Chapter 4

_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.