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By H. M. Woodrooffe

Three of the world's largest phosphate deposits are located in the USSR. These have an estimated reserve of 2,600 million short tons of elemental phosphorus. The best known lies in the Khibiny Massif, an alkalaic rock formation some 600 square miles in area with mountain peaks rising to an altitude of 3300 ft above the surrounding terrain. The Khibiny Massif is north of the Arctic Circle in the Kola Peninsula at a latitude of 67° 30' north and a longitude of 35° 30' east. It is connected by rail to Murmansk, 100 miles northwest, and Leningrad, 900 rail miles south.

Jan 12, 1972

By Arnold H. Kackman

At the Kaiser Cement and Gypsum plant near San Jose, Calif., one rod-ball mill has taken over the entire raw grinding function for the largest single cement operation in the West. Installed as part of a major overhaul performed on the plant by Kaiser Engineers, the new mill does the work of seven previous mills in feeding the plant's six kilns and keeping pace with its annual capacity of 8.5 million bbl of cement. Installation of the mill, which is the largest in the world, was started in December of 1966 and completed in April of 1967. The over-all modernization program surrounding the new mill has included the modification of existing crushing facilities; the building of new raw materials handling and blending facilities, new raw milling facilities, and new slurry handling facilities; and the installation of a digital-analog control system.

Jan 7, 1967

By P. Pietrokowsky

lntermediate phases in the binary metal alloy systems Ti-Zn, Ti-Hg, Zr-Zn, Zr-Cd, and Zr-Hg have been investigated by X-ray powder diffraction methods. Gamma-TiBHg and Zr3Hg have a beta tungsten structure; TiHg and ZrHg are analogous to ordered AuCu (L l0 type); delta-TixHg and ZrHg, are isomorphous with ordered AuCu,, (L l2 type); ZrZnz is face-centered cubic (C 15 type); TiZna crystallizes in a C 14 type structure; and Zrll-, occurs in cubic and tetragonal modifications in which a random distribution of atoms exists. Additional information for the intermediate phase TiZn, is presented. THE physical metallurgy of titanium and zir-conium when alloyed with elements in subgroup 11-B of the periodic table has received comparatively little attention in the literature. Laves and Wallbaum' reported the existence of several intermediate phases in the system Ti-Zn. They identified TiZn as a CsCl (B 2) structure and described TiZn, as an ordered Cu,Au (L 1, type) crystal structure. Gebhardt' investigated very limited zinc-rich regions in the systems Ti-Zn and Zr-Zn. Phase relationships in these partial constitution diagrams were deduced from the results of thermal analysis and metallography, X-ray results being inconclusive. The first zinc-rich intermediate phase in either system was not identified. More recently, Anderson, Boyle, and Ramsey" have had occasion to refer to a partial Ti-Zn phase diagram (unpublished data) covering the region 0 to 10 atomic pct Ti, wherein two intermediate phases corresponding approximately to TiZn,, and TiZn,, were indicated. The metals used in this investigation and typical analyses as determined by the suppliers are given in Table I. The iodide-process zirconium which was used was not hafnium free. Experimental Methods Alloy Preparation: The relative ease with which titanium and zirconium combine with other elements places extensive restrictions on the methods by which alloying can be achieved. The direct current electric arc melting procedure was found to be unsatisfactory for preparing these binary alloys and for this reason solid state diffusion methods were utilized. The iodide process titanium and zirconium rods were filed by hand. Fines were subjected to a magnetic separation and classified as to size as either finer than 200 mesh or coarser than 200 but finer than 80 mesh. Powder mixtures of various binary combinations of titanium and zirconium with zinc and cadmium were compacted in a 12 mm diameter die and then placed in Vycor or quartz vials which were evacuated and sealed. The mercury alloys were prepared in a similar manner; the proper weight of liquid mercury being placed in a vial with minus 200 mesh titanium or zirconium. These ampoules were then heat treated at various temperatures and times depending on the characteristics of the particular alloy system. Upon completion of the heat treatment the ampoules were cooled rapidly and the specimens weighed. The loss in weight varied from 1 to 3 pct (except as noted in the text) and for this reason the calculated compositions were accepted as a fair measure of the actual alloy compositions. X-Ray Dif raction Techniques: Powder diffraction experiments were conducted at room temperature with a 143.2 mm Debye-Scherrer X-ray camera in which the film was placed in the Straumanis arrangement. When copper radiation was used, a nickel filter was employed, and for the cobalt target a filter of iron oxide was used. In both cases, the /i? filter was placed between the X-ray target and the powder specimen which was mounted on a glass fiber. The lack of information based on optical metallography placed reliance on the results obtained from the X-ray experiments for determination of

Jan 1, 1955

By B. Trenary, D. D. McNaughton, C. D. Baer

High capacity off-highway haulage trucks equipped with electric wheel drives have been available for commercial applications since 1963 and, although still interesting to study, cannot be considered as a "new" type of equipment any longer. However, the electric wheel drive components which played a key role in the development of these trucks has indirectly led to another new trucking development-the gas turbine engine for off -highway vehicles. Although most of the production models of the electric-wheel haulage trucks are equipped with 700 hp engines (the largest production engine commonly available), the electric drive components of the motorized wheel were designed to transmit more than 700 hp. To utilize this added potential, 1000-hp class diesel engines are in the process of being developed, but progress has been much slower than expected. The delay has caused some engineering thoughts to concentrate on the adaptation of the 1000-hp gas turbine engines, originally designed for aircraft applications, for use in haulage trucks. The question in most minds centered around the ability of such an engine to withstand the tough usage expected of it in an open pit.

Jan 5, 1967

By M. C. Flemings, R. Mehrabian, G. E. Nereo

Analytic expressions were developed and applied in two preuious papers to predict effects of solidification variables on macrosegvegation. In this paper, experiments are reported to test the analyses quantitatively and qualitatively. Good quantitative agreement is obtained between predicted and measured compositions for the following types of segregation (all experiments were on laboratory-size ingots of Al-4.5 pct Cu alloy): (a) inuerse segregation, (b) composition distribution in ingots solidified with unidirectional heat and fluid flow, (c) simulated centerline segregation, and (d) segregation resulting fro, change in solidification cross section. In addition, qualitative agreement of prediction of theory with experiment is obtained for (a) segregation resulting from sudden change in heat extraction during solidification, (b) centerline segregation in a bidirectionally solidified ingot, and (c) under-riser positive segregation. IN two previous papers,''2 it was shown that a variety of apparently different types of macrosegregation result from the same basic mechanism. This mechanism is the flow of solute -rich liquid to feed solidification and thermal contractions. Analytic expressions were derived and examples given of their application to predict macrosegregation. Calculations were for Al-4.5 pct Cu alloy. In this paper, we describe a series of experiments designed to test results of the foregoing calculations. All experiments were on laboratory-size ingots (weighing 10 lb or less), of A1-4.5 pct Cu alloy, nominal composition. APPARATUS AND PROCEDURE A typical mold and chilling arrangement used for unidirectional solidification is shown in Fig. 1. Before casting, this assembly was placed in an electrically heated air furnace, and heated to 680" to 700°C. When the plaster reached the desired temperature (usually 1 to 2 hr after the furnace temperature), the mold was filled through a funnel extending from the outside of the furnace into the cavity. The assembly, with liquid, was held for several minutes to allow convection to subside. The coolant, either air or water (depending on the desired solidification rate), was turned on and the ingot solidified. With the four sides and top insulated, heat removal for solidification was through the bottom surface, resulting in a fully columnar structure. Design of the casting cavity was varied, as discussed below, to produce desired macrosegregation effects. However, for castings solidified with unidirectional heat flow, the top was always open to the furnace atmosphere and temperature. The bottom sur- face rested on a chill through which the heat was extracted, and all other surfaces were insulated with plaster. In one case to be discussed, the mold design was changed to obtain bidirectional solidification. In this case, two vertical chills were used (on two faces of the mold) and the bottom was insulated. In a last case discussed, that dealing with under-riser segregation, experiments were conducted in bottom-chilled sand molds at ambient temperature. Except for this one case, all experiments were conducted in the electrically heated air furnace as described above. In many ingots, thermocouples were used to obtain continuous records of solidification. In all cases, these were chromel-alumel couples with output continuously monitored on a twelve-channel recorder. Where thermocouples were employed, these were embedded in the refractory mold walls during mold-making so their heads extended to the vertical centerline. Six to nine couples were employed, placed at intervals from the chill. METAL-MEL TING PROCEDURE Aim analysis was A1-4.5 pct Cu; alloy was prepared from high-purity aluminum (99.9 pct Al) and A1-Cu master alloy (50 pctOFHC Copper, 50 pct high-purity Al). The A1-4.5 pct Cu alloy was cast in 5- to 7-lb ingots for subsequent remelting for the macrosegregation experiments. Melting for ingot casting was as follows. After preheating the melting crucible for an hour or more, the charge was melted and superheated to a temperature of 690" to 720°C. After stirring, the melt was degassed with chlorine for 10 min. After stirring again for 1 min, a gas sample, under reduced pressure, was taken. When the sample was gas-free, the crucible

Jan 1, 1969

By J. R. Lucas, H. E. Rutherford

The primary objective of this research was to evaluate the feasibility of ultrasonic testing for the purpose of analyzing the structure and properties of rock material. A secondary objective of this study was to determine experimentally the elastic wnstants of various rock specimens with the use of ultrasonic equipment. Elastic constants can definitely be determined quickly and accurately by ultrasonic investigation. With proper equipment there are indications that ultrasonic waves could be utilized in the detection of flaws, such as fractures and planes of weakness, measurement of thickness, and the study of structure of rock material. Ultrasonic principles have been applied in many industries for the purpose of determining the structural characteristics of various materials. The principal applications of interest here are detecting flaws, measuring thicknesses, and determining elastic constants. The main advantage of ultrasonic analysis is that it is nondestructive. It also has extreme sensitivity, high penetrability, good accuracy, rapid response, and the necessity to have access to only one side of the specimen. These various applications and advantages lead one to think that ultrasonic principles might be applied to rock material in situ for purposes of analyzing its structural characteristics. Therefore, the primary objective of this research was to evaluate the feasibility of ultrasonic testing for the purpose of analyzing the structure and properties of rock material. A secondary objective of this research was to determine experimentally the elastic constants of various rock specimens with the use of ultrasonic equipment. The term ultrasonics is given to that branch of acoustics dealing with periodic sounds whose fre- quencies are above the audible range or above approximately 15,.000 to 20,000 cps. The first practical production of this high frequency sound was made possible after World War I due to developments of electronically controlled sound wave sources. At the present, the maximum practically attainable ultrasonic frequency is approximately 1000 megacycles per sec. Sound waves of sufficiently high frequency can be made to travel in a beam with little spreading. Therefore, such a beam can explore a material and detect nonhomogeneities in it by reflection. This is the principle of the ultrasonic reflectoscope invented by F. A. Firestone' in 1942. An ultrasonic beam, on pulse-penetratink a solid material medium, produces an echo when it strikes a flaw which has different acoustical properties than the surrounding medium. This echo can be detected by the same transducer which sends out the original pulse. This principle is the basis of the important industrial techniques of nondestructive ultrasonic testing of metals and other solid material. Later developments in the field of ultrasonic testing of solid material have been mostly improvements in equipment and instrumentation. To date, most of the industrial applications of ultrasonic analysis of solid bodies have been in the aircraft, electrical, and nuclear energy fields on the nondestructive testing of metal. The one solid material similar somewhat to rock material, upon which some work has been done to apply ultrasonic testing techniques to study structural integrity, is concrete. Jones and Gatfield3 briefly summarize this work on concrete. Their basic conclusion was that the strength of concrete was a function of the change of the longitudinal sound wave velocity in the concrete. Only recently has any extensive study been made to apply ultrasonic testing techniques to rock material. Lutsch studied rock material by an ultrasonic pulse method to determine the extent and degree of fracture of rock faces. Lutsch states that the number of observed reflections is a measure of the degree of fracture and that only ultrasonic waves are able to detect fractured zones subjected to high pressure. Suzuki, Sasaki, and Siohara5 studied the characteristics of the sonic wave in rock for propagation over a wide range of wave lengths. They indicated that, in rock, the propagation constant and attenuation of the

Jan 1, 1962

THE Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties situated at 29 W. 39th St. in New York.

Jan 1, 1946

By Percival Roberts

IT may seem necessary to offer an apology for presenting for consideration a process which is conspicuous by its absence in the literature of the Institute, and which may be thought by some to belong to the past in metallurgy, and to have been already superseded. But the large capital invested in puddling calls for a careful consideration of the question whether the time has certainly arrived when the puddling furnace must be replaced by the converter and open-hearth furnace. May there not still be a place for puddled iron alongside of molten iron and steel, and is not the improvement of the puddling process itself worthy the attention of engineers equally with the Bessemer and open-hearth processes? The changes involved in the conversion of pig iron into wrought iron are well understood and need only be briefly alluded to. The patent of Henry Cort bears the date of 1784. Since that time the improvements in the process have mainly consisted in the replacement of sand by iron bottoms by Samuel Baldwyn Rogers in 1818, and the still more recent substitution of iron oxide for the refractory materials used for the rides and bridge of the hearth, which distinguishes the wet or boiling process from the dry or paddling process. Chemically, the process consists in the removal of the metalloids from the pig iron, a result effected mainly by the iron oxide. Silicon is first oxidized, then the phosphorus, and finally the carbon. The silicic and phosphoric acids produced pass into the cinder and the carbonic oxide burns as it escapes from the bath of metal. It is interesting in this connection to note the effect of temperature on the removal of the phosphorus from the iron. As is well known, no phosphorus is eliminated under the oxidizing influences prevailing in the Bessemer converter, while from 70 to 80 per cent. is removed in puddling. But we find, if in working cold short irons

Jan 1, 1880

By J. C. Mertz

ACCURATE knowledge of the solid solubilities of the elements that dissolve in the important base metals is needed for guidance in the preparation and heat-treatment of the alloys derived from these compo-nents. While there is still difference of opinion concerning the merits of the X-ray and microscopic methods of determining such solubilities, it is certainly true that the recent extensive use of X-ray diffraction to review the existing constitutional data has revealed many glaring inaccu-racies and has brought about a much improved knowledge of phase-boundary locations, which will inevitably come to include all of the important alloy systems. When the work is done with all necessary precautions it appears that in the majority of cases where the solubilities extend beyond a few tenths of a per cent the X-ray back-reflection technique is capable of furnishing the best of information in this field. For the most prolonged and thorough studies it is obviously advisable to combine the results of several methods, in particular, to obtain an agreement between X-ray and microscopic data. This paper reviews the work previously done on the solubilities of phosphorus, arsenic, antimony and bismuth in copper and, in considera-tion of the uncertainties thus made apparent, presents, new X-ray data obtained with the first three members of this group.

Jan 1, 1936

By S. C. Schaeker, A. W. Schlechten, A. H. Larson

PARRAVANO and Malquori' studied the equilibrium of H2S-Hz with molybdenum and its lowest sulfide which they believed to be MoS2. Mc Cabe' has shown that its composition is actually Mo2S3 and determined its dissociation pressure by means of Knud-sen effusion measurements. Stubbles and Richard- son3 have recently studied the equilibrium of gas mixtures of H2S-HZ with the two-phase solid mixtures of Mo-MozS3 and Mo2S3-MoS2. The latter investigators found that M02s3 deviated slightly from the stoichiometric composition, but they did not determine the homogeneous region of the disulfide phase. Morimoto and Kullerud, studied the Mo-S system by quenching, microscope, and X-ray methods and concluded that the disulfide is stoichiometric. The present investigation was concerned with the measurement of the sulfur vapor pressure variation with composition at 1100°C in the homogeneous region of "MoS2". These measurements were made by reacting: 1) molybdenum powder (99.97 pct Moj with sulfur vapor, and 2) MoS1.g9 (formed by reaction of Mo + H2S) with sulfur vapor in a quartz capsule. Conditions were controlled to form an equilibrated phase within the homogeneous region of the disulfide. The quartz capsule was sealed off initially under a vacuum and the residual gases were gettered by titanium powder contained in one end of the capsule. A mixture of Mo + S or MOS,., + S was in the other end. The section containing the titanium powder was heated for 24 hr at 700°C and then removed by flame sealing. The end of the capsule containing the charge was then heated to 1100°C. The other end of the capsule was maintained at a temperature which would produce the desired sulfur pressure in the capsule (liquid sulfur distilled from the charge mixture was retained in this end). After equilibration, the capsule was removed from the heating assembly and rapidly air-cooled. It is assumed that equality existed between the total sulfur pressures (PT) in the two ends of the capsule and not between the partial pressures of the different molecular species (S, SZ, Three separately controlled heating elements were used to maintain the proper temperature gradient over the length (approximately 12 in.) of the capsule. A thermocouple-Wheelco "Capacitrol" system was used for temperature control of the two end heating elements within 2"C. The center heating element was controlled directly by a " Power -stat". Separate controlling and measuring thermocouples were used for both end heating elements. Pt-Pt(l0 pct Rh) thermocouples were used for 1100°C and Chromel-Alumel thermocouples were used for lower-temperature control and measurement of the assembly. Silver foil was wrapped around the end of the capsule containing the liquid sulfur to insure a constant temperature zone. The thermal gradient over the entire length of the capsule was measured to: 1) ascertain that the length of the constant temperature zone of the liquid-sulfur end and the sulfide end was sufficient, and 2) ascertain that the liquid-sulfur zone was the zone of lowest temperature. The data obtained in this investigation are shown in Fig. 1 and Table I. The total sulfur pressure (PT) and p(S2) were calculated from the data of Braune et UZ.~ The compositions of the equilibrated disul-

Jan 1, 1964

By John V. Beall

As Mother Nature arranged it, the hottest potential mineral target in the country today, the Stillwater complex had to occur in a spectacular natural setting-the north margin of the Bear Tooth Mountains of Montana. What more appropriate backdrop for the August 17-18 field hearings of Senator Frank E. Moss (D-Utah). His subcommittee, on Minerals. Materials and Fuels, heard 37 witnesses ponder the value of minerals vs esthetics or other uses of federal lands. On August 17, four Army Hueys swept the senatorial party, the press, Forest Service Officers and such distinguished witnesses as Montana Governor Forrest H. Anderson over the Custer-Gallatin National Forests, besting the thin air of 10,000 ft p1us, they set down on Iron Plateau.

Jan 1, 1971

By M. L. Jeremic

Mining practice and underground studies show that, besides mining stresses, lateral tectonic stress also influences roadway stability. Roadways perpendicular to the direction of major lateral stress experience the majority of roof falls, accelerated floor heave, and extrusion of coal ribs into openings. They have the most severe deformations and their maintenance is difficult. Roadways parallel to the major lateral stress exhibit roof sagging and bed separation, moderate though sometimes uneven floor heave, and slabbing of coal ribs into openings. Roadways oblique to lateral stress have, to a certain degree, self-supporting roofs, uniform floor heave, and limited sloughing of coal ribs into openings. The optimal orientation of roadways is, therefore, oblique to the lateral stress direction with fewer crosscuts between them.

Jan 1, 1982

By Ralph Hultgren, Bernard York, David W. Mitchell

It is a well-known fact that magnesium-alloy castings are apt to be coarse grained if the melt is not superheated several hundred degrees above the melting point before casting. (The casting temperature varies according to the shape of the mold. A typical casting temperature is perhaps 1400°F.) British practice is to heat to 900°C. (1650°F.) for 15 min., cool rapidly to casting temperature, and cast.' In Germany superheating is carried out at 850' to 900°C. (1560° to I650°F.) depending on the amount of scrap used. It is stated that further refinement will be obtained by prolonging the period of superheating or by increasing the superheat temperature to 950°C. (I740°F.).2 In the United States superheating is carried out at 1600' to 1700°F. (871' to 927°C.), perhaps even higher in some places. It is stated that superheating effects are found as low as 1500°F. (816°C.), but several hours are required.3 These commercial treatments lead to grain sizes in sand castings that may vary from 4 to 8 grains per sq. mm.! in heavy sections and from 60 to IOO in 1/2-in. sections to perhaps 380 in thin sections. It is also generally known that the refining effect of superheating is lost if the melt is held for some time at lower temperatures before casting. Aside from these very qualitative statements, there is little to be found in the literature as to the effect of temperature and time of superheat on the final grain size. Because of the uncertainty of these factors, the Office of Production Research and Development of the War Production Board placed a research contract with the University of California, supervised by the War Metallurgy Committee. This research, which was done under the "Restricted" Project NRC-550, is the basis of this paper, which has been released for publication by the O.P.R.D. The material studied was an alloy prepared from carbothermic magnesium. The temperatures required for grain refinement proved to be widely different from those used in practice, as described in the statements in the first paragraph. This difference is attributed to the fact that the magnesium in the specimens was of carbothermic origin instead of the electrolytic magnesium in common use. Materials and Methods The magnesium alloy studied was one of the most popular sand-casting alloys, with a nominal composition of 9 Per cent aluminum, 2 per cent zinc, and 0.1 per cent (minimum) manganese and the balance magnesium. This is designated

Jan 1, 1945

By John T. Norton, R. E. Hiller

The tremendous increase in the use of metals that have been prcpared by the various cold-working processes during recent years has greatly stimulated the investigation of problems concerned with the fundamental nature of these processes. It has been observed in practice that different methods of bringing about the same dimension changes in a sample result in a rather wide range of properties. Cold working reduces the ductility of a metal, or what is perhaps more nearly correct, its "working capacity," and naturally the manufacturer wishes to produce an article that has as large a working capacity as possible, and to produce it with the smallest number of operations. It has also been known for some time that cold deformation produces a parallel alignment of the crystal grains of a metal, and that the type of this preferred orientation depends to some extent at least upon particular processes employed in the deformation. The present investigation has for its purpose the study of the relations between the various factors of a cold-working process and the preferred orientation of the metjal crystals resulting from this deformation. The work is chiefly confined to a study of cold-drawn seamless tubing. Preparation of Samples The tubing samples used in this investigation were made of steel having a carbon content of 0.10 to 0.20 per cent, and were drawn on a standard type of draw bench. In order to obtain the large reductions, the annealed stock was coated with lead, for purposes of lubrication. The reductions of area stated refer to reduction from the annealed condition without intermediate heat treatment. The cold work was done as nearly as possible at room temperature. The samples of wire and strip used for purposes of comparison were of steel of approximately the same carbon content and were prepared in the manner indicated. X-ray Method of Investigation The condition of preferred orientation in cold-worked samples is best investigated by the X-ray method that employs a small circular beam of * Assoriate Professor of Physics of Metals, Massachusetts Institute of Technology. t Graduate Student, Department of Metallurgy, Massarhusetts Institute of Technology.

Jan 1, 1932

By Albert F. Schneider

The peculiar conditions under which lead and silver ores are now smelted in Salt Lake Valley, Utah, render it advantageous to make slags that are siliceous and carry a high percentage of lime. The ores treated come from Utah, Idaho, Montana, and Nevada; nine-tenths coming from Utah. These ores are siliceous, and contain but little fluxing material; the iron present scarcely sufficing for the sulphur and arsenic. Formerly ores high in iron were furnished from Cottonwood Canons, but this supply is meagre. The ores from Idaho, Montana, and Nevada are high grade galenas, more or less impure. They generally require a large amount of iron for the sulphur, arsenic, and antimony. In the winter and spring of 1880—'81, we were treating at the Germania Works principally Bingham Canon lead ores and silver ores from Tintic. The former contained 15 to 30 per cent. silica, and only 4 to 5 per cent. iron (generally as iron pyrites); they ranged high in lead and low in silver, and carried more or less alumina; the lead was present chiefly as carbonate. The silver ores from Tintic contained sulphides, and ran as high as 80 per cent. silica. We had been running on a slag approximating 40 per cent. FeO, 20 per cent. CaO, 10 per cent. other bases, and 30 per cent. SiO2, which had heretofore been very satisfactory; but with the class of ores then coming in it was of the utmost advantage to use less iron and more lime, especially as the iron ore (50-55 per cent. iron and 5-7 per cent. silica) cost four times as much as the limestone (50-55 per cent. lime, 3-5 per cent. silica). The large amount of alumina in the slag influenced them for the worse; the addition of lime to the charge helped them, and after many experiments regarding the proportion of FeO, CaO, and SiO2, a slag approximating 35 per cent. FeO, 25 per cent. CaO, 5 per cent. other bases, and 35 per cent. SiO2 seemed to answer

Jan 1, 1883

ROESLER MAX-Geology of the Iron-Ore Deposits of the Firmeza District, Oriente Province, Cuba. Discussed by William Kelly, J. T. Singewald, Jr., B. L. Miller, J. D. Irving, L. C. Graton, C. P. Berkey 439 SINGEWALD, J. T., JR., AND MILLER, B. L.-The Manganese Ores of the Lafayette District, Minas Geraes, Brazil. Discussed by L. C. Graton, J. T. Singewald, Jr., F. Lynwood Garrison HARDER, E. C.-Manganese Ores of Russia, India, Brazil, and Chile. Discussed by J. T. Singewald, Jr., E. C. Harder 454 SCHRADER, FRANK C.-Geology and Ore Deposits of Mohave County, Arizona. Discussed by J. C. Anderson McDOWELL, J. SPOTTS-A Study of the Silica Refractories. Discussed by J. W. Richards, H. D. Hibbard, W. F. Rochow, J. B. Umpleby-: 460 PHALEN, W. C.-The Conservation of Phosphate Rock in the United States. Discussed by E. G. Spilsbury 462 NORTON, S., AND LEFEVRE, S.-The Magnetic Concentration of Low-Grade Iron Ores. Discussed by G. C. Foote, J. L. W. Birkinbine, F. L. Nason 462

Jan 4, 1917

By R. V. Whetsel, V. R. Garfias

Petroleum production in the Mexican fields during 1932, estimated at 32,400,000 bbl., was only 564,000 bbl., or about 2 per cent less than the 1931 total. Production in the northern fields declined approximately 1,100,000 bbl., the Tehuantepec output showed a drop of 340,000 bbl. and the South fields gained 865,000 barrels. Wildcatting continued at a reduced rate, the only successful completion being Presa No. 2 well which at a depth of 1535 ft. produced about 7,000,000 cu. ft. of gas. This well is an offset to Alberca No. 1 completed during 1931. General conditions in the petroleum industry coupled with the additional burden of the 21c per bbl. duty on oil imported into the United States further discouraged development activity in Mexico during 1932. Production of the Mexican fields in 1932 was distributed as follows: Production (U. S. Barrels) 1931 1932 _______________________________________________1________________________ Northern fields.................................... 14,092,000 13,000,000 South fields....................................... 10,535,000 11,400,000 Tehuantepec fields............................... .. 8,000,000 32,964,000 32,400,000 Since their discovery to the end of 1932, the fields have produced as follows: (U. S. Barrels) Northern fields..................................... 681,300,000 South fields........................................ 967,200,000 Tehuantepec fields.................................. 40,540,000 1,689,040,000 The tremendous productivity of the Mexican wells and the very small number actually drilled in the proven areas is shown in the following table:

Jan 1, 1933

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

Jan 1, 1970