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The Petroleum Division met at Fort Worth, Texas, Oct 8-9 $ The headquarters were at the Blackstone Hotel, the attendance was 175 Sixteen papers were presented, 12 of them by the authors The technical program was built up around four major topics. Drilling, Production, Engineering Education and Metallurgy There were four sessions, two each day More than 100 were present at the luncheon on Friday noon, which was addressed in turn by President Lovejoy, George Otis Smith

Jan 1, 1937

By R. M. Brick

Segregation can occur only in cast alloys that solidify over a range of temperatures with a difference in composition of liquid and solid phases within this range (ignoring monotectic systems and chemical reactions as in rimming steels). Thus a pure binary eutectic alloy should show no segregation unless undercooling occurs for one of the solid constituents of the eutectic; e.g., chill-cast Al-I2 per cent Si alloys. The phasial condition implicitly described above—solidification over a range of temperatures with a compositional difference between solid and liquid—is found in nearly all solid solutions or combinations of solid solutions and eutec-tics, Metastable conditions of solidification of these types of alloys cause coring; i.e., a difference in composition between the center of a dendrite and its periphery. This composition gradient can be detected usually only by microscopic examination of etched structures; it is a "micro" effect. The gradient of more immediate industrial concern is that between the center of a cast section and the surface layers. This gross (macro) effect is usually deter-minable only by sampling of the casting at different points, with chemical analyses of each sample. If the compositional difference is of the same type as in coring, the first parts to freeze being enriched in higher-melting-point constituents, and vice versa, the effect is called normal segregation. When what is apparently the first part of the casting to solidify shows a higher concentration of low-melting-point constituents, the effect is called inverse segregation. These macro effects are quite separate from the micro effect, coring, yet the latter must be described first because it is an essential part of the picture. Coring Solid Solution, Ni-Cu The nickel-copper phase diagram is reproduced in Fig. Ia, in which the solid lines represent the equilibrium liquidus I, 3, 7 and solidus 2, 5, 8, and where the vertical I, 4: 8 represents a 55 per cent Cu alloy. Upon moderately rapid solidification, the first dendritic axes of composition 2 (see Fig. Ib) start to form at a temperature somewhat under I. Solidification continues by growth of the dendritic nuclei, but at temperature 4 the increment solidifying is of composition 5. The rapidity of this crystal growth prevents diffusion of nickel and copper atoms from adjusting the composition of the entire dendrite at 5, which it would be under equilibrium conditions. The average composition of a specific dendrite, or the entire solid phase, at temperature 4 might be that indicated

Jan 1, 1945

SAFETY in open-pit mining receives a minimum of notoriety, but its significance in profitable and efficient operation is as great as in other methods of mining. Open-pit operators from Arizona, New Mexico, and Mexico, exchanging ideas on safety at a symposium during the recent annual meeting of the Arizona Section, AIME, discovered unanimity of opinion that the successful safety program depended on managerial and supervisory support with the vigorous cooperation of the employes. Safety Organization The operation of a safety program is dependent on the ability of management to project enthusiasm through the company organization. This requires a suitable method of communication to the supervisory and employee levels so as to approach them in a manner that will inspire cooperation. Safety committees comprised of various combinations of managerial, supervisory, and employe personnel are frequently used for this purpose. The open-cut mine of the Chino Division of the Kennecott Copper Corp., Santa Rita, N. Mex., operates its program through management, a full-time safety engineer, and two safety committees, the Departmental and Shops Safety Committee and the Central Safety Committee. The Departmental and Shops Committee consists of one employe from each department and shop and the safety engineer. The selected members serve for a period of one month. This committee meets once a month, the only representative of management being the safety engineer because it is believed that employes will speak more freely when their supervisors are not present. The duties of the committee are to report hazardous conditions and make recommendations, but the committee has no authority to approve or disapprove. The Central Safety Committee is comprised of supervisory personnel from all departments and shops, and one member of each of the five bargaining organizations. Members of this committee are permanent and hold meetings soon after the departmental group to take action on recommendations of the latter. The committee system insures participation of all levels of personnel in the accident-prevention program, thereby stimulating safety consciousness. The New Cornelia branch of the Phelps-Dodge Corp., uses three groups to conduct the safety program; the General Safety Committee, Division Safety Committee, and the operating-unit safety meetings. The unit safety meetings provide for active participation of employes in discussion of various phases of the program. Within these groups vigorous opinions regarding safety are often expressed and the workmen are critical if they recognize a digression from the adopted safe-practice procedures. These monthly discussions give the program vitality. The Division Safety Committee is composed of the division superintendent and the division department heads, and follows an established pattern in discussion of all phases of the safety program. The General Safety Committee, made up of the manager, division, and department heads, makes decisions on policies and procedures; it renders decisions on recommendations and suggestions. Management at the New Cornelia branch feels this system of safety committees and meetings has been active in advancing the program. Safety Codes In the open-pit mines of the Southwest, a safety code for operation or service of equipment, methods

Jan 1, 1952

By R. H. Winn

In this paper a heterogeneous carbonate reservoir is considered as a succession of layers of formations of radically different porosities, permeabilities, water saturations, and rock matrix types; i.e., the heterogeneity is vertical rather than radial to the wellbore. Presumably each layer is more or less homogeneous. To determine the "net oil in place" in this reservoir it is desirable to know the porosity and water saturation of each layer. In addition, the section must be subdivided into that which will produce oil, that which will produce water, and that which will produce little or nothing. In numerous wells drilled in these reservoirs radioactivity surveys, guard electrode surveys, and caliper surveys have been made. These logs have been compared with core analysis data, when available, and the analysis of the surveys compared with production data. This study, still in progress, is intended to provide improved analytical techniques if such are possible. This paper is a progress report on the work. DETERMINATION OF POROSITY The neutron-gamma log has long been recognized as a measure of hydrogen concentration.1,2,3 In reservoirs that are free of clay, shale, or other hydrogen containing matrices, it has been accepted as a measure of porosity.4,5 Empirical methods to relate relative neu-tron-gamma intensity to porosity are often employed." To provide a more precise determination of porosity from the neutron-gamma log each instrument is calibrated immediately prior to each survey by a method which refers all tools to a hydrogenous cylinder. To insure stability a calibration check is made after each survey. These calibration records are printed as an integral part of the log that is recorded in standard counts per second. A detailed description of the calibration procedure is available in the literature.' The procedure employed insures that each Survey is numerically reproducible within the limits of statistical variation. To relate the standard neutron counts per second to porosity and hole size, records were made in test wells constructed of blocks of limestone. The porosities of the blocks were accurately measured and the blocks completely saturated with fresh water. Fig. 1 presents some of the results obtained in these test wells.' The lines shown in Fig. 1 were obtained by deriving an empirical equation relating the 11 points shown so that the relationship may be projected to larger and smaller hole sizes. A detailed description of the tool is available in the literature.' Field tests indicate that the tool is adjacent to the wall of the hole most of the time when the surveys are made in uncased holes drilled with saline muds. In this circumstance porosity may be calculated from Fig. 1 if the hole size is known. When fresh muds that form thick mud cakes are employed, the centralizing effect of the mud cake must be considered and the porosity determination is less reliable. In cased holes the combined effect of variations in hole diameter and the unknown eccentricity of the casing in the hole may make porosity determinations extremely unreliable. In any event, an accurate knowledge of hole size is essen-

Jan 1, 1958

By K. Osseo-Asare

The presence of carbonaceous matter in gold ores presents a two-fold problem: (1) The poor release of gold from the carbonaceous matrix and (2) the uptake of dissolved gold by the carbonaceous leach residues. A critical review is presented of the published information from various parts of the world pertaining to the nature of the carbon-containing components of these ores and their different roles in the gold extraction process. Included in this paper are new results based on the authors' research on carbonaceous ores from the Prestea goldfields of Ghana. Methods for isolating and characterizing the carbon-containing materials are given and a discussion is presented of the interaction of the carbonaceous ores as well as the fractionated components with aurocyanide solutions. Emphasis is on basic physico-chemical phenomena, investigated with the aid of X-ray diffraction, infrared spectroscopy, adsorption, and electrophoretic mobility studies.

Jan 1, 1984

By C. E. Corson

The experiments of which the results and significance are set forth in this paper do not by any means cover the whole subject of the heat-treatment of the material referred to, yet they constitute a contribution to that general subject, rather than to the special department of' annealing. The material here considered is acid open-hearth steel, containing from 0.50 to 0.80 per cent. of carbon, with a nearly uniform percentage of other elements. This class of steel is rapidly increasing in commercial importance. It is even rumored that the rail-specifications of some railroads will hereafter require open-hearth steel. Yet this particular grade seems to

Jan 1, 1907

COLUMBIA SECTION J. C. HAAS, Chairman W. J. HALL,. Vice-chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, 720 Peyton Bldg., Spokane, Wash. W. H. LINNEY J. F. MCCARTHY At a meeting of the members of Columbia Section, which was held in the Davenport hotel, Spokane, Wash., Jan. 31, 1919, at noon, there were present' about twenty members and guests. The chairman being absent, Mr. Frederick Keffer presided. The Secretary announced the personnel of the executive committee of the section, which is: J. C. Hass, Spokane, Chairman; W. J. Hall, Wallace, Ida., Vice-chairman; S. S. Fowler, Riondel, B. C., Past Chairman; L. K. Armstrong, Spokane, Secretary-Treasurer; R. M. Betts, Cornucopia, Oregon. It was stated that the geological survey and report on Stevens Co., Wash., has been completed and will be printed soon. The geologic survey of Colville Indian reservation, by J. T. Pardee, U. S. G. S., has been published as Bulletin No. 677 and is available for distribution, The Miner's Almanac, Miners Circular No. 24, U. S. Bureau of Mines. is also available upon request. There was considerable discussion on the program for meetings during the year. It was informally agreed that, if agreeable to Coeur d' Alene members, that one meeting should be held in that district, preferably at the time of the annual visit of Institute officials. It was also proposed to hold at least one open-air meeting in Spokane with suitable program. The activities of other sections were noted with favorable comment. In this connection there was much general discussion on the subject of closer relations between the national engineering societies. It was agreed that cooperation was desirable and imperative if the greatest measure of value be realized from the profession. It was not the sense of the members, however, that complete amalgamation is desirable. This expression of local sentiment is to be presented to the Institute

Jan 3, 1919

By C. G. Durdaller, W. H. Robinson, G. M. Pound

The nucleation rate of the a (pay) to 0 (white) tin transformation was measured as a function of temperature and a tin particle size using an X-ray diffraction technique. The powder specimens of a tin were essentially monodisperse and the small dinzension of the particles of these specimens was varied from 13 to 75 p. Several types of nucleation sites of differing potency were fbund to be operative in the nucleation process, but it could not be determined whether these sites were on the free surface of the tin particles or within the volume. Assuming that they were on the free surface, the average density of the most potent sites was calculated to be 2.5 to 5.3 x 10' sites per sq cnz through the application of a Poisson distribztion finction to the isothermal data. Analysis of the temperature dependence' of the rate constmts at a given fraction transformed suggests that the active sites are regions of higher free energy and not catalytic interfaces. Appreciable induction periods were observed at the lower temperatures of transformation. Experimental studies1 of solid-solid phase transformations have led to the belief that the new phase nucleates at structural imperfections. The purpose of the present work was to learn more about the mechanism of nucleation in solids and the nature of the singularities at which nucleation occurs. In this investigation nucleation rates in the isothermal transformation of gray to white tin were measured by an X-ray diffraction technique using essentially monodisperse powders of gray tin. This particular phase transformation was chosen for study because it presented fewer experimental difficulties than most others. The experimental temperature-control problems were minimal because the two phases coexist in equilibrium at 13.3"C, and measurable transformation rates occur at temperatures only slightly above room temperature. The growth rate of the P phase into the a2 is sufficiently fast to make the measured transformation rate equivalent to the nucleation rate, provided that the particle size of the samples is small enough; for the experimental temperatures used in this study, the particle diameter must be less than 100 p. EXPERIMENTAL TECHNIQUE The P tin used in this study was obtained from Capper Pass and Son Ltd., North Ferriby, Yorkshire, England, and was of 99.999 pct purity. It was transformedS to the a phase and ground into a fine powder in an agate mortar. This powder was separated by a Roller air classifier into seven fractions whose dimensions, as determined by microscopic measurement of many thousands of particles, are given in Table I and whose distribution of size within each fraction is given in Figs. 1 and 2. The shape of the particles was roughly that of an oblate spheroid,

Jan 1, 1964

By J. D. Meakin

The self-diffusion coefficients of ß tin have been deterttlltled using a plating and sectioning technique. The principal diffusivities pavallel and perpendicu1ar to the "c" axis are given by the Arrhenius relations Dc = 8.2 exp (-25,600/RT) sq cnl per sec and Da = 1.4 exp (-23,300/RT) sq cm) per sec. The results are discussed in terms of a vacancy mecharism of diffusion. In conjunction with an investigation of diffusion in dilute indium-tin alloys we have reexamined self-diffusion in tin single crystals. The published self-diffusion coefficients of tin, eensham') have always appeared anomalous in comparison to diffusion data for other metals and do not correlate with parameters derived from creep tests.' In addition to the necessity of confirming the self-diffusion values for use in analyzing the alloy work, self-diffusion in an anisotropic lattice is of considerable fundamental interest and confirmation of the published data seemed worthwhile. For a crystal with an axis of symmetry three-fold or higher the diffusivity at an angle 6 to the axis is given by D? = (Da - Do) sin2?+ Do [1] where Da and Do are the principal diffusivities perpendicular and parallel to the axis. For a particular diffusion mechanism, again in a crystal of axial symmetry, these principal diffusivities are [2] Do - ? ?i2 COS?i In these expressions ?i is the displacement undergone by the ith atom and 8, is the angle this displacement makes with the symmetry axis. In this, as

Jan 1, 1961

By H. Reinhardt, P. Haglund, J. Rydberg, B. Lunden

As legislation to minimize pollution in effluent streams becomes stricter, it is important to treat used acid pickling baths before discharge. This is usually achieved by neutralization of the acids and precipitation of the dissolved metals in such a way that neither acids nor metals can be re-used. A process has been designed and tested on a pilot plant scale to recover both acids and metals from a stainless steel pickling bath leaving only Na2SOs in the effluent. In this process, H2SOr is added to the spent pickling liquor and the recovery of the pickling acids HN03 and HF is achieved by solvent extraction, using TBP in kerosene as the organic solvent. The extracted acids are stripped with water, giving an acid concentration high enough for direct use in the pickling bath. Molybdenum is also extracted by TBP and is recovered in a separate step. The other metals, Fe, Cr and Ni, are precipitated from the raffinate as hydroxides, dried and recycled to the metal process. In evaluating this process, comparative experiments with mixer-settler and pulsed column have been performed. The process described is being considered for use by a Swedish company pickling 70,000 tons per annum of stainless steel.

Jan 1, 1973

By Arthur McKee

As HEAT is the controlling factor in all smelting operations, it will be .most helpful to make a new set of calculations on the basis of a .unit of fuel burned at the tuyeres to carbon monoxide. This ties together the only two factors in this operation that seem to be constant with respect to each other-the fuel at the tuyere and the air or its oxygen content. If our usual smelting operations, using natural air heated to reasonably obtainable temperatures, furnish sufficient heat above this critical temperature for the purpose, it is doubtful whether additions of oxygen will be of marked benefit. A unit of fuel will not produce a single heat unit more if burned with pure oxygen than if burned with natural air and less heat will be available per unit of fuel by the amount of heat that is carried in by the preheated nitrogen in the natural air of the blast. This is more readily apparent if considered in connection with a heat balance sheet per unit of fuel at the tuyere. The heat available in the stack, as shown by the committee's report, is less by reason of the lower fuel consumption per unit of output assumed in this calculation. The balance sheet for enriched air shows a shortage of the amount of heat usually carried in with the blast; also a lack in the hearth of sufficient heat to melt the 18 per cent. additional metal and slag and in the shaft to the extent of the shaft heat required to heat the 18 per cent. additional stock to the melting point. These heat deficiencies are provided for by the largely increased conversion of carbon monoxide into carbon dioxide, which is assumed, as shown by the following figures: Calculation for natural air: Carbon dioxide 18.4 per cent. (after having eliminated the carbon dioxide from limestone) and 20.8 per cent. of carbon monoxide. Calculation for oxygen-enriched air: Carbon dioxide 28.4 per -cent. and carbon monoxide 23.2 per cent. (no carbon dioxide from stone as lime is charged instead).

Jan 11, 1924

By AIME AIME

BEFORE proceeding with the papers scheduled for the ore and foundry session*, the teller's report on the election of officers for the ensuing year was presented, a; follows: Chairman. G.C. F. MacKenzie; vice-chairmen, C.S. Robinson, J. T. MacKenzzie, C. E. Meissner; executive committee, A. L. Field, R. F. Harrington, E. F. Kenney lit. Waterhouse announced that the fall meeting will be devoted to alloy steel. This meeting will be held in Chicago the week of Sept. 22 in connection with the National Metal Congress. He also announced that oxygen in steel will be the central idea of the meeting which will be held in New York next February. The first paper, entitled "Sintering Limonitic Iron Ore at Ironton, Minn.," was presented by Perry G. Harrison (T. P. 284), the author. Sintering was first un¬dertaken in 1024 to treat Cuyuna range iron and manganiferous ores low in silica and high in moisture and containing objectionable qualities of fine... A Dwight-Lloyd machine was first installed. This machine was replaced by a larger one having a width of 72 in. The power cost was decreased from about $11.22 per ton of sinter on a 42-in. machine to about X0.14 for the 72-in. machine. The tons of sinter per man-shift was increased from 11.86 to 16.77. Improvements embodied in the larger plant reduced the cost of sintering to $0.41. The analyses of iron ore and manganiferous ore and the sinter produced from these materials was used to show the increase in value at the mine resulting from sintering. Crude iron ore actually unsalable was increased in value f.o.b. mine from a theoretical figure

Jan 1, 1930

By L. G. Austin, R. R. Klimpel

This article demonstrates that the Gilvarry and Klimpel-Austin equations for the random fracture of solids are incorrect by deriving intuitively correct expressions for simple cases and showing that the foregoing equations do not reduce to right answers. It is the purpose of this article to point out serious errors in some existing treatments of the random fracture of solids. Gilvarry ' gives the equation where B(y,x) is the cumulative fraction by weight of particles which fall below size y when particles of size x are broken. The constants i, j, k contain shape factors and densities of flaws leading to propagating fracture surfaces. The authors believe this equation to be incorrect. Klimpel and usttin' give where r~ is the number of fracture planes originating from edge flaws (per L where L is the edge length of the original particle), rs is the number of fracture planes originating from flaws on the particle surface (per S where S is the surface of the original particle) and rv is the number of fracture planes originating from flaws within the particle volume. This equation is also incorrect. The failures of these equations will be demonstrated by deriving intuitively correct expressions for simple cases and showing that the Eqs. 1 and 2 do not reduce to the correct answer. In this process, the flaws in statistical reasoning inherent in the derivations of Eqs. 1 and 2 become apparent. THE KLIMPEL-AUSTIN EQUATION Eq. 2 was derived by considering a set number of fracture planes occurring spatially at random within a given particle. This case will be treated here in its simplest form: a line with 1, 2, 3, etc., fractures occurring at random. This is illustrated in Fig. 1, with the original length of the line as Vo. The breakage of a long, thin, brittle fiber is a corresponding physical case, with the volume of a fragment proportional to its length. Assuming independence of the occurrence of the fractures, the probability of any one fracture occurring in length dV is dV/V0. The probability of the first fracture occurring at a length V to V + dV is dV/Vo. For the case of only one fracture per particle, formation of a number-size distribution of the left-

Jan 1, 1969

By Richard H. Mote

The endlessly changing pattern of mineral supply and demand offers opportunity to the alert and can bring disaster to the unwary. The discovery of ore bodies, the invention of extractive processes, the provision of new transport facilities, the political stabilization of underdeveloped areas, and many other changes can increase supply dramatically. Such new outpourings of mineral wealth from ore bodies bring fortunes to their developers, and consumers frequently find their competitive positions decidedly improved by new and cheap sources of supply. On the other hand, operators of marginal properties can find competition from newly opened high-grade mines intolerable. Consumers that have depended on the products of nearby, high-cost mines may find new, remote, low-cost supplies advantageous only to their competitors. The invention of new prospecting methods can have spectacular effects. Shortly after World War I the discovery rate of petroleum pools began to decline. The leading prospecting technique of that day, the projection downward of surface reflections of geologic structure, was proving less rewarding. Prophets foretold an oil shortage in the near future. But at that very moment scientists were perfecting the application of seismic waves to reveal underground oil-bearing geologic structures. As these geophysical methods were put into commercial use the whole outlook changed-the problem of the 1930's became how to cope with the surplus from discovery, not how to meet the ever rising demand. Many lead mines were being abandoned as unprofitable about this same time because the penalties charged by smelters for the zinc in the ores and concentrates more than counterbalanced the payments for lead and silver. Then selective flotation (at the time called differential flotation) appeared,

Jan 1, 1964

A. L. FIELD, Cleveland, Ohio (written discussion*.-)In equation 2, B is used to denote the ratio of bases (lime plus magnesia ) to acids (alumina plus silica) it being stated that this ratio gives more concordant results than the ratio either of bases to silica, or of lime to silica. I find, however, that, by making use of the ratio between true CaO (CaO by analysis minus sulfur calculated to CaS) to acids, equation 2 may he modified to agree with the observed facts within an average error of 0.0041 per cent. sulfur instead of 0.0045 per cent. The revised equation is s = 0.072 + 0.01835 - 0.00061 (t - 1400) - 0.0403B where B is the ratio of true CaO to Al2O3 Plus Si02, and the other symbols have the same significance as before. I would not appear to stress too much this slightly better agreement of the revised equation with the observed sulfur. Yet I believe that the use of this ratio of true CaO to acids is to be preferred, if for no other reason than the fact that it is more in harmony with the previous findings of the Bureau of Mines with regard to the effect of magnesia and other impurities on slag viscosity.1

Jan 12, 1919

NEW MEMBERS The following list comprises the names of those persons who became members during the period Oct. 10, 1918, to Nov. 9, 1918. ALLER, FRANK D., Copper Met., Ore Purchaser, American Smelt. & Refin. Co., 120 Broadway, New York, N. Y. AVÈRY, PAUL W., Met. Engr., Esperanza Min. Co., Apt. 8, El Oro, Mex., Mexico. BAKER, CHARLES A., Leaching Foreman, Copper Leaching Plant, Anaconda Copper Min. Co., Anaconda, Mont: BREED, CHARLES H Met., Crown Cork & Seal Co., Baltimore, Md. CHASE, R. L., Min. Engr 102S First National Bank Bldg., Denver, Colo. EICHELBERGER, FRANK, Vice-pres. and Engr., New York-Montana Testing & Engrg. Co., Helena, Mont. GESTER, G. C., Geol., Standard Oil Co. of Cal., 616 Standard Oil Bldg., San Francisco, Cal. GRIFFIN, JOHN, Mgr., Anthracite Territory, The Dorr Co., Board of Trade Bldg., Scranton, Pa. HAYNES, ELWOOD Pres., The Haynes Stellite Co., Kokomo, Indiana. Hsi, T. C:.. Sec'y, Tayeh Iron & Steel Works, Tayeh, China. HYDE, AUSTIN T., Mgr., Keokuk Plant, River Smelt. & Refin. Co., 607 Franklin St., Keokuk, Iowa.

Jan 12, 1918

By C. L. HUSTON

MY ANCESTRAL connection with the manufacture of boiler plate runs back through four generations, and my personal acquaintance with the practice reaches back to the time, in my ,boy- .hood days, when iron plates' were made in a mill operated entirely by water power. -The mill originally was driven by an old-fashioned "'breast" water wheel 20 ft. in diameter and with a20-ft. face, geared direct to the roll train. When the mill slowed up and there was danger of its stalling, the men would jump upon the rim and help the wheel around with their weight, to prevent a "sticker." Later, as large plates were called for, a flywheel was set out of line so that it could' be speeded up by gears from the water wheel and connected back again,. by reducing- gears, to the roll train. The flywheel, with its cast-iron rim and wooden spokes, made 90 r.p.m. and the roll train 45 r.p.m. In 1870, our company installed our first steam-driven plate mill two-high rolls, 84 in. long. In these early mills the hot metal was manipulated by hand.

Jan 1, 1920

By H. A. Guess

For a number of years I have used for the commercial wet assay of lead generally the ammonium molydate, and occa-sionally the ferrocyanide method. These well-known methods need no detailed description here. In the ore-selling and ore-buying establiahments of the West, 90 per cent. of all wet lead-assays are made by one or the other, and at least nine-tenths of this proportion by the molybdate method. A procedure so well-established must have merit; and, in

Jan 1, 1905

By John L. Schroder

The demands for increased productivity on the 1967 coal industry have generated new operating trends and fresh approaches to old methods, which have enabled the industry to keep pace with the expanding economy. Changes, while not radical in concept or design, have been plentiful and are marked by the refinement of the already tried, tested and proven. Perhaps not since World War II have there been demands on equipment manufacturers to design and deliver such diversified types of machines as those required by the industry in the past year. Equipment developments-following a plan which calls for higher productivity, lower maintenance costs and greater machine availability- have tended more toward increased horsepower and heavier, more rugged equipment. Electrical and mechanical components, designed in many instances with maximum reliability rather than initial costs as the main criterion, have contributed to the improvements in over-all performance. High-strength, specialty steels are finding use in a wide range of equipment applications. The horsepower capacity of electric motors being installed is more frequently being rated on a continuous basis rather than the former one hr or less and, as a result, fewer failures now occur because of overloading. These developments reflect the pyramiding cost of equipment down-time and represent definitive progress in reducing the magnitude of the problem.

Jan 2, 1968

By J. Murray Riddell, George A. Morrison

THIS paper is a companion to the one by George A. Morrison on Mining a Deep Limestone Mine in Ohio.[+] Barberton is 8 miles west of Akron, Ohio, and 23 miles south of Cleveland. The underground mining of limestone at Barberton constitutes the world's deepest limestone mine. The stratigraphy is as follows: 0-20 ft. Loam, clay, sand and gravel. Water bearing. 20-40 ft. Fractured. sandstone. Water bearing. 40-110 ft. Sandstone with interbedded shale, slightly fractured. Water bearing. 110-314 ft. Sandstone with interbedded shale, slightly fractured. Water carrying. 314-2197 ft. Shale with occasional seams of sandstone, which varies in thickness from a few inches to 4 feet. Dry. 2197-2247 ft. Limestone. Dry. 2247-2742 ft. Dolomitic limestone. Dry. 2742-2767 ft. Salt. Dry. 2767- Dolomitic limestone. Dry. All of the strata dip to the southeast, about 0.5 per cent from the horizontal. The top 110 ft. of the crust is water-bearing. The rock strata are naturally fractured to a depth of 314 ft., sufficient to allow the passage of water. In the shaft-sinking operations, a stra was encountered at a depth of 520 ft., and flows of methane gas were pierced at depths of 1350 and 1952 feet. Specifications for the mine plant called for, in part, the sinking of two vertical shafts and a hoisting plant capable of producing at the rate of 300 tons per hour. No. I shaft is 550 ft. west of No. 2 shaft. Each shaft measures 8 by 17 ft. outside of steel. General features of the design (Fig. I) are: Principal set members, 6-in. H-section; connecting angles (studdles), 3/8 by 4 by 4-in. angle irons; spacing of sets, 8 ft. centers; spacing of bearer sets, generally, 160 ft.; bearers, of 12-in. I-beams. Each bearing set featured a concrete ring about the periphery of the shaft, steel to rock, and 8 ft. in height; permanent guides, 6 by 10-in. long-leaf yellow pine, 85 per cent heart. THE SHAFT-SINKING OPERATION The preliminary shaft-sinking work consisted of driving interlocked steel piling about the exterior of the shafts to depths of 35 and 32 ft., respectively, and of such horizontal dimensions as to ultimately permit the pouring of a concrete collar 2 ft. in horizontal thickness. Following the pouring of a shaft collar, a temporary wooden headframe for shaft-sinking purposes was erected. The head-frame, while ordinary, featured: (I) a storage pocket of 300 cu. ft. capacity with truck servicing facilities, and (2) pneumatically operated dump doors, which were actuated by the hoistman, thus caring for the dumping of the "ball-and-chain"

Jan 1, 1944