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By Joseph Jensen

When the legal holders of Government permits in the Middle dome of Kettleman Hills entered into an agreement on May 27, 1929, to suspend all drilling activities on five permits, covering portions of the Kettleman Hills Middle dome, until Jan. 1, 1931, and the owners of fee lands contiguous thereto assured Secretary Ray Lyman Wilbur, of the Department of the Interior, that they too would respect a drilling suspension for a period of a little more than 19 months, none of these interested parties realized that this was the first step in a chain of events that would culminate, more than four years later, in the formation of the Middle Dome Corporation for the development of the Middle dome area in a unit plan that would be the first unit plan to be approved by the California Regional Producers Committee and recommended to the President as a satisfactory unit plan, under Section 7 of Article III of the Oil Code, approved Aug. 17, 1933. Neither did they realize that more than two million dollars would be spent before oil or gas would be successfully and continuously produced from wells drilled on that Middle dome area. On Oct. 1, 1933, under the terms of the Middle Dome Agreement, the Middle Dome Corporation assumes control of activities and is responsible for the division of all product's produced from the Middle dome area to members of the Middle Dome Corporation. This Middle dome plan is the second successful unit plan developed in California in the past three years, the first being the Kettleman North Dome Associationll formed under the agreement, of Jan. 31, 1931, for the unified operation and development of more than 12,000 acres of land on the North dome of the Kettleman Hills. All other unit plans discussed in the past four years in the state have not yet been completed, for one reason or another, but under Section 7 of Article 111 of the new Oil Code numerous plans of development, some of which may be unit plans, will be forthcoming within the next few months. There is much

Jan 1, 1934

By W. Rostoker, D. W. Levinson, A. Yamamoto

The influence of carbon on tensile strength, tensile ductility, transformation kinetics, and grain growth characteristics of selected Ti-Mo base alloys was studied. No systematic influence of carbon in tensile strength or significant deleterious effect on tensile ductility was observed. There was a marked increase in transformation rate due to carbon. Dispersed carbides exert a marked inhibiting effect on grain boundary migration, and thus effectively prevent grain coarsening during solution treatment in the ß phase field. AS part of a research program directed toward the illumination of factors governing modes of transformation, transformation kinetics, and mechanical properties obtainable through these transformations by heat treatment, Ti-Mo base alloys were selected for study. The binary system is a characteristic phase diagram type which has been studied in some detail', ' in relation to transformation kinetics and mechanical properties. Although carbon bearing alloys have acquired a bad reputation, the possibilities of melting titanium under conditions which occasion some carbon pickup are very attractive. It is therefore of considerable importance to know whether carbon, present as a dispersed carbide phase, is actually deleterious when all other detrimental factors are minimized. Basic alloy compositions containing nominally 3, 5, 7, and 11 pet Mo were prepared with systematic carbon addition up to 1 pet by weight. Various of these alloys were subjected to a series of critical and definitive experiments to delineate the effect of carbon on the transformation behavior and associated mechanical properties. Experimental Procedure Alloys were prepared from 115 Bhn magnesium-reduced sponge titanium. This sponge analyzed ap- proximately 0.05 pet C. Ti-Mo and Ti-C master alloys were made by arc-melting the sponge with high purity (99.9 + pet) molybdenum and spectro-scopic grade graphite, respectively. Alloys were then prepared from the master alloys and sponge by double are-melting. One kg ingots were prepared by melting in a nonconsumable electrode furnace. These ingots were forged at 1000°C to '/z in. rods, and cleaned and processed into electrodes for the second melting operation. The final ingots were ground to remove surface defects, then forged again to 1/2 in. or 3/8 in. diam rods for processing to test samples. It is significant that all of the alloys at all carbon levels forged satisfactorily. For convenience, the alloys will be referred to throughout the text by their nominal analyses. Samples for the study of transformation rates were prepared from 1/2 in. diam round stock. They were then solution treated in a helium filled tube furnace at 1000°C for 30 min prior to the isothermal transformation treatments in lead bath furnaces. Temperature control in both cases was within ±3oC. Following the isothermal transformation treatments the samples were water quenched. These experiments were carried out before the general adoption of the resistometric procedure for kinetic studies. The data were therefore obtained entirely by metal-lographic analysis. M, temperature was also determined by the metallographic method. Shoulder-type tensile test pieces were machined from heat treated, 1/2 in. diam slugs to provide a 0.252 in. test diam and a 1 in. gage length. The isothermal-type heat treatments were chosen from previous data' to provide three levels of strength and ductility.

Jan 1, 1957

By Orville R. Lyons

THE continuous vacuum filter, whether it be a vertical or horizontal disk, inside or outside drum, when properly applied is a very effective device for dewatering fine solids. Because of the number of variables that affect its performance, however, it is not possible to obtain consistently maximum moisture reduction in an operating plant. This paper presents a method for determining the average cake moisture and the variations in cake moisture to be anticipated when dewatering fine solids by continuous vacuum filters under normal operating conditions. Previous investigators1,2 have found that certain factors influence filter performance, drum or disk diameter, speed of rotation, percentage of immersion, and the percentage of solids in the feed influence capacity. Blinding of the filter cloth reduces effective vacuum, produces a wetter cake, and may decrease capacity. Reduced vacuum or improper adjustment between vacuum and blowing portions of the cycle will produce a wetter cake and also may decrease capacity. Widely fluctuating feed tonnages will adversely affect cake moisture and capacity. Flocculation, when properly applied, increases capacity and reduces cake moisture. Without flocculation, the slimes are the first particles sucked to the filter medium, which becomes partially blinded in consequence. With flocculation, the flocs act as coarse particles and the filter medium is not blinded. Overflocculated pulps, although filtering well, may yield wet cakes. Average Particle Size and Cake Moisture A method for predetermining the surface moisture content of coal filter cakes was published in 1949; but this method could not be applied to coals deficient in —200 mesh material or to fine mineral concentrates. Test data obtained for geared-weight types of vibrating screens4 and for centrifuges5 used to de-water coal provided definite correlations between the average particle size of a dewatered cake and the surface moisture content of the cake. It was thought that this same method of correlation should be applicable to filters, whether dewatering fine coal or fine mineral concentrates. To develop a correlation or correlations between average size of cake and cake moisture, the author collected data for filtration operations from as many sources as possible. In a considerable number of instances the information was provided by plant preparation engineers,"-" a few of the tests were on a laboratory scale: and the remainder of the data was obtained from published articles.10-17 Table I contains size-consist and miscellaneous data for coal filter cakes, and Table II contains the same data for mineral concentrate filter cakes. Fig. 1 shows the relationships existing between the average particle size of the cake and cake moisture (surface moisture for coal and total moisture for minerals) when dewatering fine solids by a variety of makes and types of filters. Average particle size is calculated by averaging the linear openings of the various pairs of screens used in the screening test, weighted in accordance with the percentages of material in the various fractions.

Jan 1, 1952

By N. H. MacMillan, O. C. Dias

Recent work by Westwood et al. (reviewed in Refs. 1-6) has established that many rocks, minerals, ceramics, and glasses exhibit phenomenologically similar chemomechanical (Rebinder) effects when deformed in different liquid environments, apparently as the result of chemisorption-induced variations in their near-surface flow and flow-dependent fracture behavior. In particular, it appears that there exists an empirical, but apparently general, correlation between the near-surface flow stress of an inorganic nonmetal and its surface charge- namely, that such a solid is hardest at its zero point of charge (i.e., when its zeta potential [ ] = 0) and softens as [ ] increases, regardless of the sign of zeta. Moreover, because near-surface flow and fracture phenomena are two of the important determinants of the rates of machining and comminution processes, both Westwood et al. and others7 have been able to use this so-called "[ ]-correlation" to develop cutting fluids and grinding aids that in many instances have given rise to several fold increases in performance. In addition, Westwood et al. have demonstrated that both aqueous and organic environments can give rise to similar improvements in cutting rate for a given combination of tool and workpiece, provided that both impart the same surface charge to the work- piece (i.e., transfer the same number of electrons to or from its surface). This last finding implies that in any application it should always be possible to find some cutting fluid that is at once effective, cheap, nontoxic, and nonpolluting. Thus, reports of apparently similar environmental influences on the mechanical behavior of diamond,8 certain organic crystals and polymers,9-14 and coa1-15-21 suggest that it is pertinent to ask: (a) whether the [ ]-correlation (or any analogous relationship) extends to coal; and (b), if so, whether this relationship can be used to guide the development of superior aids for grinding coal. Accordingly, correlations have been sought between (1) the zeta potentials, (2) the hardnesses, and (3 and 4) the drilling and grinding characteristics of coals of different rank in different aqueous and organic environments. This paper reports the results of that search.

Jan 1, 1980

By Leo J. Vogel, E. D. Hummer

INTRODUCTION by E. D. HUMMER An efficient refuse-disposal system is a necessary part of the modem cleaning plant. The large-scale refuse system and disposal area, engineered for the lifetime of the plant, has become more important due to the greater tonnages of refuse produced from increased quantities of mechanically mined and prepared coal. Laws and increased government regulations have affected the design and operation of disposal systems. THE EFFECT OF MINE AND PLANT OPERATION Refuse disposal starts at the mining face. The mining system, the type of roof support, the machinery used, and the degree of discipline at the face contributes to the amount and type of refuse that must be removed through the disposal system. Economies gained through modification of the mining system or mining machinery may be partially offset by increased dilution of the mined coal with impurities from associated rock formations. In some cases the change in the mining system and equipment has reduced the dilution. In all cases the ratio of impurities that must be removed from the raw-coal feed to the plant not only affects the maintenance and operating costs of the plant, but greatly affects the design of the refuse disposal system. The design of a mine and plant should include the location and the estimated capacity of the disposal areas for the life of the property or plant. Complete evaluation of the disposal system and an estimate of its annual cost of operation over the life of the property or plant should be incorporated in the plant and mine evaluation. Plant design should be as simple as possible, consistent with the efficient production of clean coal. Material transfer points, crushing, screening and pumping operations should be kept to a minimum to reduce degradation and the subsequent increased difficulty and cost of refuse removal. The maintenance of good process control by operating management will result in a minimum of misplaced material in both refuse and clean coal. Reduction of misplaced float material in the plant refuse is an important factor in preventing combustion in the refuse storage pile. THE REFUSE DISPOSAL AREA Combustion in refuse piles occurs when air enters the pile in sufficient quantity to support oxidation. At certain rates of air in-filtration, the heat produced by the oxidation process is not dissipated and temperature rises.

Jan 1, 1968

By S. F. Frederick, G. F. Pittinato

The deformation mechanisms operating in Ti-5Al-2.5Sn at 20°K under uniaxial and biaxial stress fields were determined by using both optical and electron microscopy. In the uniaxially stressed specimens, de-fu~rnation twins were found only in the immediate vicinity of the fracture. Twinning was, however, established as a deformation mechanism under biaxial stress conditions. The same slip systems were opera-tiz,e under both uniaxial and biaxial stress. Prismatic slip was identified as the major slip syslem; however, basal and first-order pyramidal slip also occurred, but to a lesser degree. The interaction of moving dis-locations on intersecting slip planes resulted in the formation of jogs and dipoles. Hexagonal dislocation networks were formed only under biaxial stress conditions. A discussion is given on the formation of hexagonal dislocation networks. IT has been shown that titanium alloys can exhibit unusually high strengths when tested in a biaxial stress field.'-" The high biaxial strengths are a consequence of a strong basal plane sheet texture which results in distinctly anisotropic flow properties. This texture strengthening appears to decrease with decreasing temperature2 and would seem to indicate a change in deformation modes. For example, in a uniaxial tensile test, Ti-5A1-2.5Sn yields isotropically at 20°K but is strongly anisotropic at room temperature. The increase in biaxial ultimate over uniaxial strength at 20°K is also much less than at room temperature. It is known that titanium car] form deformation twins more readily at cryogenic temperatures than at room temperature.4 Since the formation of deformation twins will reduce the degree of basal texture in sheet material,' an accompanying decrease in texture strengthening would be expected. To investigate more fully the nature of texture strengthening at cryogenic temperatures, the deformation modes of Ti-5A1-2.5Sn tested in uniaxial and 1:1 biaxial tension at 20°K were studied by optical and electron transmission microscopy. EXPERIMENTAL PROCEDURE The uniaxial and biaxial stress test specimens were prepared from 0.020-in. thick sheets of Ti-5A1-2.5Sn ELI having the composition shown in Table I. Uniaxial stress conditions were obtained by using flat tensile specimens machined from the sheet material. The longitudinal axis of the tensile specimens was aligned perpendicular to the rolling direction of the sheet. Tile biaxial test specimens were prepared by rolling precut, 19-in.-lengths of sheet into 4-in.-diam cyl- inders. Following longitudinal butt welding, the cylinders were stress relieved at 1000°F for 4 hr. A 9-in. sq "window" was then chemically milled into each cylinder's surface reducing the wall thickness in the milled area to approximately 0.006 in. The testing procedure consisted of pressurizing the cylinders while simultaneously applying a tensile load. Using this technique, a 1:l axial to hoop stress was obtained. Complete details of the specimen and testing procedures are given in Refs. 1 and 2. The biaxial and uniaxial stress specimens were all tested in liquid hydrogen. Specimens for electron transmission microscopy were prepared by first chemically milling to a thickness of about 0.001 in. followed by electrolytic polishing to electron transmission thickness. The chemical milling solution, consisting of 800 ml of water,

Jan 1, 1970

By William Plank

IN PAST YEARS, engineering educators and others have been able to study the problems relating to en-gineering education in the United States with only inadequate and, frequently, inaccurate data at their command. For the first time there is now available fairly full and accurate information on this subject, gathered and compiled by the Board of Investigation and Coordination of the Society for the Promotion of Engineering Education. This board, of which W. E. Wickenden is the director, has for the past four years been carrying out fact-finding investigations into "the objects of engineering education and the fitness of the present day curriculum," under a grant of funds from the Carnegie Corporation of New York. Twelve bulle-tins have already been published by the board and others are in the process of preparation. The studies made, thus far, have been of the various phases of engineering education in general as well as of the major branches of engineering. Within the past year. the board has completed a study of mining engi-neering education by means of a questionnaire sent to members of the Institute. A special committee, con-sisting of Charles E. Locke, Allen H. Rogers and the writer, cooperated with the board in drafting certain parts of the questionnaire and in selecting the mailing list. Similar studies have been made through the mem-bers of the four other national societies. The results of these studies have been published only in mimeo-graphed form, therefore, in order to place the data before the members of the Institute an incomplete sum-mary of the replies to the A. I. M. E. questionnaire is here given. The full report will be available for distri-bution at the annual meeting in February. The questionnaire was sent to 306 members of the Institute, a proportion about equal to the proportion of the membership of the other national societies can-vassed; 152 members replied to the questionnaire, 55 per cent of whom had received college degrees in some branch of engineering connected with the mineral in-dustry. Forty-seven educational institutions were rep-resented in the replies. Seventeen different positions were held by the members who replied, with 24 con-sulting engineers at the head of the list, 20 managers, 16 superintendents, 11 presidents, 10 professors, 6 deans, and others.

Jan 1, 1928

By J. W. Eckerd

Anthracite mining developments have not been as spectacular as the advances made for bituminous coal. The reasons are well known, i.e., steeply pitching seams of the western, eastern, middle and southern fields, and the physical conditions of the strata in which the seams are situated. Beds with moderate pitches (30º to 35º or less) have been mined with coal planers, longwall with movable props, shaker chutes, coal borers and large diameter boring machines. However, the use of this equipment has been limited to a relatively small portion of the production. Long-hole drilling has been developed from a point where holes of 25 or 30 ft have been replaced by those up to 130 ft. This has been possible through the introduction of primacord and similar detonating agents that can fire a long train of explosives with one cap. The usual practice in long-hole mining is to drive a gangway, chutes and monkey heading, or return airway, in the normal development manner. Two breasts can then be driven from the lower to the upper level to act as openings for the beginning of the long-hole work. Following completion of the development, holes can then be drilled from the monkey headings 100 ft or more up the pitch through the coal to within 15 ft or more of the upper level, depending on the nature of the coal on the roof. The thickness of the coal bed determines the spacing of the long holes, although they usually are on 6-ft centers for a 6-ft thick coal seam. The Bureau of Mines has conducted extensive investigations and tests on the development of a hydraulic mining system to be used in conjunction with hydraulic hoisting. Tests were conducted in cooperation with a large anthracite producer in a coal seam from 10 ft 6 in. to 15 ft in thickness and on a pitch from 0º to 20. This particular mining procedure is adaptable only to thick seams on relatively flat pitch as the maneuverability of the hydraulic jumbo is an important restricting factor.

Jan 2, 1968

By T. Tanaka, H. Kiuchi

The combination of the following two exothermic reactions was studied with the purpose of recovering H2 from H2S formed in acid leaching of sulfide ores, direct reduction of metal sulfides with H2 or desulfurization of crude oils: In the kinetic study of the recovery of H2, the reaction rate was measured by the two methods of single-stage and circulation blowing of H2S through molten Pb in the temperature range of 550 to 750°C. The experimental results showed that the rate determining step is in the chemical reaction itself and also that this reaction is accelerated markedly by the addition of a trace of Ni, which may be responsible for the catalytic action of Ni dissolved in molten Pb. In the experiments where Pb metal was produced, PbS was oxidized in a stream of atmospheric N2 containing 0.5 to 20 vol-% 02 or in the same 02 partial pressures as in N2 though under reduced pressures in the temperature range of 400 to 800°C. It was found from these experiments that the formation of PbSO4, basic sulfates and PbO are suppressable to yield Pb metal alone above 750°C and for 02 concentrations of less than 1 vol-%. Vapor of PbS was thought to take an important part in the Pb formation mechanism, and the probability thereof was demonstrated thermodynamically.

Jan 1, 1978

By Captain Lyle

I was very much interested in Mr. Macdonald's paper, and I can say that there is nothing in it to which I cannot heartily subscribe. In speaking of the want of knowledge that has existed, and still exists, among engineers in regard to structural materials, their strength, etc., my own experience has taught me to doubt the reliability of the ordinary testing machines.

Jan 1, 1882

By Karl Cohen

The question of attainment of competitive nuclear electric power is of interest to uranium producers because the rate of attainment of this goal determines the date when there will be a solid, non-political, domestic uranium market. It is a burning question to those of us in the civilian nuclear power business, because our entire business future hinges on how well, and how soon, we can make electricity from nuclear reactions at prices comparable to electricity from coal. For an idea of the magnitudes involved, consider that the first fuel load of the Dresden (Illinois) nuclear power station, plus spares, will be about 90 tons of 1.5 pct UO2. This requires about two-and- a-half times as much natural uranium oxide feed to the diffusion plant, or 225 tons. This, in turn, represents about a month's production from the nearby Uranium Reduction Co. mill. Note also that the 180,000 kw electric output of the Dresden station will be about 0.1 pct of the national electric generating capacity in 1960.

Jan 12, 1958

By S. H. McFarlane, K. H. Zaininger, G. W. Cullen, C. C. Wang, G. E. Gottlieb

Heteroepitaxy of silicon on stoichiometric spinel has been studied. Both boron-doped (p-type) and arsenic-doped (n-type) single-crystal silicon films have been grown by the pyrolysis of silane on sioichiometric spinel (MgAl2O4) substrates prepared by a flux technique. The spinel crystals are free from strain and subgrains, and exhibit no thermal instability at temperatures employed for silicon deposition. The growth parameters of epitaxial silicon have been studied. Effects of substrate orientation, surface preparation, and growth conditions on the silicon Properties have been determined. The silicon-spinel composite was characterized by X-ray diffraction, electron diffraction, electron microscopy, and optical techniques. Information on epitaxial orientation relationship, defect structures and film-substrate interface has been obtained. A parallel orientation relationship was found between silicon and spinel. The silicon films exhibit no subgrain structures. However, growth pyramids, microtwins, stacking faults, and dislocations are the prevalent defects. The deformation of epitaxial silicon was measured by an X-ray technique. It was found that the epitaxial silicon is strained under compres-sive stress due to the thermal expansion difference between the film and substrate. The stress was estimated using the classical plate theory and beam equation. Electrical properties of the epitaxial silicon have been measured, including resistivity, carrier concentration, and Hall mobility. MIS and vertical through diffused junction structures have been fabricated wing silicon-spinel composite. Information on MIS characteristics, minority carrier life time, and junction properties has been obtained. THE achievement of single-crystal growth of large area silicon semiconductor films on oxide insulating substrates is of technical importance to many solid state electronic devices. The semiconductor-insulator composite structure is also of scientific interest because the heteroepitaxy is determined by the spatial relationship between the atomic arrangement in the substrate and that of the atoms in the appropriate crystallographic plane of silicon. The degree of crystalline perfection of the silicon deposits depends also on the physical condition of substrate surface. Epitaxial growth of silicon on commercial flame fusion Al-rich spinel (MgO:3.3A12O3) has been reported by several investigators.'-4 The lattice of spinel of this composition is distorted. The material cracks and exsolves the excess alumina in the lattice at temperatures (-1200°C) used in fabricating silicon devices. Stoichiometric MgA12O4 spinel exhibits neither lattice distortion nor thermal instability. Results are given on the epitaxial growth and characterization of silicon on stoichiometric spinel. EXPERIMENTAL Fabrication of Silicon-Spinel Composite Structures. The MgA12O4 spinel substrate wafers were prepared from bulk single crystals grown at about 1200°C by a flux technique5 using a PbF2 flux. The crystals are free from strain and subgrains, and exhibit a typical dislocation density of less than 50 lines per sq cm. The crystals are thermally stable without cracking and exsolution of alumina to at least 1500°C. The spinel crystals were oriented for cutting by the Laue X-ray back-reflection method.6 Substrate wafers (about 25 mil thick) of (Ill), (loo), and (110) orientations have been obtained bu cutting the X-ray oriented crystals using a standard type diamond wheel. An accuracy of better than 1/2 deg is maintained throughout the operation. The spinel substrate wafers were mechanically lapped and polished to produce the flat and smooth surface which is required for silicon epitaxy. Lapping was carried out with about 30-µ boron carbide abrasives to obtain a flat coplanar surface. The lapped surface was further polished using successively finer grades of alumina, ending with the 0.3-µ grade. After polishing the wafers generally have a flatness of ±0.4 µ per cm, as revealed by interferometry. Fig. 1 shows (111) oriented MgA12O4 spinel wafers of various shapes.

Jan 1, 1970

By J. F. Abel

It can be concluded that rock mechanics instrumentation, geologic mapping, and operations research in combination will produce an accurate estimate of tunnel support requirements for establishing a steel-set load prediction model. This estimate can be used to increase safety and to reduce tunneling costs. Unnecessary supports can be eliminated; overloaded or insufficient supports can be replaced on a more scientific basis than previously possible. Only a limited number of measurements are required to develop a steel set load prediction model. The results of this study can be applied generally; but, every tunnel must be considered as a separate problem. The construction and geologic variables which were found to be significant in the prediction of rock loads in this tunnel were: steel section modulus, set blocking points, percentage of alteration, relative degree of faulting, relative water condition, distance to the nearest fault, and average joint spacing. INTRODUCTION A combined engineering geology and rock mechanics program was performed throughout the Straight Creek tunnel pilot bore in Colorado in order to develop a technique for estimation of steel tunnel support loads. The technique involves the construction of a statistical model from measured steel set loads, geologic and construction factors. The aim of the investigation was to produce a set of charts, based on these factors, which could be used by a trained man equipped with a hand lens and measuring tape, to specify a safe and economical steel size and set spacing. In order to be of practical value the measured parameters had to be rapidly measurable and capable of quantification. It was apparent from the beginning that quantitative values for many of the geologic factors would have to be arbitrary. It was impossible to ascertain in advance which of the readily determi-nable geologic and construction factors significantly affect steel set loading. As the investigation progressed the number of observations was systematically reduced in order to determine the minimum amount of data which would be necessary for a significant mathematical model. This paper presents an analysis of all the variables measured at each instrumented steel set. The statistical significance of the measured variables was determined. On the basis of this determination, a mathematical model was constructed and charts were prepared to select and space the steel tunnel supports at any given point in the tunnel. Once the effect of geologic and construction factors on set loading is sufficiently established, it is possible to exert close control over the selection of steel tunnel support size and spacing. The magnitude of this rock mechanics program can be appreciated when it is known that there were 44 instrumentation stations for which steel set loads were measured. For each of these sets there were three construction variables recorded, and nine geologic parameters determined (Table I). A rough approximation of the cost for both the collection and reduction of the data would be $50,000. This is in addition to the cost of geologic mapping.

Jan 1, 1967

By M. J. Taylor

A common method of classifying non-water- impounding mine waste structures is necessary to facilitate professional comnunications within the industry and between representatives of industry and government. Camnon classifications can a1 so he1 p quickly create and maintain a mental picture of the structures being discussed. Three categories for classification presented in this paper include: (1) configuration and location with respect to existing topography. (2) material characteristics of waste, and (3) environmental sensitivity or characteristic; of the disposal area. Configuration and location classification involve terminologies typically utilized for waste dumps over the past several years. General classification categories for non-impounding structures include: (a) valley-fill, (b) cross-valley, (c) side-hill, (d) ridge, and (e) heaped. Material characteristics can govern the location, engineering details, and environmental sensitivity of the waste structure. Material classification includes: (a) hazardous, (b) non-hazardous, (c) inert, (d) fugitive dust susceptible and (e) leachate susceptible. A1 though many characteristics are potentially applicable, this paper will focus on the categories mentioned above. Environmental sensitivity of a waste structure encompasses many objective and subjective evaluations plus many multi-disciplinary considerations. Environmental sensitivity incorporates numerous factors in addition to those highlighted in configuration and location, and material characteristic classifications. A few examples of how this categorization can govern the engineering design and location of waste dumps are provided in this paper. In addition to the verbal descriptions of classifications, a simplified version of the combined classifications with an alphanumeric format and its methodology is discussed in this paper. Surface water controls often govern the classification or vice versa. In order to maintain a non- impounding status, water must be prevented from collecting behind the structures. Depending on material characteristics, water inflow to or over the site can cause significant environmental or human consequences. Finally, the access of water to the waste dumps can play a large role in the degree of environmental sensitivity to the site. This paper provides a framework in which to discuss the other aspects of this conference and also provides insights as to how the framework is based on actual practice.

Jan 1, 1985

By David L. Rife

Fluid inclusions have been studied since the mid-1800s. In 1858, the famous English geologist H. C. Sorby, stated that ". . . there is no necessary connection between the size of an object and the value of a fact, and that, though the objects [inclusions] ... are minute, the conclusions to be derived from the facts are great."' This statement philosophically emphasizes why fluid inclusions should be studied. Fluid inclusions supply the economic geologist with "hard" data on the chemical environment and mechanisms of transport for ore fluids. Such studies enable geologists to understand more about their complex nature. The information that can be obtained from fluid inclusions is as follows: 1) Fluid inclusion "filling temperatures" measured with the microscope heating stage, reflect the hotness of an ore fluid at the time of its entrapment and are one of the most accurate methods of geologic thermometry. 2) Ore fluid densities indicate the extent to which ground water becomes mixed with ore fluids. Density is determined from the composition of inclusions, the ratios of gas to liquid (at room temperature), and from

Jan 1, 1973

By D. L. McDanels, J. W. Weeton, R. W. Jech

An investigation was conducted to determine the stress-strain behavior and tensile properties of metallic composites and to relate them to the properties of the base materials. Tungsten fibers in a copper matrix were chosen as the model sys-tem to investigate these properties. Room-temp-atzcre tensile and dynamic -modulus tests were used To meet the demand for improved structural materials, considerable effort is being directed toward the creation of composite materials. One such material under investigation is the fiber-reinforced composite, in which a ductile, relatively weak matrix is reinforced with high-strength fibers. Some work has been done on the reinforcement of metallic matrices with metallic fibers1"5 as well as with ceramic-whisker reinforcement. Summaries of much of this work have been published by Mach-lin7 and Baske~.' Work done at the Lewis Research Center of NASA-" has involved the making and testing of composites composed of a fiber, tungsten, and a matrix, copper, which were insoluble in each other. An equation was presented that showed the relation between the ultimate tensile strength of the composites and the strengths and relative volume percents of the components. This relation was verified experimentally for composites containing fibers extending the full length of the specimen as well as for composites reinforced with short-length or discontinuous fibers. Since the publication of the preliminary results,9'10 additional data have been obtained. This paper presents these data as well as analyses of the stress-strain behavior and the mechanics of deformation of uni-axially oriented, fiber-reinforced metallic composites, in which both components are mutually insoluble. EXPERIMENTAL PROCEDURE Composites were made with high-purity copper as the matrix and 3-, 5-, and 7-mil-diam tungsten wire as the reinforcing fiber. Some specimens were made in which the reinforcing fiber extended completely through the full length of the composite test section. The fibers were placed in ceramic to determine these properties. The composites were reinforced with either continuous or discontinuos tungsten fibers. The tensile properties and stress-strain behavior of composites reinforced with either type of reinforcement were similar, and in both cases the full strength of the fiber was utilized. tubes to insure axial orientation and infiltrated with copper at 2200°F for 1 hr. Composites were also made with short-length (3/8 in. long) 5-mil-diam tungsten fibers as discontinuous reinforcement and infiltrated under the same conditions. The reinforcing fibers in both cases were longitudinally oriented in the direction parallel to the tensile axis. Room-temperature tensile tests were conducted on the composites, stress-strain curves were obtained, and ultimate tensile strength and elongation were measured. Dynamic modulus of elasticity, based upon the resonant frequency induced in the flexural mode of vibration, was also determined for the composites and the components. A more detailed discussion of the experimental procedure employed in this investigation may be found in Ref. 11. RESULTS Room-temperature tensile tests were conducted on 3-, 5-, and 7-mil-diam tungsten wires which had been annealed for 1 hr at 2200°F and show the tensile strength of the wires to be 331,000, 327,000, and 290,000 psi, respectively. Since all the composites were infiltrated under these conditions, the strengths were considered to represent the strength of the fibers in the composites throughout this study. The average tensile strength of the annealed copper used as the matrix in this investigation was 27,800 psi. Results of room-temperature tensile tests on composites reinforced with 3-, 5-, or 7-mil-diam tungsten fibers are plotted as functions of composition in Fig. 1. These data represent previously reported datag,l0 as well as data more recently obtained. The line shown on each curve represents a prediction of tensile strength as a function of composition; the calculation of this line was explained in Refs. 9 and 10. A similar plot is presented in Fig. l(d) for composites reinforced with short-length, discontinuous 5-mil-diam tungsten fibers. Again, both the previously reported and the recent data are presented, and the line shown is identical to that shown for

Jan 1, 1965

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -The following report covers briefly some of the more important activities of the Institute during the year 1923 In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923. Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by the four Founder Societies bears witness to the trend in business For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers, but for the mature members, those of experience, there are few calls. During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members The A. I M E has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American coun¬tries that a large number of members residing abroad have been compelled to relinquish their membership. Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone back¬ward. The Membership Committee has declined to recommend many

Jan 1, 1923

By J. H. Westbrook

IT is always of interest to document the origin of real microstructures which closely approach various idealized morphologies. Such instances constitute excellent bases for experimental studies of the effect of microstructure on properties. Typical examples include the eutectoid steels (lamellae) used by many investigators and the two phase Cu-Cr alloys (spheres) recently employed by Hibbard and Hart The present note describes a structure with cylindrical particles. In a study of certain alloys in the Cr-C system, an alloy was arc melted whose composition was very close to the aCr-Cr,C, eutectic (3.2 wt pct C, according to the latest phase diagram published by Bloom and Grant2). The alloy was not analyzed but previous experience with the melting technique employed indicates good correspondence between intended and analyzed compositions with negligible tungsten contamination from the electrode. The phases present in the alloy were identified by X-ray powder patterns as a chromium and Cr,C,. Typical micrographs, presented in Fig. 1, show unmistakable evidence of the cylindrical geometry of the carbide phase. The eutectic grains are randomly oriented and, consequently, only a few show the true fibrous nature of the carbide particles, most being cut so as to show slightly elliptical cross sections. Within any particular grain, remarkable uniformity is to be observed with respect to the size, shape, spacing, and orientation of the carbide particles. Length to diameter ratios have been estimated from the micrographs to be at least 250:1, with diameters of about lp. This alloy may be of further interest from different viewpoints. On the one hand, it might be used to check the applicability of the equations derived by Fullman3 for computing true particle dimensions of cylindrical particles from opaque random sections. On the other hand, it might be possible to extract the carbide particles from this alloy and repack them in a ductile matrix to form a synthetic structure of the type discussed by Metcalfe et al.4 With the large l:d ratio and the small diameter of the carbide fibers, it is likely that the interdefect distance in each fiber is sufficiently great to permit realization of a large fraction of the presumed high strength of the carbide. References 1W. R. Hibbard, Jr. and E. W. Hart: Dispersion Hardening of Copper-Chromium Alloys. AIME Trans., 1955, vol. 203, p. 200; Joun-nal of Metals, January 1955. 2D. S. Bloom and N. J. Grant: The System Chromium-Carbon. AIME Trans.. 1950. vol. 188. p. 41; JouRnal of Metals, January 1950. aR. L. Fullman: Measurement of Approximately Cylindrical Particles in Ooaaue Samples. AIME Trans.. 1953, vol. 197, p. 1267; Journal of Metals. ~ebtember 1953 4 A. G. Metcalfe, C. H. Sump, and W. C. Troy: Fiber Metallurgy. Metal Progress, 1955, vol. 67, p. 81.

Jan 1, 1958

By Roshan B. Bhappu, Milton F. Lewis, Jean A. McAllister

Several alternatives are available for treating lower grade gold ores averaging 0.04 to 0.10 oz per ton. These include heap, vat, and agitation leaching and may involve conventional zinc precipitation or carbon adsorption-electrowinning systems. Each of these processes have their inherent economic and operating advantages and disadvantages and the selection of the optimum method for a given gold ore is solely based on economic evaluation of the applicable processes. In this paper an effort is made to provide engineering feasibility estimates for the above processes under varying operational conditions such as ore grade and price of gold.

Jan 1, 1974

Improvement of drilling operations through the development of new, unconventional drill bits is a prime research target at Sandia Laboratories, Albuquerque, N.M. Sandia is currently focusing efforts on four new bit designs which its engineers believe may eventually improve penetration and reduce operating costs. The Energy Research and Development Administration (ERDA) has budgeted $500,000 in support of this program to date. Two of the drill bits-one that chips rock with high voltage spark discharges, and another which fires small projectiles into the rock ahead of a regular roller bit-are designed to increase both penetration rates and downhole bit life.

Jan 8, 1975