Volume 11 (1865) (424 pages)

50 She Bining und Scientific Press, Gommuvications. In Tuts Derantaent we invite the FREE Discussion of all proper subjects—corr dents alone being r for the ideas and theories they advance, [Written for the Mining and Scientific Press.] * The Problem of Gold and Silver Extraction-A General Revicw---No, XV, BY PROF, J. LANSZWEERT. WASHINO THE CORTA. We have already alluded to the importance of this part of the patio process. We will now content ourselves with notieing the apparatus and mode. Four large tubs, built of staves, or masonry, 15 feet wide by four deep, are mounted over an arched vault, to catch the mereury which iafiltrates insensibly through the pores and amounts to no iasignibeant sum per anaum. ‘These are open at the top, communicating by a series of apertures, six by eight inches, at about hulf their hight, and are provided with dashers placed oa a vertical axis something resembling those of a barrel churn. The requisite quantity of ore heing put ia, the first water is added and the whole set in motion. The amalgam mostly settles to the hottom, while the mud passes to the aest of the sieves, where it deposits a little more ; then to the third, whieh eatehes some of the most impure and the heavier sulphurets; thence to the fourth, which receives hardly auy at all, At the expiration of three hours the eharge is drawa off, if completed, and a fresh oae added, untilthe whole“ torta” is washed, when the amalgam is removed and cleaned by handwashing in troughs or hasins, preparatory to straining aad distillation. Ta some haciendas the number of vats is only three, in others six; and still there is a trifling loss ; while iu some plaees only one is employed, and the waste is eonsequently enormons. The amalgam, containing perhaps oneeighth or one-niuth of silver, (the proportion of mercury beiag iacreased by un addition of fluid mercury, when aecessary, to the lavedere, to cateh the particles of amalgam, aad ealled the bano,) is placed in long, sleeve-like bags of strong canvas, drained and pressed by twisting, to exelude all the mercury possible, and made iato balls or cakes for distillation. ‘he expressed mercury is submitted a secoad tine to the same filteriug operation, and yields a small hall, oae-fifth per cent. generally remaining with the mereury. The dry amalgam, called “pella,” coatains from eighteen to twenty-eight (generally twenty-two) per cent. of silver, dependeat on the state of ageregation of this metal in the ore, and the degree of pressure employed. The remaiuing operations of distillation and smelting are too well known to require description. The refuse of the washing vats, the “jal,” or “ eahecilla,” as they eall it here, was formerly permitted to run out into the creek, and sold at about $8 or $10 the torta to aset of men named “despolyilladores,” or eoacentrators, whose hnsiaess it was to extract the “ polvillos’—the metallic deposit containing silver aud a little amalgam which escaped the vats— for sale to the origiaal proprietors. ‘This they did by heapiag them up 0a arude “table dormaate,” aa iaclined plane, whout eight feet square. Having piled up the ore at the head of the table, the despolvillador, seated at the foot, throws water gently oa it with a horn spooa, aad the light particles floy away with the stream and are rejected, while the heavier arrange themselves aear the place of original deposit, aad after two or three washings are saffciently eonceatrated for removal. After a preliminary washiag, generally with salt, they are returaed to the mills, or, whea coataining copper, used in the preparation of magistral. The quaatity as well as ricbaess varies wonderfully ia different ores, or different griadiag of the same ore, the former varying from onefonrth to thirty per cent. Ia Guanajuato, they are trifliog—perbaps not over two per ceat., aad by this hand-process cost six to eisht reals the arroba of twenty-five nouads, but many haciendados bave lutely iatroduced a machine, sometbiug like an Kuglish “ buddle,” in which the ores are arranged ruuid the circumference of @ great shallow busia of brick and mortar, and irrigated hy many long tin tuhes, Project-. ‘per ceut. of sulphate of irou, three to four per iug from a revolving cask filled with water in the center. ben worked entirely by hand, it employs from three to fonr nen, and reduces the cost of * polvillos” to Hlteen or tweuty cents the arroha. CHARACTERISTICS OF" THE MEXICAN ' ARASTRA.” For ages the arastra his been the favorite mode in Mexiao of extracting gold and silver from their containing rocks, and all experience foes to prove that it is the surest mode of extracting all the metals from the ore, that has ever been tried by the grinding and amalgamating process. As an amalgainator, the arastra stands unrivaled. Notwithstanding they have been thrown aside repeatedly by onr go-ahead operators, still they revert back to the “ primitivo arastra” as u last resort against an utter failure in their mining enterprises. Now it occurs to me, that instead of abusing the slow aud sure arastra, we should stndy the priaciple upon which it. works, and endeavor to improve upon its strueture, thereby increasing its effieiency and usefulness. ‘Yhere is no process now iu use that will reduee ores so eompletely as the arastra, and itis well known by praetieal men that gold cannot be thoroughly ex. tracted until the ore is eompletely reduced to . the fineness of gold itself; for a course grain . of sand may contain several fine partieles of) gold. Stamps eannot reduce the ores so fine as an arastra. for the reason that, ds soon as it is reduced to sand, the blow of the stamp forees it with the water from under the blow; asthe water gives place to the blow, of the stamp it takes the fine sand with it, and the blow falls upon the eoarse quartz that remains behind. It appears to me that the stamp and arastra should work together—one to break the mass into eoarse sand and the other to reduce it to the required fineness to complete the process. Q By “ patio” the loss of gold is twenty-five to thirty-three per eent. on the assay, and in some . places as high as forty per eent. ‘The “ pol-. villos,” which are the metallie portions (principally sulphides of iron, rieh in silver) remaining fron the washing “torta,” always eontains gold. ‘They arc treated a seeond time to obtain whatever gold and silver they may hold, but they will not yield them hy tbe eomaion method without a preliminary operation. It may be quite probable that the gold in these polvillos exists us a sud-sulphide. Vhe magistral is generally manufaetured trom the sulphide of copper, eontaining, before calcination, from six to fifteen per eent. of that metal. ‘The furuaces in which this ore is ealeined are ealled comalillos. ‘I'hey have a duuble hearth, the roof is almost or quite flat, and the bre-place in tho eenter and running longitudinally, so that the flame plays sideways. About eight arrobas of the ground ore mixed with a few handfulls of common tahle-salt is a charge for each hearth. ‘The fire is then gradually increased and the ore almost constantly stirred for the space of six to eight honrs, whien the doors and other openings are elosed to exclude the air. ‘Nhe percentage ohtained, according to the ore, is frum thirty to filty per eent. of sulphate of copper, seven to twelve cent. of copper, not availuhle as sulphide, and oue to three per cent. of copper as oxyd. Would aot the low grades of our eopper ores, if treated as above, not he profitable for the produetioa of sutphate of copper, which eonsumptioa is daily more and more inereased? CHEMICAL THEORY OF THE PATIO PROCESS. Of the rationale of the patio process many views have been given. All the olden theories supposed the formation of a chloride of silver from the electro-ehemieal action of the sulphate of copper, salt and mereury on the ore— a doctrine whieh every praetical chemist, acquaiuted with the pheuomena presented. knew to be at variance with the truth; chloride of silver never being present except aceidentally and ia minute quantities (whea aot found in the ore), and rather impeding than facilitating the operation. It was reserved for John A. Browning, an English geatleman, long resident in Spanish America, and favorably known for his practical and scientifie knowledge of the reduction of silver ore, tv propose a theory at oace simple, intelligihle, fulfilling all the requisites, and explaining all tbe phenomena of the “ benefieio de patio.” He supposes that a diehloride of eopper is formed simultaneously with the proto-chloride of mereury; by the actioa of this latter metal on the proto-eliloride ot eopper present, this di-ehloride absorbs an atom of oxygen from the.air, heing eonverted into aa insoluble oxy-ebloride, whieh dissolving in the excess of satt, eommunicates its oxygen to the sulphur of the sulphuret of silver ia thé ore, with formation of sulphnric acid and metallie silver; then going haek for aaother dose of oxygea to reseat the proeess “ ad infinitum,” actiag the part of the quadroxyd of-nitrogea in the manufacture of sulphuric acid. Metalhe silver beiac thus formed from the first, we can readily understand why in a well managed torva there is aever more thau an inappreciable quautity of chloride of silver preseat at . auy stage of the process. Dr. Browniag hag based a new ingenioas, rapid, and economical “ beneticio de patio,” upon this theory. ‘Ihe length of time required, in Guanajuaty to obtain the silver is from eighteen to forty days, according to the season, matageient and docility of tbe ores. ‘lhe loss of silver on the first assay is variously stated from one to six (and in vae case twelve) per cent., most of which is regained in the polvillos; that of mereury fifteen to eighteen per cent. of the amount employed, which is partly consunied (iu the chemical reactions) aud partly lost mechanically. Sonneuschmidt, a nsually careful and reliable authority, asserts that he never was able to detect the most insignilicant traces of merenry in the cabecilla. { cannot coneeive how he permitted himself to fall into so gross an error. In other parts where less care is used, these losses rise sometimes to thirtyfive or forty, and twenty-four per cent. of silverand merenry. ‘Ihe average fineness of the silver, exclusive of the alloy of gold, one-half of whieh at least is lost in the patio, may be put down at 988 1,000. ‘The whole expenses are averaged at forty-three per eent. for grinding alone; loss of mercury, ten per cent. (amounting to over a million pounds annually, in Mexico) ; the product of silver being estimated at 900,005 pouads, extracted from 260,000 tons of ore. Sueh an influence has the value and eonsequently the loss of mereury in the product of silver, that when the price of the former rose in the last eentury it diminished in six months the quantity of silver re duced fifty-five per cent., or more thaa half. In addition to the ingredients mentioned at the commencement—and which have been in use ever sinee the aceidental discovery of the. “ beneficio de patio” by Bartolonie de Medina— several others have been recently introduced to diminish the loss of mereury, and with eonsiderable sneeess. They cunsist chiefly of preeipitated eopper, and amalgams of zinc, eopper, or iron, and are employed instead of lime to“ eool” the torta. They have thisadvantage over lime, that the mercury instead of being precipitated as an oxyd and lost, is partly revivified by the eleetro-positive metal, and augments the product. ‘They were lirst introdueed by M. Lauckner, some years ago, nnd from ignorance have inet with much opposition, hut their importance may be judged from the fact ‘stated above, of the influenee whieh slight fluctuations in the value of mercury alone have upon the economy of the proeess, and anything tonding to diminish this sonree of expense would be feltimmediately throughout the whole miniug regioa. [To be Continued.} The Dyke in the Whitlatch Union, In our notice of the Whitlateh Union inine, tivo weeks since, we alluded to the report that the workmen some time since struck a dyke, in eonsequence of which the lead was lust, and ofter eonsiderable search to find it again operations were suspended entirely for some two or three months. In allusion to this matter a eorrespondent writes to the Reese River Reveille as follows ; An erroneous opinioa is eatertained by some of the existence of a “dyke” in this eelebrated mine. It is truly deplorahle that so good a mine as this should have suffered so inuch from a desease known as dyke on the brain. 'lhat, the Whitlateh vein is eut by dyke is aeither supported by theory or fact, as proven by the extensive exploratious that have been made. Yon are misinfurmed as to the fact of work having heen bronght to a stand still by the interposition of alarge dyke of porphyry aud elay cutting tho vein at oblique angles. I have worked ia the mine six montbs and aever saw it. “The investigations were earried on principally underground, and were characterized by Dr, Jackson as resembling the frantie efforts of a drowning beaver to eseape pursuit, rather than the sober iavestigations of intelligent workmeu.” This was tbe nnkindest cut of all. Admitting the dyke theory to be correct, mneh of the work was well directed. But that theory is abused, and I do aot hesitate to tuke issue with the learned gentlemen who adupt such views. The fact is this mine is out of the regioa of extensive movements, and is eut by two perpendicular seams in the shape of asickle the fret making its appearanee between tbe ehloride and sulphurets. ‘The conneetion has been made here, but itis hy no wise a eontinuous vein, passing hy like the blades of a pair of shears, the chloride belt seeming to be lifted up while the snlplnret seems to iacline at a greater angle. All efforts so far have failed to solve the mystery as to how the ledge is at the second fault. But I predict ‘no difficulty in the way if they will abandon the dyke theory, look for the ledge where they lost it, a thing not yet doae, drift on the line of the movement, and ere long we may look with pride as we were wont to do, oa oae of the best mines of Nevada. A wine of steamships between France and Aspiawall will he established and ready to-go into operation sometime duriag next month. {Written for the Mining and Scientific Press. ] From the Slate Range Mines, Eas. Press :—Our regular monthly mail arrived on the 5th nlt., with a fine package of your interesting papers, including that of May 6th, contaioing a’ paragraph coucerning our district, for which we are much obliged. I would, however, ask, if convenient, that you would correct the last statement that “ four loada of sage brash rnas the engine twelve hours,” to twenty-four or over. It may bo of others, situated as we are among rieh mineral leads in a desert conntry, that the fuel we use is not sage-brush, hut a little hrush in size and weight equal to a lady's open parasol, and when plucked up and thrown into windrows, is frequently blowa by the gusts of wiad clear out of sight. Yet with it we can in tweuty ntinates raise steam and start the stamps. It grows all over the plains, mixed with greasewood, which is coarser and larger and full of oil. Our lead eontinaes most enconraging, and or fifty stamps could he kept eonstantly running from it if we had them. No selection of rock is made, bat all between the casings from three to eight feet is passed through the mill. Messrs. Jeffrey & Co. (Cornish miners of much experienee) speak of the Rochester lead, in respect to its conrse, width and quality, as superior to any gold lead they have ever seen. In May last, a party of Indians visited the deserted eamps of the Austrian and Broman Co’s., on the hill, three or four miles from us, and destroyed and earried off considerable property, including ten jacks, belonging to tho Roehestvr eompany, which we had out to pasture, in a eafion, not far distant from our eainp. Mr. Senrles, with 1 dozen of his men, called on them, drove them out ond broke up their camp, and recovered some of their missing urticles. Bntthe jacks were all eaten or jerked. A gold head, ring, and some wheels of a watch wele found ainong their traps, which is almost sure to have belonged to Geo. Yarbrough, who was killed in EH] Paso last Angnst. In the party was a hig-footed Indian, whost track ‘vas seen in conneetion with the Yarbrough murder . On the 2d of June, while Messrs. John E. Yates and Jaecoh Baaer (einployees of this Co.) were trying to dig out a missed blast, in a cistern they were sinking, the charge exploded, throwing them some.feet with great force. Yates received a terrible gnsh oa the face, laying open the right side from the ear tu the corner of the mouth and down to the point of the chin. ‘This was neatly sewed up by Engineer Harvey, and is now well healed. One of his feet wns badly bruised or wrenched and has not yet recovered. Baner was badly burned in the eyes, face nad wrists and has not yet reeovered the use of the left eye, and there is dauger of its heiug permanently im-~ paired. 4 Yesterday, July Ast, Captain MeElroy and ten nren of his exvalry eompany, stationed at Camp Drum, Wilmington, arrived with two teams loaded with baggage and forage, and on Tuesday. the 4th, they are to stort ont oaa raid upon the Indians. Cc. W. T. Slate Range, July 2d, 1865. New Hay Press—The Petaluma Argus gives the following description of a hay press reeently invented by Mr. Wm. Moeh, of Sonoma eounty. It appears to be a most complete aad serviceable machiue. Itsadvantages eaa be noticed hy any one at all conversaat with the use of such machines. It is deseribed as follows: ‘“‘The press is worked hy common horse-power, nad the team is kept in constaat motiva. ‘The press is fed just as grain is fed into a thresher, nnd the only interruption to this is in shipping the hale into a false ehamber, which requires hut a few seconds of time. It requires an aetive hand to tie the hale’ and have the false chamber in readiness to reeeive the next one. ‘This diseharging apparatus aloae isa elear saving of time equal to the daily lahor of one man. ‘The bay passes between rollers into an oscillating chamber, where it falls in regular esheets or folds, and makes a compaet hale so square aad regular in shape‘that they cau be piled up in‘almost ag mueh regularity as brick. On trial, it turaed out a bale every three aninutes three feet six inches long, two feet deep aad twenty-two inches wide, of aa average weight of ahout one hundred and fifty pounds,and the hay was of the very dryest aud lightest character,” Cannon Castine IN Marrposa.—Messrs. Wileox & Yousc, founders, at Bear Valley, Mariposa county, recently cast a cannon for home use, which they presented tothe Union men of Hunter’s Valley, Mariposa county.

50 She Bining und Scientific Press, Gommuvications. In Tuts Derantaent we invite the FREE Discussion of all proper subjects—corr dents alone being r for the ideas and theories they advance, [Written for the Mining and Scientific Press.] * The Problem of Gold and Silver Extraction-A General Revicw---No, XV, BY PROF, J. LANSZWEERT. WASHINO THE CORTA. We have already alluded to the importance of this part of the patio process. We will now content ourselves with notieing the apparatus and mode. Four large tubs, built of staves, or masonry, 15 feet wide by four deep, are mounted over an arched vault, to catch the mereury which iafiltrates insensibly through the pores and amounts to no iasignibeant sum per anaum. ‘These are open at the top, communicating by a series of apertures, six by eight inches, at about hulf their hight, and are provided with dashers placed oa a vertical axis something resembling those of a barrel churn. The requisite quantity of ore heing put ia, the first water is added and the whole set in motion. The amalgam mostly settles to the hottom, while the mud passes to the aest of the sieves, where it deposits a little more ; then to the third, whieh eatehes some of the most impure and the heavier sulphurets; thence to the fourth, which receives hardly auy at all, At the expiration of three hours the eharge is drawa off, if completed, and a fresh oae added, untilthe whole“ torta” is washed, when the amalgam is removed and cleaned by handwashing in troughs or hasins, preparatory to straining aad distillation. Ta some haciendas the number of vats is only three, in others six; and still there is a trifling loss ; while iu some plaees only one is employed, and the waste is eonsequently enormons. The amalgam, containing perhaps oneeighth or one-niuth of silver, (the proportion of mercury beiag iacreased by un addition of fluid mercury, when aecessary, to the lavedere, to cateh the particles of amalgam, aad ealled the bano,) is placed in long, sleeve-like bags of strong canvas, drained and pressed by twisting, to exelude all the mercury possible, and made iato balls or cakes for distillation. ‘he expressed mercury is submitted a secoad tine to the same filteriug operation, and yields a small hall, oae-fifth per cent. generally remaining with the mereury. The dry amalgam, called “pella,” coatains from eighteen to twenty-eight (generally twenty-two) per cent. of silver, dependeat on the state of ageregation of this metal in the ore, and the degree of pressure employed. The remaiuing operations of distillation and smelting are too well known to require description. The refuse of the washing vats, the “jal,” or “ eahecilla,” as they eall it here, was formerly permitted to run out into the creek, and sold at about $8 or $10 the torta to aset of men named “despolyilladores,” or eoacentrators, whose hnsiaess it was to extract the “ polvillos’—the metallic deposit containing silver aud a little amalgam which escaped the vats— for sale to the origiaal proprietors. ‘This they did by heapiag them up 0a arude “table dormaate,” aa iaclined plane, whout eight feet square. Having piled up the ore at the head of the table, the despolvillador, seated at the foot, throws water gently oa it with a horn spooa, aad the light particles floy away with the stream and are rejected, while the heavier arrange themselves aear the place of original deposit, aad after two or three washings are saffciently eonceatrated for removal. After a preliminary washiag, generally with salt, they are returaed to the mills, or, whea coataining copper, used in the preparation of magistral. The quaatity as well as ricbaess varies wonderfully ia different ores, or different griadiag of the same ore, the former varying from onefonrth to thirty per cent. Ia Guanajuato, they are trifliog—perbaps not over two per ceat., aad by this hand-process cost six to eisht reals the arroba of twenty-five nouads, but many haciendados bave lutely iatroduced a machine, sometbiug like an Kuglish “ buddle,” in which the ores are arranged ruuid the circumference of @ great shallow busia of brick and mortar, and irrigated hy many long tin tuhes, Project-. ‘per ceut. of sulphate of irou, three to four per iug from a revolving cask filled with water in the center. ben worked entirely by hand, it employs from three to fonr nen, and reduces the cost of * polvillos” to Hlteen or tweuty cents the arroha. CHARACTERISTICS OF" THE MEXICAN ' ARASTRA.” For ages the arastra his been the favorite mode in Mexiao of extracting gold and silver from their containing rocks, and all experience foes to prove that it is the surest mode of extracting all the metals from the ore, that has ever been tried by the grinding and amalgamating process. As an amalgainator, the arastra stands unrivaled. Notwithstanding they have been thrown aside repeatedly by onr go-ahead operators, still they revert back to the “ primitivo arastra” as u last resort against an utter failure in their mining enterprises. Now it occurs to me, that instead of abusing the slow aud sure arastra, we should stndy the priaciple upon which it. works, and endeavor to improve upon its strueture, thereby increasing its effieiency and usefulness. ‘Yhere is no process now iu use that will reduee ores so eompletely as the arastra, and itis well known by praetieal men that gold cannot be thoroughly ex. tracted until the ore is eompletely reduced to . the fineness of gold itself; for a course grain . of sand may contain several fine partieles of) gold. Stamps eannot reduce the ores so fine as an arastra. for the reason that, ds soon as it is reduced to sand, the blow of the stamp forees it with the water from under the blow; asthe water gives place to the blow, of the stamp it takes the fine sand with it, and the blow falls upon the eoarse quartz that remains behind. It appears to me that the stamp and arastra should work together—one to break the mass into eoarse sand and the other to reduce it to the required fineness to complete the process. Q By “ patio” the loss of gold is twenty-five to thirty-three per eent. on the assay, and in some . places as high as forty per eent. ‘The “ pol-. villos,” which are the metallie portions (principally sulphides of iron, rieh in silver) remaining fron the washing “torta,” always eontains gold. ‘They arc treated a seeond time to obtain whatever gold and silver they may hold, but they will not yield them hy tbe eomaion method without a preliminary operation. It may be quite probable that the gold in these polvillos exists us a sud-sulphide. Vhe magistral is generally manufaetured trom the sulphide of copper, eontaining, before calcination, from six to fifteen per eent. of that metal. ‘The furuaces in which this ore is ealeined are ealled comalillos. ‘I'hey have a duuble hearth, the roof is almost or quite flat, and the bre-place in tho eenter and running longitudinally, so that the flame plays sideways. About eight arrobas of the ground ore mixed with a few handfulls of common tahle-salt is a charge for each hearth. ‘The fire is then gradually increased and the ore almost constantly stirred for the space of six to eight honrs, whien the doors and other openings are elosed to exclude the air. ‘Nhe percentage ohtained, according to the ore, is frum thirty to filty per eent. of sulphate of copper, seven to twelve cent. of copper, not availuhle as sulphide, and oue to three per cent. of copper as oxyd. Would aot the low grades of our eopper ores, if treated as above, not he profitable for the produetioa of sutphate of copper, which eonsumptioa is daily more and more inereased? CHEMICAL THEORY OF THE PATIO PROCESS. Of the rationale of the patio process many views have been given. All the olden theories supposed the formation of a chloride of silver from the electro-ehemieal action of the sulphate of copper, salt and mereury on the ore— a doctrine whieh every praetical chemist, acquaiuted with the pheuomena presented. knew to be at variance with the truth; chloride of silver never being present except aceidentally and ia minute quantities (whea aot found in the ore), and rather impeding than facilitating the operation. It was reserved for John A. Browning, an English geatleman, long resident in Spanish America, and favorably known for his practical and scientifie knowledge of the reduction of silver ore, tv propose a theory at oace simple, intelligihle, fulfilling all the requisites, and explaining all tbe phenomena of the “ benefieio de patio.” He supposes that a diehloride of eopper is formed simultaneously with the proto-chloride of mereury; by the actioa of this latter metal on the proto-eliloride ot eopper present, this di-ehloride absorbs an atom of oxygen from the.air, heing eonverted into aa insoluble oxy-ebloride, whieh dissolving in the excess of satt, eommunicates its oxygen to the sulphur of the sulphuret of silver ia thé ore, with formation of sulphnric acid and metallie silver; then going haek for aaother dose of oxygea to reseat the proeess “ ad infinitum,” actiag the part of the quadroxyd of-nitrogea in the manufacture of sulphuric acid. Metalhe silver beiac thus formed from the first, we can readily understand why in a well managed torva there is aever more thau an inappreciable quautity of chloride of silver preseat at . auy stage of the process. Dr. Browniag hag based a new ingenioas, rapid, and economical “ beneticio de patio,” upon this theory. ‘Ihe length of time required, in Guanajuaty to obtain the silver is from eighteen to forty days, according to the season, matageient and docility of tbe ores. ‘lhe loss of silver on the first assay is variously stated from one to six (and in vae case twelve) per cent., most of which is regained in the polvillos; that of mereury fifteen to eighteen per cent. of the

amount employed, which is partly consunied (iu the chemical reactions) aud partly lost mechanically. Sonneuschmidt, a nsually careful and reliable authority, asserts that he never was able to detect the most insignilicant traces of merenry in the cabecilla. { cannot coneeive how he permitted himself to fall into so gross an error. In other parts where less care is used, these losses rise sometimes to thirtyfive or forty, and twenty-four per cent. of silverand merenry. ‘Ihe average fineness of the silver, exclusive of the alloy of gold, one-half of whieh at least is lost in the patio, may be put down at 988 1,000. ‘The whole expenses are averaged at forty-three per eent. for grinding alone; loss of mercury, ten per cent. (amounting to over a million pounds annually, in Mexico) ; the product of silver being estimated at 900,005 pouads, extracted from 260,000 tons of ore. Sueh an influence has the value and eonsequently the loss of mereury in the product of silver, that when the price of the former rose in the last eentury it diminished in six months the quantity of silver re duced fifty-five per cent., or more thaa half. In addition to the ingredients mentioned at the commencement—and which have been in use ever sinee the aceidental discovery of the. “ beneficio de patio” by Bartolonie de Medina— several others have been recently introduced to diminish the loss of mereury, and with eonsiderable sneeess. They cunsist chiefly of preeipitated eopper, and amalgams of zinc, eopper, or iron, and are employed instead of lime to“ eool” the torta. They have thisadvantage over lime, that the mercury instead of being precipitated as an oxyd and lost, is partly revivified by the eleetro-positive metal, and augments the product. ‘They were lirst introdueed by M. Lauckner, some years ago, nnd from ignorance have inet with much opposition, hut their importance may be judged from the fact ‘stated above, of the influenee whieh slight fluctuations in the value of mercury alone have upon the economy of the proeess, and anything tonding to diminish this sonree of expense would be feltimmediately throughout the whole miniug regioa. [To be Continued.} The Dyke in the Whitlatch Union, In our notice of the Whitlateh Union inine, tivo weeks since, we alluded to the report that the workmen some time since struck a dyke, in eonsequence of which the lead was lust, and ofter eonsiderable search to find it again operations were suspended entirely for some two or three months. In allusion to this matter a eorrespondent writes to the Reese River Reveille as follows ; An erroneous opinioa is eatertained by some of the existence of a “dyke” in this eelebrated mine. It is truly deplorahle that so good a mine as this should have suffered so inuch from a desease known as dyke on the brain. 'lhat, the Whitlateh vein is eut by dyke is aeither supported by theory or fact, as proven by the extensive exploratious that have been made. Yon are misinfurmed as to the fact of work having heen bronght to a stand still by the interposition of alarge dyke of porphyry aud elay cutting tho vein at oblique angles. I have worked ia the mine six montbs and aever saw it. “The investigations were earried on principally underground, and were characterized by Dr, Jackson as resembling the frantie efforts of a drowning beaver to eseape pursuit, rather than the sober iavestigations of intelligent workmeu.” This was tbe nnkindest cut of all. Admitting the dyke theory to be correct, mneh of the work was well directed. But that theory is abused, and I do aot hesitate to tuke issue with the learned gentlemen who adupt such views. The fact is this mine is out of the regioa of extensive movements, and is eut by two perpendicular seams in the shape of asickle the fret making its appearanee between tbe ehloride and sulphurets. ‘The conneetion has been made here, but itis hy no wise a eontinuous vein, passing hy like the blades of a pair of shears, the chloride belt seeming to be lifted up while the snlplnret seems to iacline at a greater angle. All efforts so far have failed to solve the mystery as to how the ledge is at the second fault. But I predict ‘no difficulty in the way if they will abandon the dyke theory, look for the ledge where they lost it, a thing not yet doae, drift on the line of the movement, and ere long we may look with pride as we were wont to do, oa oae of the best mines of Nevada. A wine of steamships between France and Aspiawall will he established and ready to-go into operation sometime duriag next month. {Written for the Mining and Scientific Press. ] From the Slate Range Mines, Eas. Press :—Our regular monthly mail arrived on the 5th nlt., with a fine package of your interesting papers, including that of May 6th, contaioing a’ paragraph coucerning our district, for which we are much obliged. I would, however, ask, if convenient, that you would correct the last statement that “ four loada of sage brash rnas the engine twelve hours,” to twenty-four or over. It may bo of others, situated as we are among rieh mineral leads in a desert conntry, that the fuel we use is not sage-brush, hut a little hrush in size and weight equal to a lady's open parasol, and when plucked up and thrown into windrows, is frequently blowa by the gusts of wiad clear out of sight. Yet with it we can in tweuty ntinates raise steam and start the stamps. It grows all over the plains, mixed with greasewood, which is coarser and larger and full of oil. Our lead eontinaes most enconraging, and or fifty stamps could he kept eonstantly running from it if we had them. No selection of rock is made, bat all between the casings from three to eight feet is passed through the mill. Messrs. Jeffrey & Co. (Cornish miners of much experienee) speak of the Rochester lead, in respect to its conrse, width and quality, as superior to any gold lead they have ever seen. In May last, a party of Indians visited the deserted eamps of the Austrian and Broman Co’s., on the hill, three or four miles from us, and destroyed and earried off considerable property, including ten jacks, belonging to tho Roehestvr eompany, which we had out to pasture, in a eafion, not far distant from our eainp. Mr. Senrles, with 1 dozen of his men, called on them, drove them out ond broke up their camp, and recovered some of their missing urticles. Bntthe jacks were all eaten or jerked. A gold head, ring, and some wheels of a watch wele found ainong their traps, which is almost sure to have belonged to Geo. Yarbrough, who was killed in EH] Paso last Angnst. In the party was a hig-footed Indian, whost track ‘vas seen in conneetion with the Yarbrough murder . On the 2d of June, while Messrs. John E. Yates and Jaecoh Baaer (einployees of this Co.) were trying to dig out a missed blast, in a cistern they were sinking, the charge exploded, throwing them some.feet with great force. Yates received a terrible gnsh oa the face, laying open the right side from the ear tu the corner of the mouth and down to the point of the chin. ‘This was neatly sewed up by Engineer Harvey, and is now well healed. One of his feet wns badly bruised or wrenched and has not yet recovered. Baner was badly burned in the eyes, face nad wrists and has not yet reeovered the use of the left eye, and there is dauger of its heiug permanently im-~ paired. 4 Yesterday, July Ast, Captain MeElroy and ten nren of his exvalry eompany, stationed at Camp Drum, Wilmington, arrived with two teams loaded with baggage and forage, and on Tuesday. the 4th, they are to stort ont oaa raid upon the Indians. Cc. W. T. Slate Range, July 2d, 1865. New Hay Press—The Petaluma Argus gives the following description of a hay press reeently invented by Mr. Wm. Moeh, of Sonoma eounty. It appears to be a most complete aad serviceable machiue. Itsadvantages eaa be noticed hy any one at all conversaat with the use of such machines. It is deseribed as follows: ‘“‘The press is worked hy common horse-power, nad the team is kept in constaat motiva. ‘The press is fed just as grain is fed into a thresher, nnd the only interruption to this is in shipping the hale into a false ehamber, which requires hut a few seconds of time. It requires an aetive hand to tie the hale’ and have the false chamber in readiness to reeeive the next one. ‘This diseharging apparatus aloae isa elear saving of time equal to the daily lahor of one man. ‘The bay passes between rollers into an oscillating chamber, where it falls in regular esheets or folds, and makes a compaet hale so square aad regular in shape‘that they cau be piled up in‘almost ag mueh regularity as brick. On trial, it turaed out a bale every three aninutes three feet six inches long, two feet deep aad twenty-two inches wide, of aa average weight of ahout one hundred and fifty pounds,and the hay was of the very dryest aud lightest character,” Cannon Castine IN Marrposa.—Messrs. Wileox & Yousc, founders, at Bear Valley, Mariposa county, recently cast a cannon for home use, which they presented tothe Union men of Hunter’s Valley, Mariposa county.