IMPROVEMENTS IN CALCINING CERTAIN ORES, AND IN THE CONSTRUCTION OF furNACES FOR THAT PURPOSE; AND FOR CONVERTING CERTAIN PRODUCTS ARISING IN THE PROCESS INTO AN ARTICLE OF COMMERCE, NOT HERETOFORE PRODUCED THEREFROM. Patent dated December 31, 1852. THOMAS BENJAMIN SMITH, of Bristol. This invention has reference more particularly to the first operation in smelting sulphuret copper, and other ores; namely, their calcination, by which a portion of the sulphur is expelled, and the metals they contain are oxidized. The inventor proposes to avoid the inconvenience and injury of the ordinary process caused by allowing the free vapors to pass into the open air; and, by condensing the metals which are evolved in the process in flues or pipes, to use the sulphurous vapors for the manufacture of sulphuric acid. For these purposes he uses nearly-closed chambers, furnaces, or retorts, which are heated from without, and by passing heated air into these he does not admit the products of combustion from the fire to mix with the vapors or gases evolved in the process of calcination, as such products would render these vapors unfit for the manufacture of sulphuric acid. With the chamber, furnace, or retort employed he connects suitable flues or pipes, to carry away the vapors, in which he condenses the volatilized metals, while the sulphurous vapors are carried away to suitable chambers, and proceeded with in the ordinary manner of obtaining sulphuric acid from them. When sulphuric acid is not needed, the process of calcination may be much facilitated, by introducing a much larger quantity of air, which will be an advantage to the smelters. The inventor also proposes to use a portion of heated oxygenated air at times, to assist the calcination of metallic ores. Claims.-1. The improved plan of constructing a calcining furnace as before described. 2. The improved mode of calcining, whether the manufacture of sulphuric acid be combined therewith, or not, as described. 3. The use of heated air blown into, or on to the ore in the chamber, furnace, or retort, whereby the calcination of the ore is much facilitated. 4. The manufacture of sulphurous acid from the sulphurous acid obtained in and by the process of calcination. COPPER SMELTING. Mr. William Henderson, of Bow Common, has lately taken out a patent for the invention of "improvements in manufacturing sulphuric acid and copper from copper ores, regulus, and matts." The patentee proposes to separate the sulphur from the other matters, and treat it for the manufacture of sulphuric acid, and to act upon copper ores and regulus so that they may be converted into copper by more simple processes than hitherto; dividing his copper ores into three distinct classes, and treating each variety differently, according to the per centage of sulphur they may contain. This first class comprises all above 25 per cent. of sulphur, the second all between 10 and 25 per cent., and the third all under 10 per cent. He states the difficulties in the way of manufacturing sulphuric acid in copper ores have been threefold-the first is, the high heat by which the greater portion of the sulphur is separated from the copper, would destroy the vitriol chambers; the second, the carbonic acid gas and other gases in combination with the smoke, if they did not injure the chamber, are so great as to necessitate a large quantity of nitrate of soda to neutralize them; and third, a large amount of sulphur is sublimed or changed from the ore, which, if passed into a vitriol chamber in this state, would remain as sulphur, and very much retard the production of sulphuric acid. The first objection he proposes to remove by separating all the available sulphur by calcination at a low heat, and superseding, as much as practicable, roastings; the second, by removing a certain class of ores without the aid of fuel, and another sort, in close calciners, by causing the smoke and the gases from the ore to pass separately from the fur nace; the third, by conveying the gases from the calciners over the kilns in which the ores of the first class are burning by their own power of combustion; by this means all the sulphur that has been sublimed is readily converted into sulphurous acid. The first class of ores he proposes to burn in small cylindrical kilns, after the manner of mundic kilns, they being broken into pieces not larger than a goose's egg; this mode of calcination, we may observe, in round or square kilns, dry built, is universally used in Sweden and Norway. In these countries where fuel is cheap, about 4 fms. of wood is sufficient to calcine from 80 to 100 tons of ore; the sulphur obtained from them is, however, put to no practical use. The second class are calcined in closer furnaces; and the third, with the calcined ores of the first and second class, are likewise smelted for regulus. The whole of these are to be crushed fine enough to pass through an eight-hole sieve. We shall not enter into further detail of Mr. Henderson's patent, as a great portion of it, as he candidly admits, is known before. That by it he may obtain sulphuric acid in an easier method than that at present employed is possible, but it is questionable whether it would be at a less cost. The simple fact of dividing the ores into three classes would of itself show the increased amount of labor that must accrue, and this would likewise be the case in the tedious operations which would have to be carried on through the smelting works. The admixture of silex to form a silicate of iron in the slag would likewise cause an extra expense, and it is problematical whether the sulphuric acid so obtained would repay the cost of its production. Many improvements which are found to work well theoretically, when practically tried are found wanting. We by no means infer that this is the case in the present instance, but looking at the number of patents that have been issued for improvements in copper ores, and the few that have been practically useful, we are inclined to suspend our judgment until some positive results are attained. Lately we have seen the project of a German, who proposes to obtain at a profitable rate the copper from ores of per cent. JOURNAL OF SILVER AND LEAD MINING OPERATIONS. SILVER COINAGE. The coinage of silver at the Mint at Philadelphia has been as follows: Silver bullion deposited for the same period, value, $860,000. The silver coinage of all the mints of the United States has been annexed. Only gold is coined in the mints of Charlotte and Dahlonega. The total coinage at all the mints since their organization to October, 1851 has been $239,963,933 85. SHIPMENTS OF LEAD FROM THE UPPER MINES IN AUGUST, 1853. railroad 66 from Dubuque, Potosi, &c., Total,. Shipped same month in 1852, NORTHERN LEAD MINES. 24,702 700 6,041 81,443 34,245 The following correspondence has appeared since the September number of our Magazine was issued. We shall invariably find a place for all mining reports vouched for by the officers of a company. Thus we hope to be able to preserve in our pages, and furnish to our readers all that is reliable in the progress of every mine of any pretensions in the country: HON. J. C. FORSYTH, PRESIDENT :— SIR,―The usual monthly report of Captain Dunkin, the mining agent, together with vouchers Nos. 443 to 447, inclusive, is herewith transmitted. The monthly balance sheet will be transmitted by Captain Dunkin, from Rossi, by the next mail, so that the Board can compare the same with the vouchers. Since the important development of mineral mentioned in Captain Dunkin's report, as having been recently made in Crystal shaft, one of your committee, (Mr. Myers) has made a personal examination of the mine underground, in company with the Secretary. The magnificent leader of lead there uncovered, cannot fail to inspire the most unbounded confidence in the success of the mine, lying as it does, under the extreme eastern portion of the works, and answering the expectation of those who anticipated that the lode would reappear, (the bar of poor ground having been passed,) at about the depth where it is actually found in all its original strength. This leader is eighteen inches in width, and presents every appearance of continued increase. It has steadily increased, and uninterruptedly for the last eight feet of excavation, and now presents a literally solid leader of the purest Galena, unmixed with spar or any other substance, at the least eighteen inches wide across the lode, and for the whole length of the shaft of about eight feet, without the least show of failing at either end. When it is considered that the leader at the lowest portion of the mine, near the most western works, is worth, in the opinion of Captain Dunkin. $120 a fathom, the most confident expectations may, it seems to your committee, be entertained that the rich lode which appears in the Crystal Shaft, extends throughout the whole length of the present excavations at the base. The best feeling seems to prevail at the mines amongst all classes, and your committee cannot refrain from offering to the Board their congratulations at this most opportune development of the treasures of the mine. Ogdensburg, Aug. 24, 1853. We have the honor to be, sir, Your obedient servants, THE EXECUTIVE COMMITTEE OF THE GREAT NORTHERN LEAD MINES. GENTLEMEN:-I beg to lay before you this my monthly report on these mines: In the Engine Shaft the lode is three feet wide, improving in its appearance, and I think the time not far distant when I shall be able to speak of important improvements at this point. In sinking under the bottom of the western section the lode is just as when last reported-three feet wide, worth $120 per fathom. In sinking the Crystal Shaft under the bottom of the eastern section, we have made an important discovery of a solid leader of lead, eighteen inches wide, worth at least $500 per fathom-lode 34 feet wide. The importance of this discovery will be seen when you consider the richness of this lode above in the former workings; and it proves the correctness of the theory advanced by those who were of opinion that the lode would be rich again below, provided that there was no alteration in the circumstances in connection with the lode or stratum in which it is embedded. The dressing and smelting are going on favorably, and for the time to come our returns will be regular. I congratulate the stockholders on the present prospects of the mine, and I think in a little time it will make one of the most important and valuable mines in the United States. I am, gentlemen, your ob't servant, JOHN DUNKIN, JR. Lead Mines, Rossie, Aug. 23, 1853. SILVER. The territory of the Spanish Peninsula is one of the richest in Europe in silver, and possesses great advantage over the other nations. Spain, till these late years, has produced 184,158 marcos (113,5334 lbs. troy), of silver, whose value has surpassed 35,000,000 of reals (about $1,822,000), but since the discovery of the Hiendelaencina mines in the province of Guadalajara, that produce has much increased. One of these mines alone, in the said province, has already yielded upwards of 20,000,000 of reals (1,050,000.) According to the last documents published by the Spanish Government, that country produced in 1846, 547,143 quintals (510,484 cwt.). of lead, whose value amounted to 37,000,000 of reals, (1,927,000.) THE SILVER MINES OF CHIHUAHUA, MEXICO. The particulars of the following information concerning the Silver Mines of Chihuahua, are chiefly taken from a memoir written by a Mexican gentleman well acquainted with the subject, and were translated for the New-York Daily Tribune-where they appeared with other facts over the signature of that accomplished miner and geologist, "Julius Froebel." Some of these silver mines have been at periods among the richest on record. The silver in the western part of the State, of the mines of the Sierra Madre and its neighborhood, almost always contains a greater or smaller proportion of gold, which usually gives to the marc of the alloy a value of nine and a half to ten dollars, while silver of the common degree of fineness is paid by the mint of the State, at the rate of eight to eight and a half dollars for 1 marc or 8 ounces. Under a certain ratio, which is rather high there, the separation of gold and silver does not pay. Jesus Maria.-This famous mining place is a town in the Sierra Madre, on the head waters of the Rio Mayo, and near the frontier of the State of Sonora. Immense wealth was extracted from the numerous mines in its neighbor hood at the time of the Spaniards. Its silver ores always contain_gold in a ratio to make the marc worth ten dollars. The mine called Santa Ludubigen has been worked since the expulsion of the Spaniards. In the six months from May to October, 1839, it yielded a net profit of $400,000, and in the two years 1845 and '46, again $500,000 were cleared by the concern. The chief mine of Jesus Maria, however, which is the Santa Juliana, has never been worked since the time of the former masters of the country. This mine is 300 varas (278 yards) deep, and is now filled with water. According to a reliable calculation, $200,000 would be necessary to begin working it again, on as large a Scale as would correspond to its importance. The ores have proved never to contain less than 3 marcs or 24 ounces of silver, and have even reached 40 marcs or 320 ounces in one carga, which is 300 lbs., the marc, by its quantity of gold, being worth 10 dollars here, as already mentioned. To clear this mine of its water, a steam-engine would be necessary, and it may be observed in this respect that there is no want of wood for fuel at Jesus Maria, all the mountains of the Sierra Madre being covered with timber. How profitable the mines of this place could be made, if worked with all the means of advanced art, may be seen from the fact that numerous persons of the "gambusinos," make a living, and other persons who provide them with small funds, even make money, by a minute part of the treasures which they contain. Some gentlemen living at Jesus Maria, lend money to the miners under the condition of being repaid, after the time of one month, in bullion at a price 16 per cent. lower than the mint of Chihuahua is paying. One gentleman, investing a capital of 20,000 dollars in this kind of speculation, fully doubled it in one year. And the mint of Chihuahua, paying 16 per cent. more than the miner receives, pays nevertheless about 20 per cent. less than the silver is really worth, having besides the advantage of 1 month's interest by retaining the silver alloyed with gold, that time for the purpose of the separation. At a distance of 12 leagues from Jesus Maria, a very rich mine was discovered some years ago. This is the mine of Pertenencia.-The ores of this place have been found to contain from 3 upwards to 120 marcs of silver in each carga, or 300 lbs. The average ratio proved to be 8 marcs. For a certain length of time 300 cargas were extracted every week, containing 2,400 marcs of silver, corresponding to a value of 24,000 dollars per week. The expenses of mining for that quantity of ores were 600 -those of extracting the silver from the ores 3,000-total expenses 3,600 dollars. These, subtracted from the above produce, left a net profit of $21,400 per week. Were it the purpose of these notes to exhaust the subject, a great number of other mines in the neighborhood of Jesus Maria might be named. This, however, would not add a corresponding share of interest to our statements, and it is thought more proper to draw the attention of the reader only to the more prominent facts concerning the mineral wealth of this country. Corralitos.-This mining place is situated in the northern part of the State, on the Rio de las Casas Grandes, which flowing in a northern direction towards the Rio Gila, but not reaching that river, empties into the Laguna de Guzman. The place is distant from the capital of the State about 90 leagues. The silver here, too, is alloyed with a certain proportion of gold, which, however, appears to be smaller than in the ores of Jesus Maria, the marc being worth here but 9 dollars. Two mines have been worked at Corralitos, of which the one has been bought, some years ago, by the present owner, for the sum of 40,000 dollars. At that time it has yielded 1,000 marcs every month. The monthly expenses amounted to 4,000 dollars, and a monthly net profit of $5,500 was obtained in that manner. How it continued since that time we have not been informed. But the nature of the mine would allow an increase of its produce to four times the amount just mentioned. Some difficulties however exist. Corralitos is one of the places most exposed to the depredations of the Apache Indians, who live in the neighboring mountains. These savages, by stealing |