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In comparisons of a trial extruded brick containing 33 per cent coalwash and 67 per cent clay and a trial pressed brick containing 100 per cent coalwash with a standard extruded clay face brick, the mixed feed stock trial brick compared favourably with the standard brick. If a highly plastic clay is used to mix with the coalwash, satisfactory results are obtained in respect to dimension, strength, water absorption, efflorescence, resistance to salt attack, hardness, colour, weathering, mineralogy and porosity. Although a brick containing only coalwash can be successfully manufactured in a press, its mechanical and physical properties are inferior. This mixed feed stock brickmaking technology leads to the utilisation of a by-product with a potential saving of raw material costs. The extent of use is likely to depend on the proximity of the coal washery and the brickworks and the economicsof transportation costs.

Jan 1, 1992

By Edward Bullard

El presente texto señala los problemas tecnológicos, económicos y políticos que plantea la explotación de minerales de los fondos marinos. En ese sentido, las investigaciones internacionales realizadas sobre el Mar Rojo durante la última década y el proyecto JOJDES en el Atlántico proporcionan un conocimiento completo de las posibilidades del beneficio de los minerales.

Mar 1, 1975

By R. E. Reed-Hill

A simple accurate graphical method for orienting fcc crystals using (111) slip traces on a single surface is described. Solutions placing the pole of the surface in a unit stereographic triangle are obtained using a Wulffnet, a (111) standard projection showing the four (111) planes, and a (111) standard projection ruled into unit stereogmphic triangles. The multiplicity of solutions is described in relation to this method. AN accurate, rapid single-surface technique for orienting fcc crystals, using (111) slip or twin traces, has been a matter of continuing interest, as evidenced by the periodic appearance of papers on this subject.'-4 This note presents a new method possessing some advantages over those previously reported. It is an analog to the technique for hcp metals5 where the solution is based upon a stereographic rotation of the specimen surface on a (0002) standard projection that contains the planes of the possible features that might account for the observed traces. In the hexagonal solution, the axis of rotation is the basal-plane trace in the surface. In the fcc case, the axis of rotation is one of the observed ( 111) slip or twin traces. It has been observed that the solution is greatly facilitated if the indicated movements of the (111) traces during the rotation of the surface are plotted directly on a paper copy of a Wulff net as shown schematically in Fig. 1. The trace selected to represent the axis of rotation is assumed to fall at the north-south poles of the Wulff net. The directions of the other traces are then plotted as points at the proper angles around one-half of the basic circle of the net. The loci of points corresponding to the movements of these traces (directions) during a 90-deg rotation of the surface, about the polar axis of the net, are then easily and accurately drawn by following the appropriate small circles on the Wulff net. The solutions to the problem are obtained with the aid of a (111) standard projection of the (111) planes, see Fig. 2. This is normally a Xerox copy of a carefully drawn master made on high-quality tracing paper. The (111) standard projection is superimposed over the Wulff net and rotated about its center until the points of intersection of the loci of surface traces, drawn on the Wulff net, and the great circles representing the (111) traces, all lie along a common meridian of the Wulff net as demonstrated in Fig. 3. This latter great circle represents a possible position of the surface. The pole of this plane is then plotted on the (111) standard projection. Its location in a unit stereographic triangle may be readily obtained by superimposing (over the standard projection) another tracing paper (111) standard projection subdivided into unit stereographic triangles. The result of this last operation is shown in Fig. 4. MULTIPLICITY OF THE SOLUTIONS The maximum possible number of (111) traces on a single grain surface is four. Any one may be selected as the axis about which the surface is rotated. Corresponding to each such choice are three possible surface-pole orientations, related to each other by a simple 120-deg rotation about the pole of the (111) basic circle. This is a direct result of the threefold symmetry of the (111) standard projection. Since each of the four rotations will normally give a different set of three-pole positions, there are, accordingly, twelve possible solutions. Each of these twelve solutions places the surface pole in the same relative position in a stereographic triangle so that all are crystallo-graphically equivalent. Accordingly, only a single solution is required to obtain a basic orientation of the crystal. It should be noted, however, that the orientations obtained by reflecting* any of these twelve orien- *The reflected orientations may be obtained by a 90-deg rotation of the opposite sense to that shown in Fig. 1. This rotation places the correspond-ing trace loci in the lower hemisphere of the Wulff net rather than in the upper hemisphere. tations through the surface are also possible orientations that could account for the surface traces. Thus, a given set of four traces always corresponds to a pair of basic orientations related by reflection through the specimen surface. This ambiguity can only be re-

Jan 1, 1967

By H. M. Chance

The Taviche district is about 12 miles from the town of Ocotlan in the State of Oaxaca, and about 250 miles south of the City of Mexico. Its altitude rises to something more than 5,000 ft.; and although within the tropics (latitude about 17° N.) the climate is mild and salubrious, neither excessively hot in summer nor cold in winter. The phrase, "perpetual spring," which has been applied to it, aptly describes the weather during my stay. Sugar-plantations, bananas and other tropical and semitropical fruits flourish in the valleys, while the hills

Jan 1, 1905

By Richard Paul Seelig

THE following review covers published information on pressing of metal powders at room temperature. Only those operations are considered which occur between the time the powder is filled into the cavity and the compact is ejected from the die. Thus, this review does not concern hot pressing, coining or sizing feed or flow problems, commercial presses nor designs. It was also necessary to disregard to a large extent the effect of pressing on subsequent operations and on properties after sintering. The pressing operation is considered independently in its function to compact loose metal powder into useful shapes which can subsequently be handled. There are some comments by the writer in connection with a few of the findings quoted in the literature in order to stimulate thought and discussion. The selection of references quoted in the text is in some cases arbitrary although an attempt was made to favor papers containing novel ideas, techniques or results which may stimulate future research. In order to enable the reader to check further into the subjects mentioned, the original, rather extensive, bibliography is appended even though not all the references are touched on in the printed version of this review. EXPERIMENTAL APPROACH The equipment used by various workers, for example a die design created by Bridgman,22 is very interesting. The die insert has a conical external surface. The vertical pressure exerted on the punch transmits itself to the die which in turn is pushed harder into its tapered retainer. Thus, the higher the pressure exerted on the punch, the higher also the pressure exerted inwards on the die inserts. In as much as this pressure counteracts the internal pressure from the compact the two stresses balance each other so that it is possible to obtain tremendous pressures without breaking the die. The die collar was made from an oil hardening tool steel, heat treated to a tensile strength of some 300,000 psi. The die was closed at the bottom by a plug made from special tool steels. Bridgman found that there is no steel which will withstand a compressive stress of 700,000 psi without continuous slow flow or immediate fracture. Therefore, the only material suitable for use in the pressing punch was sintered carbide. In view of the ingenious design it was possible to use special tool steel as die material. Jones22 raises the question whether this method of pressing has practical application in powder metallurgy. Al- though these tremendous pressures cannot readily be utilized without many special precautions, the tapered die and retainer idea is believed to be useful even for lower pressures. Bridgman, himself,8 calls attention to the fact that the properties

Jan 1, 1947

By K. T. Koone, R. J. Blackwell

One of the more important problems to be solved in designing a miscible flood is related to the size of the solvent bank used. Size of the bank may be critical to economic success. Too large a bank loses money; too small a bank may deteriorate and fail to maintain the miscibility needed for high recovery. An important factor in deterioration of a small bank is permeability channeling. In a highly stratified reservoir, solvent speeds ahead in the more permeable zones and mixes laterally with fluids bypassed in adjacent, low-permeability strata. Numerical solutions have been obtained .for the differential equations that describe the movement of a slug through a two-layer system in which mixing occurs both in the direction of flow and transversely. The solvent slug is assumed to have the same density and viscosity as the resident fluid and the pushing fluid. These solutions have been verified by comparing them with similar concentration profiles obtained in the laboratory in a 36-ft stratified model packed with glass beads. The theoretical study revealed that when the dominant mechanism causing a bank to fail is lateral mixing the bank size needed for a given recovery may increase with length rather than decreasing as the square root of reservoir length, as suggested by one-dimensional mixing theory. From a comprehensive examination of the variables, a generalized correlation is developed that relates strata thicknesses, bank size, fluid velocity, mixing coefficients, system length and simple solvent-resident fluid phase behavior to the area miscibly swept. INTRODUCTION Miscible displacement, or solvent flooding, continues to receive widespread attention as a method for increasing oil recovery over that possible in conventional gas-drive or waterdrive projects. A basic economic requirement in the application of such processes is the use of as little solvent as possible. A basic physical requirement is that enough solvent be used to maintain miscibility. Economics places an upper limit on the size of a solvent slug, and physical considerations establish a lower limit. Consequently, the practicality of any given miscible process requires that the economic limit be greater than the lower limit imposed by physical requirements. Procedures exist for determining the economic limit; however, procedures for determining realistic minimum bank sizes exist for only special reservoir situations. In the past, bank size has usually been selected on the assumption of a piston-like displacement for which only longitudinal mixing is important. This assumption leads to the favorable conclusion that bank size, expressed as per cent of pore volume, is inversely proportional to the square root of length. Collins considered the problem of transverse mixing of solvent with fluids in bypassed zones with the assumptions that no forward mixing occurs and that the concentration is uniform in the permeable stratum of interest. 1 Lauwerier considered a mathematically similar problem in thermal recovery operations.2 Their work suggests the much less favorable conclusion that bank size could be directly proportional to the length or even higher powers of the length. This paper considers the physical behavior of a small solvent bank as it moves through a real reservoir, without imposing many of the restrictive assumptions of past treatments. To facilitate mathematical description, an idealized, two-layer model that permits mixing both laterally and in the direction of flow will be considered. A calculation procedure for solving the descriptive equations will be developed for a displacement involving fluids of equal density and viscosity. In addition, laboratory experiments designed to check the computational results will be described, and the coincidence of calculated and observed results will be discussed. The use of many solutions for a variety of bank sizes, strata thicknesses and characteristic system lengths to develop a usable correlation between

Jan 1, 1966

By W. C. Kerr

A BRIEF sketch only is here intended, with a few illustrations, in order to give a general notion of the character and structure of these veins. I have stated elsewhere, several years ago, that these veins were wrought on a large scale and for many ages by some ancient peoples, most probably the so-called Mound Builders; although they built no mounds here, and have left no signs of any permanent habitation. They opened and worked a great many veins down to or near water-level ; that is, as far as the action of atmospheric chemistry had softened the rock so that it was workable without metal tools, of the use of which no signs are apparent. Many of the largest and most profitable of the mines of the present day are simply the ancient Mound Builders' mines reopened and pushed into the hard undecomposed granite by powder and steel. Blocks of mica have often been found half imbedded in the face of the vein, with the tool-marks about it, showing the exact limit of the efficiency of those prehistoric mechanical appliances. As to the geological relations of these veins, they are found in the gneisses

Jan 1, 1880

By W. C. Kerr

A brief sketch only is here intended, with a few illustrations, in order to give a general notion of the character and structure of these veins. I have stated elsewhere, several years ago, that these veins were wrought on a large scale and for many ages by some ancient peoples, most probably the so-called Mound Builders; although they built no mounds here, and have left no signs of any permanent habitation. They opened and worked a great marly veins down to or near water-level; that is, as far as the action of atmospheric chemistry had softened the rock so that it was workable without metal tools, of the use of which no signs are apparent. Many of the ladgest and most profitable of the mines of the present day are simply the ancient Mound Builders' mines reopened and pushed into the hard undecomposed granite by powder and steel. Blocks of mica have often been found half imbedded in the face of the vein, with the tool-marks about it, showing the exact limit of the efficiency of those prehistoric mechanical appliances. As to the geological relations of these veins, they are found in the gneisses

Jan 1, 1880

SECTION I Page Page New York Section War Meeting on Employment xxxii Sulphur and Pyrite v Local Section News xxxiv War Minerals Committee xviii Forthcoming Meetings xxxvi St. Louis Meeting xx Library xxxvii Minutes, of Meeting, Executive Membership xli Committee xxvi Institute Committees Iv Members in Military Service xxvi Officers and Directors lxii Personal xxx

Jan 10, 1917

By Stephen Hardcastle

Personnel Heat Exposure Issues In Canada?s Deep Mechanized Mines ?Project developed in 2004 ?Base/precious metal industry identified heat stress/management as a major challenge affecting productivity and operating costs ?Project started in 2005 ?Current research nearing completion ?Guidelines, further data analysis and ?Communicating the Science? will continue into 2011 Managing Heat Exposure Control?. The cost implications ?Controlling the environment ?Ventilation already a major expenses/energy user ?Large Canadian mines are currently delivering massive volumes of air 15-20 tons of air/ton ore ?Large investments in ventilation upgrades, mechanical cooling

May 1, 2010

By H. Doi, Y. Fujiwara, K. Miyake

In order to throw light on the mechanism of plastic deformation of WC-Co alloys, compressive tests of WC-(7 to 43) vol pct Co alloys have been carried out at room temperature, and stress-micro strain relation has been investigated in detail. The analysis of the factors affecting the yield stresses reveals that the yield stresses can be predicted by modified Oro-wan's theory if one properly estimates the planar in-terfiarticle spacings. Conzpressive straining of some of the alloys by 0.066 to 0.17pct increases the decrements by a factor of as much as 3.4 to 14, whereas the corresponding increase in the electrical resistivities is less than 10 pct. The analysis of the decrement data in terms of -Gramto and Lücke theory shows that the marked increase is attributed to increased dislocation darnping itt the binder (cobalt) phase. By cornbilling the decrement data and the conzjwession duta, one obtains the relation between flow stress in shear (?t) and increase in dislocation density (p): At = const . v6 . This is interHeted to mean that the mechanism of strain hardening of CirC-Co alloys is essentially sarne as the one for dispersion strengthened alloys. The possible effect of bridge formations between the carbide particles has also been examined. OWING to the combination of hardness, strength, and other physical and chemical properties, WC-Co alloys have opened the way for unique fields of applications, the recent ones being, for instance, anvils for super-high-pressure generation apparatuses. In such applications, the alloys are frequently subjected to very high compressive stresses: these stresses may cause the alloys to deform plastically and eventually to fail. However, much remains obscure regarding the nature of the plasticity of the alloys. Evidently, the alloys owe their high strength to the hard carbide particles which frequently occupy as much as 80 to 90 pct in volume fraction, whereas the ductility required for practical applications is provided by the small amount of the binder phase between the carbide particles. When the volume fraction of the carbide phase is not very large, deformation behavior of the alloys may be described by some of the current dispersion strengthening theories. However, greatly increasing the carbide phase is thought to lead to some carbide skeleton structure or bridge formations owing to the increased chances for direct contacts between the carbide particles;1,2 this may appreciably affect the plasticity of the alloys. Regarding the effect of formation of the carbide skeleton structure, it is interesting to note the work by Ivensen et al.3 on compression tests of the alloys containing somewhat large carbide particles; they observe extensive generation of slip bands in the carbide particles after application of some preliminary compressive stresses. They interpret the results in terms of plastic deformatiot: of the carbide particles which are supposed to have formed a skeleton structure; the binder phase plays only a passive role, at least in the early stages of the deformation. That carbide crystals exhibit microplasticity at room temperature is apparent from the work of Takahashi and Freise4 and French and Thomas5 on indentation of WC single crystals. On the other hand, Dawihl and coworkers6-10 maintain that even when volume fraction of the carbide phase is very large (for instance, more than 90 pet), a very thin binder layer generally exists between the carbide particles. They interpret the results of the extensive mechanical tests in terms of the plasticity of such a layer. Gurland and Bardzil11 point out that decrease in ductility of the alloys with increase in the carbide phase is caused by the effect of plastic constraint exerted by the dispersed carbide particles. Drucker12 further develops this concept from a continuum-mechanics approach on an assumption that a continuous thin binder layer separates the carbide particles. A common feature of the studies reported so far on the plasticity of the alloys is that the information deduced is invariably qualitative in nature. Thus, very few systematic experiments for obtaining reliable and sufficiently detailed stress-strain curves of the alloys varying widely in the microstructural features have been carried out. In particular, it may be of special interest to investigate in detail the early stages of the plastic deformation of the alloys in order to shed light on the strengthening mechanism. However, such work appears to be extremely rare. Doi et al.13 recently reported a first brief account of the results of some quantitative analysis of the plasticity of the alloys in terms of dislocation theory. Their experiment was rather limited in the composition range covered (volume fraction occupied by the carbide phase: 79 to 83 pct), and thus they could not necessarily elucidate the controlling mechanism of plastic deformation of the alloys of a more general composition range. Consequently, in the present investigation, deformation behavior and some other physical properties of the alloys were investigated and discussed in more detail over a much wider composition range. SPECIMEN PREPARATION WC-Co alloys used in this experiment were prepared in cylindrical or rectangular form by sintering in vacuo compressed mixtures of tungsten carbide and cobalt

Jan 1, 1970

By Edward Medina Bárcena

El proyecto minero Cerro Lindo, luego de haber aprobado los estudios de factibilidad técnica-económica, inicia su fase de construcción en el 2006 y culmina en el 2007. En ese sentido, el presente texto describe el incremento de la producción y expansión. Para esta nueva expansión, se realiza un estudio de factibilidad, donde se determinan CAPEX y OPEX. Además, se determina la rentabilidad del proyecto y de un periodo de recuperación del capital invertido (US$ 168 millones). El período de construcción se inicia en junio de 2011 y culminará en diciembre de 2012.

Oct 1, 2012

By Luis Huere

La extracción del oro en PAD de lixiviación es una operación que cada vez se utiliza más para la extracción del metal de sus menas, esto se realiza evidentemente por los bajos costos de procesamiento por este método, entre otros motivos. La recuperación del oro es siempre baja comparada con la recuperación por lixiviación en tanques de agitación. La lixiviación de finos siempre es un problema por la canalización de la solución lixiviante y la formación de charcos o “cochas”, generando esto bajas recuperaciones y más aún ante la presencia de arcillas en el mineral perjudican aún más la recuperación de oro de estas menas.

Sep 1, 2017

By E. N. Durussel

"The Fox Mine has been producing copper/ zinc ore since 1970 at a rate of approximately one million tons per year, and until 1978all production was derived from longhole open stopes. In June 1978, a trial stope using bighole mining methods was started to eliminate the development of two sublevels between 400 level and surface. The trial proved to be successful, and bighole mining is now an accepted mining method for both stopes and pillars at Fox Mine.When production blasting was started in the first stope, the biggest problem encountered was the production of large amounts of sulphur dioxide gas as a result of secondary sulphide dust explosions. This gas generation resulted in lost production time and caused minor damage to underground installations to the blast level, and to the headframe. Sulphur dioxide generation has been noted in secondary drawpoint blasts and, on rare occasions, in drift rounds.This paper discusses the occurrence of the sulphur blasts and the practices and precautions used to prevent their reoccurrence at Fox Mine.IntroductionThe Fox minesite is located 30 miles southwest of Lynn Lake, Manitoba. With production startup in 1970, Fox Mine is owned and operated by Sherritt Gordon Mines Limited.The Fox orebody occurs as a large lenticular zone of semi-massive sulphides approximately 1,500 feet long and 15 to 100 feet wide running east and west. Dipping 70 degrees to the north, the orebody tends to bottom out at the 3200-foot level and reaches to within 15 feet of surface."

Jan 1, 1981

CESIUM metal production increased sharply in 1963. Domestic Production.--Cesium metal was produced by The Dow Chemical Co., Midland, Mich., MSA. Research Corp., Callery, Pa., and by Penn Rare Metals, Inc., Revere, Pa. American Potash & Chemical Corp., Trona, Calif., produced some combined cesium and rubidium. This company, Penn Rare Metals, Inc., and Rocky Mountain Research, Inc., Denver, Colo., produced various cesium compounds. Complete production data on cesium and rubidium and their compounds were not available for publication. Consumption and Uses.-Substantially more pollucite was consumed to produce cesium metal and compounds in 1963 than in 1962 but the overall consumption of pollucite continued to be small.

Jan 1, 1964

By Wheeler P. Davey, Robert T. Phelps

A study of solid solutions has long been a source of interest because of the conditions controlling their formation. X-ray investigations so far have been conducted with the idea that there were two types of solid solutions. In the first type, an atom of the solute was supposed to replace an atom of the solvent in the crystal lattice. In the second type, an atom of the solute was supposed to lie in one of the interstices between the atoms of the solvent. These pictures both require that the sizes of the atoms must play an important part in the process of solution. It is the purpose of the present investigation to study the mechanism of solid solution, using pure silver as the solvent, and pure aluminum as the solute. X-ray measurements show that these elements have the same "shape" of atomic domains1 (they both crystallize as face-centered cubes) and that their atomic diameters differ by less than one per cent.' The results of the present investigation point toward a chemical rather than a physical picture of the nature of solid solution, and make the older pictures merely special cases of a more general picture. The new theory has the advantage, too, that it offers a rational explanation of certain phenomena which hitherto have been only interesting detached facts. The aluminum-silver system which was chosen for this study has been studied by various methods by several workers. By means of thermal analysis Gautier2 and Petrenko3 have determined the phase diagram. Hansen studied the aluminum-rich alloys by means of thermal and microscopic analyses. He showed that at high temperatures silver dissolved in aluminum to the extent of 47 per cent by weight at 560" C. But this solubility decreased to 1 per cent at 200" C. Westgren and Bradley5 made an extensive X-ray study of these alloys. They used the change in the lattice parameter of silver as a criterion of the solution State College, Pa.

Jan 1, 1932

By M. J. King

Non-ferrous metals such as copper, nickel, lead, zinc, gold and platinum group metals are often found in sulphide mineral deposits. Various pyrometallurgical and hydrometallurgical processes are employed to extract the valuable metals from their minerals. These processes result in the production of sulphur bearing by-products or wastes. This paper provides a review of sulphur bearing by-products and the techniques used for their production. It focuses primarily on elemental sulphur, sulphuric acid and various fertilizer options. Liquid sulphur dioxide, oleum and gypsum by-products are also discussed.

Jan 1, 2009

By Arthur V. Abbott

TO rightly use materials, two kinds of knowledge are essential: first, the actual strength of the substance; and secondly, the forces to which, in the structure, it may be subjected. Nearly all of the data which we have at the present time have been obtained from the experiments made on the materials used in Europe, and by foreign investigators. The materials commonly used in this country, es-

Jan 1, 1884

By Clifford C. E

1 eat my peas with honey I've done it all my lifeIt makes them taste rather funny But it keeps them on the knife.Innovation is that elusive characteristic which involves the determination of multiple and unique response to a problem, and then commitment to and action from the best of the alternatives.

Jan 1, 1993

This Technical Memorandum Report is a collection of three working memoranda, prepared during the course of our work for the Bureau of Mines and bound together for convenient reference. These working memoranda present preliminary performance estimates, for baseband voice and narrow- band through-the-earth electromagnetic communications systems of principal interest to the Bureau, for operational/emergency mine communications. The calculations were prepared to obtain early indications of the feasibility and governing parameters of such communications systems. They are based on limited, but pertinent, coal mine electromagnetic noise data acquired to-date by Bureau of Mines contractors; and of theoretical signal-attenuation characteristics for two transmitter antenna types of present interest to the Bureau. The memoranda examine the cases of baseband voice and narrowband communications for uplink and downlink transmissions, for frequencies up to 3kHz. Downlink transmissions are via a horizontal wire antenna, up- link transmissions via a vertical-axis loop antenna, for typical mine depths of 300, 600, and 1000 feet. Representative coal-mine overburden conductivities of 10-2 mhos/meter (moderate and common) and 10-1 mhos/meter (high) were used; for voice and narrowband, 10-1 for narrowband only. Examples of high, moderate, and low; surface and subsurface; harmonic and broadband-impulsive noise conditions were taken from NBS and Westinghouse (WGL) mine noise data, together with examples of high- and low levels of ELF atmospheric noise taken from M.I.T. Lincoln Laboratory data. These feasibility calculations are not intended to serve as definitive and complete treatments, but as a starting point: to establish first-order estimates of the magnitude and variability of transmitter power requirements under different noise, overburden conductivity, and mine depth conditions; to identify relationships, conditions, or frequencies that are likely to limit or enhance system performance; to reveal items requiring further investigation and data still required; and to suggest practical methods for optimizing system performance. These objectives were met by the calculations. Simple experiments to support these calculations can and should be carried out; together with more detailed investigations of specific modulation, coding, noise-suppression, voice-compression and signal-conditioning techniques, aimed at producing through-the-earth operational/emergency mine-communication systems that are not only effective, but practical and economically sound.

Jan 3, 1972