Mining mill

“ Mining operations are more susceptible of mechanical improvements than agricultural: the first great application of the steam-engine was to mining; and there are unlimited possibilities of improvement in the chemical processes by which the metals are extracted. There is another contingency, of no unfrequent occurrence, which avails to counterbalance the progress of all existing mines toward exhaustion: this is, the discovery of new ones, equal or superior in richness. ”

“ Mill of the Pittsburg-Silver Peak Gold Mining Co., Blair, Nevada.
Water may be too scarce for the needs of a mine or its community. There may not be sufficient to supply boilers or a mill, or for the domestic purposes of the [89] workers. On the other hand, water may be so abundant in the mine workings as to prove a deterrent factor in profitable operation. With shaft mines, having deep workings and low grades of ore, if water must be delivered mechanically, the costs for such drainage are frequently prohibitive of mining. ”

“ Mining industry, for example, usually yields an increase of produce at a more than proportional increase of expense. It does worse, for even its customary annual produce requires to be extracted by a greater and greater expenditure of labour and capital. As a mine does not reproduce the coal or ore taken from it, not only are all mines at last exhausted, but even when they as yet show no signs of exhaustion, they must be worked at a continually increasing cost ”

“ We soon began crushing the piles of quartz that had been taken out during the winter by various miners, and tried our own rich-looking black stuff from the Keystone. The mill was run day and night. I took charge from midnight till noon and Stubbs from noon till midnight. None of the rock was found rich enough to pay for mining [Pg 94] and milling. That tried in one or two other mills was no better. General discouragement followed, and everybody stopped mining in our gulch. Some went to work for wages in other mines, to get a fresh supply of provisions, etc. ”

“ The various grades of mill fiber may be produced only where mills are located at or near the mines. As the utilization of all grades can be accomplished only with the assistance of mills, such mills are necessary for efficient mining. ”

“ This is neither milling, metallurgy, nor ore dressing, but is more properly called Sorting. It is one of the operations connected with mining. Milling may be either ore dressing or metallurgy.
In the operations of placering, there is a simultaneous excavation of a deposit and an extraction of the valuable contents. In this case, shall we call the process mining or metallurgy? If it is a gold [15] placer, one may see the recovery of the metallic values. Here, the usage of the majority of practical mining men will uphold us in always speaking of the work as mining. ”

“ A small mill on a large mine, under rapid development, will result in extensive ore-reserves, while a large mill eating away rapidly on the same mine under the same scale of development would leave small reserves. On the above scheme of valuation the extension in depth would be worth very different sums, even when the deepest level might be at the same horizon in both cases. ”

“ Probably more mines have been ruined by bad mill management than by bad mining, though every experienced man must have seen in his time many most flagrant instances of bungling in the latter respect. Shafts are often sunk on the wrong side of the lode or too near or too far away therefrom, while instances have not been wanting where the (mis) manager has, after sinking his shaft, driven in the opposite direction to that where the lode should be found. ”

“ These mines, with their prolonged subterranean workings, their stamping and crushing mills, and the smelting works which have been established near them, fill the district with noise, hubbub, and smoke by night and day; but I had turned altogether aside from them into a still region, where each miner in solitude was grubbing for himself, and confiding to none his finds or disappointments. Agriculture restores and beautifies, mining destroys and devastates; turning the earth inside out, making it hideous, and blighting every green thing, as it usually blights man's heart and soul. ”

“ These deposits are naturally the first to fail in productiveness, but the neighboring hills are formed of a gold-bearing quartz which is being crushed, night and day, by hundreds of powerful machines; and the works still pay ten thousand miners fair day-wages, besides giving the organized companies who employ them satisfactory dividends. Thus mining has been largely robbed of its adventurous character in this neighborhood, and perhaps also of most of its alluring charm, having become a sort of regular industry, like coal-mining, or even brick-making. ”

“ Wooden booths flung signs to the streets bigger than the booths themselves: "Mineral Companies Promoted," "Mining and Smelting," "Mines, Options, Leases,"—there was no end to the variations of the eternal theme of mining. Town lots, switches of flats, and hill ridges were being swapped and sold and leased from the curb-stone; leases were being made from buggies and options were being granted from a horse's back. ”

“ Large areas, although so popular in England, do not compensate for large bodies of payable ore; the most remunerative mine is generally one of comparatively small area, but containing a large lode formation of payable, but often low grade, ore.
It is worse still, of course, to buy a practically worked out mine, though this too is sometimes done. It must be remembered that mining, though often so profitable, is nevertheless a destructive industry, thus differing from agriculture, which is productive, and manufactures, which are constructive. ”

“ An ore must be an aggregate or association of natural [20] minerals, or a single mineral, from which metal may be profitably recovered. Mines are excavations in the earth from which ore, coal or gems are taken. Mining is the art or practice of operating mines.
Throughout the subject, we see the inseparable idea of profit. The work of carrying on operations in a railroad tunnel is not mining; the driving of adits through barren rocks to reach ore bodies is not mining; the sinking of shafts through worthless "wash" or rocks with a view of opening avenues for the removal of ore is not mining. ”

“ The want of capitalists in the mine country, and of practical skill in the boring, blasting, sinking shafts and galleries, oppose obstacles to the [Pg 160] successful progress of mining. There is but one regular hearth-furnace for smelting in the whole district; and that is on the modern plan of English furnaces. There are not over four or five regular shafts in about forty mines; there is not an engine, either by horse, steam, or water power, for removing water from the mines, several of which have been abandoned on this account, with rich prospects of ore in view. ”

“ The miner should never excavate the low-lying plain, nor one which is perfectly level, unless it be in some mountain, and rarely should he mine in the other kinds of plains.
With regard to the conditions of the locality the miner should not contemplate mining without considering whether the place be covered with trees or is bare. If it be a wooded place, he who digs there has this advantage, besides others, that there will be an abundant supply of wood for his underground timbering, his machinery, buildings, smelting, and other necessities. ”

“ Having considered the accepted definition of a mine, let us now extend our reasoning a little and inquire just what is meant by mining. At first thought, one would say that mining is, in a broad sense, the art or practice of excavating, at a profit, the ores of metals, the beds of coal, the gravels of placers and the deposits containing precious stones. Are we justified in letting this definition stand as it is? If we do not make any change, we must exclude all quarries, sand banks, clay pits, and the numerous sorts of works that are producing the non-metallic minerals of commerce. ”

“ Not so with silver and gold mines. They are most unreliable in both quality and quantity. Costly buildings and machinery are often erected to economize the mining of the ore, only to find no mine to operate by the time the buildings are completed and the machinery is working. ”

“ When they stepped off the car Alice exclaimed, “This looks exactly like a picture of a mining town that’s in my geography!”
“Of course it is,” laughed Uncle Will, “because this is a mining town. All the mining isn’t done in the West you know. The iron ore and the coal for the furnaces35 are mined right here on the spot—that’s the reason these mills are just where they are, my dear.” ”

“ Indeed, this system of mining partakes of the nature of quarrying rather than that of mining in the ordinary sense, the ore being scooped from the surface of the ground. One naturally thinks of a mine as being subterranean; but in the great open-pit mines in the Lake Superior region, which are the largest mines in the world, all the mining is done at the surface of the earth. ”

“ The miner should try to obtain a mine, to which access is not difficult, in a mountainous region, gently sloping, wooded, healthy, safe, and not far distant from a river or stream by means of which he may convey his mining products to be washed and smelted. ”

“ The ore as taken from the mine concentrates four tons into one, which has a gross value of one hundred dollars, and with the first concentrator, whose capacity was one hundred and twenty tons daily, returned three thousand dollars per day to the owners. The company employ one hundred and fifty men, and are well equipped for profitable mining. ”

“ A mine thus consists of a series of horizontal galleries generally one above the other, but sometimes running parallel, traversed at irregular intervals by vertical shafts, and all communicating together, either directly or indirectly.
A person unacquainted with the details of mining, on hearing of many hundreds of men employed in a single mine, might naturally imagine that a visit to its recesses would afford a picturesque and imposing spectacle of gregarious labour and bustle, tremendous noise, and much artificial brilliancy to cheer the gloom. ”

“ Mining may be said to begin whenever there is produced an output upon which there is some profit. Exploitation may be in valuable ground. If so, we may say that mining is in progress during the exploitation. The driving of levels or drifts in an ore body—or of entries in a bed of coal—produces the valuable products of the mine, and we may, therefore, consider that mining is taking place.
The driving of a crosscut through barren rock to reach an ore body is dead work; but the driving of a drift or level in a vein is either exploitation or mining. Dead work produces no ore. ”

“ It is not my intention to detract anything from the dignity of agriculture, and that the profits of mining are less stable I will always and readily admit, for the veins do in time cease to yield metals, whereas the fields bring forth fruits every year. But though the business of mining may be less reliable it is more productive, so that in reckoning up, what is wanting in stability is found to be made up by productiveness. Indeed, the yearly profit of a lead mine in comparison with the fruitfulness of the best fields, is three times or at least twice as great. ”

“ It is becoming more and more important for the active mining man to post himself upon the methods and economies of this latter-day mining practice. The development of this open or surface mining has introduced entirely new economic ideas. With no costs for timbering of mine passages, for ventilation, or for hoisting, and with a very material decrease in manual labor per ton mined, immense masses of rocks are now really ore, although a few years ago they were nothing but lean, country rock. ”

“ After a mine is once opened and preparations have all been perfected to operate [106] upon a certain scale of output, it is quite essential that exploitation and production be maintained without material fluctuations, if the greatest economy is to be attained. Exploitation, i.e., development work, must be kept well in advance of actual mining operations to assure plenty of working space for the extraction of the normal output. ”

“ In this the stoping contracts run vertically, and each party of contractors has one or more mills or timbered chutes through which the rich ore is conveyed to the level below and loaded in cars. The ore as mined is hand-picked and the barren material allowed to remain in the stope where it falls. In this method of mining no pillars need be left under the levels, as the rock-filling gives sufficient support to the roof. This method of mining affords the maximum of safety to the miners. ”

“ The facilities offered by the system of cross workings for disposing of the rubbish, most frequently a nuisance to the miner, and expensive to get rid of, the solidity which it procures by the banking up, the consequent economy of timbering, and saving of expense in the excavation of the rock, reckoning from the second story, are so many important circumstances which recommend this mode of mining. ”

“ Since the first discovery of lead in this Territory, the number of mines has been much increased, and hardly a season passes without some new discovery. Every discovery of importance soon becomes the centre of mining attraction. As the ore is found in the diluvial soil, it is generally exhausted on reaching the solid rock; and after penetrating a considerable area of the surface with any, or but partial success, the locality is abandoned, and a new one sought. As the mines are worked without capital, and the ore is dispersed over a wide area, the number of localities is almost indefinite. ”