Volume 08 (1864) (474 pages)

The Mining and Scientific Press. 179 exeaped in abundanee frum the stamp pits, was deep red brown, or hermatite red.’ Again, he found oue-third of the gold remained after roasting, in evme manner nssocinted with the sulphnret of silver, and other products formed by the process of roasting. Degenhardt las an opinion that the gold forms n sulphnret and ts perhaps earried off through the chimney, on account of the silver, which formerly wns alloyed by the gol: having entirely disnppenred dnring the proeess of roasting. Philips in his + Metallurgy.’ says : ‘Gold is uot directly attacked by sulphor at nny temperature ; but when fased with the alkaline sulphurets, is rapidly neted on with tho formation of u donble sulphuret, in whieh the sulphuret of gold aets the part of nn aeid.’ “Tan fully impressed with the belief that the ore if ever roasted will canze yon a loss of that gold, whieh could have becn much easier ascertained by sinply stamping it, and enusing it to pass over mercnry or skins.’” — ILS. Correspondence. Whether the loss from roasting, results maiuly fron the earrying nway of the extremely fine particles of gold by the upward current of nir from the burning mass, as a light breath of wind cnrrics off the leaf gold in a guilder’s room; or whether some chemicnl change in the gold oceurs by whieh it is oxydized ; or whether the loss results from suhlimation nre matters with regard to whieh there is yet much diversity of opinion. All are ngreed, however, that serious loss nrises from hoth the first and third suppositions ; hnt with regard to the “ oxydization ” much donbt exists —althnugh there is great probability that such a chemical chauge may take place to n limited extent. , Whiutever difference of opinion may exist withregard to the enuses of loss, the practieal qnestion of the economy of roasting is now very definitely settled among European operators iu gold ores, nad it shonld be considered n couceded fact among nur own miners, tbat gold or silver ores roasted, either in open heaps or reverberntory furnaces, or in any other manner, will not yield ns much ore as a similar portion of the same ore taken from the same heap, nnd equally ricb, will do withont heing roasted. SULPIURETS—THFIR NATURE AND TREATMENT. It is a mistaken idea, nnd one which has too gengenerally obtained, that practical gold mining needs but little or no study beyond that necessary for the mere mechanicnl extraction of the ore from its veins, nnd the most economical method of redueing the sane, preparatory tu its passage over the blankets or through some approved apparatus for amalgamntion. In no part of the world is this idea more general than in Califurnin. This fact arises, no doubt, in the circumstance that here are found great numbers of veins exceedingly rieh in the precious metal, where but very little attention is needed to realize almost fabulous returns. Here, men in their anxious haste to get rich, cannot stop to study or closely exnmine, but pass on from one loculity to another, in the eager search for a great strike,” where they may take ont their “ pile ” in a few months, or years at most, and then go elsewbere to enjoy their gains. While a scanty few are succeessful in such practice, the reat mags, tbus goon from one location to another for months and years, until they hecome perhnps discouraged and disgusted with the very idea of mining. It wns owing to this latter charaeteristie of our miners that_quartz mining was so well nigh abandoned a few years since in this State ; itis to the wiser policy of patient and intelligent application—of study and close examination, that we now hehold tbis interest taking a leading ‘position in our industrial pursuits. It is to he hoped that the period is not far distant when a full and thorough itivestigation of the properties and condition of our mineral veins shall be made by men of energy, and of acquirements and experieuce, whieb shall fully qualify them for such a task. Each class of mineral veins isa study of itself. The study of iron alone will occupy a life time; so niso of lend, copper, silyer or gold. ‘Tbe masses of operators, as we have clsewbere said, canuot go into the intricacies of such stilies, but with a very little uttention they may be enabled to make an application ef general principles to particular localities. Jt is a proper exposition of these principles and their application to some of our most important veins that we now need. ‘This isa work, the onus of which should fall upon the government. Of this matter we nlay speak more at length at another time. We set ont to give an account of the nature and treatment of sulphurets, and will now return nenin to our subjeet. The snlphuret of iron, or iron pyrites, although one of tlhe most common and widely diffused minerals on the globe, is nevertheless one uf tho least understood. Many of the phenomena conneeted with this mineral are very curious nnd interesting, notwithstnnding the little that is nenrately known of them. The very combination, even of this mincral, isa matter of doubt. Although it is well known that it consista of sulphur and iron, still the peeuliar state iu which they nre combined, and the condition of their separnte ingredients during the period of combinatiou, are matters which have never yet heen explained. It has not yet been shown whether these pyrites cousist of an aggregate of sulphur nnd iron, ora chemical compound of the two. Some veins abound with bright glistening pyrites of a cuhieal form ; somo with those of n dull black color ; and others still with cellular cavities partially filled with soft and almost impalpable powder, varying from a light to n dark brown, which is the resultant of a natural decomposition of the pyrites, and is ealled the sulphate of iron. Some of the cavities of the eellular or “ honey comb ” quartz eontain the pore flour of sulphur unmixed with anything save, perhaps a trace of gold. The iron has entirely disappeared, tbrough the unbroken and compact mass of quartz, without leaviug even 2 stain to mark its former habitation, or ita exit. Howit has thus dis appeared none have yet toldus. That these cavities once contained chrystals of sulpburet of iron there can be no doubt. What mystic power has formed them, filled them with hard and perfeet ehrystals, and subsequently changed their condition “and removed a large portion of their component parts without in the least disturbing the nicely formed nnd delicate angles, or any portion of tho surronuding and relractory silica, has never yet been satisfactorily ascertained. There can he little doubt, however, that galvanism, the great supposed agency of Nature iu her wondrous and inyisible laboratory, has acted an important part in conductiug this curious process. It has long heen known that iu many great gold bearing veins, these sulphurets, although oecupying hut a very small portion of the mass of the ore, (say from three to eight per cent. only) nevertbeless eontain a large proportion, and in many eases a large majority, of the gold contained in the entire mass. It is furthermore well known that the gold is more readily collected from the quartz itself, than from tbe sulphurets, and tbe great diserepency hetween the asgay and the practical yield, is mainly owing to the refractory nature of the sulphurets in yielding up their portion of the gold inthe working proecss. Hence it becomes absolutely necessary that the szdphurets should become a subject of careful and continuous study. Experiments have fully shown that a process suitable to one class of sulphurets will not answer so well for another. ‘This fact was suflicieutly proved by the Russian experiments already alluded to, in the following manner, and with the anuexed results. 1st. A giveu quantity of argentiferous pyrites, not containing gold, and in which tbe actual quantity of silver was determined by assay, was taken and to them were added agiven quantity of powder of gold chemically prepared. ‘The mixture was then roasced upon a tile, in a muffle. This experiment was repeated several times, with the following results, viz : 14, 16, 20,22, 26,37 and 40 per cent. less gold was obtained than was originally put into the mass! 2d. ‘fo demonstrate that the presence of sulphur tity of powder of gold was mixed with an ore of iron, Coutaining the oxide of irom and water and ecarbonic avid, but iu which was neither gold or sulphur. ‘The mixture was rousted as nbove, and the results showed a Joss of from seyeu to tweuty-three per cent. of gold dust. 3d. Experimenta with different lots of pyrites nixed with the same sort of iron ore as above, into which given quantities of gold were thrown, showed losses varying from four to twenty-four per cent. 4th. Gold nixed with ordinury voleani¢ sulphur, nnd treated precisely as nbove, lost ouly four per cent., probably beenuse the powder of geld was so suddeuly melted into an ugglomerated mass that there was no opportunity for it to pass off in its originul form with the vapors of the sulphur. The unavoidable eonclusion from these experiments is, that gold, when mixed with suhstances susceptible of volatizntion hy the action of hent, volatizes with them, i proportions commensurate with the peculiar condition of the bases with which it 7s mixed. The officer in his Report to the government nlso states that the more heat employed in the process of roasting, the greater was the loss of gold. It appears from the report to be n very marked fact that the loss varied very materially with tbe diflerent qualities and eonditions of the’ore. There is one circumstance noted hy M. Bassingnult, who, among others, has repeated these experiments, which, if correct, is of considerable importance. He found that hy the addition of common salt to the mass during the roasting proeess, the result showed mucb less loss than without that addition! IMPORTANT DEVELOPMENTS. The Ophir company, during the past weck, has struck some valuable ore about sixty feet north of the Central Co’s line, in a new winze which they are sinking from their lower gallery. ‘he point whcro this ore has been struck is nearly one hundred feet helow the lowest place at which the mine has yet been regularly worked. It is at ahout the level where their seventh gallery will he commenced. A small quantity of ore only has been taken out, but it is very rich ; computed to be worth from $800 to $1,000 per ton. The extent of the deposit of course cannot be known until they commence drifting upon it. We understand it to be the purpose of the Superintendeut to run a gallery from this point, along the direction of the }ead and through the Mexican mine, to intersect the maiu shaft which is now heing put down nt a point ahout one hundred feet north of the Mexican north live. This drift or gallery will thns be ahout 340 feet7in length. This strike may be regarded as one of the most important developments recently made in the Comstock lode ; as all the developments hitherto made, at any considerable depth on this lead have been anything but promising, considering the extraordinary richness of the ore found near the surface. This strike is highly eneouraging to the adjoining “ Mexienn” nnd “ Central ” companies, who are sinking toward the same level. Something new and important is also reported from the Gould & Curry, the past week. This company is now said to be getting out ore quite different in appearance from anything hitherto found in tbe Comstock lode. This ore is the color of raw umber nnd contains streaks of a bright blue miueral, similar to blne cnrhonate of copper, and is filled with bright scales of native silver. We do not know whether a large amount of this character of ore is likely to he found. The above developments, ndded to the genernlly encouraging appearance of the mines in that region at this time, appear to he creating a renewed confidence in the permanance and ultimate profit of the mining interest generally. Over The Mounraixs—The Virgioia Union says a great many ladies are coming over from California this spring. The Union is glad to see them coming —the society of the ‘Territory needs tbe ameltiorawas not the cause of tho loss of gold, a givon quan-. ting influence of woman,

The Mining and Scientific Press. 179 exeaped in abundanee frum the stamp pits, was deep red brown, or hermatite red.’ Again, he found oue-third of the gold remained after roasting, in evme manner nssocinted with the sulphnret of silver, and other products formed by the process of roasting. Degenhardt las an opinion that the gold forms n sulphnret and ts perhaps earried off through the chimney, on account of the silver, which formerly wns alloyed by the gol: having entirely disnppenred dnring the proeess of roasting. Philips in his + Metallurgy.’ says : ‘Gold is uot directly attacked by sulphor at nny temperature ; but when fased with the alkaline sulphurets, is rapidly neted on with tho formation of u donble sulphuret, in whieh the sulphuret of gold aets the part of nn aeid.’ “Tan fully impressed with the belief that the ore if ever roasted will canze yon a loss of that gold, whieh could have becn much easier ascertained by sinply stamping it, and enusing it to pass over mercnry or skins.’” — ILS. Correspondence. Whether the loss from roasting, results maiuly fron the earrying nway of the extremely fine particles of gold by the upward current of nir from the burning mass, as a light breath of wind cnrrics off the leaf gold in a guilder’s room; or whether some chemicnl change in the gold oceurs by whieh it is oxydized ; or whether the loss results from suhlimation nre matters with regard to whieh there is yet much diversity of opinion. All are ngreed, however, that serious loss nrises from hoth the first and third suppositions ; hnt with regard to the “ oxydization ” much donbt exists —althnugh there is great probability that such a chemical chauge may take place to n limited extent. , Whiutever difference of opinion may exist withregard to the enuses of loss, the practieal qnestion of the economy of roasting is now very definitely settled among European operators iu gold ores, nad it shonld be considered n couceded fact among nur own miners, tbat gold or silver ores roasted, either in open heaps or reverberntory furnaces, or in any other manner, will not yield ns much ore as a similar portion of the same ore taken from the same heap, nnd equally ricb, will do withont heing roasted. SULPIURETS—THFIR NATURE AND TREATMENT. It is a mistaken idea, nnd one which has too gengenerally obtained, that practical gold mining needs but little or no study beyond that necessary for the mere mechanicnl extraction of the ore from its veins, nnd the most economical method of redueing the sane, preparatory tu its passage over the blankets or through some approved apparatus for amalgamntion. In no part of the world is this idea more general than in Califurnin. This fact arises, no doubt, in the circumstance that here are found great numbers of veins exceedingly rieh in the precious metal, where but very little attention is needed to realize almost fabulous returns. Here, men in their anxious haste to get rich, cannot stop to study or closely exnmine, but pass on from one loculity to another, in the eager search for a great strike,” where they may take ont their “ pile ” in a few months, or years at most, and then go elsewbere to enjoy their gains. While a scanty few are succeessful in such practice, the reat mags, tbus goon from one location to another for months and years, until they hecome perhnps discouraged and disgusted with the very idea of mining. It wns owing to this latter charaeteristie of our miners that_quartz mining was so well nigh abandoned a few years since in this State ; itis to the wiser policy of patient and intelligent application—of study and close examination, that we now hehold tbis interest taking a leading ‘position in our industrial pursuits. It is to he hoped that the period is not far distant when a full and thorough itivestigation of the properties and condition of our mineral veins shall be made by men of energy, and of acquirements and experieuce, whieb shall fully qualify them for such a task. Each class of mineral veins isa study of itself. The study of iron alone will occupy a life time; so niso of lend, copper, silyer or gold. ‘Tbe masses of operators, as we have clsewbere said, canuot go into the intricacies of such stilies, but with a very little uttention they may be enabled to make an application ef general principles to particular localities. Jt is a proper exposition of these principles and their application to some of our most important veins that we now need. ‘This isa work, the onus of which should fall upon the government. Of this matter we nlay speak more at length at another time. We set ont to give an account of the nature and treatment of sulphurets, and will now return nenin to our subjeet. The snlphuret of iron, or iron pyrites, although one of tlhe most common and widely diffused minerals on the globe, is nevertheless one uf tho least understood. Many of the phenomena conneeted with this mineral are very curious nnd interesting, notwithstnnding the little that is nenrately known of them. The very combination, even of this mincral, isa matter of doubt. Although it is well known that it consista of sulphur and iron, still the peeuliar state iu which they nre combined, and the condition of their separnte ingredients during the period of combinatiou, are matters which have never yet heen explained. It has not yet been shown whether these pyrites cousist of an aggregate of sulphur nnd iron, ora chemical compound of the two. Some veins abound with bright glistening pyrites of a cuhieal form ; somo with those of n dull black color ; and others still with cellular cavities partially filled with soft and almost impalpable powder, varying from a light to n dark brown, which is the resultant of a natural decomposition of the pyrites, and is ealled the sulphate of iron. Some of the cavities of the eellular or “ honey comb ” quartz eontain the pore flour of sulphur unmixed with anything save, perhaps a trace of gold. The iron has entirely disappeared, tbrough the unbroken and compact mass of quartz, without leaviug even 2 stain to mark its

former habitation, or ita exit. Howit has thus dis appeared none have yet toldus. That these cavities once contained chrystals of sulpburet of iron there can be no doubt. What mystic power has formed them, filled them with hard and perfeet ehrystals, and subsequently changed their condition “and removed a large portion of their component parts without in the least disturbing the nicely formed nnd delicate angles, or any portion of tho surronuding and relractory silica, has never yet been satisfactorily ascertained. There can he little doubt, however, that galvanism, the great supposed agency of Nature iu her wondrous and inyisible laboratory, has acted an important part in conductiug this curious process. It has long heen known that iu many great gold bearing veins, these sulphurets, although oecupying hut a very small portion of the mass of the ore, (say from three to eight per cent. only) nevertbeless eontain a large proportion, and in many eases a large majority, of the gold contained in the entire mass. It is furthermore well known that the gold is more readily collected from the quartz itself, than from tbe sulphurets, and tbe great diserepency hetween the asgay and the practical yield, is mainly owing to the refractory nature of the sulphurets in yielding up their portion of the gold inthe working proecss. Hence it becomes absolutely necessary that the szdphurets should become a subject of careful and continuous study. Experiments have fully shown that a process suitable to one class of sulphurets will not answer so well for another. ‘This fact was suflicieutly proved by the Russian experiments already alluded to, in the following manner, and with the anuexed results. 1st. A giveu quantity of argentiferous pyrites, not containing gold, and in which tbe actual quantity of silver was determined by assay, was taken and to them were added agiven quantity of powder of gold chemically prepared. ‘The mixture was then roasced upon a tile, in a muffle. This experiment was repeated several times, with the following results, viz : 14, 16, 20,22, 26,37 and 40 per cent. less gold was obtained than was originally put into the mass! 2d. ‘fo demonstrate that the presence of sulphur tity of powder of gold was mixed with an ore of iron, Coutaining the oxide of irom and water and ecarbonic avid, but iu which was neither gold or sulphur. ‘The mixture was rousted as nbove, and the results showed a Joss of from seyeu to tweuty-three per cent. of gold dust. 3d. Experimenta with different lots of pyrites nixed with the same sort of iron ore as above, into which given quantities of gold were thrown, showed losses varying from four to twenty-four per cent. 4th. Gold nixed with ordinury voleani¢ sulphur, nnd treated precisely as nbove, lost ouly four per cent., probably beenuse the powder of geld was so suddeuly melted into an ugglomerated mass that there was no opportunity for it to pass off in its originul form with the vapors of the sulphur. The unavoidable eonclusion from these experiments is, that gold, when mixed with suhstances susceptible of volatizntion hy the action of hent, volatizes with them, i proportions commensurate with the peculiar condition of the bases with which it 7s mixed. The officer in his Report to the government nlso states that the more heat employed in the process of roasting, the greater was the loss of gold. It appears from the report to be n very marked fact that the loss varied very materially with tbe diflerent qualities and eonditions of the’ore. There is one circumstance noted hy M. Bassingnult, who, among others, has repeated these experiments, which, if correct, is of considerable importance. He found that hy the addition of common salt to the mass during the roasting proeess, the result showed mucb less loss than without that addition! IMPORTANT DEVELOPMENTS. The Ophir company, during the past weck, has struck some valuable ore about sixty feet north of the Central Co’s line, in a new winze which they are sinking from their lower gallery. ‘he point whcro this ore has been struck is nearly one hundred feet helow the lowest place at which the mine has yet been regularly worked. It is at ahout the level where their seventh gallery will he commenced. A small quantity of ore only has been taken out, but it is very rich ; computed to be worth from $800 to $1,000 per ton. The extent of the deposit of course cannot be known until they commence drifting upon it. We understand it to be the purpose of the Superintendeut to run a gallery from this point, along the direction of the }ead and through the Mexican mine, to intersect the maiu shaft which is now heing put down nt a point ahout one hundred feet north of the Mexican north live. This drift or gallery will thns be ahout 340 feet7in length. This strike may be regarded as one of the most important developments recently made in the Comstock lode ; as all the developments hitherto made, at any considerable depth on this lead have been anything but promising, considering the extraordinary richness of the ore found near the surface. This strike is highly eneouraging to the adjoining “ Mexienn” nnd “ Central ” companies, who are sinking toward the same level. Something new and important is also reported from the Gould & Curry, the past week. This company is now said to be getting out ore quite different in appearance from anything hitherto found in tbe Comstock lode. This ore is the color of raw umber nnd contains streaks of a bright blue miueral, similar to blne cnrhonate of copper, and is filled with bright scales of native silver. We do not know whether a large amount of this character of ore is likely to he found. The above developments, ndded to the genernlly encouraging appearance of the mines in that region at this time, appear to he creating a renewed confidence in the permanance and ultimate profit of the mining interest generally. Over The Mounraixs—The Virgioia Union says a great many ladies are coming over from California this spring. The Union is glad to see them coming —the society of the ‘Territory needs tbe ameltiorawas not the cause of tho loss of gold, a givon quan-. ting influence of woman,