dissabte, 29 d’agost de 2015

THE WARS OF IF ...THERE WILL BE BLOOD SOMEWHERE SOMEHOW DOCTOR WHO SAYS YES..... THE A B C OF MINING A Handbook for Prospectors Treating fully of Exploratory and Preparatory Work of the Physical Properties of Ores, Field Geology, the Occurrence and Associations of Minerals, Methods of Chemical Analysis and Assay, Blow-pipe Tests, Promising Indications, and Simple Methods of Working Valuable Deposits, together with Chapters on Quartz and Hydraulic Mining and especial Detailed Information on Placer Mining, with an Addenda on Camp Life and Medical Hints. BY CHARLES A. BRAMBLE, D.L.S., Late of the Editorial Staff of "The Engineering and Mining Journal," and formerly a Crown Lands and Mineral Surveyor for the Dominion of Canada. ILLUSTRATED. Chicago and New York: RAND, McNALLY & COMPANY, PUBLISHERS. Copyright, 1898, by Rand, McNally & Co. Many men seem to think that should their destinies lead them into parts of the world where there is mineral wealth they will have little chance of discovering the deposits without the technical education of a mining engineer. This is wrong. The fact is that the sphere of the prospector does not cover that of the engineer. The work of the one ends where that of the other begins, and many of the most successful discoverers of metallic wealth have been entirely ignorant of the methods by which a great mine should be opened, developed, and worked. A few simple tools and a not very deep knowledge of assaying, with an observant eye and a brain quick to deduce inferences from what that eye has seen, are the most valuable assets of a prospector. In time he will gain experience, and experience will teach him much that he could not learn in any college nor from any book. Each mining district differs from every other, and it has been found that certain rules which hold good in one region, and guide the seeker after wealth to the hidden treasure that has been stored up for eons of time, do not apply in another region. To show what may be done with imperfect, improvised apparatus, an Australian assayer, who has since become famous, started up country in his youth with the following meager outfit: A cheap pair of scales, a piece of cheese cloth, a tin ring 1½ inches by ½ inch, a small brass door-knob, some powdered borax, some carbonate of soda and argol, a few pounds of lead lining taken from a tea chest, an empty jam pot, a short steel drill, a red flower pot. With this modest collection of implements he made forty assays of gold ores that turned out to be correct when repeated in a laboratory. About the best advice that can be given to a man who has determined to go to some out of the way region where there is a possibility of his discovering minerals is to recommend him to visit the nearest museum and gain an acquaintance with the common rocks. Should he be unable to do this he had better provide himself with small, inexpensive specimens from the shop of some dealer. It is almost impossible to teach a beginner to distinguish the various rocks by any amount of printed instruction; the only way to learn to recognize them is to handle them and note carefully their color, weight, and the minerals that go to make them up. The explorer should be able to recognize at a glance, or at any rate after a very short inspection, the sedimentary rocks, such as sandstone and limestone; the metamorphic rocks, that is, rocks that have been altered by the agency of great subterranean heat in ages long past, and which were probably stratified rocks at one period, such as granite and gneiss, and the truly igneous rocks—trap, diabase, diorite, etc. He must know also that mysterious rock which the western miner calls porphyry, and to which is ascribed most wonderful virtues in the way of ore attraction; while dolerite and dolomite must be to him familiar terms and substances. This sounds easy enough but the student will find that a good deal of hard work is necessary before he can readily recognize each of these rocks. It is even more necessary that he should learn the metals thoroughly. Each one differs from all the rest in some particular. Often this difference will be an obscure one, but to the careful investigator the recognition of the substance will be in the end certain. They may differ in weight, in color, in hardness, in a dozen different ways, so that to the man who has made a study of this subject a determination is always possible. Stratified rocks are either sand, clay, or calcareous, which means lime-bearing. In their natural position they were horizontal, but owing to subsequent volcanic action they are, in some localities, tilted at all conceivable angles. The eruptive rocks have burst through them in places, changed their character, divided them by intrusive masses, and generally enriched them with mineral deposits. Everything now known points to the theory that the contents of veins were deposited in the lodes by infiltration. In a few instances famous mines have no veins, but are literally hills of mineral; they are then of low grade, but much more remunerative than average high grade mines, owing the vast quantity of ore, and the ease with which it can be mined. The famous Treadwell mine, on Douglas Island, Alaska, has ore that is worth less than four dollars a ton, but it is quarried, and 640 stamps work day and night. There is about a dollar a ton profit, and hundreds of thousands of tons are treated annually. The tin mine known as Mount Bischoff, in Tasmania, and the Burra copper mine in Australia are other instances. Each of these deposits was found as an outcropping on the bare top of a low hill, and none of them has walls. A fault may throw the vein up or down, and a good deal of exploration may have to be done before it is recovered. A lenticular vein consists of a series of double pointed ore bodies like lenses which may be strung out, overlapping, or not. The outcrop of a vein is never the same as its strike, except on a level surface. A stringer of ore branching off from the main vein is known as a chute, shoot, or chimney. In developing a ledge or lode, first find out what the ore is. Gold is shown in the mortar, especially after roasting. Silver may be recognized at sight, or by assay tests, or blow pipe; copper, by its vivid colors,—green or blue for carbonate and red for oxide or metallic copper. The ore often differs in various parts of the vein. Explore your lode along the surface, across, and down its dip. When you find it continuous it will be time enough to think of a vertical shaft. The top of a shaft must be timbered with logs, so as to give sufficient fall to get rid of the mineral when it is hoisted. The first thing the prospector has to consider is his outfit. The more complete this is the better, but ninety-nine times out of a hundred the difficulties of transportation in a wild region are so enormous that he will have to do without a great many things that he would like to have. He must endeavor to make up for the lack of tools by ingenuity; then he may get along fairly well. A pan, he must have. In this he will wash carefully all his samples. Then, a flask of quicksilver is more precious to him even than gold; for, having it, he can resort to pan-amalgamation, which will save the precious metal even when it is in minute particles. This process may be described as follows: A pound or two of the ore in powder is placed in the pan and water is added until the mass becomes a thin pulp. One ounce of quicksilver and a small piece of that deadly poison, known to the chemist as cyanide of potash, and as prussic acid to the ordinary man, should be added, and the mass should be stirred thoroughly, for two hours if you can stand it. Then turn in water and wash off the dirt and the amalgam will be found in the bottom of the pan. This you must collect very carefully. You should have a square piece of chamois skin or a piece of strong white cotton cloth. In either case the amalgam is put in the center of this square and the cloth twisted until all the superfluous quicksilver is pressed out and your amalgam remains nearly free from mercury. This amalgam placed on a shovel and held over a brisk fire will soon show the yellow color of gold. If you have no mould you may make one of clay, put your gold therein with a little borax, and very soon, the fire being hot enough, you will have a tiny ingot of the precious metal. But most prospectors are satisfied when they have obtained their sponge gold, and do not carry their operations further in these rough and ready tests. The prospector of to-day is often a very different man from his predecessor of a generation ago. The old gold hunter used to sally forth armed with a pick, shovel and pan, and usually a very little grub. In his stead men are now taking the field who have had the benefits of a thorough education, both practical and theoretical, and provided with all the equipment necessary for their work. Some of these men carry an outfit somewhat as follows: An iron mortar holding half a gallon, together with a pestle a rough scale for pulp, a more delicate one showing troy grains and pennyweights, a 40-mesh sieve, a burro furnace and muffle, one cupel mould, a couple of dozen scorifiers, tongs to handle the cupel and scorifiers, two annealing cups, a spirit lamp, a dozen test tubes, a pouring mould, five or six pounds of borax and about as much carbonate of soda, five pounds of bone ash, ditto of granulated lead, a pint of nitric acid, ditto of hydrochloric acid, ditto sulphuric acid, ditto of ammonia, twice as much alcohol and two pounds or so of granulated zinc. As a blow pipe outfit he will take a blow pipe, spirit lamp, nitrate of cobalt in solution, cyanide of potash, yellow prussiate of potash, red prussiate of potash, a sheet or two of filtering paper and a couple of three-inch glass filters. With this outfit he can determine any mineral he may come across. By patience and observation the man who starts out to take up prospecting as a road to fortune may easily master the rudiments of his business. It will not take him long to become familiar with the commoner rocks, and the more valuable ores. His own rough tests in the field must be confirmed by competent assayers upon his return to civilization, and in this matter he should be very guarded. The most reliable assays are made either at the different government assay offices or by some of the large metallurgical works whose reputation is world wide. Prospecting is hard work, but the life is healthy and full of excitement, only the explorer should have courage, hope, and good temper, for each and every one will be as necessary in his chosen vocation as his pan and pick. When alluvial or placer gold has been found it is reasonable to suppose that the vein from which it was derived may also reward diligent search, for it is undoubtedly true that most placer gold has come from quartz veins. This, however, is believed not to be invariably the case, a recent school of mineralogists contending that pure masses of alluvial gold have been formed from the accretion or growth of the gold deposited from certain gold salts. This is in any case probably exceptional, and the prospector who finds gold in gravel should seek in the adjacent country for the quartz lodes from which it came.The Comstock lode was first worked for gold, and the miners threw away the black sulphide of silver worth $3,000 to the ton. The Broken Hill mine in Australia was claimed as a tin deposit by its finder; it is now the greatest silver producer in Australasia. Such instances could be multiplied almost indefinitely, chance entering into a majority of mineral discoveries.

Important deposits may be expected at or about the line of unconformability where slates, shales, quartzites, sandstones, limestones, schists and other sedimentary deposits are pierced by intrusive masses of igneous rocks.
Veins filling the cracks that once existed between two differing rocks are known as contact veins. Such veins are often very rich. Curiously enough large masses of true igneous rock rarely contain valuable deposits of mineral, but where such intrusive masses cut dikes or walls of porphyry, or diorite, the region is worthy of careful investigation. 

In an open country the prospector should keep to the hill tops if on the lookout for veins, as the outcrops show more distinctly on the bare ridges, but alluvial deposits are only found in valleys and along the borders of streams. In any case, much of the northern part of this continent can only be prospected by following the streams, on account of the dense growth of forest with which the soil is covered. The true line of strike of a vein can be determined only on a level stretch. The line of strike and the line of dip are always at right angles to one another; the outcrop may follow the strike or it may not.
A pick, shovel, and pan, are absolutely necessary to a prospector's proper equipment. A good pocket lens, cheesecloth screen, and small iron pestle and mortar are often useful. The pan is the most essential part of the outfit, and is always bright from use.
The regular gold miner's pan is 13¾ inches in diameter across the top, 10 inches across the bottom and 1/8 inches deep. The best are made of sheet iron and have a joint around the bottom rim which is of some assistance in retaining the spangles of gold.
A more primitive instrument than the pan is the batea. This requires more skill than the pan, and is much in favor with South American miners. It is made of hard wood, 20 inches in diameter, 2½ inches deep in the center, inside measurement, and sloping gradually to nothing at the sides.
The horn spoon has been handed on from antiquity. It is made from a black ox horn, at least a black one is the best as it shows the gold better; it is eight to ten inches long by three inches wide, cut off obliquely.
When gold is suspected in quartz, but there is visible to the naked eye more or less iron, copper, and other base metals, it is well to crush the quartz into coarse fragments. Roast on a shovel or other convenient tool over a hot fire, and finally pulverize in the mortar. If panned it will now reveal much of its gold, while, had these measures not been taken, the sample might have given negative results and been declared valueless.
After pulverizing, the ore should be passed through the cheese cloth screen before panning. If the approximate value of the ore is sought, the sample must be dried and weighed before crushing; and the resulting gold weighed. Thus:
Sample is to 2,000 lbs. as gold found is to Ans.
About 13 cubic feet of quartz weigh a ton before being disturbed; when broken to medium sized lumps 20 cubic feet may be taken as representing a ton. Although experience teaches the miner to estimate very closely the value of his sample, it is better for the tyro to have a small pair of scales with grain weights. A grain of gold, if tolerably pure, is equal to four cents. Above all things avoid the too common error of panning the pick of the rock, as a false estimate is bound to follow and only too probably eventual loss.
A yard of gravel before being dug makes one and a half yards afterwards. A pan of dirt is usually about 20 pounds, although it is not well to fill quite full in actual work.
Many a valuable mine has been found by following up "float" ore. Float is detached fragments of the vein or gangue, and it becomes more and more abundant as the lode is approached until it finally ceases abruptly. This indicates that the vein has been reached or passed, and a trench dug throughout the alluvial soil at right angles to the assumed line of the vein will probably reveal it. The float and mineral of course drift down hill; if the side of the mountain be saddle-shaped the float will spread out like a fan as it washes down, but if concave the force of gravity will concentrate it within a narrow space in the ravine. Float found at the foot of a hill has come, as a rule, from that hill. The nearer the vein the less worn will be the edges of the float and mineral. The gangue or vein-rock in which the metal is found may be calcite or calc spar, fluor spar, heavy spar or baryta, or quartz. Gold is almost always found in this last matrix. The upper parts of most quartz lodes are usually oxidized, that is to say, the atmosphere has acted upon the iron pyrites, freeing the sulphur and staining the quartz yellow, red, or brown, by oxide of iron. This is known as "gossan" or the "iron hat." Such quartz is frequently honeycombed and rotten. Below the water level these veins run to sulphides in which decomposition has not set in, and the gold contained in the quartz is no longer "free milling," i.e. will not give up its gold to mercury without a preliminary treatment. 

Certain minerals are likely to be found associated. Cassiterite goes with boron and tourmaline, topaz, fluor spar and lithia-mica; all containing fluorine. It is also found with wolfram, chlorite and arsenical pyrites. Magnetite is often accompanied by rocks containing garnet, epidote and hornblende. Zinc blend and galena may occupy the same vein, which is likely to be of baryta or heavy spar. Much galena carries silver. Gold is associated with many metallic sulphides such as iron, magnetic, and copper pyrites, mispickel, galena, blend, stibnite and tetrahedrite. Gypsum accompanies salt.
Surface indications may be described as: Form of ground, color, outcrop, decomposed and detached mineral, mineral deposits from springs, altered or peculiar vegetation and other similar guides. A hard quartz outcrop often stands up like a wall and is traceable for miles. The Rainbow silver bearing lode of Butte, Montana, stood 20 feet above the surface. Soft minerals, such as clay, are cut into and sunk below the surrounding level. Deposits of Kaolin or China clay are usually so found.
Any special bright coloration of the rocks of a district merits investigation. Copper gives green, blue, and red stains; iron, red or brown; manganese, black; lead, green, yellow or white; cobalt, pink; cinnabar or quicksilver, vermilion. The nickel deposits of New Caledonia were made known to the world by the explorer Garnier in 1863, his curiosity having been aroused by the delicate green coating given the rocks by an ore containing water, quartz, nickel and magnesium.
Hard beds of shale decompose on the surface into soft clay, and a still more noticeable change is the conversion of ores containing sulphur into oxides. This chemical change causes the gossan or "iron hat," for which token of underlying wealth the prospector should be eternally watchful. This alteration may extend downward four or five hundred feet from the surface, but in such cases the true weathering has ceased long before the limit of discoloration is reached, and the change of substance is due to the filtering of surface waters through the vein.
Gossan varies greatly in its nature. Galena becomes anglesite, cerussite, pyromorphite and mimetite. Copper pyrite changes into native copper, melaconite, cuprite, malachite, chessylite, or perhaps into a phosphate, arsenate, or silicate of the metal. Carbonate of manganese gives the black oxides and silver sulphide ores are, after weathering, known as native silver, kerargyrite and embolite.
The ore in the gossan is very generally more valuable than it will be below, and this is especially true of gold and silver ores. The gold having been set free from the close embrace in which the iron pyrite held it previous to the latter's oxidation, it is now readily caught by quicksilver. Silver under similar conditions becomes chloride, and likewise amalgamates without difficulty.
Seams containing native sulphur often show no trace of that element on the surface, having weathered into a soft, white, gray or yellowish-white granular, or pulverulent, variety of gypsum.
Veins of asbestos often decompose into a white powder found in the crevices of the rocks; fibrous asbestos existing in the interior.
Petroleum shows in an iridescent film upon still pools, and the odor is a sure guide to its nature.
A "dipping-needle" is valuable to the prospector on the lookout for iron ore; by its use he may discover masses of magnetic ore and trace their extent. As he carries the compass over the ground the needle dips toward any iron mass he approaches; directly over the ore it becomes vertical.

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    1. 6 T-REX WITH P.M.S IS A HUGE HEAD_______