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By Roy E. Dickerson

CUBA differs considerably from the other Greater Antilles in many geologic fundamentals. Cuba is geosynclinals; whereas Jamaica, Hispaniola. (Haiti), and Puerto Rico are geoanticlinal. (Scliuchert, Chas., Historical Geology of the Antillian. Caribbean Region, p. 13, 1935.) Rocks of lowermost Cretaceous age exist in large volume in Cuba, where- as they are generally absent in the other islands. Since many of the surface indications of petroleum are intimately associated with lowermost Cretaceous rocks, the Vinales limestone,, this difference is most important. The Vinales limestone in many places in Pillar del Rio and Santa Clara provinces reeks with light tars when broken with a hammer. The late David White and his associates on the U. S: Geological Survey studied

Jan 1, 1937

By R. W. Raymond

THE absence of a convenient glossary of terns connected with mining and metallurgy has long been felt by the general public. It is to meet this want, not to furnish a technical manual for experts, that the following glossary has been prepared. It originated in an attempt on my part to revise for publication the manuscript of a compilation prepared from the appendix of Yale's work on Mining Titles and one or two other sources, to serve as an appendix to a new work on mining law, about to be published by Mr. H. N. Copp, of Washington, D. C. This revision soon assumed, contrary to my original intention, the proportions of a reconstruction ; and with the consent of Mr. Copp, and for the purpose of receiving from my fellow-members valuable aid, I presented my still incomplete work as a paper at the Lake Superior meeting of the Institute, inviting from any quarter suggestions of new terms or better definitions to be incorporated in the glossary before its final publication. This invitation was so widely and generously responded to, that I cannot undertake to make in this place' individual acknowledgments to those members of the Institute, and professional colleagues outside of it, who hays favored me with ' assistance and advice. The labor bestowed upon this paper since its presentation, at the Lake Superior meeting has considerably exceeded that of its first preparation, as

Jan 1, 1881

By Herbert H. Kellogg, Hugo Vasquez- Rosas

Recently the long-chain primary amines have been used extensively for the flotation of silicate minerals. The use of amines to float sulphide minerals has been investigated by several authorsl-5-l8 but most of this work has been done with the short-chain (less than six carbon atoms) primary amine compounds or the more expensive secondary, tertiary and quaternary amines. Perhaps the fact that the long-chain amines are good collectors for the common gangue minerals has led investigators to omit them from consideration as collectors for the selective flotation of metallic sulphides. The work reported in this paper was designed to investigate the use of a typical long-chain amine salt, laurylamine hydro-chloride, as a collector for the flotation of galena-sphalerite ores. The results show that laurylamine hydrochloride (LAmHCl), when used in small amounts, is a good collector for the selective flotation of sphalerite and galena from the common gangue minerals. The differential flotation of sphalerite from galena was not accomplished but the amine flotation of sphalerite after the standard xanthate flotation of galena is possible. The experimental work reported herein is not complete enough to be able to say whether amine flotation of lead-zinc ores would prove superior to xanthate flotation, or whether the method is even applicable to a more complex ore than the one used for this work. However, the apparent reagent costs for the flotation operations described in this paper seem to be less than for xanthate flotation. This fact alone should be sufficient to encourage the millman to investigate the use of these amine reagents, especially as these reagents are available on a commercial scale at a reasonable price. This paper has as its secondary purposes to illustrate how contact-angle measurements have aided in this investigation, and to bring forward some evidence concerning the mechanism of the collecting action of primary amines. Contact-angle Tests The contact-angle measurements were made by the method described by del Giudice6 and used in recent work by Taggart and his collaborators.7-9 The mineral specimens for the contact-angle tests were carefully chosen, to avoid cracks and inclusions of other minerals. All specimens were mounted in "transoptic" plastic mounts and the surfaces were cleaned by polishing with levigated alumina on a cloth-coverkd glass polishing wheel. Distilled water was used on the lap during the polishing and at all subsequent steps in the contact-angle tests. The mounted mineral specimens were handled with glass forceps and special care was exercised to prevent exposure of the clean surface to air or any other source of contamination.

Jan 1, 1947

By Herbert H. Kellogg, Hugo Vasquez- Rosas

Recently the long-chain primary amines have been used extensively for the flotation of silicate minerals. The use of amines to float sulphide minerals has been investigated by several authorsl-5-l8 but most of this work has been done with the short-chain (less than six carbon atoms) primary amine compounds or the more expensive secondary, tertiary and quaternary amines. Perhaps the fact that the long-chain amines are good collectors for the common gangue minerals has led investigators to omit them from consideration as collectors for the selective flotation of metallic sulphides. The work reported in this paper was designed to investigate the use of a typical long-chain amine salt, laurylamine hydro-chloride, as a collector for the flotation of galena-sphalerite ores. The results show that laurylamine hydrochloride (LAmHCl), when used in small amounts, is a good collector for the selective flotation of sphalerite and galena from the common gangue minerals. The differential flotation of sphalerite from galena was not accomplished but the amine flotation of sphalerite after the standard xanthate flotation of galena is possible. The experimental work reported herein is not complete enough to be able to say whether amine flotation of lead-zinc ores would prove superior to xanthate flotation, or whether the method is even applicable to a more complex ore than the one used for this work. However, the apparent reagent costs for the flotation operations described in this paper seem to be less than for xanthate flotation. This fact alone should be sufficient to encourage the millman to investigate the use of these amine reagents, especially as these reagents are available on a commercial scale at a reasonable price. This paper has as its secondary purposes to illustrate how contact-angle measurements have aided in this investigation, and to bring forward some evidence concerning the mechanism of the collecting action of primary amines. Contact-angle Tests The contact-angle measurements were made by the method described by del Giudice6 and used in recent work by Taggart and his collaborators.7-9 The mineral specimens for the contact-angle tests were carefully chosen, to avoid cracks and inclusions of other minerals. All specimens were mounted in "transoptic" plastic mounts and the surfaces were cleaned by polishing with levigated alumina on a cloth-coverkd glass polishing wheel. Distilled water was used on the lap during the polishing and at all subsequent steps in the contact-angle tests. The mounted mineral specimens were handled with glass forceps and special care was exercised to prevent exposure of the clean surface to air or any other source of contamination.

Jan 1, 1947

By J. D. Livingston

THE hardening of alloys by the precipitation of a second phase has long been an important technological process. One approach towards improving our understanding of this phenomenon has been a correlation of mechanical properties with such parameters as particle size and inter par ticle spacing.' Several reviews of such data have appeared.2-4 A major limitation to this approach has been that for most alloys the particles are submicroscopic in size in the range of optimum hardness. Precipitation-hardening copper-cobalt alloys, therefore, are of interest, because the ferromagnetic properties of the precipitate make it possible to measure particle size, number of particles, and so forth, from magnetic measurements alone.5, 6 Livingston and Becker7 have applied these techniques to a study of precipitation hardening in an alloy of 2 pct Co in copper. It was found from magnetic measurements that nearly all the cobalt to be precipitated was out of solution within a few minutes at 600°C, whereas the peak in tensile yield stress was not attained until a much longer aging time. Thus during the first 1000 min of aging time at 600°C the Yield stress was increasing while a constant volume of precipitate was coarsening, i.e., while particle size and interparticle spacing were increasing. Peak yield stress was reached at an average particle radius of about 70A. The earlier study was confined to one alloy at one aging temperature, so that the volume fraction of precipitate was fixed and, therefore, particle size and interparticle spacing could not be independently varied. The work has now been extended to several alloys of varying percentage cobalt in copper, and to aging at various temperatures. It was hoped that such a study might clarify the relative importance to precipitation hardening of particle size, interparticle spacing, and volume fraction of precipitate. EXPERIMENT The alloys studied contained 0.7, 1.3, 2.0, and 3.2 wt pct Co in copper. They were prepared from electrolytic copper and electrolytic cobalt in a vacuum -induction furnace, worked to 3/8-in.-diam rod, and machined into tensile specimens with a gage section 1 1/2 in. long and 3/16 in. in diam. All specimens were given a solution treatment consisting of a 30-min anneal in nitrogen at 1000° C followed by a quench into iced brine. Subsequent aging was done in nitrogen and followed by a water quench. Average grain diameter was approximately 0.01 in.

Jan 1, 1960

By Walter R. Hibbard, George H. Eichelman, William P. Saunders

INTEREST in the various products of the austenite eutectoid transformation in iron-carbon alloys, particularly as produced by the isothermal sub-critical techniques introduced by Davenport and Bain,1 has resulted in the application of similar heat treatments to other eutectoid transformations. Studies2.3.4 of the beta copper-aluminum alloy eutectoid transformation revealed microstructures very similar to those found in iron-carbon alloys. Investigations5,6 of the kappa phase in the copper-silicon alloy system have established the eutectoid type transformation of this phase into terminal alpha and intermediate gamma phases. This transformation has been reported' as forming a eutectoid type structure in a very sluggish manner by a long time isothermal treatment. The purpose of the present investigation is to study the products of the kappa eutectoid transformation as affected by transformation temperatures by means of microscopic and hardness methods. PREPARATION OF ALLOYS The copper-silicon alloy equilibrium diagram is shown in Fig I. The kappa field converges to a minimum silicon solubility at the eutectoid composition and all other completely kappa alloys are hypereutectoid. Thus, kappa decomposition involves first the proeutectoid precipitation of gamma, followed by the eutectoid transformation of a lower silicon content kappa (5.2 pct). Smith5 has indicated that alloys containing between 5.4 and 5.7 pct silicon could be hot rolled, but that the latter composition was desirable in order to permit a wider kappa temperature range. The alloy was prepared by adding Baker's commercially pure silicon to an ingot of copper-silicon alloy containing 2.34 pct silicon remaining from the investigation of Brick, Martin and Angier.7 Following the casting techniques of Krynitsky, Saunders and Stern,8 the ingot was melted under a heavy layer of dried charcoal in a clay-graphite crucible in a gas-fired pot furnace. Small lumps of silicon were held under the melt surface with a graphite rod. After the silicon had dissolved, the alloy was chill-cast and then remelted without a cover, stirred thoroughly, skimmed and poured into a preheated cast iron mold. The cast microstructure is shown in Fig 2. The casting, 10 X 4 X ¾ in., was annealed at 750°C for 21 brand furnace cooled. About 1/16 in. was milled from all surfaces. The plate was cut in half longitudinally and the bottom half analyzed by A.S.T.M. methods.9 The composition by weight was as follows: copper 94.24 pct, silicon 5.56 pct, iron 0.11 pct.

Jan 1, 1948

By Arthur F. L. Bell

Prior to 1908 the oil production in the State of California had been almost entirely a heavy fuel oil, with a high flash point, but changed within a short period to a large percentage of refining oil with a low flash, by reason of the heavy production of light oil coming in from the Santa Maria field, the Midway field, and the increased production of the Fullerton field. This is clearly shown in the following tabulation of California's pro- The bringing in of these high percentages of light oil with their dangerous low flash and the increasing demand for the refined products necessitated the devising of some cheap and efficient means of quickly separating the lighter elements either in the field or at the main distributing points; also it became necessary to remove the excessive percentage of water which many of the light oils carried in emulsion. Union Oil Co. Port Harford Plant Probably the first important attempt to top light oil in California by other means than the ordinary stills was tried about 1908 by the Union Oil Co., at its plant at Port Harford, San Luis Obispo County, with Santa Maria oils. The process was the invention of Hubert G. Burroughs who afterward obtained a patent for the process, No. 998,837, dated July 25, 1911. The apparatus used consisted of a series of 12-in. pipes mounted in units of three pipes, one above the other, the crude oil being admitted to the upper pipe and filling it about two-thirds of its

Jan 1, 1916

By Byron M. Bird

JIGGING is the stratification of a mass of solid particles in upward pulsations of water or in alternating upward and downward pulsations. The stratification usually is effected in a rectangular open-top container having a perforated bottom through which the pulsations of water are applied to the materials to be separated; in separating coal, to a mass of coal and refuse. Jigging usually is a continuous process involving three steps: (1) the reception of the raw coal, (2) the stratification of the coal and refuse so that the refuse settles to the screen plate, and (3) the overflow of the cleaned coal and the withdrawal of the refuse collected on the screen. The jig is the most universal washer ever devised. It is handling in practice a wide range of closely sized coals and ores, mixed sizes of coal from 8-in. to 0 through ¾ -in. to 0, and mixed sizes of ores down to 7/32-in. to 0 and even smaller. It is treating materials ranging in specific gravity from that of gold at 19 to that of coal at 1.30. It is handling feeds in which the proportions of high-gravity materials range from 90 per cent or higher, as for some iron ores, to 10 per cent or less for some coals. It is handling feeds containing all shapes of particles-round, rectangular, and , flat. It is handling simple separation problems and difficult separation problems. Thus, it is an almost universal separating device. One might add that it has been one of the most misunderstood types of washers, from both a theoretical and a practical point of view. Although considerable progress has been made in coal jigging in the past 10 years, the jig probably has more unexplored possibilities than any other type of washer. In this chapter the object has been to treat the jigging process in a practical manner and to give information that will help the reader to improve his particular operation. Inasmuch as performance data from operating plants would contribute little of value, none has been given. Instead, the emphasis is upon jigging principles as a foundation for attacking the problems that arise. These principles are in reality tentative conclusions from research in the field of jigging during the past 10 years and most of this chapter should be regarded as a progress report on an investigation still under way. As all really difficult problems in jigging arise from an attempt to treat a large range of sizes in one operation, nearly the entire discussion will be

Jan 1, 1943

By B. N. Das, J. B. Darby, P. A. Beck, Y. Shimomura

A POWDER pattern for the (Cr, Mo, Co)R-phase annealed at 1200°C was reported in 1951.1 Through the courtesy of Prof. D. P. Shoemaker of Massachusetts Institute of Technology the authors became aware of inconsistencies of this pattern with that to be expected from the structure of the R-phase, as determined by Komura, Shoemaker, and Shoemaker.' In addition, Professor Shoemaker also noted that the powder pattern reported8 for the (Cr, Mo, Co)D-phase, annealed at 1300°C, agreed fairly well with that to be expected from the newly determined structure of the R-phase. In view of these findings, the previously reported powder patterns of the R-phase and of the D-phase were compared carefully. It was found that most lines in the two patterns (22 lines) were to a fair degree of accuracy related to each other by a single conversion ratio for the corresponding d spacings. The value of the conversion ratio was found to be 1.0058, so that the d spacings of the D-phase pattern previously reported were larger than the correspond- ing d spacings for the reported R-phase pattern by approximately that factor. The intensity relationships between corresponding lines in the two patterns were similar, as judged visually. The following exceptions were noted: Lines Nos. 2, 3, 19, 20, 21, 22, 23, 24 and 25 of the D-phase pattern,:' all designated weak or very weak, were missing in the apparently somewhat fainter R-phase pattern used.' Lines 1, 2, 3, 5, 15 and 34 (all weak or very weak), reported for the R-phase, were missing in the D-phase pattern, Table I. In view of these observations it seemed probable that the two patterns differed from each other mainly by a slight change in lattice parameters (with c/a remaining approximately constant), and that the pattern previously reported for the R-phase contained some weak extraneous lines, most likely to be attributed to impurities. In order to check the foregoing assumption, two specimens of an alloy containing 43 pct by weight of cobalt, 41 pct molybdenum, and 16 pct chromium, which was within the composition range of stability of both the D-phase at 1300°C and of the R-phase at 1200°C, were homogenized at 1200 and 1300°C, respectively, and quenched. X-ray diffraction patterns of the powders of these two specimens, obtained with CrK radiation, were compared carefully with each other and with the D-phase pattern previously

Jan 1, 1959

By John Chipman, Theodore B. Winkler

In order to understand more fully the complexities of the reactions occurring between the liquid steel and the slag in the basic open-hearth steelmaking furnace, investigations in this country and. abroad have turned to laboratory equilibrium studies. This paper is one of a series of reports on investigations being conducted at the Massachusetts Institute of Technology. The experimental work was completed early in 1942. The slag systems found in the basic open hearth are very complex, being made up of at least eight major components and as many others whose effect might be classified as minor. The first two papers of the series, by Fetters and Chipman,l,2 as well as the paper by Taylor and Chip-man,3 dealt with the simplest possible slag system that would resemble those found in the basic ope), hearth—the slag system consisting of CaO-MgO2-SiOz-FeO. (Taylor's rotating induction furnace eliminated the necessity of contamination of the slag by MgO.) Having arrived at some reasonable conclusions regarding the physical chemis- try of the reactions between molten iron and the simple slags at equilibrium, the next step was to investigate more complex slag systems. The major purpose of the present investigation was to determine what factors control the distribution of phosphorus between molten iron and the more complex basic slags at equilibrium, and to what extent these factors are influential. The slags used contained CaO, MgO, SiO2, FeO, Fe2O3, P2O6, MnO, Al2O3 and CaF2, but not all of the slag samples contained all of these components at one time. Review of Literature Although a number of interesting papers have been published on the subject of dephosphorization of an iron bath, there are as yet no results from laboratory studies that give thoroughly reliable information on the dephosphorization reaction. Even for the supposedly simple Fe-O-P system involving iron-phosphorus melts and iron oxide-iron phosphate slags, the experimental results are contradictory and no formulas have been established that adequately fit the equilibrium conditions. The Fe-O-P system has been studied by Schackmann and Krings,4 von Samson-Himmelstjerna,6 Oelsen and Maetz,6 Bischof and Maurer,7 Diepschlag and Schürmann,8 and Herty,9 and the results of their investigations appear in Table I. A number of different equilibrium constants and distribution . Ratios

Jan 1, 1947

By Theodore B. Winkler, John Chipman

In order to understand more fully the complexities of the reactions occurring between the liquid steel and the slag in the basic open-hearth steelmaking furnace, investigations in this country and. abroad have turned to laboratory equilibrium studies. This paper is one of a series of reports on investigations being conducted at the Massachusetts Institute of Technology. The experimental work was completed early in 1942. The slag systems found in the basic open hearth are very complex, being made up of at least eight major components and as many others whose effect might be classified as minor. The first two papers of the series, by Fetters and Chipman,l,2 as well as the paper by Taylor and Chip-man,3 dealt with the simplest possible slag system that would resemble those found in the basic ope), hearth—the slag system consisting of CaO-MgO2-SiOz-FeO. (Taylor's rotating induction furnace eliminated the necessity of contamination of the slag by MgO.) Having arrived at some reasonable conclusions regarding the physical chemis- try of the reactions between molten iron and the simple slags at equilibrium, the next step was to investigate more complex slag systems. The major purpose of the present investigation was to determine what factors control the distribution of phosphorus between molten iron and the more complex basic slags at equilibrium, and to what extent these factors are influential. The slags used contained CaO, MgO, SiO2, FeO, Fe2O3, P2O6, MnO, Al2O3 and CaF2, but not all of the slag samples contained all of these components at one time. Review of Literature Although a number of interesting papers have been published on the subject of dephosphorization of an iron bath, there are as yet no results from laboratory studies that give thoroughly reliable information on the dephosphorization reaction. Even for the supposedly simple Fe-O-P system involving iron-phosphorus melts and iron oxide-iron phosphate slags, the experimental results are contradictory and no formulas have been established that adequately fit the equilibrium conditions. The Fe-O-P system has been studied by Schackmann and Krings,4 von Samson-Himmelstjerna,6 Oelsen and Maetz,6 Bischof and Maurer,7 Diepschlag and Schürmann,8 and Herty,9 and the results of their investigations appear in Table I. A number of different equilibrium constants and distribution . Ratios

Jan 1, 1947

By Kenneth S. Ritchie

The natural emulsion samples used in this study were shipped directly from twelve California oil fields, through the courtesy of the superintendents of the main producing companies in those fields. Representative parts of each sample were chosen for the slides. Preparation of the slides was generally made in less than two minutes, including time of exposure; in a few cases, about five minutes was required. The short time was intended to minirmize the changes in conditions. Whenever comparison was of value, standard conditions were established. Spreading by gravity was adopted instead of smearing. Cover glasses were not allowed to rest on the films. General Characteristics of Emulsions The main purpose of the general views (Figs. 1-16) is to illustrate the general characteristics of the dispersed droplets together with any other constituent or impurity that may be found in each emulsion. The magnification is given so that dimensions could be measured from the plates. The slides used for these views had spherical recesses; they gave the best light. Where crystals were intended to be shown in the picture a filter (green was the best') was usually used. Emulsions that showed a tendency to move by concentrated light were pictured without a condenser.

Jan 1, 1931

By Edwin Hopkins

THE year 1923 started a few days after the Venezuelan Oil Concessions, Ltd., discovered a 140,000-bbl. well at. La Rosa and a well of between 2500 and 5000 bbl. at La Paz, on the opposite side of Lake Maracaibo. These nearly simultaneous events changed, overnight, the general aspect of oil affairs in Venezuela. Up to that time, big things had been expected by the companies then in the district, but many major companies had shown little interest in the country. Within a few weeks the Pure Oil. Co. and the Gulf Oil Corpn. entered the field and acquired large properties. The Texas Co. purchased several concessions and the Standard of California, Atlantic Refining Co., and Mexican Petroleum Co. established offices. Representatives of many other companies visited the district during the first few months of the year. The sudden influx of buyers naturally caused a great rise in prices and this, together with overproduction in the United States, doubtless caused the slowing up of concession transfers in the latter part of the year. The following property transfers occurred: (1) The Gulf Oil Corpn. contract with the Maracaibo Oil Exploration Corpn., whereby the Gulf acquired the right to select 100,000 acres from the Maracaibo's zones. (2) The Gulf Co. purchase of one-quarter interest in seven concessions of the New England Oil Corpn., Ltd. (3) The Gulf Oil Corpn. purchase of several concessions of Kunhardt and others in the Perija district. (4) The Gulf Oil Corpn. purchase of certain portions of the one-kilometer Lake zone that were not covered by parcels or Government reserves (namely the "sobrantes"). (5) Pure Oil Co. purchase of all Government reserves turned back by Maracaibo Oil Exploration Corpn. in the districts of Mara and Miranda. (6) Standard Oil Co.: of New Jersey deal with the British Controlled Oilfields, Ltd., for control of approxi-mately the eastern third of the .district of Buchivacoa, state of Falcon. (7) Royal Dutch deal with the British Controlled Oilfields, Ltd., for the control of the central third of the district of Buchivacoa, Falcon. (8) The Texas Co. purchase of several concessions in Perija and one west of Mene Grande on the east side of Lake Maracaibo. (9) Purchase by the British Equatorial Oil Co., Ltd., of Goverment reserves corresponding to certain Creole Syndicate parcels under the margin of Lake Maracaibo near La Paz. (10) The Lago Petroleum Co. acquired a concession on all of Lake Maracaibo except a 1-Km. strip along the shore.

Jan 3, 1924

By Karl W. Mote

CALIFORNIA'S iron and steel industry had its beginning in San Francisco in 1849 when the first iron casting was poured at the old Union Iron Works. Soon after, in 1856 at Grass Valley, enough iron ore was smelted to supply pig iron for the castings of a quartz mill there. From 1880 to 1886, iron ore was produced from the Hotaling mine in Placer County and converted to pig iron in a local blast furnace using charcoal. From 1907 to 1914, the Noble Electric Steel Co. produced pig iron from iron ore mined at the Shasta Iron Co. mine, and followed this for three years in the production of ferro-alloys. Between 1917 and 1941, the State's industry in- creased its capacity for open hearth and electric furnace scrap treatment, but the real impetus was supplied by the need for more steel at the beginning of World War II. The result was the State's first integrated steel plant-the Kaiser Steel Corp. facilities at Fontana.

Jan 7, 1958

By Bradley Stoughton

A LL over our great country I have been privileged to see, during the last six weeks, the manifestation of a new spirit among engineers. Partly under the inspiration of leaders whose influence has been felt not only nationally, but internationally, - partly through the recognition of the service that engineers have been able to render to the nation during the recent crisis, a new self-consciousness has been acquired by the individuals, and now this self-consciousness seeks expression in opportunities for service and participation in public affairs. The engineer . no longer sees himself a mere reservoir of information to be tapped when some one is in need of cold facts, no. more an administrator of mere material things, but a potential administrator of- public affairs, a citizen and a human being, with the responsibilities, as well as the privileges of citizenship.

Jan 1, 1920

By George M. Rigg, Samuel M. Cassidy

During 1937 a program was begun to mechanize and modernize the then 28-year old Isabella mine of the Weirton Coal Co., which is on the Monongahela River, in Fayette County, Pennsylvania, at one edge of what is generally known as the Coke Region. Weirton Coal Co. is a subsidiary of the National Steel Corporation, and produces metallurgical grade coking coal for the Weirton Steel Co., Weirton, W. Va. Improvements subsequently made included a cleaning plant for washing the entire mine output, shovel-action track-mounted machines for mechanically loading all the coal, universal-type track-mounted cutting and shearing machines, post drills, 8-wheel mine cars of 10 tons capacity, cable-reel gathering locomotives and other auxiliary equipment. This paper presents the factors, reasons and results of decided changes from the mining system generally prevailing in the region, as well as abandonment of selective mining practices in favor of complete seam extraction. Coal-seam Conditions Fig. 1 illustrates the Pittsburgh coal seam on the property. Cover over the seam averages 450 ft., and 675 ft. is the maxi- mum. Main roof varies from very weak to medium strong; usually it disintegrates rapidly on exposure to air. The "wild" coal makes a fairly strong immediate roof if supported by crossbars and if unbroken affords a seal to the main roof. The draw slate is very weak and treacherous. The floor is characterized by numerous irregular bottom rolls, or "horsebacks," protruding from a few inches up to 3 ft. into the coal. Some are soft, but many are hard and flintlike. Although the bottom slate usually is hard, the underlying fire clay causes it to buckle and heave readily with any moderate increase in roof pressure or where damp. As a whole, the bottom is weaker than the main roof. The coal is characterized by numerous closely jointed face and butt cleats and a woody, springy nature when shot, both having a decided influence on face practices. As shown in Fig. I, at both the top and bottom of the main coal seam is a layer of coal of higher ash and sulphur content than the body of coal in the middle. Factors That Influence the Mining System Equipment was bought and organization for mechanical loading was made on the basis of working each mechanical unit as near its full capacity as possible, to lessen investment cost and obtain best operating efficiency. This led to combination double and triple-shift operation at the start, and, very shortly, to all sections being triple shifted.

Jan 1, 1947

By Samuel M. Cassidy, George M. Rigg

During 1937 a program was begun to mechanize and modernize the then 28-year old Isabella mine of the Weirton Coal Co., which is on the Monongahela River, in Fayette County, Pennsylvania, at one edge of what is generally known as the Coke Region. Weirton Coal Co. is a subsidiary of the National Steel Corporation, and produces metallurgical grade coking coal for the Weirton Steel Co., Weirton, W. Va. Improvements subsequently made included a cleaning plant for washing the entire mine output, shovel-action track-mounted machines for mechanically loading all the coal, universal-type track-mounted cutting and shearing machines, post drills, 8-wheel mine cars of 10 tons capacity, cable-reel gathering locomotives and other auxiliary equipment. This paper presents the factors, reasons and results of decided changes from the mining system generally prevailing in the region, as well as abandonment of selective mining practices in favor of complete seam extraction. Coal-seam Conditions Fig. 1 illustrates the Pittsburgh coal seam on the property. Cover over the seam averages 450 ft., and 675 ft. is the maxi- mum. Main roof varies from very weak to medium strong; usually it disintegrates rapidly on exposure to air. The "wild" coal makes a fairly strong immediate roof if supported by crossbars and if unbroken affords a seal to the main roof. The draw slate is very weak and treacherous. The floor is characterized by numerous irregular bottom rolls, or "horsebacks," protruding from a few inches up to 3 ft. into the coal. Some are soft, but many are hard and flintlike. Although the bottom slate usually is hard, the underlying fire clay causes it to buckle and heave readily with any moderate increase in roof pressure or where damp. As a whole, the bottom is weaker than the main roof. The coal is characterized by numerous closely jointed face and butt cleats and a woody, springy nature when shot, both having a decided influence on face practices. As shown in Fig. I, at both the top and bottom of the main coal seam is a layer of coal of higher ash and sulphur content than the body of coal in the middle. Factors That Influence the Mining System Equipment was bought and organization for mechanical loading was made on the basis of working each mechanical unit as near its full capacity as possible, to lessen investment cost and obtain best operating efficiency. This led to combination double and triple-shift operation at the start, and, very shortly, to all sections being triple shifted.

Jan 1, 1947

By W. T. Cardwell

This paper presents a theory for estimating the rate of gravity drainage of a liquid out of a sand column. Account is taken of the variation in permeability to the liquid as the saturation in the upper part of the sand becomes less than 100 pct. The theory is confirmed by previously published experimental data. Introduction Petroleum engineers have expressed the need for 4 theory of gravity drainage. Brunner,' in particular, has pointed out that some type of mathematical theory is necessary to begin the application of laboratory data to field problems. Muskat and his associates2'3-4 have recently made contributions to the theory of gas-drive behavior and have indicated an intention to apply their methods to water-drive systems. No theory of gravity drainage rates has been developed, however, and it seems desirable to formulate one at this time. Differential Equations of Capillary Flow The flow of liquids in partially saturated porous media has been studied by many investigators.6-10 Richards6 presented derivations of fundamental differential equa- tions governing two-phase capillary flow; and used simplified forms of those equations in solving a steady-state problem. Muskat and Meres6 presented and used equations different from those of Richards. Their equations did not explicitly involve capillary pressure gradients; but included, on the other hand, terms expressing the effects of the evolution of gas from the liquid phase during flow. Leverett8 stated in 1940 that "previous work on the flow of fluid mixtures in porous solids [had] failed adequately to account for all of the three influences that cause motion of the fluids: capillarity, gravity, and impressed external pressure differentials." Leverett's basic equations, however, were specialized forms of the general equations of Richards,5 which had actually taken account of the three influences mentioned by Leverett, but had not been used in a problem involving all three. The fact is that our knowledge of capillary flow and our ability to express this knowledge in differential equations exceed our ability to solve the equations except in a few cases. General differential equations have usually been of little more than formal value. In solving practical problems, it has been necessary to develop specific equations, preserving terms that involved the factors important in those problems, and purposefully neglecting other terms that were not of predominating influence. This is the method followed here. It is believed that the solution of the particular problem and the scheme of the solution itself are new.

Jan 1, 1949

By C. E. Arnold

In attacking the problems of mining and treating large disseminated copper orebodies such as those occurring in the Miami or the Ray district of Arizona, one of the vital questions to be decided is, "What is the value of the orebody per ton in place?" The importance of this question lies in the fact that its answer helps to reach a decision concerning the method of mining to be employed. Let it be assumed for the moment that milling and smelting practice, especially the latter, is more or less standardized, and has a cost incapable of much variation, while the cost of mining has a considerable range owing to the large number of mining methods by which a mine may be exploited. For instance, a method may be adopted whereby all the available ore can be extracted perfectly clean (i.e., unmixed with barren material) at a relatively high cost; or a method may be used involving the necessary dilution of a portion of the ore with waste, in order to recover that portion, thus giving a relatively poorer extraction but nevertheless a lower working cost than the former method. Naturally, between these two extremes there lie intermediate methods. In order to arrive at a solution of a mining method problem that is of any value, it is necessary that accurate and complete estimates of mining, milling, and smelting performances and costs shall be established. By way of illustration is given a case of mining, by the system of undercutting and caving, a large orebody with an average content of 1.50 per cent. copper supposedly all in sulphide form, to which case has been applied those results in mining operations which one may fairly assume are to be expected when viewed in the light of G. R. Lehman's ore-drawing experiments, which form the subject of a paper to be presented at this meeting. It is assumed that the total costs will be as shown in the table on page 204. To attain these costs, a daily production and treatment of 14,400 tons has been assumed. Other assumptions are as follows: 15 per cent. of orebody is to be extracted clean by development work and undercutting; 63.8 per cent. (75 per cent. of 85 per cent.) is to be extracted clean by caving, leaving 21.2 per cent. part of which is to be extracted by diluting with waste, and the remainder lost. Dilution and extraction are to

Jan 1, 1917

By H. M. Otte

Certain choices for the shear elements of the inhomogeneous distortion in the phenomenological theory of martensite formation are examined for their agreement with crystallographic and X-ray data of iron alloys. The assumption that the shear elements must represent slip or twinning systems characteristic of bcc metals is found to covey all observations, even when a small uniform dilatation is taken into consideration. In bct martensite, (011) becomes a possible twinning or faulting plane, in addition to {112), and qualitatively similar X-ray line broadening is to be expected from both. The basic concept inherent in the current theoriesl-4 of the formation of martensite is that the interface between the parent (austenitic) and product (martensitic) phase is an invariant strain plane (i.e., one that is undistorted and unrotated). Experimental evidence that the interface is of such a nature is available in certain transformations2'5'6 but for the transformation in iron alloys direct observation has not proved enlightening. Internal strains resulting from the formation of the small martensite platelets within the parent austenite matrix7 make it difficult to produce the desired evidence. Indirect evidence, however, such as the continuity of scratches in passing from untrans-formed to a transformed region, strongly indicates that the habit plane in iron alloys is an invariant strain interface. The scatter in habit planes in a given specimen8 would suggest that internal stresses have a slight but definite influence. On the other hand, composition changes which affect the lattice parameter can alter the habit plane appreciably, and by an amount greater than the scatter.' The success of the theories depends on the choice made for the "inhomogeneous distortion" or "complementary shear'' in the analysis and also on the choice for the parameter 6 representing a small uniform dilatation. In the approach developed by Wechsler, Lieberman, and Read'," it is implicitly assumed that 6 is unity. In the case of iron alloys, all observations cannot be explained without varying either the inhomogeneous distortion or 6 . Bowles and Mackenzie3 considered only the effect of varying d. They found it difficult to reconcile the wide scatter of habit planes with the theory and were forced to the conclusion that it may also be necessary to consider variations or different choices of the inhomogeneous distortion. Wechsler and Read" considered a limited number of possible choices for the inhomogeneous distortion, but no variation in 6, though this could easily have been introduced if so desired. It is the purpose of the

Jan 1, 1961