Volume 08 (1864) (474 pages)

A Mining Journal--Devoted to News, Art, Science and Progress. VOLUME VIIL SAN FRANCISCO, SATURDAY, MARCH 12, 1864. NUMBER 11. Contents: No. 11 —Maneu 12 —Rarthquakes—Thelr Causes and Effects; Ventl lntion of Mines: Communicatlons—The Great Desert and Its Mines, No, 2: San Lats Oblygar Virginig City—Uer Mines, Growth and Future Prospects: Jordan Creek. Chureliill Mines; About Clovea; Mechunleal De ti t—Rallroad switches nnd Snenads, Stonm and BlectruMagnetic Power, Steel Bollors,; Remarkable Instance, Patent Department—linprovemen! onthe Arastra, Now Amalyainator, Sinins ea Reese River—A Compmrative Ke. view of Various Dixtricta: The Mining Share Market, Editurlals, Incorpnrations: Full Reports for the week of the Sau Francisco Stock Market: Wushoo Stock Report, Chippings; Ete. Gditorint. VENTILATION OF MINES. From what has already been said upon the subject of mining veutilation, it will be perecived that a eoutinuous current of air through a mine can be effected only by produeing two columns of air, one of whieh shall be lighter thau the otber; the lightest ascending and its place being supplied by a descending of heavier or denser air. In sinking a shaft, after reaching a depth of fifty or sixty feet, more or less, according to accidental circumstances, ventilation can only be effected by establishing this condition. Under favorable circumstances, and to a limited depth, a current may be established naturally. This eurrent is established as follows : —In winter the air in the bottom ofa shaft, which is being worked, soou becomes heated by contact with the walls of the shaft, which are then warmer than the outside atmosphere, and by the aninal heat, and vapor evolved from the workmen. This heated air finds a natural exit upward along the walls of the shaft, while its place is supplied by a down current oceupying the center of the shaft. In summer this mode of ventilation is muel less reliable, from the fact that the air on the surface is then, especially during calm, sunny days, warmer and consequently lighter than the air which naturally exists at the bottom of the shaft. Natural ventilation, under such circum-stances can only be kept up by incidental causes— such as the movements of surface curreuts, (winds,) tho liberation of lighter gases, or the percolation of water, whieh latter cause has a tendency to produce a downward current along the walls of the shaft— the reverse, it will be uotieed, of the movement of the columns in winter. ‘Che greater the superficial dimensions of the shaft nnder these circumstances, the more easy is the renewal ol the air effected. To aid and quicken natural ventilation in an isolated shaft, ventilating partition frames are employed. ‘bat is, the shaft is divided into two compartments by a thin beard partition continuing from the niouth of the shaft downward as the workinen deseend. ‘The joints of this partition should be as close as is consistent with the rough work ; the interstices between the plauks being caulked, or covered with stiff clay, or something equally impervious to the atmosphere. If with this assistance the ventilation is not sufficiently established, a chimney should be erected over the smaller partition, and . carried to some considerable hight above the month . ef the main opening to the shaft. By this means} the miner will almost invariably secure a difference of density, or weight, in his two columus of air, as illustrated in figure 4, number eight of this vol ume, and cousequently fully establish the current necessary for proper yeutilation. When the shaft is on the ineliuo of a hill, tbe chimney may, if more convenicnt, be carried upward along the surface of the hill slope to any desired elevation. If the excavation be a gallery or tunnel, (the latter term is most cominonly used iu California) with but one opening to the almosphere, a similar partition may be carried along tlie tunnel as it progresses, oceupying but a small space in one of its upper angles. In this case the better arrangement is to construct a frame, or long box, made like an underground drain, of four boards carefully nailed together, with the sections adjusted into one another like the joints of a stove pipe. The joints should be made as close az possible, and will be all the more serviceable if carefully caulked and pitehed. This arrangement will be found more serviceable if the farther or last joint put up is made funnel shaped, presenting as large au opening as is consistent with the space to spare in the tuuuel. This latter section may be constantly carried forward and the new ones inserted between it and the main line of pipe, as it may be termed. This pipo or chamber should always he constructed as large as is oonsistent with economy and the working space required in the tunnel or gallery. When a shaft or tunnel is thus divided by a partition, it may be considered the sume az though the workings were connected with the exterior atmos. phere by two separate openings—as by the tunnel mouth and an air shaft, or by two shafts. The application in this instance of the laws of the movements of aeriform fluids as already defined in our previous articles under this head must be perfectly apparent to even tbe most casual reader. ‘The partition issuing from the tunnel, may be extended by a perpendicular chimney, or upward along the incline of the hill, as already described iu ease of the isolated shaft. It will readily be perceived that the arrangement described for use in tunnels will avoid all necessity for air shafts, which are oftentimes opened at great expense. The New Almaden Quicksilver mines bave been ventilated npon this principle for several years. It was first iutroduced there, if we are not mistaken, by the present and long time efficieut superiutendent, Sherman Day, Ksq. Natural ventilation is always better in temperate or northerly climates, thau in hot or equatorial regions. ‘Ibis is caused in part from the fact that the difference between the temperature of the walls of the excavation and the atmospheric air is greater in wiuter or cold weather, than in summer or warn weather. The same favorable difference is observablo between the cooler hours of night and the warmer hours of sunshine. In addition to which the presence of the workmen, the lighted eandles, the steam with which the air of mines is constantly saturated, ete., all act as an augmentation of temperature in the mine, and consequently aid in giving intensity to tho outflow of air through the upceast shaft or opening, whatever it may he. Of course, for reasons already given, whenever in natural ventilation the atmosphere rises to a greatcr temperaturo than that in the mine, the current of ventilation will change its direetion, When there is very nearly au equilibrium between the exterior and interior atmosphere, the veutilating current is notieed to oscilate from one directiou to the other, disturbed from the slightest agitation of the atmosphere either withiu the mine orupon the surface. Hence it will be seen that natural ventilation is subject to frequent irregularities, and is sometimes altogether insuffieient without some artificial aid. Whien such aid is resorted to, the proeess ig styled artificial or physical ventilation, We propose to devote a final chapter to this subject. COPPER MINES. The Lake Superior News and Journal, in its issue of January 8th, publishes a very able article on mining matters, in which, after showing the results obtained by well-conducted compauies in that region, such as tbe Knowlton, Caledonia, and Bohewiau, it says: Such are the practical results of the proper managenient in copper mining. It is more than to own good ground, with the stock placed, with an ageut working it, but with all this done and its productiveness proved—that sufficient money be furnished by the stockholders to fully and properly open the ground with such machinery as will also make its products to the fullest extent available, this may take $200,000, but what of that, if then—as any good mine will—it will return from $100,000 to $200,000 in dividends, with the value of its stock increased ten-fold. ‘he only reason why we havo no more Quincy, Pewabic and Franklin mines, is because so few have pursued the policy they did, or rather, adopted the efficient means they did to develop them. ‘There is plenty of just as good ground, to say no better, as they possess, and with equal improvements, with the same working, would stand in the same rank. The above remarks from the News and Journal apply equally well to mining operations in this State. It is useless to expect that copper mining will prove generally remunerative here until capital is brought to bear, both iu developing our mines and in the erectiou of machinery. Iu California, as elsewhere, we ean only now and then expect to find a mine that will puy its way from the start,as the “ Union” has doue. We have as yet, but three or four copper mines iu the entire State which have been opeued so as to admit of auything like an extensive and systematic working, and we are fully satisfied that but very few will ever be developed into valuable mines exeept by means of a large outlay of capital. Fifty, seveuty-live or an hundred thousand dollars, intelligently invested in opening up a mine and the erection of maclinery, for concentration, may be eonsidered a reasonable figure. No very bright prospects, as a general thing, are to be expected from uo assegsments at all, or even from 50-cent assessmeuts. Tt will be found sound policy for our copper miners, even after they beeome fully satisfied that they have a“ good thing,” to be liberal with capitalists, and seeure a thorough opening of their miues at the start. Organized companies will be wise if they assess largely aud sufficiently to place themselves at oneo upon such a souud basis that failure will be impossible ;

A Mining Journal--Devoted to News, Art, Science and Progress. VOLUME VIIL SAN FRANCISCO, SATURDAY, MARCH 12, 1864. NUMBER 11. Contents: No. 11 —Maneu 12 —Rarthquakes—Thelr Causes and Effects; Ventl lntion of Mines: Communicatlons—The Great Desert and Its Mines, No, 2: San Lats Oblygar Virginig City—Uer Mines, Growth and Future Prospects: Jordan Creek. Chureliill Mines; About Clovea; Mechunleal De ti t—Rallroad switches nnd Snenads, Stonm and BlectruMagnetic Power, Steel Bollors,; Remarkable Instance, Patent Department—linprovemen! onthe Arastra, Now Amalyainator, Sinins ea Reese River—A Compmrative Ke. view of Various Dixtricta: The Mining Share Market, Editurlals, Incorpnrations: Full Reports for the week of the Sau Francisco Stock Market: Wushoo Stock Report, Chippings; Ete. Gditorint. VENTILATION OF MINES. From what has already been said upon the subject of mining veutilation, it will be perecived that a eoutinuous current of air through a mine can be effected only by produeing two columns of air, one of whieh shall be lighter thau the otber; the lightest ascending and its place being supplied by a descending of heavier or denser air. In sinking a shaft, after reaching a depth of fifty or sixty feet, more or less, according to accidental circumstances, ventilation can only be effected by establishing this condition. Under favorable circumstances, and to a limited depth, a current may be established naturally. This eurrent is established as follows : —In winter the air in the bottom ofa shaft, which is being worked, soou becomes heated by contact with the walls of the shaft, which are then warmer than the outside atmosphere, and by the aninal heat, and vapor evolved from the workmen. This heated air finds a natural exit upward along the walls of the shaft, while its place is supplied by a down current oceupying the center of the shaft. In summer this mode of ventilation is muel less reliable, from the fact that the air on the surface is then, especially during calm, sunny days, warmer and consequently lighter than the air which naturally exists at the bottom of the shaft. Natural ventilation, under such circum-stances can only be kept up by incidental causes— such as the movements of surface curreuts, (winds,) tho liberation of lighter gases, or the percolation of water, whieh latter cause has a tendency to produce a downward current along the walls of the shaft— the reverse, it will be uotieed, of the movement of the columns in winter. ‘Che greater the superficial dimensions of the shaft nnder these circumstances, the more easy is the renewal ol the air effected. To aid and quicken natural ventilation in an isolated shaft, ventilating partition frames are employed. ‘bat is, the shaft is divided into two compartments by a thin beard partition continuing from the niouth of the shaft downward as the workinen deseend. ‘The joints of this partition should be as close as is consistent with the rough work ; the interstices between the plauks being caulked, or covered with stiff clay, or something equally impervious to the atmosphere. If with this assistance the ventilation is not sufficiently established, a chimney should be erected over the smaller partition, and . carried to some considerable hight above the month . ef the main opening to the shaft. By this means} the miner will almost invariably secure a difference of density, or weight, in his two columus of air, as illustrated in figure 4, number eight of this vol ume, and cousequently fully establish the current necessary for proper yeutilation. When the shaft is on the ineliuo of a hill, tbe chimney may, if more convenicnt, be carried upward along the surface of the hill slope to any desired elevation. If the excavation be a gallery or tunnel, (the latter term is most cominonly used iu California) with but one opening to the almosphere, a similar partition may be carried along tlie tunnel as it progresses, oceupying but a small space in one of its upper angles. In this case the better arrangement is to construct a frame, or long box, made like an underground drain, of four boards carefully nailed together, with the sections adjusted into one another like the joints of a stove pipe. The joints should be made as close az possible, and will be all the more serviceable if carefully caulked and pitehed. This arrangement will be found more serviceable if the farther or last joint put up is made funnel shaped, presenting as large au opening as is consistent with the space to spare in the tuuuel. This latter section may be constantly carried forward and the new ones inserted between it and the main line of pipe, as it may be termed. This pipo or chamber should always he constructed as large as is oonsistent with economy and the working space required in the tunnel or gallery. When a shaft or tunnel is thus divided by a partition, it may be considered the sume az though the workings were connected with the exterior atmos.

phere by two separate openings—as by the tunnel mouth and an air shaft, or by two shafts. The application in this instance of the laws of the movements of aeriform fluids as already defined in our previous articles under this head must be perfectly apparent to even tbe most casual reader. ‘The partition issuing from the tunnel, may be extended by a perpendicular chimney, or upward along the incline of the hill, as already described iu ease of the isolated shaft. It will readily be perceived that the arrangement described for use in tunnels will avoid all necessity for air shafts, which are oftentimes opened at great expense. The New Almaden Quicksilver mines bave been ventilated npon this principle for several years. It was first iutroduced there, if we are not mistaken, by the present and long time efficieut superiutendent, Sherman Day, Ksq. Natural ventilation is always better in temperate or northerly climates, thau in hot or equatorial regions. ‘Ibis is caused in part from the fact that the difference between the temperature of the walls of the excavation and the atmospheric air is greater in wiuter or cold weather, than in summer or warn weather. The same favorable difference is observablo between the cooler hours of night and the warmer hours of sunshine. In addition to which the presence of the workmen, the lighted eandles, the steam with which the air of mines is constantly saturated, ete., all act as an augmentation of temperature in the mine, and consequently aid in giving intensity to tho outflow of air through the upceast shaft or opening, whatever it may he. Of course, for reasons already given, whenever in natural ventilation the atmosphere rises to a greatcr temperaturo than that in the mine, the current of ventilation will change its direetion, When there is very nearly au equilibrium between the exterior and interior atmosphere, the veutilating current is notieed to oscilate from one directiou to the other, disturbed from the slightest agitation of the atmosphere either withiu the mine orupon the surface. Hence it will be seen that natural ventilation is subject to frequent irregularities, and is sometimes altogether insuffieient without some artificial aid. Whien such aid is resorted to, the proeess ig styled artificial or physical ventilation, We propose to devote a final chapter to this subject. COPPER MINES. The Lake Superior News and Journal, in its issue of January 8th, publishes a very able article on mining matters, in which, after showing the results obtained by well-conducted compauies in that region, such as tbe Knowlton, Caledonia, and Bohewiau, it says: Such are the practical results of the proper managenient in copper mining. It is more than to own good ground, with the stock placed, with an ageut working it, but with all this done and its productiveness proved—that sufficient money be furnished by the stockholders to fully and properly open the ground with such machinery as will also make its products to the fullest extent available, this may take $200,000, but what of that, if then—as any good mine will—it will return from $100,000 to $200,000 in dividends, with the value of its stock increased ten-fold. ‘he only reason why we havo no more Quincy, Pewabic and Franklin mines, is because so few have pursued the policy they did, or rather, adopted the efficient means they did to develop them. ‘There is plenty of just as good ground, to say no better, as they possess, and with equal improvements, with the same working, would stand in the same rank. The above remarks from the News and Journal apply equally well to mining operations in this State. It is useless to expect that copper mining will prove generally remunerative here until capital is brought to bear, both iu developing our mines and in the erectiou of machinery. Iu California, as elsewhere, we ean only now and then expect to find a mine that will puy its way from the start,as the “ Union” has doue. We have as yet, but three or four copper mines iu the entire State which have been opeued so as to admit of auything like an extensive and systematic working, and we are fully satisfied that but very few will ever be developed into valuable mines exeept by means of a large outlay of capital. Fifty, seveuty-live or an hundred thousand dollars, intelligently invested in opening up a mine and the erection of maclinery, for concentration, may be eonsidered a reasonable figure. No very bright prospects, as a general thing, are to be expected from uo assegsments at all, or even from 50-cent assessmeuts. Tt will be found sound policy for our copper miners, even after they beeome fully satisfied that they have a“ good thing,” to be liberal with capitalists, and seeure a thorough opening of their miues at the start. Organized companies will be wise if they assess largely aud sufficiently to place themselves at oneo upon such a souud basis that failure will be impossible ;