Volume 39 (1879) (446 pages)

22 MINING AND SC IENTIFIC PRESS. (July x2, 1879. Ornamental Cottage. Ws give on this page a design by J. H. Hobbs & Sons, of Pbiladelpbia, which may please some of our readers, who enjoy tbe ornamsntal in house building, Althougb this design inclines toward the elaborate and ths ornate in the style ofits fiuish, there is nothing excessive or not in keepiug with the general plan. It is well adapted for a suburban or village cottage, ratber than fur a more strictly rural situation. Its form gives the exterior a yariety of outlines which would distinguisb it from most village houses as they are commonly dssigned. By reference to the ground plan it will be seen that it is arranged for comfort and convenience, There is no waste room. Ths three Principal rooms open directly into the front hall, which being room-like and large in its dimensions gives the impression of spaciousness to one entering the house. There is also a fine stairway upon one side of the hall. Attached to tbe kitchen, there is a large store-room, also a pantry. There can he a hack stairway arranged betweeu the dining-room and kitchen, if desired, The second story, not shown in the engravings, is intended to be divided into four large chambers, each having a fireplace and clothes press. All the rooms arc free and have separate entrances to the upper hallway. ; Coocerniug painting a house with such a varied outline and uneven surface, the architects write nsas follows: ‘‘The paint should he only of one color, and trust to nature by the force of shade, sunshine aud reflection to gild, darken and playfully light up and tint the various parts, which she does with far more delicacy than the patcby red blues and other striped colors, we so often see disfiguring otherwise good and beautiful designs.” It should be remembered when the mind is occupied with ornament in architecture that good architecture consists in so arranging the parts, their projections, hights and quantities to produce the effect of fitness, propriety and elegance, not in baviug a handsome cornice, an exquisite bracket or any delicate carvings, but a certain modesty should pervade tbe whole and nothing should stand forth go ostentatiously as to rob the rest of their just powers of attraction. It will be noticed that this plan bas the equare bay window. We cannot refrain from speaking a good word for this form wherever it is in harmony with the general design, We bave found it much more satisfactory than the octagon sbape, both from the greater interior epace enclosed, the greater facility for viewing, and the harmony of tbe shape with a rectangular room within. In the plat of the first floor given in tbe engraving, the following are the rooms and Measurements: A, front porch; B, hall, 11 feet 11 inches hy 17 fect11 inches; C, parlor, 16 feet by 20 fest 7 inches; D, sitting-room, 13 feet 10 inches by 19 feet; #, dining-room, 17 feet 11 inches by 18 feet; #, kitchen, 16 feet by 17 feet 11 inches; @, store-room, 9 feet 1 incb by 9 feet 1 inch; H, side porch. Mining Decision. Tbe Supreme Court of the United States bas, as a oourt of last resort, decided the case of tbe Flagstaff silver mining company, of Utah, vs. Helen Tarhet, affirming the judgment of the Snpreme Court of the Territory of Utah. The following is the syllabus: : A location of a mining claim upon a lode or vein of ore, should be laid along the same lengthwise of the course of its apex at or near the eurface, aa well under the Mining act of 1866, as under tbat of 1872. If located otherwise, the location will only secure so much of the lode or vein as it actually covers. Fach locator is entitled to follow tbe dip of the lode or vein to an indelinite depth, though it carries bim outside of tbe side lines of the location; but this right is based on the hypothesis that tbe side nes substantially correspond with tbe course of the lode or vein at the surfacs, and it is bounded at each end by the end lines of the location, crossing the lode or vein, and extended perpendicularly downwards, and indefinitely in their own direction, Tf a location be laid crosswise of a lode or vein, so tbat its greatest length crosses tbe same instead of following the course thereof, it will secure only so much of the vein as it actually crosses at the surface, and the side lines of tbe location will become the end lines thereof, for the purpose of defining the rights of the owners. _A locator working subterraneously into the dip of the vein belonging to another locator, who is in possession of bis location, is a trespasser, and liable to an action for taking ore therefrom, Tbe case was referrcd to before in these columns, when the Territorial Court rendered its decision, and attention is now called to it because the question is settled forever beyond all controversy, Concenrratep sulpburic acid attracts water with such avidity that in a damp atmospbere it will double its volume in a few days, Chemists use itto dry air and otber gases, and to keen instruments, such as balances, dry, . Coal Mining at Mt. Diablo. {Extracts from Graduating Thesis of J. O’CALLAGHAN, University of California.] The coal measures of Mt. Diablo are situated in a range of hills balf way between ths summit of the mountain and the San Joaquin river. This range is parallel to the San Joaquiu, which is about five miles distant, and it is separated from Mt. Diablo by a deep valley. The altitude diminishes gradually from 1,700 feet in the western to 200 feetin tbe eastern part. The strata are tertiary, and are all elevated at an angle, probably by the mountain breaking through them. The general dip is to the north, being 32° in the western and 15° in the eastern part of the measures, which are about 12 miles long, as shown by tbe ontcrop of the strike which runs in a general east aud west direction. These strata are composed chiefly of heavy bedded sandstones, carbonaceous shales, clays and coal seams. J The mine of the Black Diamond Co. is situated in the most westerly portion, where the dip is greatest. -This region is deeply dissected hy narrow parallel canyons, which run from the San Joaqnin plains to the summit of this range of hills, The canyon in whicb this company’s mine is situated opens into a sort of DESIGN FOR AN OR ampbitheater, caused by tbe main canyon branching into three or four smaller raviues. Here are the hoistiug works, coal bunkers dumps, etc., while a few bundred yards down the creek is the towu of Nortonville, in which most of the miners live. _ Although there are four seams of coal in the Black Diamond Co.’e property, only two of tbese are workable. These are about 1,000 feet apart, borizontally. The upper or Clark vein is of an average thickness of 28 to 38 inches, not heing interstratified by slate or clay, but is all good workable coal, except where crushed hy tbe bendingfof the etrata. The lower or Black Diamond vein has an average thickness of from four to six feet, but it is not such good coal as the Clark vein, and it is more expensive First Floor. to work, tbe roof and the floor being composed of ehale and clay, : Opsning Up, Formerly these miues were worked by running in borizontal tunnels to the seams, but this was not profitable only to a limited depth, and this means of opening up is now entirely abandoned. In the case of a tunnel tbere is no outlay necessary for boisting or pumping, as tbe mine drains naturally. The next method of reaching the seam was by an inclined shaft or slope run in at right angles to tbe seam, and after striking it, a counter slope was sunk on the seam. The incline now in use, and through whicb most of the coal has heen boisted, is called the Mt. Hope slope. It is situated at tbe bead of the principal ravine, 797 feet above low water, and is sunk at an angle of 37° 15’ to the south, striking tbe Clark vein at a distance of 293 feet. At this level a gangway runs east and weston the seam, and on this, at a point 85 feet east of . . tbe foot of the Mt. Hope slope, is a counterslope sunk on the seam, and at present worked to a depth of over 700 feet. The slope and counter-slope are botb doubletracked, and strongly timbered every tbree or four feet. é The cars are hoisted by around tbres-quarterinch rope. This passes over a pulley three feet . in diameter and is then wound on a cylindrical drum six feet in diameter, the motion of whicb is regulated by a 12-foot fly wheel. The engine has a 14x30-inch cylinder, and boists a car in about 30 seconds, 2 The counter-slops is fitted with a similar plan for boisting. Though the slope was much better than a tunnel and had a greater production, still it is mucb inferior to a vertical sbaft for many reasons. Tbe incline necessitates a greater handling of cars and causes a greater loss of power. Two separate hoisting engines are needed, and one of these is underground, while only one engine is necessary for a shaft, and that one is on the surface near the boilers. The only objection toa shaft is the great outlay necessary for machinery, etc., before any coalis produced. But by using double cages and increasing tbe speed the production can be enormously increased. The Black Diamond ehaft is situated about 620 feet northwest of the Mt. Hope slope, being NAMENTAL COTTAGE 839 feet above water level. It bus a rectangular shape, the dimensions being 22 feet 4 incbes by 11 feet 10 inches from out to out. This is the most convenient form, there being no pressure sufficient to necessitate a round or square sbaft. It is divided into three compartments. Two are for hoisting, and are eix by nine feet inside, The third was designed for pumping, but is now used for ventilation, and contains a ladder which runs the whole depth. This shaft is very heavily timhered all the way down by one anda half foot Oregon pine, the sections being placed about two feet apart, and is a fine piece of work, requiring very little repairing. At regular distances down tbe shaft levels are run out to strike the seams. The distance between two levels measured on tbe eeam is called a ‘‘hft.” The lift is made as bigh as possible, because every level entails an additional expense; still the higbt is hmited by the difficulty of transportation and ventilation. The average hight of tbe liftsin this mine is from 300 to 350 feet, this variation being caused by the change of dip in the seams. At eacb etation there is a difference of level of eix feet between tbe levels running to tbe two seams, eo that by one etoppage, a car from eacb seam could be run on tbe double cage. Machinery and Hoisting Piant. In tbe case of the tunnel, a borse could be used to draw out tbe cars, and borse power could even heused as a motor to draw the cars up the slope; but steam now entirely replaces these more primitive means. There is a great saving by using steam, as the surplus power cau be utilized in pumping and carrying on many of tbe minor operations, such as surface transportation, running the screens, etc. When the Black Diamond tnnnel was sunk, a very extensive system of boisting macbinery was adopted. Attbe moutb of the shaft isa well-braced and substantial hoisting frame constructed of heavy pine timbers two feet square, ‘This frame is about 30 feet bigb, tbus affording ample room for the cages to come above the surface without hitting the top. This frame consists of six principal uprights all sligbtly incliued and bound together by a firm rectangular frame or top in which the pulley wheels work. Two of these uprigbts, in the liue of greatest pulling force, are much more inclined than tbe otbers so as to act as hraces, Tbe pulley wheels, two in number, are tbe large wheels over whicb tbe cable passes. The diameter of these is five or six feet, and they are provided with guides to prevent the cable shipping off. in the drums it is very important tbat the diameter be large, as a short bend ie very de. structive to iron rope, In Europe tbe average drum is 20 to 25 fest, while bere it is no more than five or six feet in diameter, Thers are two kinds of drums in use at these mines; the ordinary wooden cylindrical drum for round cables, and ths spool or bobbin drum for flat cables. The latter is used at the Black Diamond shaft. There seem to be many advantages of the flat cable and bobbin over ths round cable and cylindrical drum. _ The flat cable winds upon itself and thus by increasing the diameter at each winding prevents tbe acceleration of a descending cage, which if the shaft were deep would necessitats a conical drum in case of a round rope. The flat rope seems better than the round rope, as its diameter is less than that of round cable of equal strength. The flat rope can be mended easily and last for two or three years. Two bobbins are fixed on the same sbaft, and thus the engine bas to hoist ths weight of the cual, as the cage and empty car balance an equal weight of ths otber cage. By this means the motion is always uniform, The engine used at the Black Diamond shaft has two horizontal 24-incb cylinders with fiyefoot stroke, and the power is applied directly to the shaft, thus doing away with a fly-wheel. The foundation of the drum and engines is of solid brick built from bedrock, The steam is supplied to the various enginee by 10 large Cornish boilere, so connected that any two may be repaired without causing tbe others tostop. This great number is necessary because the ouly water available for use ie mine water, and as this is very sulphurous, incrustations form very rapidly. The steam pipes are packed in asbestos, but there is necessarily a great loss hy condensation in pipes many hundred feet long, The fuel used is the slack coal from the screenings, and many tons of this almost unsalable fuel are burned each day. Opening Out. Whether the seam be reached by an incline or by a level the same system of opening out and working the coal is adopted. The system here in use differs from the ordinary one on account of the steep dip and the thinuess of the seams. From the point where the level reaches the eeam a gangway is drifted to the right and left on the seam; the dimensions of this gangway are determined by the thickness of the seam, the strength of the roof and the requirements of transportatiou and ventilation. The average dimeneions in these minee are 8 feet wide at the floor, 5 feet wide at the roof, and 5 feet from floor to roof. By adopting this trapezoid form, the requisite width is obtained and the least support is removed from the roof, These gangways are given a grade of a few inches in a bundred feet. The floor consists of rolley-way and a rude channel on either eide for drainage. Faulting is a chief feature of this mine, and it causes great difficulty in drifting, Almost every case is that of a simple slip, in which the strata on the hanging wall have eunk, The direction of the gangway must then be changed until it again cuts the seam, and it must cut it in such a way that the foot wall of the seam is about four feet from the floor of the gangway, so that care can be easily loaded from the shoots, Working the Seam. Every 20 feet along the gangways on tbe seam sboots four feet wide are run up tbe seam, only the thickness of the eeam being worked out. Safety pillars of coal 20 feet square are left all along the upper part of the gangway. The face of the seam is thus worked by a eystem of irregular steps. As the coal is detacbed from the mass, it ie allowed to slide down the sboots on slides conetructed of sections of old boiler iron, which are laid so as to overlap one anotber. Thus by the simple action of gravity the coal may be transported several hundred feet, and by opening the mouth of the shoot it may be loaded into cars in the gangway. Timbering. Pine and redwood are the only materials used for timbering, All timbers are cut outside and are numbered eo tbat they can be sent in and fitted without further trouble. Tbe etations and levels being tbe most permanent, are strongly timbered witb the heaviest timbers. The method of timbering the gangways is very simple, consisting of two uprights surmounted by a cap piece or crown. The uprights are inclined, so as to shorten the crown piece without loeing space. The size of the timbere is -eigbt feet long by eight by ten inches in cross-section. These timbers need continual repairing, some being replaced every two or three weeke, On an average the timbering is replaced every three months, Tbe stopes are timbered witb redwood pieces fonr by six inches. Underground Traneportation. Tbe cars are of such a size that when loaded tbey can be easily handled by one man, The usual capacity is one ton of loose coal. They are made of heavy pine planks strongly handed with wrougbt-iron, The internal dimensions are: Length, six and onc-balf feet; width, two feet two incbes; hight, in front, two feet five inches; in rear, two feet eleven inches, These cars run on ordinary strap rails, which are epiked on wooden stringers. The gauge is three feet. Trains of from five to eix of tbese cars are drawn from tbe working parts of the minee to the sbaft by single borses. Tbe average distance is over one-third of a mile, Hoieting. The cage is made of iron and bas two plate

22 MINING AND SC IENTIFIC PRESS. (July x2, 1879. Ornamental Cottage. Ws give on this page a design by J. H. Hobbs & Sons, of Pbiladelpbia, which may please some of our readers, who enjoy tbe ornamsntal in house building, Althougb this design inclines toward the elaborate and ths ornate in the style ofits fiuish, there is nothing excessive or not in keepiug with the general plan. It is well adapted for a suburban or village cottage, ratber than fur a more strictly rural situation. Its form gives the exterior a yariety of outlines which would distinguisb it from most village houses as they are commonly dssigned. By reference to the ground plan it will be seen that it is arranged for comfort and convenience, There is no waste room. Ths three Principal rooms open directly into the front hall, which being room-like and large in its dimensions gives the impression of spaciousness to one entering the house. There is also a fine stairway upon one side of the hall. Attached to tbe kitchen, there is a large store-room, also a pantry. There can he a hack stairway arranged betweeu the dining-room and kitchen, if desired, The second story, not shown in the engravings, is intended to be divided into four large chambers, each having a fireplace and clothes press. All the rooms arc free and have separate entrances to the upper hallway. ; Coocerniug painting a house with such a varied outline and uneven surface, the architects write nsas follows: ‘‘The paint should he only of one color, and trust to nature by the force of shade, sunshine aud reflection to gild, darken and playfully light up and tint the various parts, which she does with far more delicacy than the patcby red blues and other striped colors, we so often see disfiguring otherwise good and beautiful designs.” It should be remembered when the mind is occupied with ornament in architecture that good architecture consists in so arranging the parts, their projections, hights and quantities to produce the effect of fitness, propriety and elegance, not in baviug a handsome cornice, an exquisite bracket or any delicate carvings, but a certain modesty should pervade tbe whole and nothing should stand forth go ostentatiously as to rob the rest of their just powers of attraction. It will be noticed that this plan bas the equare bay window. We cannot refrain from speaking a good word for this form wherever it is in harmony with the general design, We bave found it much more satisfactory than the octagon sbape, both from the greater interior epace enclosed, the greater facility for viewing, and the harmony of tbe shape with a rectangular room within. In the plat of the first floor given in tbe engraving, the following are the rooms and Measurements: A, front porch; B, hall, 11 feet 11 inches hy 17 fect11 inches; C, parlor, 16 feet by 20 fest 7 inches; D, sitting-room, 13 feet 10 inches by 19 feet; #, dining-room, 17 feet 11 inches by 18 feet; #, kitchen, 16 feet by 17 feet 11 inches; @, store-room, 9 feet 1 incb by 9 feet 1 inch; H, side porch. Mining Decision. Tbe Supreme Court of the United States bas, as a oourt of last resort, decided the case of tbe Flagstaff silver mining company, of Utah, vs. Helen Tarhet, affirming the judgment of the Snpreme Court of the Territory of Utah. The following is the syllabus: : A location of a mining claim upon a lode or vein of ore, should be laid along the same lengthwise of the course of its apex at or near the eurface, aa well under the Mining act of 1866, as under tbat of 1872. If located otherwise, the location will only secure so much of the lode or vein as it actually covers. Fach locator is entitled to follow tbe dip of the lode or vein to an indelinite depth, though it carries bim outside of tbe side lines of the location; but this right is based on the hypothesis that tbe side nes substantially correspond with tbe course of the lode or vein at the surfacs, and it is bounded at each end by the end lines of the location, crossing the lode or vein, and extended perpendicularly downwards, and indefinitely in their own direction, Tf a location be laid crosswise of a lode or vein, so tbat its greatest length crosses tbe same instead of following the course thereof, it will secure only so much of the vein as it actually crosses at the surface, and the side lines of tbe location will become the end lines thereof, for the purpose of defining the rights of the owners. _A locator working subterraneously into the dip of the vein belonging to another locator, who is in possession of bis location, is a trespasser, and liable to an action for taking ore therefrom, Tbe case was referrcd to before in these columns, when the Territorial Court rendered its decision, and attention is now called to it because the question is settled forever beyond all controversy, Concenrratep sulpburic acid attracts water with such avidity that in a damp atmospbere it will double its volume in a few days, Chemists use itto dry air and otber gases, and to keen instruments, such as balances, dry, . Coal Mining at Mt. Diablo. {Extracts from Graduating Thesis of J. O’CALLAGHAN, University of California.] The coal measures of Mt. Diablo are situated in a range of hills balf way between ths summit of the mountain and the San Joaquin river. This range is parallel to the San Joaquiu, which is about five miles distant, and it is separated from Mt. Diablo by a deep valley. The altitude diminishes gradually from 1,700 feet in the western to 200 feetin tbe eastern part. The strata are tertiary, and are all elevated at an angle, probably by the mountain breaking through them. The general dip is to the north, being 32° in the western and 15° in the eastern part of the measures, which are about 12 miles long, as shown by tbe ontcrop of the strike which runs in a general east aud west direction. These strata are composed chiefly of heavy bedded sandstones, carbonaceous shales, clays and coal seams. J The mine of the Black Diamond Co. is situated in the most westerly portion, where the dip is greatest. -This region is deeply dissected hy narrow parallel canyons, which run from the San Joaqnin plains to the summit of this range of hills, The canyon in whicb this company’s mine is situated opens into a sort of DESIGN FOR AN OR ampbitheater, caused by tbe main canyon branching into three or four smaller raviues. Here are the hoistiug works, coal bunkers dumps, etc., while a few bundred yards down the creek is the towu of Nortonville, in which most of the miners live. _ Although there are four seams of coal in the Black Diamond Co.’e property, only two of tbese are workable. These are about 1,000 feet apart, borizontally. The upper or Clark vein is of an average thickness of 28 to 38 inches, not heing interstratified by slate or clay, but is all good workable coal, except where crushed hy tbe bendingfof the etrata. The lower or Black Diamond vein has an average thickness of from four to six feet, but it is not such good coal as the Clark vein, and it is more expensive First Floor. to work, tbe roof and the floor being composed of ehale and clay, : Opsning Up, Formerly these miues were worked by running in borizontal tunnels to the seams, but this was not profitable only to a limited depth, and this means of opening up is now entirely abandoned. In the case of a tunnel tbere is no outlay necessary for boisting or pumping, as tbe mine drains naturally. The next method of reaching the seam was by an inclined shaft or slope run in at right angles to tbe seam, and after striking it, a counter slope was sunk on the seam. The incline now in use, and through whicb most of the coal has heen boisted, is called the Mt. Hope slope. It is situated at tbe bead of the principal ravine, 797 feet above low water, and is sunk at an angle of 37° 15’ to the south, striking tbe Clark vein at a distance of 293 feet. At this level a gangway runs east and weston the seam, and on this, at a point 85 feet east of . . tbe foot of the Mt. Hope slope, is a counterslope sunk on the seam, and at present worked to a depth of over 700 feet. The slope and counter-slope are botb doubletracked, and strongly timbered every tbree or four feet. é The cars are hoisted by around tbres-quarterinch rope. This passes over a pulley three feet . in diameter and is then wound on a cylindrical drum six feet in diameter, the motion of whicb is regulated by a 12-foot fly wheel. The engine has a 14x30-inch cylinder, and boists a car in about 30 seconds, 2 The counter-slops is fitted with a similar

plan for boisting. Though the slope was much better than a tunnel and had a greater production, still it is mucb inferior to a vertical sbaft for many reasons. Tbe incline necessitates a greater handling of cars and causes a greater loss of power. Two separate hoisting engines are needed, and one of these is underground, while only one engine is necessary for a shaft, and that one is on the surface near the boilers. The only objection toa shaft is the great outlay necessary for machinery, etc., before any coalis produced. But by using double cages and increasing tbe speed the production can be enormously increased. The Black Diamond ehaft is situated about 620 feet northwest of the Mt. Hope slope, being NAMENTAL COTTAGE 839 feet above water level. It bus a rectangular shape, the dimensions being 22 feet 4 incbes by 11 feet 10 inches from out to out. This is the most convenient form, there being no pressure sufficient to necessitate a round or square sbaft. It is divided into three compartments. Two are for hoisting, and are eix by nine feet inside, The third was designed for pumping, but is now used for ventilation, and contains a ladder which runs the whole depth. This shaft is very heavily timhered all the way down by one anda half foot Oregon pine, the sections being placed about two feet apart, and is a fine piece of work, requiring very little repairing. At regular distances down tbe shaft levels are run out to strike the seams. The distance between two levels measured on tbe eeam is called a ‘‘hft.” The lift is made as bigh as possible, because every level entails an additional expense; still the higbt is hmited by the difficulty of transportation and ventilation. The average hight of tbe liftsin this mine is from 300 to 350 feet, this variation being caused by the change of dip in the seams. At eacb etation there is a difference of level of eix feet between tbe levels running to tbe two seams, eo that by one etoppage, a car from eacb seam could be run on tbe double cage. Machinery and Hoisting Piant. In tbe case of the tunnel, a borse could be used to draw out tbe cars, and borse power could even heused as a motor to draw the cars up the slope; but steam now entirely replaces these more primitive means. There is a great saving by using steam, as the surplus power cau be utilized in pumping and carrying on many of tbe minor operations, such as surface transportation, running the screens, etc. When the Black Diamond tnnnel was sunk, a very extensive system of boisting macbinery was adopted. Attbe moutb of the shaft isa well-braced and substantial hoisting frame constructed of heavy pine timbers two feet square, ‘This frame is about 30 feet bigb, tbus affording ample room for the cages to come above the surface without hitting the top. This frame consists of six principal uprights all sligbtly incliued and bound together by a firm rectangular frame or top in which the pulley wheels work. Two of these uprigbts, in the liue of greatest pulling force, are much more inclined than tbe otbers so as to act as hraces, Tbe pulley wheels, two in number, are tbe large wheels over whicb tbe cable passes. The diameter of these is five or six feet, and they are provided with guides to prevent the cable shipping off. in the drums it is very important tbat the diameter be large, as a short bend ie very de. structive to iron rope, In Europe tbe average drum is 20 to 25 fest, while bere it is no more than five or six feet in diameter, Thers are two kinds of drums in use at these mines; the ordinary wooden cylindrical drum for round cables, and ths spool or bobbin drum for flat cables. The latter is used at the Black Diamond shaft. There seem to be many advantages of the flat cable and bobbin over ths round cable and cylindrical drum. _ The flat cable winds upon itself and thus by increasing the diameter at each winding prevents tbe acceleration of a descending cage, which if the shaft were deep would necessitats a conical drum in case of a round rope. The flat rope seems better than the round rope, as its diameter is less than that of round cable of equal strength. The flat rope can be mended easily and last for two or three years. Two bobbins are fixed on the same sbaft, and thus the engine bas to hoist ths weight of the cual, as the cage and empty car balance an equal weight of ths otber cage. By this means the motion is always uniform, The engine used at the Black Diamond shaft has two horizontal 24-incb cylinders with fiyefoot stroke, and the power is applied directly to the shaft, thus doing away with a fly-wheel. The foundation of the drum and engines is of solid brick built from bedrock, The steam is supplied to the various enginee by 10 large Cornish boilere, so connected that any two may be repaired without causing tbe others tostop. This great number is necessary because the ouly water available for use ie mine water, and as this is very sulphurous, incrustations form very rapidly. The steam pipes are packed in asbestos, but there is necessarily a great loss hy condensation in pipes many hundred feet long, The fuel used is the slack coal from the screenings, and many tons of this almost unsalable fuel are burned each day. Opening Out. Whether the seam be reached by an incline or by a level the same system of opening out and working the coal is adopted. The system here in use differs from the ordinary one on account of the steep dip and the thinuess of the seams. From the point where the level reaches the eeam a gangway is drifted to the right and left on the seam; the dimensions of this gangway are determined by the thickness of the seam, the strength of the roof and the requirements of transportatiou and ventilation. The average dimeneions in these minee are 8 feet wide at the floor, 5 feet wide at the roof, and 5 feet from floor to roof. By adopting this trapezoid form, the requisite width is obtained and the least support is removed from the roof, These gangways are given a grade of a few inches in a bundred feet. The floor consists of rolley-way and a rude channel on either eide for drainage. Faulting is a chief feature of this mine, and it causes great difficulty in drifting, Almost every case is that of a simple slip, in which the strata on the hanging wall have eunk, The direction of the gangway must then be changed until it again cuts the seam, and it must cut it in such a way that the foot wall of the seam is about four feet from the floor of the gangway, so that care can be easily loaded from the shoots, Working the Seam. Every 20 feet along the gangways on tbe seam sboots four feet wide are run up tbe seam, only the thickness of the eeam being worked out. Safety pillars of coal 20 feet square are left all along the upper part of the gangway. The face of the seam is thus worked by a eystem of irregular steps. As the coal is detacbed from the mass, it ie allowed to slide down the sboots on slides conetructed of sections of old boiler iron, which are laid so as to overlap one anotber. Thus by the simple action of gravity the coal may be transported several hundred feet, and by opening the mouth of the shoot it may be loaded into cars in the gangway. Timbering. Pine and redwood are the only materials used for timbering, All timbers are cut outside and are numbered eo tbat they can be sent in and fitted without further trouble. Tbe etations and levels being tbe most permanent, are strongly timbered witb the heaviest timbers. The method of timbering the gangways is very simple, consisting of two uprights surmounted by a cap piece or crown. The uprights are inclined, so as to shorten the crown piece without loeing space. The size of the timbere is -eigbt feet long by eight by ten inches in cross-section. These timbers need continual repairing, some being replaced every two or three weeke, On an average the timbering is replaced every three months, Tbe stopes are timbered witb redwood pieces fonr by six inches. Underground Traneportation. Tbe cars are of such a size that when loaded tbey can be easily handled by one man, The usual capacity is one ton of loose coal. They are made of heavy pine planks strongly handed with wrougbt-iron, The internal dimensions are: Length, six and onc-balf feet; width, two feet two incbes; hight, in front, two feet five inches; in rear, two feet eleven inches, These cars run on ordinary strap rails, which are epiked on wooden stringers. The gauge is three feet. Trains of from five to eix of tbese cars are drawn from tbe working parts of the minee to the sbaft by single borses. Tbe average distance is over one-third of a mile, Hoieting. The cage is made of iron and bas two plate