sluices, under which head a description of the plate may be +found. Some amalgamating bowls or basins are little Chilean mills and +arastras, made of cast iron. One plan of amalgamation is to use a cast +iron bowl about four feet in diameter and a foot deep. Near the bottom +are horizontal iron arms, which revolve and stir the quicksilver and +pulverized quartz together. Four or five of these bowls sit in a row +but at different levels: the bottom of the first bowl being level with +the top of the second, and so on. The pulverized quartz passes through +them all. Under each bowl a fire is kept up, because heat forms the +action of amalgamation. If there be any pyrites in the quartz, some +common salt is thrown in to assist in releasing the gold from the +embraces of the sulphurates, and preparing it to be seized by the +mercury. Another amalgamating bowl revolves on an axis that stands at +an angle of about seventy-five degrees to the horizon, so that the +material in the bowl is continually moving; and the bottom is divided +by little compartments, which make a constant riffle. In other bowls +the pulverized quartz is forced with water through the mercury. The +methods of amalgamation differ very much, and a book might be filled +with a description and discussion of the processes used at different +quartz-mills in California. + +_Sulphurets._--Many auriferous quartz veins contain considerable +quantities of sulphurets or pyrites of iron, copper and lead, and their +presence prevents amalgamation, and thus causes a great loss of gold. +It is said that on some occasions in good mills, not more than twenty +or thirty dollars have been obtained from a ton of vein-stone which had +seven or eight hundred dollars of gold in every ton. The best method of +treating the quartz containing pyrites, is to roast it, and thus drive +off the sulphur, but this process is so expensive that it is seldom +used; and the common practice is to crush and amalgamate the rock, and +save the concentrated tailings for some future time, when there may be +a sale for them, or when it will be cheaper to reduce them. The +pulverized sulphurets are decomposed by exposure to the air, and after +the tailings have been preserved for a time, they may pay better at the +second amalgamation than at the first. A mixture of common salt assists +the decomposition of the pyrites. + +_Chief Quartz-Mills._--The most productive quartz-mill in the state is +the Benton mill, on Fremont's Ranch, in Mariposa county. It is also the +largest, having forty-eight stamps. There are four mills on the estate, +with ninety-one stamps in all, and their average yield per month is +sixty thousand dollars. A railroad four miles long, conveys the quartz +from the lode to the mills. The Allison quartz mine in Nevada county, +produces forty thousand dollars per month. The Sierra Buttes +quartz-mill, twelve miles from Downieville, yields about fifteen +thousand dollars per month. These last mills run night and day, and +crush and amalgamate ten thousand tons of rock a year, or twenty-eight +tons per day. Forty men are employed, twenty-five to quarry the rock, +five in the mill to attend to the stamps and amalgamation, one to do +carpentry, one for blacksmithing, and eight for getting out timber, +transporting quartz, and so forth. The cost of quarrying, crushing and +amalgamating a ton of rock, is six dollars. The wages of the men are +from fifty to seventy dollars per month with boarding. The average +wages is sixty dollars. About ten miles eastward of Sonora, in Tuolumne +county, are some rich veins of auriferous quartz, the most prominent of +which are the Soulsby and Blakeslee lodes. The Soulsby mill produced +forty thousand dollars in three weeks, when it commenced work in 1858, +but it has not been so profitable of late. + +_Silver Mining._--Silver mining has not yet been established fairly as +a business in California. The silver ores of Washoe were discovered in +1859, and mining has been fairly commenced there, but the mines of +Esmeralda and Coso, within the limits of this state, were not found +until the summer of 1860, and up to the present time no mills have been +established there. + +Silver mining differs much from gold mining. Gold is always found as a +metal, never as an ore, and the separation from the accompanying +vein-stone with which it is mixed mechanically, is much more simple and +easy than the reduction of the argentiferous ores in which the silver +is chemically combined with base substances, for which it has a strong +affinity. Chemical knowledge and chemical processes are more necessary +in mining for silver than for gold; and while all auriferous quartz is +of the same kind, and may be treated in the same manner, there are many +different kinds of silver ores, each of which requires a peculiar +treatment. The reduction of silver ore costs on an average, from three +to five times as much as the reduction of auriferous quartz. + +The silver ore of Esmeralda and Coso is a sulphuret of silver, nearly +all the veins having the same material, though the amount of it +scattered through the vein-stone differs greatly in different lodes. In +some veins there is much free gold, that is, little specks of metallic +gold which can be separated from the other material in the same manner +that gold is separated from auriferous quartz. The methods of reducing +silver ore are so numerous and complex, and vary so much in different +districts and under different circumstances, that it is impossible to +know now what process will be used in Esmeralda and Coso, the resources +of which places have been so little studied. Besides it is said that +new processes for reducing silver ore have been invented, far superior +to all the old methods; and these processes are kept secret. It is +therefore unnecessary that I should go into a long description of the +various processes practised elsewhere. Silver ore after pulverization +is smelted by mixing with it fifty per cent. of lead in metal or ore, +and ten per cent. of iron, and exposing the whole to a heat sufficient +to melt the silver which runs off. The metal thus obtained is not pure +but contains much lead, which is driven off by heat while the silver is +kept in a molten condition for a period of four or six hours. The cost +of smelting in California at present, is about one hundred and +twenty-five dollars per ton. In most of the other methods of reducing +silver ore, the ore is roasted to drive off the sulphur. In the barrel +amalgamation, which has been used at Washoe, and will probably be used +at Esmeralda also, half a ton of ore, after being pulverized and +roasted, three hundred pounds of water, and one hundred pounds of +wrought iron, in little fragments, are put into a barrel, which +revolves on a perpendicular axis. At the end of two hours the mass has +taken the consistence of thick cream, when five hundred pounds of +quicksilver are put in, and after the barrel has revolved four hours +more, the amalgamation is complete. More water is now poured in; the +barrel revolves very slowly to let the amalgam all settle to the +bottom, the mud runs off through a cock four inches above the bottom, +and the mercury and amalgam are then drawn off through a little hole in +the bottom of the barrel. + +_Quicksilver Mining._--The ore from which quicksilver is obtained is a +sulphuret. The sulphur is driven off by heat, and the metal, which +rises in fumes from the ore, is collected by condensation. The miners +are Cornishmen and Mexicans. The ore is in large masses underground, +not in a connected vein of regular thickness; and after one mass is +exhausted, much labor is often vainly spent in search of another. There +are, however, usually little seams of ore running from one large +deposit to another, and it is the business of the mining captains to +observe these veins closely, and trace them up when a "fault" occurs. +There are no scientific rules for finding the ore; and the business of +searching for the large deposits is never intrusted to educated mining +engineers, but always to mining captains, who have themselves been +laborers, and have learned by experience where to seek. The New Almaden +mine produces two hundred and twenty thousand pounds of metal in a +month. The _hacienda_, or reducing establishment of the mining company, +has fourteen brick furnaces, each fifty feet long, twelve feet high, +and twelve feet wide. At one end of each furnace is the fire chamber, +which may be nine cubic feet inside; next to that is the ore chamber of +about the same size; and beyond that is the condensing chamber, in +which there are a number of partitions alternately running up from the +bottom and down from the top, with a space for the fumes to pass, their +course being up and down, and up and down again, and so on, for a +distance of thirty feet to the chimney, which is forty feet high. In +the bottom of the condensing chamber is water. The walls between the +fire chamber and the ore chamber, and between the latter and the +condensing chamber, are built with open spaces, so that the heat, smoke +and fumes can pass through. The ore is placed in the ore chamber in +such a manner as to leave many open spaces. The heat drives off the +sulphur and mercury of the ore in fumes, which in passing through the +condensing chambers, deposit the mercury, and the smoke and sulphur +escape through the chimney. In the Enriqueta and Guadalupe mines the +quicksilver is condensed in a close iron retort, and the sulphur is +absorbed by quicklime. + +Copper ore is dug from several mines in California, but it is all +exported to be smelted elsewhere. + +_Platinum._--Platinum, iridium and osmium, three white metals of about +the same specific gravity with gold, are found with the latter metal in +the placers in the basin of the Klamath and Trinity Rivers. Their +particles are usually fine scales, very rarely reaching a quarter of an +ounce in weight, and the largest piece of either ever found was less +than an ounce and a half. They cannot be separated from the gold by +washing, but they do not unite with quicksilver, and therefore they are +separated from the more precious metal by amalgamation. They have no +regular market in the state; miners never make them the chief object of +search, and they have not been studied, so it is not known to what +extent they might be obtained. + +_Del Norte and Klamath._--Del Norte county in the north-western corner +of the state, is about forty miles long from east to west by thirty +from north to south. The mining population in it is small. Most of the +mining is done along the banks of the Klamath River, which runs about +twenty miles through the south-eastern portion of the county. There are +some miners on the head-waters of Althouse Creek, which runs northward +into Oregon. The county assessor, in his report for 1860, does not +mention the existence of any quartz-mill or mining-ditch in the county. +The mining districts are very mountainous and difficult of access. They +obtain most of their supplies from Crescent City. The mining is chiefly +in shallow placers, in deep and narrow ravines, and on bars of the +Klamath River. + +Klamath county lies immediately south of Del Norte, and is about the +same size. It is almost exclusively a mining county, and has a +population of about eighteen hundred. The diggings are placers in the +bars and banks of the Klamath River and its tributaries, the Trinity +and Salmon Rivers, and many small creeks. The principal mining places +are Orleans Bar, Gullion's Bar, Negro Flat, Cecilville, Weitspeck and +Red Cap. The whole county is very rugged and mountainous, and much of +it is covered with heavy timber. The diggings are so difficult of +access, and are so protected by mountains against ditches, that they +will last for many years. There is probably no part of the state where +the single miner, without capital, has a better chance to dig gold with +a profit. Nearly the whole beach of the county is auriferous. + +_Siskiyou._--Siskiyou county lies east of Del Norte and Klamath, is +forty miles wide from north to south, one hundred miles long from east +to west, and reaches to the eastern boundary of the state. It has a +population of 7,629, the large majority of whom are engaged in mining. +The mining district is all in the western end of the county, along the +banks of the Klamath River and its tributaries, the Scott and Shasta +Rivers. The Klamath runs through a deep _canon_; the Scott and Shasta +Rivers, have pleasant open valleys, but the diggings along their banks +are chiefly among the _canons_ near the Klamath. Hydraulic and tunnel +claims are rare. There are six quartz-mills in the county, and fifteen +mining ditches, of which last the principal is the Yreka canal, forty +miles long, bringing water from the head of Shasta River to the town of +Yreka. In 1859, there were four quartz-mills in the county, one of +which was at Mugginsville, one in Scott's valley and two in Quartz +valley. I have no information about the situation of the two built +since that time. The principal mining towns are Yreka, Scott's Bar, +Hawkinsville, Johnson's Bar, Deadwood and Cottonwood. + +_Trinity and Shasta._--South of the western part of Siskiyou and the +eastern part of Klamath, lies Trinity county, ninety miles long from +north to south, and about twenty miles wide on an average. The northern +part of the county is the basin of the Trinity River, and is +auriferous. From the county assessor's report for 1860, it is to be +inferred that there is not a quartz-mill or a mining-ditch in the +state. The county is very mountainous, and most of the mining is done +in rugged _canons_ along the Trinity River. The chief mining towns are +Weaverville, Cox's Bar, Big Bar, Arkansas Flat, Mooney's Flat and +Trinity Centre. + +South of Siskiyou and east of Trinity lies Shasta county, which is on +an average forty miles wide from north to south and one hundred miles +long, reaching to the eastern border of the state. There is a rich +auriferous district about twenty miles square, in the vicinity of the +town of Shasta, in the south-western part of the county. The diggings +are mostly in the basins of Clear Creek, Cottonwood Creek, Rock Creek +and Salt Creek, all of which enter into the Sacramento. There are four +quartz-mills in the county, one at French Gulch, one at Middle Creek, +one at Muletown, and one at Old Diggings. The county has twenty-seven +mining ditches, with a joint length of one hundred and forty-one miles, +an average of five miles each. The chief mining towns are Shasta, +Horsetown, French Gulch, Muletown, Briggsville, Whiskey and Middletown. + +_Plumas and Sierra._--South of the eastern part of Shasta county lies +Plumas, which is about seventy miles square. About one third of the +county, in the south-western part of it, comprising that portion +drained by the head waters of Feather River, is auriferous. It lies +high above the level of the sea, and the work of mining is interrupted +during a considerable portion of the winter, by cold, snow and ice. +Hydraulic and tunnel claims in deep hills, furnish a large portion of +the gold yield of the county. There are five quartz-mills, one at +Elizabethtown, one at Eureka Lake, and three at Jamison Creek. The +principal mining towns are Quincy, Jamison City, Indian Bar, Nelson's +Point and Poorman's Creek. + +South of Plumas is Sierra county, which is fifty miles long from east +to west, and twenty miles wide from north to south. The North Fork of +the Yuba River runs through its centre, and the Middle Fork is its +southern boundary. Though small, it is one of the richest mining +counties of the state, and in proportion to the extent of its mining +ground, is much richer than any other county. All its territory is four +thousand feet above the sea level, at the lowest. Most of the mining is +done in hydraulic and tunnel claims in deep hills. Near the centre of +the county is a mountain called the Downieville Butte, or the Yuba +Butte, eight thousand eight hundred and forty-six feet high, on the +sides of which are found some rich quartz leads. In 1859 there were +eleven quartz-mills in Sierra county, of which seven are at the Butte, +two at Downieville, one at the Mountain House, and one at Sierra City. +The principal mining towns are Downieville, Monte Cristo, Pine Grove, +St. Louis, La Porte, Poker Flat, Eureka City, Forest City, Alleghany +Town, and Cox's Bar. One of the most remarkable features of the placers +of the state, is the blue lead, which was first discovered in Sierra +county, and has been more thoroughly examined there than elsewhere. The +"blue lead" is a stratum of blue clay very rich in gold. It is found +deep under other strata. The general opinion is, that the blue lead +occupies the bed of a large antediluvian river, which ran parallel with +the Sacramento and about sixty miles eastward of it. It has been traced +twenty miles or more, passing near Monte Cristo, Alleghany Town, Forest +City, Chip's Flat and Zion Hill. Mr. C. S. Capp wrote thus to the San +Francisco _Bulletin_: + +"This is not one of the many petty leads, an inch or two in breadth and +thickness, which, after being traced a few hundred feet, end as +suddenly and mysteriously as they commence; but it is evidently the bed +of some ancient river. It is often hundreds of feet in width, and +extends for miles and miles, a thousand feet below the summits of high +mountains, and entirely through them. Now it crops out where the deep +channels of some of the rivers and ravines of the present day have cut +it asunder; and then, hidden beneath the rocks and strata above it, it +only emerges again miles and miles away. Wherever its continuity has +been destroyed, the river or gulch which has washed a portion of it +away, was found to be immensely rich for some distance below, and the +materials of which the lead is composed are found with the gold in the +bed of the stream. It is evidently the bed of some ancient stream, +because it is walled in by steep banks of hard bed-rock, precisely like +the banks of rivers and ravines in which water now runs, and because it +is composed of clay which is evidently a sedimentary deposit, and of +pebbles of black and white quartz, which could only be rounded and +polished as they are by the long continued action of swiftly running +water. The bed-rock in the bottom of this lead is worn into long smooth +channels, and also has its roughness and crevices like other river +beds. The lighter and poorer qualities of gold are found nearest to its +edges, while the heavier and finer portions have found their way to the +deeper places near the centre. Trees and pieces of wood, more or less +petrified and changed in their nature, which once floated in its +waters, are also every where encountered throughout this stratum. + +"The clay and fine gravel in which these pebbles and boulders are found +to be tightly packed, is of a light-blue color, which gives the name to +the lead. Much of this clay is remarkably fine and free from coarse +particles, and is smooth and unctuous to the touch. It is said to be +strongly impregnated with arsenic, as was shown by chemical analysis, +and contains large quantities of iron and sulphur in solution, for +pyrites and sulphurets of iron are deposited in shining metallic +crystals in every vacant crevice. Fine gold is found among this clay, +and the heavier particles beneath it, upon the bed-rock. This stratum +varies in thickness from eighteen inches to eight or ten feet, while +the whole lead varies in width from a hundred and fifty to five hundred +feet. + +"The same lead has been found at Sebastopol, four miles above Monte +Christo, and also higher up among the mountains. It appears at Monte +Christo, which is four miles above the high-lying Downieville, and over +three thousand feet above it, and at Chapparal Hill on the side of a +deep ravine; then at the City of Six, which is also on very high land, +about four miles from Downieville, across the North Yuba. It is next +found at Forest City, on both sides of a creek, and is there traced +directly through the mountain to Alleghany Town and Smith's Flat, on +the opposite side. There it is again cut in twain by a deep ravine. It +crops out on the other side at Chip's Flat, where it has been followed +by tunnels passing completely through the mountain to Centreville and +Minnesota on the other side. Here it is obliterated by the Middle Fork +of the Yuba, but it is believed to be again found at Snow Point, on the +opposite side of the river, and again at Zion Hill, several miles +beyond. There is no reason for doubting that after thus reaching over +twenty miles, it still extends further. Hundreds of tunnels have been +run in search of it. Where the line it follows was adhered to, they +have always found it, and have been well rewarded for their labor. +Millions of dollars have been taken from this lead, and its richness, +even in portions longest worked, is yet undiminished. These tunnels +have cost from $20,000 to $100,000 each, and interest in the claims +they enter sell readily at from $1,000 to $20,000, in proportion to the +amount of ground within them remaining untouched, and the facilities +which exist for working it. Many of these claims will yet afford from +five to ten or more years' profitable labor to their owners, before the +lead itself within them is exhausted. As in some of them quartz veins +and poorer paying gravel have been found, many of them may be valuable +to work from the top down as hydraulic claims." + +This idea that the blue lead occupies the bed of an antediluvian river +is however not universally accepted. Mr. B. P. Avery, who has written +numerous newspaper articles upon the mineral deposits, asserts that the +"blue lead," as it is called, is not a "lead" but an extensive stratum +which is many miles wide, and is found all the way from the foot hills +to the summit of the Sierra Nevada. In reply to this, it is said that +while a bluish stratum of clay similar to that of the blue lead is +found over a wide district, that it is evidently different in origin +from the blue lead itself, which is confined to a narrow bed, and +marked by the signs found in all the other ancient river beds of the +state. + +The Sierra Butte Quartz Mining Company has some of the best auriferous +quartz lodes in the state. One lode called the Cliff Ledge, is +twenty-five feet wide; and another called the Aerial Ledge, is about +three feet wide. In the Cliff Ledge, the paying rock averages about six +feet in thickness next the foot wall. The average yield is eighteen +dollars per ton. The quartz is bluish white in color, and very hard +when first taken from the lode, but on exposure to the air it slowly +crumbles into sand. + +_Yuba and Butte._--West of Sierra county, and drained by the same +streams, is Yuba, which reaches to the Sacramento River, lying half in +the mountains and half in the plains, the mining district being in the +former half. The principal mining towns are Camptonville, Timbuctoo, +Foster's Bar, Texas Bar and Long's Bar. In 1859 there were nine +quartz-mills in the county, three at Brown's valley, and one each at +Camptonville, Dobbin's Ranch, Dry Creek, Honcut, Indiana Creek and +Robbin's Creek. The assessor in 1860 reported only two quartz-mills in +the county. There are twenty-two ditches in the county, with an +aggregate length of nine hundred and fifty-two miles, an average of +forty-three miles each. The most important ditch, called "Bovyer's," +supplies Timbuctoo with five thousand inches of water in the winter, +less in the summer. The diggings at Timbuctoo are in a deep hill, which +is washed away by the hydraulic process. + +West of Yuba and Plumas counties lies Butte, which is drained by the +Feather River. The principal mining towns are Oroville, Bidwell's Bar, +Forbestown, Natchez and Whiterock. In 1859 there were seventeen +quartz-mills in the county, of which four were at Oregon Gulch, at +Columbiaville and Hansonville, three each, two at Yankee Hill, and at +Evansville, Gold Run, Long Bar, Nesbitt's Flat and Spring Valley, one +each. The assessor reports for 1860, twenty-nine quartz-mills, worth +fifty thousand dollars, and crushing in the aggregate one hundred and +sixty-two and a half tons per day. There are sixty-four mining-ditches, +with an aggregate length of five hundred and eighty-three miles. The +bars and beds of Feather River were once very rich, and some of the +most extensive enterprises of river mining in the state have been +undertaken within the limits of Butte county. The greatest flume ever +built in California was that of the Cape Claim Company, near Oroville, +in 1857. It was three quarters of a mile long and twenty feet wide, and +furnished employment for two hundred and fifty men from May till +November. The expenditures during that period were $176,985, and the +receipts $251,426, showing a clear profit of $74,441. The next year, +after the water had fallen, the company commenced its labors again; +spent $160,000 and received $115,000, and thus lost $45,000. North of +Oroville is a "table-mountain" with a top of basalt, covering a rich +deposit of auriferous clay. + +_Nevada and Placer._--South of Yuba and Butte is Nevada, the richest +mining county of the state. Within its limits the tom, sluice, +under-current sluice, and crinoline hose were invented, and the ditch +and hydraulic power were first applied to placer-mining; and +quartz-mining was first undertaken extensively. In 1859 there were +thirty-two quartz-mills in the county, and twenty-eight mining-ditches, +with an aggregate length of three hundred and ninety-four miles. No +part of the mineral region of the state is better supplied with water +than Nevada county. The richest quartz district is in the vicinity of +Nevada City, which has fifteen mills, and Grass Valley, five miles +distant, has seventeen. The great Allison mine, which has the richest +lode in the state, is in Grass Valley. + +The quartz mines here are much troubled with water, and during the +winter of 1860-61, many of the mills were compelled to stop for weeks +until the shafts could be drained by steam engines, after having been +filled by a long and heavy rain. The annual gold yield of Grass Valley +has been estimated at four millions of dollars. North San Juan has the +finest hydraulic claims, and Sweetland the largest tail-sluices. The +Eureka Lake Ditch Company has more ditching and water than any other +company in the state. Their main ditch is seventy-five miles long, and +there are one hundred and ninety miles of branches, making a total of +two hundred and sixty-five miles, which have cost nine hundred thousand +dollars. The daily sale of water is six thousand inches, with a weekly +income of six thousand dollars. The principal mining towns are Nevada, +Grass Valley, North San Juan, Rough and Ready, Orleans Flat, Moore's +Flat and Humbug City. + + + + +INDEX. + + + PAGES. + +Chief Industry 3 + +Metals obtained 3 + +Gold Mines 3 + +Placer Mines 5 + +The Sluice 7 + +Amalgamation 9 + +Cleaning up 11 + +Riffle-Bars 12 + +Double Sluices 13 + +Rock-Sluices 13 + +Hydraulic Mining 14 + +Blasting 16 + +Tail-Sluice 16 + +Tunnel-Sluice 17 + +Ground Sluice 17 + +Long Tom 17 + +Cradle 18 + +Pan 20 + +Dry Washing 22 + +Dry Digging 22 + +Puddling-Box 22 + +Quicksilver-Machine 23 + +Tunnel-Mining 23 + +Shafts 24 + +River-Mining 24 + +Beach-Mining 26 + +Mining-Ditches 27 + +Prospecting 27 + +Quartz-Mining 27 + +Distribution of Gold in Quartz 28 + +Prospecting Quartz Rock 30 + +The Divining Rod 31 + +Quarrying Quartz 31 + +Arastra 32 + +Chilean Mill 34 + +Stamps 34 + +Separation 34 + +Sulphurets 36 + +Chief Quartz-Mills 36 + +Silver Mining 37 + +Quicksilver Mining 38 + +Platinum 39 + +Del Norte and Klamath 39 + +Siskiyou 40 + +Trinity and Shasta 40 + +Plumas and Sierra 41 + +Yuba and Butte 43 + +Nevada and Placer 44 + + + + + + +End of Project Gutenberg's Hittel on Gold Mines and Mining, by John S. 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