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By Russell H. W. Chadwick

Reviewing events in the minerals industry, in economic geology, and in my own exploration work, I find that the most compelling subject for comment is the increasing ferment in ore deposits theory. New discoveries and continued investigations of bedded deposits of lead and zinc, copper, iron, uranium, etc., coupled with the availability of much new and significant data from sedimentary and metamorphic petrology, geochemistry, and oceanography, has led many economic geologists like myself to become disenchanted with former simplistic notions. Now disenchantment among serious people should presuppose both valid objections to the old, and valid new substitutes. I can sum up my own position and, I believe, what most of the recent writers on ore deposits theory are trying to tell us, by saying that a physico-chemical (bench science) approach to a natural science is neither correct nor useful, and that the obvious cure is a return to the study of the geology of ore deposits. More specifically, ore should be viewed merely as an unusual concentration produced, in stages, by the natural processes inherent in the geochemical cycle. In criticizing the conceptual basis of a science, one is involved simultaneously in the inherent character of the science, its subject matter, and the old and new concepts. I have found it impossible to make a clean separation along those lines. As a result, and as the title suggests, these are not-quite-random reflections on genesis, a matter near and dear to all true treasure hunters since Agricola.

Jan 1, 1967

By W. J. D. Stone

"For several years, the existence of a deposit of barite (BaS04) near Brookfield, Nova Scotia, has been known. A very large deposit of strontium (SrS04) near Sydney, Cape Breton, is a more recent discovery. Cape Chemical Syndicate has been formed to work the deposits. A five-million-dollar integrated mineral processing and chemical plant is planned for Sydney to produce various compounds of barium and strontium. The mineral processing plant includes the Jones Wet Magnetic Separator and will produce high-purity barite and celestite. These products will be processed further in the fine grinding plant and the chemical plant. The general project is described, covering the deposits, processing and markets."

Jan 1, 1969

For too long we, as an industry, have borne the brunt of irrational claims, poor science and even worse, journalism with regards to our affect on the environment. To some of us, the overwhelming media attention on greenhouse warming, the polluting outputs of mineral processing or unthinkable depletion of natural resources has left us embarrassed and more unfortunately has turned bright young people away from a career in the minerals industry.This paper shows the hypocrisy associated with an element of the green movement and dispels some general myths on mining disseminated by radical environmentalists.The fallacy of the greenhouse warming effect will be scrutinised by common sense and the mining industryÆs use of land will be discussed and put in proper perspective.Problems associated with safety and emissions and the means to overcome such are discussed briefly.

Jan 1, 2004

By B. Ehgartner, M. Karmis, C. Haycocks

INTRODUCTION Interaction effects between mining operations developed on different levels of contiguously placed bedded deposits are a major problem in many parts of the United States. Efficient design criteria, derived from careful analysis of field studies as well as theoretical and model analysis, have shown that many problems that may result from seam interaction can be avoided, minimized, or on occasion used with beneficial results. Selection of seam mining sequence is rarely based only on ground control considerations, but rather on factors such as seam ownership, characteristics and accessibility. Therefore all possible mining sequences and methods must be considered in the development of multi-seam design criteria. Increased utilization of the longwall method of mining creates special problems in multi-seam mining due to the inevitability of caving and, therefore, subsidence. Considerable valuable experience has been gained in this direction from British mining operations where interaction problems are extremely common and the longwall method is the primary method used. However, limitations persist in the application of much of this information to U.S. conditions due to variation in layouts between advancing and retreating longwall systems and the inherent difference in the geologic environment. Considerable field data is available for U.S. room and pillar operations, and where successful pillaring operations have been carried out close parallels may be drawn with ground control mechanisms in longwall operations. VARIABLES AFFECTING INTERACTION Analysis of ground control multi-seam problems shows that factors contributing to interaction may be classified into variables that are fixed by the geo- logic environment and those that depend on engineering design. These may be described as follows (Haycocks et al, 1982): Fixed: (i) Depth*, (ii) Innerburden thickness*, (iii) Innerburden physical characteristics*, (iv) Stress field, (v) Seam thickness, (vi) Coal characteristics, (vii) Completed mining operations either above or below the seam to ve mined, and (viii) Age of workings. Mining: (i) Height, (ii) Dimensions and geometry*, (iii) Method*, and (iv) Spatial location of entries* *These variables are regarded as being critical effects. Few attempts have been made to quantify the variables controlling interaction. Dunham's (1978) linear regression analysis, combined with the National Coal Board's MRDE Roadway Monogram, is probably the most noteworthy. This study involved eighteen multi- seam longwall mines in the United Kingdom. The following variables were taken into account: seam depth, pillar width, opening shape, floor and roof conditions, rate of face advance, vertical seam interval, and age and geometry of overlying workings. A multi-linear regression analysis of these variables fitted by appropriate field values developed a prediction equation for lower seam stability. Although the study included many variables, it neglected the nature or geology of the innerburden. The prediction equation was found unreliable, but it did show the significance of geometry as a factor controlling lower seam stability. MINING SEQUENCES Irrespective of the type of mining method selected only four possible mining sequences are possible for two seams. Finlay and Winstanley wrote in 1934. .. "Experience has shown that whether the upper or lower seam was worked first, the subsequent working of the other seam in the same area seriously affected the roads in the seam first worked." Those effects depended upon the four basic mining sequences: 1) The upper seam is mined out prior to mining the underlying seam; i.e., the seams are mined sequentially downward and mining of the underlying seam is not commenced until operations above are completed and have ceased.

Jan 1, 1982

By Frederick B. Kuhnow

Harmonic energetic delamination a building is being considered for demolition at a formerly known atomic power lab. The building is within a containment structure under a negative pressure, so that no radioactive material is leaked out to the environment. A new approach was developed to make this work possible.

Feb 1, 2020

By H Kim, M J. Sun

Global steel companies are actively combating climate change by reducing carbon emissions. Traditional steel production, using the blast furnace (BF) – basic oxygen furnace (BOF) process, heavily depends on coal and emits substantial CO2. To mitigate this, companies are transitioning to the more eco-friendly DRP (direct reduction plant) – EAF (electric arc furnace) process, which lowers CO2 emissions. This study quantitatively evaluates the impact of increased hydrogen consumption on the carbon footprint of product (CFP) through an analysis of direct reduction process heat and mass balances. The study prioritises a comprehensive material balance based on mass conservation principles. The heat balance is calculated using differences in enthalpy through state energy properties, avoiding heat consumption. Validation using operational data from Hyundai Steel Dangjin works’ blast furnaces shows close alignment between calculated results and actual data, with less than 1 per cent error. This methodology facilitates a detailed analysis of the direct reduction process, offering insights into its feasibility and efficiency. Analysis of the operational impact by increasing the hydrogen ratio demonstrates reduced CO2 emissions and increased heat requirements due to the endothermic nature of hydrogen reduction, in contrast to the exothermic CO reduction. Possible solutions include raising reducing gas temperature or enhancing flow rate. The study effectively utilises designed heat and mass balances to assess material quantities and thermal balance under different operational conditions. It lays the foundation for the initial direct reduction process design, aiding in deriving and optimising operational parameters. Additionally, it provides valuable insights into the challenges of increased hydrogen, contributing to the production of greener steel by addressing these issues.

Aug 21, 2024

By Carlos Bravo R.

El presente texto describe el proceso del sistema de transporte del fierro a través de fajas transportadoras en la minería Marcona. Anteriormente los camiones era el sistema de transporte utilizado en la minería de Marcona. Sin embargo, dado los riesgos de seguridad del sistema locomotor, se empleó el método de las fajas transportadoras. Dicho sistema entra en funcionamiento a partir de 1966 y se extiende hasta San Nicolás. La operación del sistema integral de fajas transportadoras se convierte en uno de los sistemas más modernos del mundo y permite una mayor productividad de tonelajes a transportar, rindiendo mecánicamente y eléctricamente en la minería.

Nov 20, 1967

By Caroline Antunes Correa

Durante o processo por estampagem incremental, parâmetros como velocidade relativa, tamanho e material da ferramenta de estampagem, podem mudar as características superficiais do material. Para um biomaterial ser utilizado em implantes, um dos principais aspectos que pode influenciar sobre o processo de osseointegração são propriedades superficiais como rugosidade e molhabilidade. Nesse contexto, esse trabalho visa avaliar o efeito do processo de estampagem incremental seguido pelo tratamento térmico sobre a rugosidade e molhabilidade de chapas de Ti-cp com estampagem. A composição química e a morfologia das superfícies foram avaliadas por MEV/EDS. Resultados preliminares indicaram que a morfologia superficial é fortemente modificada pelo processo de estampagem incremental.

Aug 16, 2017

By G E. Craig, W. M. Williams

A simple, easily constructed apparatus suitable for the zone refining of iron and other reactive materials is described. After eight passes at one inch per hour, the iron produced showed a marked drop in hardness to 49 Brinell. In addition, an arbitrarily -defined recrystallization temperature was lowered by about 35°C and the rate of grain growth greatly increased. CERTAIN materials, of which iron is one, are so reactive that they cannot be zone refined in any known container without becoming contaminated. For such substances, the floating zone method ( 1) may be used. In this method, the specimen is supported vertically in an inert atmosphere and the molten zone supports itself by its own sur-face tension. The method was first applied to silicon (2) and has since been used for other reactive metals such as zirconium and titanium. Smith and Rutherford (3) have previously reported on the floating zone refining of iron; the efficiency of the method for reducing the car-bon content was demonstrated on

Jan 1, 1962

By J. B. Janus

This report, the 22d in a series, gives analytical data showing composition and quality of tipple and delivered samples of coal collected during fiscal year 1972. This coverage lists mines located in 20 States. Ultimate analyses are given for most of the coalbeds listed. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. The deliveries were sampled in accordance with instructions issued by the Bureau of Mines, and the samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

The following is an incomplete list of members and guests who called at Institute headquarters during the period July 10, 1919, to Aug. 10, 1919. Howard C. Arnold, Washington, Pa. J. S. Lane, New York City, N. Y. L. M. Banks, Denver, Colo. H. W. Lawrie, Washington, D. C. George S. Blair, Pittsburgh, Pa. J. L. McAllen, Latouche, Alaska. Richard H. Catlett, Newark, N. J. David F. McFarland, Urbana, Ill. George L. Clark, Council Bluffs, Iowa. James F. Magee, Lancaster, Pa. Capt. Frederick S. Cook, Portland, Ore. A. G. McGregor, Warren, Ariz. John J. Croston, Atlanta, Ga. Emory M. Marshall, Santa Fe, N. M. Thomas Davis, Seattle, Wash. Benjamin L. Miller, Bethlehem, Pa. J. C. Dick, Salt Lake Cite, Utah. 2d Lieut. C. 0. Noble, U. S. Army. Chris. G. Dobson, Vancouver, B. C. Irving Perrine, Hutchinson, Kans. H. S. Emlaw, Grand Rapids, Mich. Fred S. Porter, Seattle, Washington. F. A. Fahrenwald, Cleveland, Ohio. Capt. H. R. Robbins, Peking, China Lieut. James L. Head, St. Louis, Mo. Joseph P. Ruth, Jr., Denver, Colo. A. A. Holland, Napanu, Canada. William A. Simkins, San Francisco, Calif. W. E. Hopper, Washington, D. C. T .V. Smirnoff, Siberia. Harry Hotchkin, Chicago, Ill. Harrison Souder, Cornwall, Pa. L. L. Hutchison, Tulsa., Okla. F. J. Sur, Denver, Colo. Paul S. King, Wilmington, Del. Harry Wolf, Denver, Colo. George K. Anderson, Jr., lies accepted a position as manager for Wight & Co., producers of air-cooled blast-furnace slag, at Longdale, Va. J. M. Armstrong, with the Caribbean Petroleum Co., has been transferred from Philadelphia to Maracaibo, Venezuela. Fred Sherman Baker, who has been with the Oriental Consolidated Mining Co., at Unsankinko, Chosen, Korea, is now at Columbia City, Ind. Ray J. Barber has removed from Roxbury, Mass., to New York City, and is now consulting engineer for the Roxbury Cold Mines, Inc.

Jan 9, 1919

By Nicola Baldo, Marco Pasetto

"Recycling of tyre rubber in the road pavement, may be one of the best way to reduce waste tires in large quantities and, at the same time, improve some engineering properties of asphalt mixtures. The paper discusses the results of an experimental study, developed in order to analyse the potentialities of crumb rubber from road tyres in bituminous mixtures, using the dry process. Two types of porous asphalt mixtures and reference mixes without rubber were formulated by the traditional Marshall methodology, and mechanically evaluated by means of the Indirect Tensile Stiffness Modulus test, the Creep test (with confinement), and the Indirect Tensile Fatigue Test. Results of this study indicate that the tyre rubber has a positive influence on the performance characteristics, depending also on the grading and volumetric properties of the mix being studied: an interesting increase of the fatigue life, a better stiffness behaviour at lower temperatures and a bigger permanent deformation resistance at high temperatures are guaranteed. Introduction Recycling the rubber from used tyres, in the construction of road pavement layers, is potentially one of the more interesting and advantageous solutions from both the technical and environmental points of view, in order to reduce the total amount of car and lorry tyres to dispose. In road-building techniques, a technology, termed “wet”, for modifying bituminous binders with crumb rubber has by now become well consolidated. There have been numerous scientific studies conducted on this technology and its applications, particularly in the United States, where it has been adopted and codified in specific technical regulations (ASTM D-6114). If the wet process can be considered amply tested, the same cannot be said for a second technology, termed “dry”, which deserves careful study to evaluate its suitability and advantages. In “dry” processes, the rubber is usually used as a partial substitute of aggregate of equivalent grading and mixed with bitumen after integrating the crumb rubber in the lithic skeleton."

Jan 1, 2008

By Zhiyang Long, Ruiling Xiao

"A mine shaft is one main development method of establishing access in an underground mine. The construction technology of the mine shaft sinking is complicated and large equipment setup on surface and in the mine shaft. The paper briefly reviews a single-line operation method, parallel operation method and mixed operation method as well as the features of the one operation method with the excavation, lining and installation. The special construction technology mainly would include ground freezing methods, full diameter shaft drilling methods, caisson methods, grouting technology and concrete curtain methods as well as other methods. The paper summarizes the shaft sinking numbers and effects by the special construction methods during different periods. The paper states the shaft sinking conditions and the each created record conditions in the coal, metallurgy, non-ferrous metal, hydropower, highway, railway, nonmetallic and other industries. The paper has a prediction on the shaft sinking requirements and development tendency in the future for China.INTRODUCTIONA mine shaft is one main development method of access in an underground mine. In recent years in China the new shaft mines represent 45% of the total number of new mines. With the development of new mining area under construction and the development of deeper mines, the ratio of the mine shaft as access for underground mines will increase. The construction technology of the mine shaft engineering will be complicated, the operation site footprint will be small and the working environment will be more difficult. The mine shaft sinking operation will often be varied by the geological conditions and affected by underground water inflows, seam gas outbursts, geothermal and other natural conditions. The safe construction of the mine shaft sinking will be challenged by all these conditions. Although the mine shaft engineering will only be about 5% of the total mine roadway engineering, the mine shaft construction period often will take over 40% of the total mine construction period. With the progress of modernized mine production technology and the construction of a high production and high efficient mine, the mine transportation roadways mostly would be set in the seam and the engineered amount of the mine rock roadways reduced year by year could cause more prominent long extensions of the mine shaft construction period. Therefore, in order to speed up the construction, to shorten the mine construction period and to realize the investment benefits as early as possible, the technical level of the mine shaft sinking should firstly be improved and the construction speed of the mine shaft engineering and sinking should be speeded up, which would have important significant benefits."

Jan 1, 2019

By C. Arson

"Optimizing hydraulic fracture injection parameters in order to maximize hydrocarbon extraction and to avoid extensive borehole spalling is still an open issue. In this paper, the Differential Stress Induced Damage (DSID) model is employed to simulate the anisotropic damage distribution around pressurized boreholes drilled in fractured shale. The loading path is purely mechanical: excavation and fluid injection are simulated by stress relaxation followed by pressurization. We investigate the effect of pre-existing fracture orientation, in-situ stress and injection pressure on the propagation of anisotropic damage during pressurization. Finite Element results indicate that (1) damage initiates and develops when the ratio of two in-situ stress component deviates from 1, and the magnitude of damage is proportional to this stress deviation; (2) For a given in-situ stress field, damage initiates for a certain threshold of injection pressure, and the damage zone extends as the injection pressure increases; (3) A pre-existing fracture only affects the damage zone locally; the orientation of that fracture does not affect the damaged zone, which is controlled by in situ stress and injection pressure.INTRODUCTIONHydraulic fracturing is used to increase shale permeability and to enhance hydrocarbon extraction. In order to maximize the extraction ratio and to avoid wellbore spalling and clogging during fluid injection, the parameters related to injection for each particular site need to be optimized. Therefore, it is necessary to clearly understand how shale responses upon excavation and pressurization.It is well known that breakouts grow in the direction of minimum compression and that plastic deformation around wellbores tends to arrest breakouts (Zoback et al., 1985). Laboratory acoustic emission tests revealed that fractures propagate along the direction of maximum compression stress, and fractures (breakouts) are surrounded by the Excavation Damaged Zone (EDZ), in which rock properties are weakened by the presence of micro cracks (Eberhardt et al., 1999; Martino et al., 2004). The anisotropy from orientated foliations and cracks may influence the development and propagation of fractures and breakouts (Everitt et al., 2004). Sonic televiewer logs proved that during hydraulic fracturing, fluid injection further alters the stress distribution (Evans et al., 2005). Shale natural fabric strongly affects the evolution of the EDZ around boreholes."

Jan 1, 2015

By M. Nilmani, H. Pham

"A mathematical model was developed for the dissolution of particles in gas-stirred liquid baths, linking the hydrodynamic flow field of the bath, the average particle trajectory and liquid-side mass transfer controlled dissolution kinetics. The model was validated by comparison with experimental data for the dissolution rates of urea particles in gas-stirred aqueous CaCl2 solutions measured during this study. The dissolution rates of urea. particles were measured using an image analysis system.The effects of operating conditions on the dissolution rates of urea particles were investigated. It was found that the key operating parameters influencing the utilisation efficiency of particles were the gas flowrate, particle diameter and lance submergence. An optimisation of the operating conditions for the model urea-aqueous CaCl2 system indicated that the utilisation efficiency increased with decreasing gas flowrate and decreasing particle size for a given lance submergence.IntroductionThe utilisation solid reagents in molten baths varies from one process to another, depending upon the rates and mechanisms of the reactions between the particles and melts, as well as the trajectory and residence time of the particles in the melts. Previous studies have not attempted to predict the utilisation efficiency of injected solids by coupling the motion of the particle with its dissolution rate. Instead, the particles have usually been assumed to remain suspended in the bath until completely dissolved, and the mass transfer coefficients were based on the average specific mechanical energy dissipation rates in the bath. Investigations of this nature relevant to the present study have been undertaken by Apelian et al. [1], Brucato et al. [2] and Langberg and Nilmani[3]. The objective of the present study was to develop a mathematical model, incorporating both the reaction kinetics between the particles and liquid and the particle motion simultaneously, to predict the dissolution rates and times of the particles. The mathematical model was validated by comparison with experimental dissolution rates of a cold model analogue system measured using an image analysis technique, and then applied to optimise the operating conditions in the model system."

Jan 1, 1996

By Hugh H. Waesche

OF all the military services, the Signal Corps is the most concerned with piezoelectric minerals because of its function as a supply service to the strategic and tactical military forces. Consequently this paper is written from the point of view of one associated with that organization. The Signal Corps is responsible for the research, development, and supply of communications, radar, and components to the using services of the Department of the Army and to some extent the other branches of the National Defense Department. Their work therefore includes the study of the sources, characteristics, and application of quartz and other piezoelectric materials. These materials have become a vital consideration in strategic planning and are essential for efficient tactical operation by all the Armed Forces. The Signal Corps at the beginning of World War II was responsible for both Army Ground and Air Force electronic equipment. Since that time this Army service organization has probably done more in the development of frequency control devices using piezoelectric materials than any other group.

Jan 1, 1949

Jan 1, 1895

By L Gill

The four basic types of electric motors -squirrel-cage, wound rotor, synchronous and D.C. -are de-scribed, with particular reference to speed-torque characteristics. The three classifications of squirrel-cage motors, C.E.M.A. B, C and D, are compared, and methods of selection for specific drives are outlined. Wound rotor and synchronous motors are covered from the viewpoint of construction details, methods of operation and control required. The application of these motors to crushers, conveyors and ball mills is described and reasons for their selection are given. The application of D.C. motors to haulage equipment and mine hoist drives is included, and the basic principles of a variable voltage drive are illustrated. Efforts have been made through-out to provide specific examples of motor selection, with particular reference to the mining industry. THIS paper will attempt to answer the question -"which motor should be used for a specific drive?" Although it is impossible to cover the complete subject of electric motor application here, we hope to give some idea of the types of motors available and why certain types are used on specific applications.

Jan 1, 1963

By V. Z. Sun

One of the major concerns of ground control in a coal mine is safety against failure of one of three components (i.e. roof, pillar, or floor) of the mine entry. In order to better design and evaluate stability of the mine entry with a certain confidence, a reliability approach is introduced rather than using the conventional safety factor (SF) method only. Advantages of using the reliability approach is that it not only takes variability of both rock/coal properties and stress distribution into consideration, but also assesses the stability of each component and mine entry as a whole system. Therefore, it is anticipated that, by using this approach, the current ground control technology in coal mine will convey a better sense of confidence. The results of a case example show a significant influence on the current design concept and stability evaluation of mine entry.

Jan 1, 1997

By Kenneth C. G. Heath

The paper point out the economics importance of the Torco process as lubricant and fuels of the motor in the mining. It is possible to envisage an arrangement in which TORCO would be used to treat a sulphide ore, the acid used to dissolve the metallic ccoper in the concentrate and the copper produced in cathode form by electrowinning. However, there are studies point out that it would be as profitable as conventional flotation, smelting and refining. To carry out full testing of the TORCO process on anyore would be expensive, involving sending several hundred tons to one of the pilot plants located in Johann esburg or Milan. Such pilot plant testing should & be considered as confirmatory rather than exploratory, and a good economic case for using theTORCO process would have to be made out based of mallet scale testing before in curring the larger expense.

Nov 20, 1969