Tin ore

“ The ore of this metal is so poisonous, that the steam arising from the furnaces in which it is smelted infects the grass of all the neighboring places, and kills the animals which feed on it: culinary vessels lined with a mixture of tin and lead, are apt to convey pernicious qualities to the food prepared in them. There are various preparations of lead, serving for different purposes. ”

“ When it is intended to wash certain ores, an operation founded on the difference of their specific gravities, it may happen that by slightly changing the chemical state of the substances that compose the ore, the earthy parts may become more easily separable, as also the other foreign matters. With this view, the ores of tin are subjected to a roasting, which by separating the arsenic, and oxidizing the copper which are intermixed, furnishes the means of obtaining, by the subsequent washing, an oxide of tin much purer than could be otherwise procured. ”

“ Iron ore, tin, copper and tungsten are extracted from the earth, refined, put to some use or wasted as the case may be, but they are gone. They may be replaced by other minerals. Through geological ages they may redeposited in the earth's crust. ”

“ On making a comparative estimate of the expense by the blowing-house process, and by the reverberatory furnace, it has been found that the former yields about 66 per cent. of tin, in smelting the stream or alluvial ore, whose absolute contents are from 75 to 78 parts of metal in the hundred. One ton of tin consumes a ton and six-tenths of wood charcoal, and suffers a loss of 15 per cent. In working with the reverberatory furnace, it is calculated that ore whose mean contents by an exact analysis are 70 per cent., yields 65 per cent. ”

“ They are more or less penetrated with the ore, forming sometimes numerous beds of very great thickness; while, in the more antient or the primitive formations, these ores exist only in very small quantity associated with tin. Mercury is, generally speaking, a metal sparingly distributed in nature, and its mines are very rare. ”

“ CHAPTER XII. TIN—TUNGSTEN—TITANIUM. TIN.
Tin occurs in nature as cassiterite (containing from 90 to 95 per cent. of oxide of tin) , which mineral is the source from which the whole of the tin of commerce is derived. Tin also occurs as sulphide combined with sulphides of copper and iron in the mineral stannine or bell-metal ore. It is a constituent of certain rare minerals, such as tantalite. ”

“ The ore is therefore very rich, and the metal produced is of excellent quality. Hitherto these deposits have been washed by Chinese and natives of the country in a very rough and unscientific manner, and the tin-stone is smelted in a most primitive way, the produce realized being 68 per cent. ”

“ When we compare the first and second tabulations with the third it is at once apparent that with the possible although only occasional exception of iron the production of an ore-body from the normal rocks which constitute the outer mass of the earth requires the local concentration of each of the metals by one or several geological processes, and to a degree that is only occasionally developed in the ordinary course of nature. ”

“ For although it should be mixed with Lead, the Minera of Lead, or Salt of Lead, yet they would not remain conjoin’d, but the Lead is easily melted, floweth, and leaveth the Ore, which by strong blowing is reduced into Scoria, retaining much gold, which so is lost, as well as the other which flew away in smoak, and at the best but a very little saved, which hath entred the Lead. ”

“ The production of ore which occurs in the upper parts of the veins, furnishes us with the saline ores; for here the water, air and earth are principally active. In the upper depths are found most frequently the oxygenized metals, or as they are called mineral spars, as spathic-iron, malachite, calamine, lead-spar, pyromorphite, &c. ”

“ But, intermediate in richness between these two extremes, the iron ores mined to-day and these 2 and 3% ores, there is an incalculably great quantity of ore capable of mechanical concentration, and another perhaps vaster store of ore which we do not yet know how to concentrate mechanically, so that the day when a pound of iron in the ore will cost as much as a pound of copper in the ore costs to-day is immeasurably distant. ”

“ That the thing is so, I will prove by a certain similitude or comparison; make proof in what manner you please, of gold or silver Ore, and observe how much good metal that contains, afterwards prove the same in a great quantity upon Coals, and you shall find much less in that, than in your small proof; when nevertheless the contrary ought to be, because a great fire hath a greater force of acting upon the Ore, than a small one; and this is the only cause, because a great quantity requireth a more violent fire than a small one; which is averse to all crude and volatile Minerals. ”

“ Iron Ore.—An ore is a portion of the earth’s substance containing metal for which it is mined and worked; the class to which it belongs depends upon the amount and variety of the metal it contains. Any ore that is to be used for the extraction of a certain metal must contain the metal in sufficient amounts to make the operation profitable. ”

“ In iron ore, the metallic oxide or carbonate makes up nearly the whole rock; in gold ore, the metal is the merest incidental constituent, from the petrologic point of view.
Concentration.—The essential fact in the formation of ores is the unusual concentration of the metal. There are vast quantities of all the metals disseminated through the rock substance of the earth and even throughout the hydrosphere, but they do not constitute ores because they have no economic value. They become ores when concentrated in accessible places to a workable richness. ”

“ The manner in which metallic substances are distributed through the earth's crust, and more especially the phenomena of those nearly vertical and tabular masses of ore called mineral veins, from which the larger part of the precious metals used by man are obtained,—these are subjects of the highest practical importance to the miner, and of no less theoretical interest to the geologist. ”

“ There are now forty mines along the course of a single river in the Ural. The grains of ore are obtained from the sand by washing. The metal as found is usually associated with gold, iron, osmium, iridium, and other rare metals, and has to be purified from them. ”

“ The ore melts, the earth of the Lead unites with the phlogiston of the coals, and so is reduced to metal, which runs through the coals, and falls into an earthen vessel placed at the bottom of the furnace to receive it. ”

“ The ore is found in detached pieces and solid masses, in beds, in red clay, accompanied by sulphate of barytes, calcareous spar, blende, iron pyrites, and quartz. The ore is of that kind called, by mineralogists, lead-glance, or galena, and is the sulphuret of lead, of chemistry. As it is dug up or quarried from the adhering spar, it presents a very rich appearance. It has a [Pg 171] broad, glittering grain, of a lead-gray colour, which passes into a bluish shade. The ore is easily broken by the blow of a hammer, and may be pounded to a fine powder, still preserving its glittering appearance. ”

“ What gneiss and mica-schist, calx and salt, are in the bright valleys, such is the ore in the dark valleys; the former are the differenced ore, and this is their identification.
714. There is no peculiar metallic body or seed, which had already existed in the primary creation as something special or peculiar, and which by one process only, as perhaps even by its gravity, was precipitated or posited from the fluid mass. One and the same substance, if found exposed in a valley to the light, becomes earth; but ore when it is in a dark passage. ”

“ A metalliferous rock is spoken of as an ore when it contains metallic minerals (or in some cases non-metallic minerals, such as sulphur) in such quantities and mixtures as to make possible their profitable extraction. The metal contained in an ore is sometime found in its elemental form, as in the case of gold or platinum, but more frequently as a sulphur compound, or as an oxide carbonate or silicate. Often several different forms of one metallic element are found in the same deposit and several metals are often found together. ”

“ A very slight difference of composition of perfectly dressed ore may readily be understood to affect its reducibility; and hence it is, that ore from different veins, or the same vein in different strata, as before observed, is frequently found to work very differently when smelted singly in the hearth. It happens, therefore, that with the best workmen, some varieties of ore require more coal and lime, and a greater degree of heat, than others ”

“ The ore is then conveyed into a vessel containing an absorbing fluid metal, so constructed that every particle of the ore is brought into contact with the metal. For the production of reducing gases, steam and air are passed through highly heated materials, having an affinity for oxygen, and the gases so produced are utilized for raising the ore to a high temperature. ”

“ What is the fineness and goodnefs of the Ore, by which the Mine is wont to be estimated? And what are the marks and characters, that distinguish one sort from another?
64. What proportion of Metal it affords? (As in our Iron-mines 'tis observed, that about three Tuns of Iron-stone will afford one Tun of Metal: And I have had Lead-Ore, which an Ingenious man, to whom I recommended such Tryals, affirm'd to me to afford three parts in four of good Lead.) ”

“ Seldom, however, do the processes go far enough in nature to produce an ore which can be used directly without some further mechanical sorting. Ore minerals concentrated in placers are those which resist abrasion and chemical solution during the processes of weathering and transportation, and which have a density sufficiently high so that they are partially sorted out and concentrated from the accompanying quartz and other minerals. ”

“ As soon as the liquid reaches boiling point, the stamped and roasted ore is run into the vat, and at the end of another half-hour about 1 cwt. of mercury is added, further quantities being added as required at different stages of the process. The stirring is kept up continuously for eight to twelve hours, according to the character and richness of the ores. ”

“ Lead, iron, coal, gypsum, manganese, zinc, antimony, cobalt, ochre of various kinds, common salt, nitre, plumbago, porphyry, jasper, chalcedony, buhrstone, marble, and freestone, of various qualities. The lead and iron ore are literally exhaustless, and of the richest quality. To say there is probably iron ore enough in this region to supply the United States with iron for one hundred thousand years to come, would not be extravagant. Here, too, is water power in abundance, rapid streams, with pebbly beds, forests of timber, and exhaustless beds of bituminous coal. ”

“ When the miner hoists his ore [1] to the surface, the contained metal may be either in the native uncombined state, as, for example, native gold, native silver, native copper, or combined with other substances forming minerals of more or less complex composition, as, for example, telluride of gold, sulphide of silver, sulphide of copper. In both cases the valuable mineral is always associated with minerals of no value. ”

“ The reason of this is, that the strata of rocks which lie beneath the ground in all this region consist, in a great measure, of beds of coal and of iron ore. The miners dig down in almost any spot, and find iron ore ”

“ After discovering an ore of some valuable metal, it is essential to ascertain if its quantity and state of combination will justify an adventurer in working the mine, and smelting its products. The metal is rarely found in a condition approaching to purity; it is often disseminated in a mineralizing gangue far more bulky than itself; and more frequently still it is combined with simple non-metallic substances, such as sulphur, carbon, chlorine, oxygen, and acids, more or less difficult to get rid of. ”

“ This is chiefly observed in those Silver-veins, that are of so hard and dry complexion, yet those which are usually more soft, abounding in oleaginous Sulphures, before burning are first ground into powder in such Mills as I have often seen in Glass-houses: and then they receive a gentle calcination, the Mineralist mingling therewith Ingredients sutable to the peccant humour, if l may so speak, of the Ore. ”

“ Ore-deposits are but a special phase of the rock-forming processes already discussed. They have peculiar interest because of their industrial value. An ore is simply a rock that contains a metal that can be profitably extracted, though for convenience the term is used more broadly to include unworkable lean ores and ore material. The metal need not preponderate or form any fixed percentage of the whole, for the criterion is solely economic and not petrologic. A gold ore rarely contains more than a very small fraction of one percent. ”

“ Although many of these grains are wholly copper black, they are occasionally only depositions of the mineral upon specks of carnelian, chalcedony, or agate, or are more frequently composed, in part, of what is apparently an imperfect steatite. The ore is so connected with, and so much resembles in color the rock, of which it may be said to be a constituent part, that they might easily, during a hasty examination, be confounded. ”

“ An American scientist has just concluded a very interesting and suggestive experiment. He took a crushed sample of rich ore from Cripple Creek, which carried 1100 ozs. of gold per ton, and digested it in a very weak solution of sodium chloride and sulphate of iron, making the solution correspond as near as practicable to the waters found in Nature. The ore was kept in a place having a temperature little less than boiling water for six weeks, when all the gold, except one ounce per ton, was found to have gone into solution. ”