Search Documents

By Eckley B. Coxe

THE plummet lamp, to which I called the attention of the Institute, at the Bethlehem meeting, in August, 1871, with the improvement of the compensating ring, suggested by Mr. Heller, having come into general use for mine surveying in this country, and my attention having been called to the fact that it could not be employed in mines in which there was danger of meeting with fire-damp, I have so modified it that it can be used in all cases with safety. Mining engineers, who are in active practice in those districts where fire-damp is met with in the mines (and I am sorry to say it is becoming much more common in the anthracite regions), know how dangerous their work is when they are called upon to survey such mines, particularly when they are obliged to run lines in those parts of a mine which have been unworked, since by opening of doors, brattice, etc., to get the sights, they are liable to disarrange the currents of air, and cause any fire-damp that may have accumulated in the old workings to find its way into the levels, etc., where the party is at work. It is, therefore, very dangerous to leave an open light (such as the original form of plummet lamp) in an old breast or gangway, even when the safety lamp has shown that no fire-damp is present, for the opening of the doors, etc., may drive the fire-damp to the light, and thus endanger the lives of the engineers. The improved form of plummet lamp, now shown to you, can be used either with or without the safety apparatus. Upon the top of the plumb-bob portion of the old lamp a screw is cut, upon which a ring A is screwed. (See Plate II.) On the external cylindrical part of this ring two small conical holes are drilled, 180° apart. The compensating ring, by which the plumb-bob part of the lamp is suspended, passes over the ring A, and is fastened to it by two small screws having conical points, which fit into the conical holes in the ring A. The safety apparatus resembles, to a certain extent, that of the Mueseler lamp. It consists of a ring B and plate C, which are united by four rods. The plate C has a cylindrical hole in the middle, and four apertures distributed radially around it. In the central cylindrical hole is fitted a conical brass chimney, which projects below the plate C, and is fastened to the latter, being kept ver-

Jan 1, 1875

By V. A. Zanadvoroff

THE mine and concentrator of the Howe Sound Co., Chelan Division, are at Holden, in a remote section of the Cascade Mountains of northwestern Washington. Holden is at an elevation of 3200 ft., in the narrow valley of Railroad Creek. This creek drains into Lake Chelan, at a point some 40 miles up the lake from the town of Chelan. The concentrator treats 2000 to 2500 tons of low-grade copper-gold-zinc ore per day. Concentration is achieved by the differential flotation process, with recovery of 94 per cent copper and 82 per cent gold in the copper concentrate, followed by the recovery of 65 to 70 per cent zinc in the zinc flotation circuit. The final flotation tailing is deslimed, and coarse sands, representing 60 to 70 per cent of the total, are cyanided. The tonnage of tailing material amounts to 1900 to 2370 tons per day. GENERAL CONSIDERATIONS The property is within the Chelan National Forest. Railroad Creek is a fishing stream, being stocked regularly with trout from State hatcheries. Consequently, in planning a milling operation, the Howe Sound Co. was obliged to avoid any pollution of the stream by tailing material, and also destruction of valuable stands of timber. Moreover, the selected tailing disposal sites should not mar the natural beauty of the valley. In addition to these requirements, the problem of tailing disposal at Holden was complicated by topography and climatic conditions. The valley is long and narrow, averaging 1200 to 1500 ft. in width. Its walls are flaring at a steep angle. There are no extensive flat areas suitable for deposition of tailing. All valleys tributary to Railroad Creek, also the well-marked paths of snowslides, must be avoided. Finally, the direction of prevailing winds and possible dust hazard arising therefrom dictated the necessity of selecting the tailing-disposal sites downstream from the mill building and two campsites. Heavy snowfall during the winter months of November to March, inclusive, impedes building of the retaining dike, making it necessary to prepare the needed storage space during the summer months. It is inadvisable, also, to do any dike building during the freezing weather, because the dike becomes unstable with the spring thaws, producing inevitable "sloughing" of the built-up borders. TAILING-DISPOSAL SITES The existing tailing-disposal areas are near the south wall of the valley. They were developed, and put to use in the following sequence: No. I. Area.-Covers approximately 10 acres. Built up to the height of 60 ft.

Jan 1, 1946

By A. D. Smigelskas, E. O. Kirkendall

THIS is the third paper in a series on the diffusion of zinc in alpha brass.1 At the time of the first-paper it was accepted that diffusion in a substitutional type of solid solution depended upon an equal interchange of solute and solvent atoms across the diffusion interface (or past a given lattice reference point). Discrepancies in the size of the areas under the diffusion curves on each side of the interface, if observed, were explained on some other basis than the fact that the solute atoms might cross the diffusion interface without an equal number of solvent atoms diffusing across the interface in the opposite direction. The second paper presented evidence indicating that zinc atoms in alpha brass diffuse across the interface more rapidly in one direction than the copper atoms diffuse across the interface in the opposite direction. This phenomenon forced the interface to move in the opposite direction of the diffusion of zinc atoms to provide space for the additional zinc atoms dissolved in the alpha brass. That the interface and columnar grain structure on one side would remain intact during this mass movement was not expected; however, it is gratifying that they did. While the evidence was sufficiently satisfying to the author, it was decided that additional experiments were in order to prove that zinc diffuses more rapidly than copper in alpha brass. It is the purpose of this paper to present the results of these experiments. PROCEDURE A bar of 70-30 wrought brass was selected, to avoid the relatively large volume change in going from beta to alpha brass as in the previous investigation. A bar 7 in. (18-cm.)* long and about ¾ in. (1.9 cm.) wide was surface ground and polished with abrasive paper on plate glass to 0.4184 ± .0002 in. (1.0625 ± 0.0005 cm.) thick. Six 0.005-in. (0.013-cm.) diameter molybdenum wires, chosen because of their very low solubility in copper and alpha brass, were stretched lengthwise along each of the two plane surfaces. Glass tubes placed at right angles to the wires every ½ in. held the wires tightly against the brass. The sample was then emersed in an acid copper sulphate plating bath and electroplated to a depth of about 0.020 in. (0.050 cm.) copper on all sides. The glass tubes were no longer necessary to hold the molybdenum wires in place and were removed. The sample was then electroplated to a depth of

Jan 1, 1946

By Grafton M. Thrasher

Discussion of the paper of GRAFTON M. THRASHER, presented at the New York meeting, February, 1916, and printed in Bulletin No. 106, October, 1915, pp. 2129 to 2138. RICHARD MOLDENKE, Watchung, N. J.-Mr. Thrasher is to be commended for developing a very interesting comparison between high- and low-carbon and silicon malleable cast irons for an equal degree of chill. His deductions are unquestionably correct, though the application to daily practice is open to serious criticism, from the standpoint of the man who receives the castings, as will be shown later on. Running over some of the points which affect the tests in question: Mr. Thrasher admits that the temperature of pouring has a serious influence on the degree of chill shown in the test plugs he made. This is a well-known fact, and I would like to add that another serious trouble comes from oxidized iron when the heats have been unduly prolonged. Such metal always shows more chilling action for a given silicon and carbon content than normally melted iron. Indeed, the test piece quoted giving the extreme of the chill line (1.07 per cent. Si and 2.47 per cent. total carbon) was such a poor heat, a ferro-silicon addition never "doctoring" up the metal sufficiently to show normal good strength. In spite of these irregularities, which would simply change the curve slightly, I take it that Mr. Thrasher's results can be accepted as reliable enough to establish the relationship of silicon and total carbon as shown. When, however, the claim is made that silicon and carbon can be substituted for each other in mixture-making (a claim which may be perfectly correct metallurgically), a very important factor is forgotten, causing the purchaser of the castings much annoyance. This is the contraction (erroneously called shrinkage) of the castings. They will no longer be true to pattern. The lower the total carbon is allowed to drop, the greater the contraction, and increasing the silicon correspondingly will not correct this trouble. No wonder that recently, in revising the Standard Specifications for Malleable Castings it was necessary to increase the variation of castings from requirements considerably over what was formerly found sufficient. The habit of running up the proportion of silicon and escaping danger from grayness of the metal by copious steel additions was evidently too tempting to manufacturers, as their molding losses were thus kept down and a very soft malleable iron resulted. The customer, however, got serious variations in his work, which was not the case when the total carbon was kept between 3.25 and 2.75, and the silicon held as low as possible without undue cracking of the hard castings.

Jan 5, 1916

By F. A. Orth

COAL-mine opera- tors face a difficul- ty in notifying men when there is no work. If the miners come to the shaft when there is no work, they must be paid, by agreement, two hours' wages. This involves a considerable loss since it is not uncommon to em- ploy two or three hun- dred men or more at a single shaft. Many mines have solved the problem by using an electric siren. This carries the "no work" message to all of the miners within a ra- dius of from one and one- half to two miles, so they do not trudge uselessly to work and the operator saves the two-hours wage payment. At the Valley Smokeless Coal Co., Johns- town, Pa., such a siren serves as a start and quit- work signal for three mines which previously re¬ quired three individual signal systems. Similar units are used by the Old Ben Coal Corp. mines, Dolly's Smokeless Coal Co., Rhonda Coal Co., Bird Coal Co., and hundreds of others. Many other applications of the electric siren have been found in mines. They are used on underground locomotives, to awaken miners in the morning, to tell them it is time to come to work, to sound the start and quit-work signal, and to warn of fire or accident. The sirens are most generally used to give a start and quit-work signal, fire, and general emergency alarms as well as no-work signals. They require 3 and 5 hp. to operate. The smaller unit has a sound radius of from three-quarters to one mile, while the larger siren can be heard over a distance of from one and one-half to two miles. The 5-hp. unit has been heard for as great a distance as 14 miles, and 10 miles is not at all uncommon. One of the outstanding features of the 3 and 5-hp. units, which is uncommon in the smaller sirens is that they may be adapted to sound code signals. When used to sound a fire or general emergency alarm the siren may tell at the same time where the fire or acci-dent is. When a remote control device is used with a siren it is possible to operate the siren from any number of distant points. Any number of "start" buttons may be placed at various places. By using one "start and stop" button where the remote control is mounted, and one or more "start" buttons at various places about the plant, it is necessary to run only two wires to the various "start" buttons. If "start" and "stop" buttons are used altogether, then three wires must be run.

Jan 11, 1927

By Herbert Hoover, Harlod Washburn

This paper is in the nature of a rough preliminary report on the progress that has been made in the application of the mass spectrometer to various problems arising in the petroleum industry. A few years ago the authors considered a number of the problems that were arising in the qualitative and quantitative measurement of small amounts of hydrocarbons. The methods available of making analyses by chemical techniques appeared to leave much room for improvement. Without going into the reasons at this point, attention was turned to the possibility of employing physical instead of chemical methods of accomplishing the desired results. A preliminary investigation disclosed that the mass spectrometer presented a possibility of solving many problems which could not easily be accomplished by other methods. Work was begun in developing the necessary apparatus and technique. A great deal of encouragement and many valuable suggestions were received from Dr. Robert A. Millikan, Dr. W. R. Smythe, and Dr. W. N. Lacey, of the California Institute of Technology, and from Dr. E. 0. Lawrence, who recently received the Nobel Prize, of the University of California. The authors particularly wish to acknowledge the very great willingness of these outstanding scientists to be helpful in solving many of the problems that were involved. So far as the authors are aware, this was the first application of the mass spectrometer to commercial work. The results were considerably better than had at first been anticipated. Briefly, it is possible to run a qualitative and quantitative analysis of an unknown mixture of hydrocarbon gases, with an accuracy of better than plus or minus 5 per cent of each of the various constituents. An exceedingly high degree of sensitivity has been obtained, and a relatively short time is required to complete an analysis. Furthermore, it is unnecessary to separate a mixture of gases into its various components in order to complete the analysis. The Mass Spectrometer The mass spectrometer should not be confused in any way with the optical 01 grating type of spectrograph now in general use. The operation of the mass spectrometer is entirely different in principle and bears practically no resemblance to the optical or grating instruments. The original conception and development of the mass spectrometer dates from and is generally credited to Aston, of Cambridge, England. An early accomplishment of his research, about 20 years ago, was the discovery that the inert gas neon was actually a mixture of two kinds of atoms, one of the atomic weight 20 and the other of atomic weight 22. These two components occurred mixed in such proportion as to yield the usual atomic weight of 20.2. The study was continued and most of the elements were shown to be mixtures of components whose atomic weights can, to in

Jan 1, 1941

By O. L. Culberson, J. J. McKetta

INTRODUCTION The equilibrium constants for methane and for water, and for ethane and water have been calculated from experimental data for the two binary systems.2,3,11,12 These constants are for the two-phase systems for the temperature range of 100" to 340°F and the pressure range of 200 to 10,000 psia. The constants for ethane are greater than those for methane. Equilibrium constants for a natural gas from a natural gas-water system6 are about the same as those for methane. Equilibrium constants for water in all three systems are very nearly the same over the greater part of the range of temperatures and pressures studied. In ideal solutions, the vapor-liquid equilibrium constants for a component should be the same in all such solutions at a given temperature and pressure.5 Few solutions are ideal, and consequently the use of generalized constants often leads to error in situations where they do not actually apply. In decidedly non-ideal systems, it is desirable to have equilibrium constant data for the specific system. Vaporization equilibrium constants may be calculated either by thermodynamic methods or from experimental vapor-liquid equilibrium data. In the thermodynamic calculation. the equilibrium constant K may be shown to be" K = fP,/fl'..........(1) where fPi is the fugacity of the pure component i at the given temperature and at the vapor pressure of the pure component, and fp is the fugacity of pure i in the gaseous state at the temperature and total pressure of the system. At best the thermodynamic calculation results in a K applicable to ideal solutions. Equilibrium constants calculated from Equation (1) have been found to have only limited agreement with experimental values, even though the solutions for which they were calculated approached ideality."'" If the more volatile component is at a temperature above its critical, the accuracy of the equilibrium constant for the component is made more doubtful by the use of the vapor pressure term under such conditions. In order to make the thermodynamic calculation on a component above its critical temperature, one must resort to one of the empirical methods of extrapolation of the vapor pressure to conditions above its critical point.13 Application of the thermodynamic equilibrium constant then to the methane-water or the ethane-water systems would be risky since the systems are non-ideal, and the methane and ethane are above their critical in most petroleum operations. ETHANE-WATER SYSTEM In the temperature range of from 100° to 340°F and for pressures up to 10,000 psia, the vapor-liquid equilibrium data 'References given at end of paper. Manuscript received in the office of the Petroleum Branch March 16, 1951.

Jan 1, 1951

By T. Egleston

circumstances, would prefer the steel with which they are now familiar, to a specimen that Mr. Sandberg has described as having broken into seventeen pieces under the wheels. After blowing such low manganese steel, it may be coaxed into a rail, but it is a wonder that it holds together so long as it does, with so great a nornber of minute flaws. I would not in any way depreciate chemistry, but I think it should be kept in its proper sphere. Let the chemist look after the quality of pig metal, and apply common sense in the avoiding of extremes, then the most fastidious railroad cannot find fault with the result. PROFESSOR EGLESTON, New YORK City : It is not my place as an engineer to apologize for the chemists, but as no one seems disposed to do so, and as they have had more than their share of criticism, 1 am glad to say that I believe there are chemists in this Institute whose work and word are just as reliable, arid perhaps even more so, than that of the average engineer. But we ought to make a distinction; there are chemists and chemists. With the ordinary commercial chemist, who looks upon the science as so much merohandise, I have not a particle of sympathy; but with the chemist who looks upon his profession as engineers do upon theirs, I have every sympathy. When matiufactorers and engineers go to a chemist and ask him to make an investigation, and scretv him dowu to the lowest point, turning the equivalent of his brains into cents and mills, they ustially get an exact equivalent in poor work for miserable pay, and no one has or should have any sympathy with them, and the under these conditions has no right to ask for any, and no reason to criticise any work that he may get under such circumstances. But I am disposed to think that the chemists who have been replwented and discussed at this meeting do their work conscientiously, and that it is as reliable as that of almost any profession. I believe, however, that this problem of steel rails is being investigated in a wrong direction. I said so at the Pittsburgh meeting, and I think the discussion of this meeting will prove it to all those who have heard it. I think the chemigt is incapable of solving this problem unlees he goes very far into the domain of physical chemistry, so far that it becomes physics and not chemistry; and that the physicist will be the one on whom we must rely in the future for the elucidation of the subject. The chemist may aid the physicist, but it is my decided opinion that we are looking in the wrong place to get the explanation of the phenomena.

Jan 1, 1881

By J. J. McKetta, O. L. Culberson

INTRODUCTION The equilibrium constants for methane and for water, and for ethane and water have been calculated from experimental data for the two binary systems.2,3,11,12 These constants are for the two-phase systems for the temperature range of 100" to 340°F and the pressure range of 200 to 10,000 psia. The constants for ethane are greater than those for methane. Equilibrium constants for a natural gas from a natural gas-water system6 are about the same as those for methane. Equilibrium constants for water in all three systems are very nearly the same over the greater part of the range of temperatures and pressures studied. In ideal solutions, the vapor-liquid equilibrium constants for a component should be the same in all such solutions at a given temperature and pressure.5 Few solutions are ideal, and consequently the use of generalized constants often leads to error in situations where they do not actually apply. In decidedly non-ideal systems, it is desirable to have equilibrium constant data for the specific system. Vaporization equilibrium constants may be calculated either by thermodynamic methods or from experimental vapor-liquid equilibrium data. In the thermodynamic calculation. the equilibrium constant K may be shown to be" K = fP,/fl'..........(1) where fPi is the fugacity of the pure component i at the given temperature and at the vapor pressure of the pure component, and fp is the fugacity of pure i in the gaseous state at the temperature and total pressure of the system. At best the thermodynamic calculation results in a K applicable to ideal solutions. Equilibrium constants calculated from Equation (1) have been found to have only limited agreement with experimental values, even though the solutions for which they were calculated approached ideality."'" If the more volatile component is at a temperature above its critical, the accuracy of the equilibrium constant for the component is made more doubtful by the use of the vapor pressure term under such conditions. In order to make the thermodynamic calculation on a component above its critical temperature, one must resort to one of the empirical methods of extrapolation of the vapor pressure to conditions above its critical point.13 Application of the thermodynamic equilibrium constant then to the methane-water or the ethane-water systems would be risky since the systems are non-ideal, and the methane and ethane are above their critical in most petroleum operations. ETHANE-WATER SYSTEM In the temperature range of from 100° to 340°F and for pressures up to 10,000 psia, the vapor-liquid equilibrium data 'References given at end of paper. Manuscript received in the office of the Petroleum Branch March 16, 1951.

Jan 1, 1951

By Harlod Washburn, Herbert Hoover

This paper is in the nature of a rough preliminary report on the progress that has been made in the application of the mass spectrometer to various problems arising in the petroleum industry. A few years ago the authors considered a number of the problems that were arising in the qualitative and quantitative measurement of small amounts of hydrocarbons. The methods available of making analyses by chemical techniques appeared to leave much room for improvement. Without going into the reasons at this point, attention was turned to the possibility of employing physical instead of chemical methods of accomplishing the desired results. A preliminary investigation disclosed that the mass spectrometer presented a possibility of solving many problems which could not easily be accomplished by other methods. Work was begun in developing the necessary apparatus and technique. A great deal of encouragement and many valuable suggestions were received from Dr. Robert A. Millikan, Dr. W. R. Smythe, and Dr. W. N. Lacey, of the California Institute of Technology, and from Dr. E. 0. Lawrence, who recently received the Nobel Prize, of the University of California. The authors particularly wish to acknowledge the very great willingness of these outstanding scientists to be helpful in solving many of the problems that were involved. So far as the authors are aware, this was the first application of the mass spectrometer to commercial work. The results were considerably better than had at first been anticipated. Briefly, it is possible to run a qualitative and quantitative analysis of an unknown mixture of hydrocarbon gases, with an accuracy of better than plus or minus 5 per cent of each of the various constituents. An exceedingly high degree of sensitivity has been obtained, and a relatively short time is required to complete an analysis. Furthermore, it is unnecessary to separate a mixture of gases into its various components in order to complete the analysis. The Mass Spectrometer The mass spectrometer should not be confused in any way with the optical 01 grating type of spectrograph now in general use. The operation of the mass spectrometer is entirely different in principle and bears practically no resemblance to the optical or grating instruments. The original conception and development of the mass spectrometer dates from and is generally credited to Aston, of Cambridge, England. An early accomplishment of his research, about 20 years ago, was the discovery that the inert gas neon was actually a mixture of two kinds of atoms, one of the atomic weight 20 and the other of atomic weight 22. These two components occurred mixed in such proportion as to yield the usual atomic weight of 20.2. The study was continued and most of the elements were shown to be mixtures of components whose atomic weights can, to in

Jan 1, 1941

Discussion of the paper of WALTHER MATHESIUS, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 539 to 555. JOSEPH W. RICHARDS, So. Bethlehem, Pa.-This paper answers. partly the difficult questions which have come up as to why it is not economical to use higher blast temperatures in the smelting of Mesaba ores, such as the high temperatures used in European practices, and the answer is very plain that the ores will not stand the higher temperature. But the paper does not go into detail as to what special difficulties were found with the higher temperature of blast, and I would ask the author to kindly specify them. W. A. FORBES, New York, N. Y.-A large part of the troubles that furnace men experienced in using high-blast heats in smelting Mesaba ores in the early days of using Mesaba ores, was clue to the attempt to use these soft ores on furnaces having the same lines as the furnaces used in smelting the hard Old Range ores. As the result of observation and study, the dimensions of the lower part of the blast furnaces have been changed and the difficulties of the blast-furnace men in operating with a large percentage of Mesaba ore and high-blast temperatures have been largely overcome. The changes I refer to in particular are: (1) steepening the angle of the bosh; (2), decreasing the height of the bosh; (3) increasing the diameter of the hearth. JOSEPH W. RICHARDS.-Mr. Forbes's answer is quite satisfactory, and the moral which it points is that when the furnace is run with a higher temperature in the smelting zone, the furnace lines which were adapted for the lower temperatures are not necessarily those best suited for the higher hearth temperatures. If. enriched blast were used in a furnace, and higher temperatures run, it would be found necessary to further modify the lines of the furnace to meet the new conditions and to get the maximum output with economy. J. E. JOHNSON, JR., New York, N. Y.-It seems to me this is one of the few papers which could well have been a little longer. The data which Mr. Mathesius has given us, I think should be considered in connection with the paper which Mr. Brassert read before the American Iron and Steel Institute last spring, in which he described how they had obtained remarkable results with furnaces with steep but very short boshes; the angles have been raised to 80°, and the boshes made so short that they no longer appear as a conspicuous part of the shape of the furnace.

Jan 5, 1915

By H. Furman Byars

INTRODUCTION of bottom dump hauling units into the Ray, Ariz., stripping operation of the Isbell Construction Co., was motivated by several reasons, with what appears to be debatable results. The accepted theory of truck design for use in open-pit holds that end dump vehicles are the most adaptable for the work. But, because operations of the bottom dump, under certain construction and haulage conditions, proved economically feasible, the unit was put to work in the Ray copper pit. The decision to try bottom dump was reached after considerable observation of the unit in action on construction of earth filled dams, levees, airport construction and several other similar tasks. Basic tire design also motivated the choice. All things being equal, a vehicle running on low pressure single tires will outperform another operating on dual high pressure tires, providing load carrying capacities are the same. The investment required to equip a vehicle with four single tires to handle the same load as one with dual tires mounted on two axles and single front axles is about 60 pct greater. Thus, in order to reach the break even point on tire costs, single tires must operate 60 pct longer. Comparison is made with a truck outfitted with 10 16:00x25 tires. Two other factors were considered in selecting bottom dump trucks. It was felt the bottom dump principle would work well in dumping ore into a hopper where gate design fits this particular method. Also, with the absence of hydraulic dumping, ore pollution with oil is reduced. The mechanical simplicity of the unit also lent weight to its choice. Ordinary reasoning indicated maintenance costs would be low compared with other units carrying similar loads. The bottom dumping principle is not new. It dates back to the days when horses were used to haul the same kind of rig. The unit employed at Ray holds 25 cu yd struck measure, or approximately 42 short tons. Dumping is accomplished by releasing an air cylinder opening a dog holding the doors. Doors are closed by a cable system operating off a wheel wind deriving power by friction with the trailer tire. The unit is mounted on four 27.00x33 and two 14.00x24 tires on the front axle. The power unit is a 300 hp Cummins engine. Hydraulic power boosts the steering. A straight mechanical drive and friction clutch with 10 speeds is used. Conditions Not Ideal Top performance of the truck can be expected only under the conditions for which it was designed, in particular grades under 5 pct, handling fine material, and dumping where one thin layer can be placed on top of another. The machine will handle 42 tons per haul, operating at high speed, with only seconds used for dumping. On a 2 or 3 pct grade over a one mile haul,

Jan 1, 1952

By Oswald J. Heinrich

The responsibility resting upon the owners and managers of mines where fire-damp is generated, renders it a matter of imperative duty that a frill and correct statement of any explosion that occurs should be given to the public. But such a statement must be based on the testimony of impartial eye-witnesses or trained experts. Then a sad experience may result in the adoption of effective preventive measures. In the absence of any official and professional body of mining experts in the State of Virginia, the writer desires to submit to his professional brethren of the American Institute of Mining Engineers an account of an explosion which recently took place in a colliery under his management, and earnestly desires a thorough and impartial discussion on the Fats submitted. Description and Plan of the Mine.—The "Grove" shaft is situated at the nearest point 825 feet from the last old workings upon the Midlothian property, south of the old Pump shaft works. (See Plate 111.) The shaft was sunk by the former company, some thirty years ago, to the depth of 622 feet. An incline over 230 feet long, starting in a northwest direction at a depth of 105 feet above the shaft bottom, had been driven to explore the coal on the dip. A return of very small dimensions had been driven round the shaft on the south side, entering the upcast chamber. With the information obtained from the former company that a seam of coal about four feet thick, at a depth of 490 feet, had been found, and with the information obtained by the present proprietor, R. T. Burrows, of Albion, N. Y., by means of two boreholes on the dip west of the old shaft, in both of which workable seams of coal at various depths had been ascertained, the clearing out and thorough retimbering of this shaft were commenced in March, 1873. Borehole No. 1, at a depth of 4773 feet from surface, revealed a seam of coal. This borehole was afterwards carried to a depth of 1140 feet to the granite, without finding any other seam of coal. Borehole No. 3, at a depth of 608 feet, revealed the first coal-seam, 14 1/2 feet thick; at 633 feet, the second, 12 feet thick; at 662 feet the third, 1 foot thick, and at 692 feet the fourth, 43 to 5 feet thick. The borehole was stopped at a depth of 715 1/2 feet.

R. H. Sweetser.—Mr. Reinartz spoke of slag containing 18 per cent FeO. I think he expressed the iron as oxide. I should like to ask at what point, in iron contents, it is usual practice to quit sending that open-hearth slag to the blast furnace? L. F. Reinartz.—NO problem is involved in disposing of open-hearth slag to our blast furnaces because, on account of the grades of iron and steel made by our company, the iron oxide in the slag is sufficiently high to make it very acceptable to the blast-furnace operator. I have been told that if the total iron oxide in the slag is under 18 to 20 per cent, it is not economical to use such slag in a blast furnace. J. T. Mackenzie,* Birmingham, A1a.—Mr. Reinartz mentioned sulfate in the limestone. I wonder if he did not use the wrong word. We always have assumed that the sulfate sulfur is practically harmless. Most limestone carries some pyrite (sulfide sulfur) which we thought was what gave the sulfur pick-up. L. F. Reinartz.—I have had no experience, personally, in the use of limestone high in sulfates. I have been told, on several occasions, by other open-hearth men, that the sulfates will be reduced and increase the sulfur content of the metal. We have never found any pyrite in our limestone. A. Hayes,† Middletown, Ohio.—I should think that sulfates would be readily reducible to sulfites, and possibly to sulfides at various distances through the slag layer, from the top down to the interface between the bath and the slag, because reducing conditions are certainly sufficiently strong next to the bath in the slag to reduce sulfates to sulfides. A. L. Feild,‡ Baltimore, Md.—What is Mr. Reinartz's theory as to the effect of silica in the slag on the iron oxide content of the metal? L. F. Reinartz.—I have no particular theory as to the effect of silica in the slag on the iron oxide content of the metal. I know from practical experience that it does have an influence on reduction of iron oxide in the metal. We know that if the silicon content of the charge, and, therefore, the silica of the slag is increased, the iron oxide in the slag will be decreased. Based on Dr. Herty's work, we assume that the iron oxide is correspondingly decreased in the metal. C. H. Herty, JR.,§ Bethlehem, Pa.—In the theory of iron oxide control, we have tackled the matter from the physical standpoint, rather than the chemical standpoint or from the slag itself, and we worked on the basis that the change in iron oxide content in a slag—that is, whether the slag increases or decreases in iron oxide—is due to the simple fact that if you put more iron oxide into the slag from the gas than you put oxygen from the slag into the metal, the slag must increase in iron oxide;

Jan 1, 1935

By J. G. Tilton

While most of the Pittsburgh coal horizon is dependably regular, there are areas where it is dis-turbed by sandstone cutouts which can seriously hamper mining operations. Because these channel sandstones often cut out the coal abruptly, they are difficult to detect by core drilling; and mine operators, for want of a better way to discover them, have largely trusted to luck to avoid them. This paper, based on a study the author is presently conducting, is an attempt to point out some sources of information and signposts which might aid the operator in determining the presence of a cutout before he begins to mine. The presence of sandstone cutouts in the Pittsburgh coal has been known for many years. Some of these irregularities were observed at outcrops and others were discovered by drilling, but the majority were and are found during mining operations. These sandstone cutouts are commonly called "faults" and have been a bane to mining companies wherever they have been encountered. Profiles of some typical deposits appear in Fig. 1. The cutouts disrupt the normal system of mining, replace valuable coal reserves, create ventilation problems by emitting large quantities of gas and sometimes oil, limit the number of entries that can be economically driven, affect the quality of the coal, disrupt the normal structure of the coal, and create roof control problems. It might be expected that such severe disturbances in the structural regularity of the coal would instigate determined and extensive searches for possible cutouts prior to mining operations, but this apparently has not been so except in isolated cases. Two reasons may be cited to explain this lack of exploratory work. The first and probably the strongest reason is the over-all regularity of the Pittsburgh coal. No coal seam in the country exhibits the horizontal continuity and relative regularity of the Pittsburgh coal. It lies in an almost unbroken sheet across southwestern Pennsylvania, eastern Ohio and northern West Virginia, and has been recognized as far east as the Potomac Basin of western Maryland. Over 5729 square miles are underlain by this coal, of which 2077 square miles are in Pennsylvania, 2214 square miles in West Virginia, 1410 square miles in Ohio, and 28 square miles in Maryland. The area covered by this study is outlined by the map in Fig. 2. Over most of this territory the coal has the following characteristic structure as illustrated in Fig. 3: roof coal, draw slate, breast coal, parting, bearing in coal, parting, brick coal, parting, and bottom coal. With such regularity of thickness and structure, mines were opened and laid out with confidence that the coal would be present. Extensive drill testing was considered unwarranted and it was also quite expensive because the coal dipped to the west away from the Monongahela River. Consequently, drill holes were widely spaced and rarely encountered ad-

Jan 1, 1968

By Ralph M. Hunter

UNTIL recent years, maintenance of surface coal handling facilities was a relatively simple task. Equipment consisted principally of conveyors, screens and crushers of comparatively simple construction. Electrical equipment consisted of motors and starters, with little, if any, interlocking. In most cases failure of any component affected only the grades of coal loaded so that even a prolonged break-down did not affect mine operation materially. However, with the introduction of modern cleaning plants, the picture has changed. The equipment is much more complex and therefore more difficult to maintain. In many cases failure of any component of the plant prevents loading of coal. Even if provision is made to by-pass, the quality of coal loaded is lowered, affecting markets. In the case of plants designed to permit full seam mining, marketable coal cannot be loaded without operation of the cleaning plant. Under these conditions it is apparent that considerable thought and effort toward better maintenance are justified. In order to assure continuous, efficient and economical operation, maintenance should receive consideration, not only after the plant is in operation, but while it is being designed. It is hardly necessary to say that the designer should strive for sturdiness and wearing qualities. It is sometimes not realized, however, that even the best parts will sooner or later require replacement or repair. The designer should, therefore, give consideration to accessibility. Anyone who has had to do with cleaning plant maintenance is familiar with installations where several hours are required to get at a part that can be repaired or replaced in a few minutes, once it is accessible. As in most cases, experience is the best guide. The men who operate and maintain this equipment know the problems encountered. Whenever available, the opinions of these men should be sought and heeded. As an example, we might consider the refuse elevator on a Chance Cone. Our company is now operating three of these cones, the first of which was installed in 1941, and the latest in 2946. Exact records are not available, but well over 50 pct of delays charged to the Chance Cones have been caused by the refuse elevator. This elevator receives refuse from the cone and carries it to a point above the water level of the cone, discharging onto a dewatering and desanding screen. Since the elevator operates under water and necessarily has close clearances in the lower boot, it tends to jam on large pieces of refuse or tramp iron. The chain, buckets and boot are also subjected to the action of water, sand and refuse, which accelerate normal wear. In case of jamming or chain-breakage it is necessary to drain the elevator and the cone so that even a minor fault in the elevator causes a considerable loss of time for the cone. In our new plant, which will contain two Chance Cones, the refuse elevator has been eliminated. This was accomplished by raising the cone so that the refuse gates could discharge directly onto the dewater-

Jan 1, 1948

By D. H. Baldwin, R. E. Reed-Hill

DURING the course of experiments involving oxygen equilibrations with a high-purity Pd-5 at. pct Rh alloy, the appearance of a subscale was noted. Most of the heat treatments in a pure oxygen atmosphere were performed at 900°C. The presence of the subscale was noted when the oxygen partial pressure was in excess of approximately 95 mm, up to 1 atm, the highest pressure used. According to available thermodynamic information' on the free energy of formation of Rh2O3 (the only reliably reported solid oxide of rhodium), this oxide should not be stable under these conditions, nor, of course, any oxide of palladium. Extraction of the subscale from the matrix was affected by treatment with aqua regia, and the resulting X-ray diffraction powder pattern is shown in Table I. This pattern is not that of Rh2O3, nor that of any known rhodium or palladium oxide. It can be indexed on a hexagonal lattice with a. = 5.22Å and co = 6.0Å. In addition to this unknown material, there was a weak Rh2O3 pattern. An X-ray fluorescence analysis of the powder gave 3214 palladium counts per sec and 5381 rhodium counts per sec, thus indicating the likelihood of a double oxide of palladium and rhodium. In view of the fact that the above result was obtained on a single sample, it is perhaps best not to insist upon the above ratio of about 0.6, but possibly to tentatively assume 0.5 or 1/1. The small amount of Rh2O3 in the X-ray pattern might have occurred on cooling, and it seems possible that the double oxide, below some temperature level, is not as stable as Rh2O3. To examine this point, some of the extracted double oxide was heated on a sheet of pure palladium in air at 900°C, and allowed to furnace-cool over a period of several hours. The X-ray diffraction pattern of the powder showed approximately the same intensity of Rh2O3 and the "hexagonal" oxide as before, but, in addition, a rather faint pattern of another crystalline species made its appearance. This finding again suggests partial transformation of the major (double) oxide to other oxides on cooling from 900°C. Application of the phase rule shows that only one equilibrium oxide (subscale) could have been present at temperature. Vacuum-fusion, oxygen analysis of the extracted subscale showed 7.7 ± 0.7 pct O. Combining this information with that of the X-ray fluorescence analysis suggests the formula PdRhO. This compound should have an oxygen content of 7.07 pct, which is within the range of error of the oxygen analysis. However, until a more careful stoichiometric study is made, it is suggested that the formula be written

Jan 1, 1965

By R. A. Perry

A speiss is an artificial arsenide, sometimes an antimonide, formed in lead smelting, smelting of oxide copper ores, and in some lead-refining operations. The production of speiss is closely allied with the amount of arsenic and metallic iron in the blast-furnace charge, while dross is produced mostly from the copper and sulphur, with varying amounts of antimony, arsenic and nickel. Most speiss is essentially an iron arsenide containing some sulphur, copper and nickel, if these elements are present in the furnace. The recent introduction of the soda treatment of lead drosses has produced a speiss high in copper. Speiss is not miscible to any extent with molten copper, lead, matte or slag. Miscibility increases with temperature. This property of the speiss is clarified in the latter part of this paper. Most speisses are produced in conjunction with matte and their sulphur content points to the solubility of matte in speiss. . Some plants have insufficient speiss to warrant separate treatment. When arsenic is high in the blast-furllace charge, there may be sufficient speiss to tap separately from the first settler. Arsenic From the foregoing, it is obvious that a study of the treatment of speiss would not ,be complete without consideration of arsenic. Inasmuch as perhaps go per cent of the blast-furnace feed may be sinter, a definite knowledge of the properties of arsenical ores and compounds that go in to the roaster and sinter feeds is of value. Lcad smelters obtain their arsenic from ores and concentrates, as well as from flue dusts shipped from other plants, particularly copper smelters. The percentage of arsenic in ores is usually low, although occasional lots of high arsenical products are smelted. These crude ores may be sulphides, as arsenopyrite; or oxides like scoiodite, which carry gold or lead minerals. The small amount of arsenic in the original ores received is greatly increased by a circulating load of arsenic in secondary products at are resmelted for their lead or precious metals. More important than the arsenic present directly in the concentrates treated is that in fumes and dusts that may originate in the blast furnace or sinter plant of the lead smelter, or may come from a copper smelter as lead-bearing converter fume or roaster dust. Thus the lead smelter not only must treat its own arsenic but is compelled to handie that from some copper and perhaps other lead plants. Where copper and lead plants exchange products, each plant may be forced to re-treat part of the arsenic it has shipped ,outside its own confines. Speiss from the lead blast furnace contains chiefly iron and arsenic with some lead, copper and sulphur and often appreciable amounts of gold and silver. If its copper content is sufficient this speiss may be sent to the copper smelter where usually it is treated in the converter and the copper is separated as blister. Much of the arsenic and most of the lead are recovered as converter fumes

Jan 1, 1944

R. H. Sweetser.—Mr. Reinartz spoke of slag containing 18 per cent FeO. I think he expressed the iron as oxide. I should like to ask at what point, in iron contents, it is usual practice to quit sending that open-hearth slag to the blast furnace? L. F. Reinartz.—NO problem is involved in disposing of open-hearth slag to our blast furnaces because, on account of the grades of iron and steel made by our company, the iron oxide in the slag is sufficiently high to make it very acceptable to the blast-furnace operator. I have been told that if the total iron oxide in the slag is under 18 to 20 per cent, it is not economical to use such slag in a blast furnace. J. T. Mackenzie,* Birmingham, A1a.—Mr. Reinartz mentioned sulfate in the limestone. I wonder if he did not use the wrong word. We always have assumed that the sulfate sulfur is practically harmless. Most limestone carries some pyrite (sulfide sulfur) which we thought was what gave the sulfur pick-up. L. F. Reinartz.—I have had no experience, personally, in the use of limestone high in sulfates. I have been told, on several occasions, by other open-hearth men, that the sulfates will be reduced and increase the sulfur content of the metal. We have never found any pyrite in our limestone. A. Hayes,† Middletown, Ohio.—I should think that sulfates would be readily reducible to sulfites, and possibly to sulfides at various distances through the slag layer, from the top down to the interface between the bath and the slag, because reducing conditions are certainly sufficiently strong next to the bath in the slag to reduce sulfates to sulfides. A. L. Feild,‡ Baltimore, Md.—What is Mr. Reinartz's theory as to the effect of silica in the slag on the iron oxide content of the metal? L. F. Reinartz.—I have no particular theory as to the effect of silica in the slag on the iron oxide content of the metal. I know from practical experience that it does have an influence on reduction of iron oxide in the metal. We know that if the silicon content of the charge, and, therefore, the silica of the slag is increased, the iron oxide in the slag will be decreased. Based on Dr. Herty's work, we assume that the iron oxide is correspondingly decreased in the metal. C. H. Herty, JR.,§ Bethlehem, Pa.—In the theory of iron oxide control, we have tackled the matter from the physical standpoint, rather than the chemical standpoint or from the slag itself, and we worked on the basis that the change in iron oxide content in a slag—that is, whether the slag increases or decreases in iron oxide—is due to the simple fact that if you put more iron oxide into the slag from the gas than you put oxygen from the slag into the metal, the slag must increase in iron oxide;

Jan 1, 1935

Albert SaUveur, Cambridge, Mass. (communication to the Secretary*):—On close examination I think it will be found that the evidence by which Mr. Corson claims to have shown the inaccuracy of a statement I made a few years ago, is far from convincing. This statement is: "Hot work as such has no influence upon the structure of the metal. Indirectly, however, by retarding crystallization until a lower temperature is reached, it may influence its structure most decidedly ; but the same results could be accomplished by heat treatment alone, i.e., by re-heating the unworked metal to the temperature from which the worked piece was allowed to cool undisturbedly." The Melallographist, vol. ii., p. 267 (under the head of "Changes of Structure Brought About by Work"). Of the two pieces of steel tested by Mr. Corson, one was worked and finished at a a cherry-red" and the other reheated to a cherry-red, and the assumption was made that in both cases the temperature was about 715' C., although no pyrometric device was used to record it. The possibility of considerable difference in temperature alone is so great as to invalidate Mr. Corson's inferences. The apparent temperature,

Jan 1, 1907