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By R. J. Evans

The generation and disposal of solid waste from electric utility plants using a lime or limestone wet-scrubbing system and the potential effects on the environment were estimated for 1975 and 1980. The study indicated that in 1975 approximately 5.8 million tons of desulfurization solid waste (50 percent solids) will be generated. In 1980, when it is estimated that desulfurization will become commercially accepted, approximately 71.4 million tons of this material will be generated for disposal and/or utilization. The desulfurization waste material when combined with lime, fly ash, and water may have potential for use as a roadbase material, landfill reclamation, and synthetic aggregate.

Jan 1, 1974

By Chandra Sekhar Gahan

The present study aimed to investigate the depyritization of coal using iron oxidizing and sulphur oxidizing acidophilic chemolithotrophic microorganisms in an iron free 9K growth medium at varying pulp densities. Three different coal samples used in the shake flask study from three different countries such as domestic anthracite (Korean), Indonesian and Chinese lignite. Experiments were carried out in batch at a controlled temperature of 35 °C and varied pulp densities of 8%, 10% and 12% (w/v) with a working volume of 100 ml containing 10 ml of microbial inoculum and 90 ml of the iron free 9K growth medium. Coal samples were crushed and ground to fine size fractions <100 microns by attrition mill wet grinding. The progress in the experiments were followed by the regular measurements of pH, redox potential, viable planktonic cell count, residual Fe2+ ion concentration, amount of acid addition and amount of slaked lime addition. The pyritic sulfur removal percentage varied between 90-95% with highest sulfur removal with China coal (95%) followed by Korean Coal (93-94%) and slightly lower level for Indonesia coal (90%). However the pyrite oxidation was highest for Korean coal ranging between 78-80% followed by a similar level of pyrite oxidation of 50-61% for the Chinese and Indonesian coal. It was found that 10-12% pulp density would be fairly feasible for all the different coals tested leading to an economical process. Another benefit from this study is the iron free 9K growth medium, which will reduce the operation cost and overall it?s an environment friendly process.

Sep 1, 2012

By Douglas Glenn Stalheim

The uniformity of the final cross sectional microstructure and subsequent final mechanical properties and shape of structural steels is dependent on the type or types of recrystallization behaviors that are created. There are three main recrystallization behaviors that are the foundation of the metallurgy created during production. Alloy design and subsequent processing design strategy drive how much of each recrystallization behavior is created through the cross section of the product. Carbon manganese steels create only one basic behavior while the addition of microalloys, in particular niobium, can add two additional behaviors. The behaviors are intertwined with each other and build upon each other. The three behaviors are Type I, static recrystallization, Type II, no-recrystallization, and Type III, metadynamic/dynamic recrystallization. How much of each behavior is generated through the cross section through the production influences the final transformed microstructure and corresponding mechanical properties and shape performance. This paper will discuss the three behaviors, how they are generated, how to identify which behavior is occurring through modeling or actual mill data. Actual examples from production will be discussed.

Aug 16, 2017

By McKee DJ

Many workers have observed an inverse relationship between final concentrate grade and valuable component recovery achieved by a flotation circuit, i.e. an increase in either grade or recovery may only be achieved at the expense of the other. The relationship is termed a "grade-recovery" curve and, in theory, limits the separation obtained by the circuit. However, circuit surveys in a nickel concentrator indicate that the operating "grade-recovery" curve of a circuit is not only determined by the nature of the ore and the circuit operating conditions, but also by the circuit design, particularly in terms of stage capacities. The surveys show that different capacity circuits can produce different operating curves for the same ore, and that capacity reallocation between stages has the potential to improve both grade and recovery. In particular, the relationship between circuit design and operating curve position is shown to be a function of the circulating loads generated by the circuit design, balancing the beneficial effects of recycling material against the proportion of plant capacity consumed by recycling.

Jan 1, 1986

By Robert H. King

An analysis of low-voltage shielded trailing cables is performed to develop a method for calculating the differences in operating costs between shielded and non-shielded cables. Two types of shield constructions are considered (SH-C and SH-D) for the three major underground coal mining methods. Data from laboratory and in-mine testing are presented in addition to an analysis of safety benefits. Recommendations for further investigations are proposed. Example calculations with sensitivity analyses are presented. Recommendations for further investigation include costs impact considerations.

Jan 1, 1980

By B. Genc

Improving student success rates without compromising the quality of graduates is one of the biggest challenges expanding university programmes are facing in South Africa. By establishing a new Mine Design Laboratory (MDL) for higher learning in Mining Engineering, the School of Mining Engineering at the University of the Witwatersrand (Wits Mining) has achieved one of the important goals in its five-year strategic plan, i.e. to improve throughput in all years of study. Although the establishment of the laboratory has been a costly exercise, results so far have shown an improved success rate in most subjects taught in the facility. This paper outlines the design and equipment of the laboratory, the facilities incorporated, a comparison with the old laboratory, and the performance of students?all of which indicate how important it is to have proper facilities to improve the teaching of, and learning by, large classes. Through this initiative, Wits Mining has taken an important step that will contribute to addressing the skills shortages in the mining industry.

Jan 1, 2012

By H. Huang, R. N. Gow

"The reactivity of an enargite mineral electrode was investigated spectroelectrochemically under conditions typically found in alkaline sulfide leach solutions, with pH 11-13 and Na2S additions of 50 and 250 gL-1. A bulk enargite electrode was cycled between 0 and -1,000 mV for each set of solution conditions. Raman spectroscopy was used to determine and compare surface formations against species in mass-balanced EH-pH diagrams generated using STABCAL. Previously, it was determined that arsenic could be selectively leached under alkaline conditions at an average solution potential of -300mV, across the pH range 11-13. Operating under such conditions allowed for the selective leaching of arsenic with elemental sulfur formation. From several of the voltammograms obtained during this current testing, the formation of elemental sulfur appeared at increasingly reducing conditions with increasing sulfide concentration. At high concentrations, copper started to dissolve, possibly as a bisulfide complex, reducing the selectivity of the leach, unlike previous studies. However, the presence of the higher sulfide concentration is also anticipated to prevent passivation by consuming any surface formation of elemental sulfur. This study provides insight into the operating parameters of alkaline sulfide leaching in regards to the selectivity of arsenic leaching, as well as guidance for control of reagents and solution potential and, of course, the need for water treatment afterwards.IntroductionEnvironmental limitations on the pyrometallurgical processing of arsenic-bearing concentrates have forced operations to consider other solutions. Attempts to hydrometallurgically process enargite (Cu3AsS4) fall into two categories: the co-dissolution of arsenic and copper under acidic conditions, and the selective leaching of arsenic under basic conditions. The authors believe that the selective leaching of arsenic is more amenable because it produces a solid copper phase, preferably chalcocite (Cu2S) or covellite (CuS) that could then be processed using conventional methods already in place in the copper and gold industries. Potential leaching methods include alkaline sulfide leaching (Achimovicovica et al., 1999; Anderson and Twidwell, 2008a,b; Tongamp et al., 2009 and 2010), hypochlorite leaching (Vinals et al., 2003; Curreli et al., 2005; Mihaljovic et al., 2007), ammoniacal leaching (Gajam and Raghavan, 1983), and acid leaching (Gow et al., 2014b) with or without fine grinding to mechanically activate the enargite surface and increase normally slow leach reaction kinetics (Achimovicova et al., 1999; Balaz et al., 2000; Balaz and Achimovicova, 2006). In this study, the reactivity of enargite under alkaline sulfide leach conditions was examined."

Jan 1, 2015

By Francis Flynn

MANY excellent papers, descriptive of the milling and smelting of every kind of commercial ores, the refining of virgin metals, the casting into various shapes demanded by the trade, the rolling into shapes best suited to the factory machinery and the making of composition alloys to suit every requirement have been issued by the many technical societies dealing with non-ferrous metals. It is a wonderful collection of papers, of which the mining and metallurgical engineers may well be proud, but strange as it may seem, metallurgists in general appear to take the stand that when they have delivered suitable alloys to the foundry and rolled products to the factory their duty to write papers has ceased, at least in so far as the A. I. M. E. is concerned. Still we read in the daily papers that the mining companies are absorbing metal-manufacturing industries. The purpose of this paper is to describe the reclaiming of non-ferrous scrap metals at manufacturing plants, taking as an example the automobile industry.

Jan 1, 1929

By M. Gholinejad

Applying non-explosive expansion material (NEEM) is one of the safest methods for rock fracturing, especially in a hard rock quarry. An experimental study was conducted to determine the pressure exerted by NEEM in a hole, which is necessary for analysing rock fracturing, particularly in a numerical modelling. Stress distribution was developed in a thick-wall cylinder in order to measure the tangential strain on the external boundary. In the experiments, nine pipes of different materials and varying diameters were selected and then loaded internally with a general type of NEEM. Through electrical strain gauges, the tangential strains were recorded on the external boundary of the pipes. The results obtained from these tests and existing data from previous researchers were utilized for the statistical analysis. A new experimentally-derived formula is proposed for determining the pressure exerted by NEEM by multiple parameter regression with a high correlation coefficient. The proposed model has a nonlinear form with three independent parameters i.e. the hole diameter, the time, and the modulus of elasticity of the material.

Jan 1, 2012

By P. Kim, M. Tangstad, T. Larssen, R. Kawamoto

The reduction rates of MnO and SiO2 were investigated for various charge compositions. The empirical activation energies of MnO and SiO2 reduction from SiMn slags were calculated between 1500 and 1650 °C under CO atmospheric pressure. The amounts of metal produced at different temperatures were compared, and the Arrhenius plots were described for each slag A, slag B and synthetic slag, which shows that the raw material have significant influence on the reduction rate. The rate of Mn-produced in slag A was faster than slag B despite of the relatively lower driving force. The lower rate constant in slag B implies that other kinetic factors, such as viscosity, affects the reduction rate. The estimated activation energies of MnO were 920, 304 and 975 kJ/mol MnO for slag A, slag B and synthetic slag, respectively. The rates of Si-produced were similar and slow for all slag types. However, the different activation energies of SiO2 between industrial ores and synthetic materials implied that the trace elements can have catalytic effects toward SiO2 reduction in SiMn slags. The estimated activation energies of SiO2 reduction were around 800 kJ/mol for slag A and slag B.

Mar 1, 2017

By G. Zain, Abdel-Zaher M. A. Abouzeid, Y. S. Mustafa, A. A. S. Seifelnassr

The main forces acting on minerals in conventional size reduction units are compression, impact, attrition, and/or abrasion. Usually a combination of these forces shares the breakage action of the minerals with one or more of these forces dominating the breaking action, depending on the machine used. The present work concentrates on the behavior of quartz when stressed with compression force in a confined piston die. Several size fractions within the size range minus 10 mm to plus 0.85 mm were compressed in the piston die. The measured parameters are compression load, bed thickness, displacement as a result of compression, rate of displacement, and the size distribution of the products. It was found that the size distributions are, to some extent, different from those produced by the ball mill or the high-pressure roll mill. This is mainly because of the differences in the type of the acting forces in each case. It was also found that the cumulative weight of the distributions is reasonably normalizable with respect to the median particle size of the product. The specific energy expended is inversely proportional to the median size of the products, and the reduction ratios, xf/xp, are directly proportional to the applied compression force, and hence, to the specific energy expended. A simple model is suggested for predicting the particle size distribution as a function of the expended energy. The calculated values of the size distributions match fairly well with the experimental values, except at the very low energy levels, where most of the energy expended is consumed in the rearrangement and packing of the particles in the confined space with little or no breakage.

By Griffith. F. E., Glei

"INTRODUCTION For many years protective grounding of electrical equipment has been advocated as a means of safeguarding equipment against damage and of minimizing shock hazards to persons. Several codes are in effect covering in considerable detail the items to be observed in obtaining effective grounding in and about industrial plants. Although the coal-mining industry does not have a comprehensive code of its own covering the grounding of electrical installations, a number of States and individual coal-mining companies have issued codes, standards, or rules that include certain requirements with reference to grounding. As early as 1916, 4/ and again more recently, 5/ the Bureau of Mines recommended grounding, particularly as a means of preventing shock to men working on or around electrical equipment.It is common knowledge among electrical engineers of public utility and mining companies that connecting a wire from the frame of a machine to a rod or pipe driven into the earth does not necessarily assure desired protection of surface equipment. In fact, it has often been found necessary to use several interconnected rods and to treat the surrounding earth with salt or other chemicals before the connection to earth would have sufficiently low resistance to give satisfactory results. Even these expedients have not produced the desired results in some localities. It has also been found that ground connections initially having a low resistance may attain high resistance during some seasons of the year. In spite of such difficulties with surface equipment, it has sometimes been assumed that a mining machine resting on the floor in a coal mine is grounded by virtue of its contact with that floor. It has also been assumed by persons endeavoring to comply with grounding requirements that a peg or rod driven into the mine floor would provide a sufficiently low-resistance contact with the earth to be satisfactory as an electrode for connecting the grounding wire from frames of equipment. That both assumptions may be wholly untrustworthy has been proved by the authors in actual tests with underground machinery."

Dec 1, 1943

By H Turrer, M Badawi, R Belissont, Y Foucaud, E Kleiderer, L Southavy, J Mesquita, Y Basselin

The Mont Reed iron ore deposit, owned by ArcelorMittal, is situated approximately 140 km southwest of the Mont-Wright mine in the southern region of the Labrador Trough, Canada. Acquired by Québec Cartier Mining (QCM) in the 1960s, the Mont Reed mining property has remained unexploited due to the complex nature of the ore in the area. However, during the last years ArcelorMittal’s R&D team has been dedicated to developing a process to beneficiate the Mont Reed ore and produce high-quality pellet feed suitable for direct reduction furnaces. Extensive research revealed that achieving a good liberation degree of particles required grinding the material below 75 μm (P80 of 53 μm). To find the most effective technology for this task, a detailed comparison between ball mill and vertical stirred mill grinding was conducted. Both grinding technologies underwent detailed testing in bench-scale experiments. The ground products were comprehensively characterised, including size distribution analysis and chemical analysis per size fraction. Additionally, liberation analysis was performed using an automated scanning electron microscope (SEM). To determine the grinding specific energy, a method previously developed at Samarco (Brazil) for fine grinding of iron ores was employed. Furthermore, magnetic separation and flotation tests were conducted on the ground products. After a thorough evaluation of all the results, it was observed that both ball mill and vertical stirred mill grinding produced samples with similar physical characteristics. However, the vertical mill demonstrated higher efficiency in grinding the material. To conclude the study, an economic evaluation was conducted for both options considering various factors. Overall, ArcelorMittal’s R&D team’s dedicated efforts have brought them closer to unlocking the potential of the Mont Reed ore deposit and paving the way for its future utilisation to the production of high-quality pellet feed.

Sep 18, 2023

By D. L. Everhart

The search for new deposits raises two important questions: Where did the metallic ions that formed the orebodies come from? What processes and geologic factors were involved in ore replacement? A review of the wide geological variety of recent uranium discoveries tells how these questions are being answered. SOONER or later intelligent exploration for uranium leads to these questions: Where did the metallic ions that formed the orebodies come from? What processes and geologic factors were involved in ore replacement? These matters, of course, make a big difference in how best to look for orebodies. Before these questions are discussed it might be well to point out other factors bearing on the subject. The whole business of uranium exploration is only a little over ten years old, participation by the public is only about six years old, and real interest and activity by more than a few large mining companies has arisen only in the past two or three years. Throughout this short period, uranium exploration has been affected by the unique influences of necessary security measures and by division of the overall job into individual projects by a large number of specialists in diverse fields. This has meant that a normal interchange of information on the nature of uranium deposits has really only just begun. Compared to the vast amount of published studies on iron, copper, lead, zinc, and gold deposits over the past 50 to 75 years, current knowledge of uranium deposits is in its infancy and much of the pertinent information is still scattered about in a number of unpublished sources. The volume of reports on all phases of uranium exploration is now beginning to mount at a remarkable rate, and geologists with widely varying specialized backgrounds in uranium geology are engaging in spirited debates over the origin of uranium and the relative importance of geologic controls of various deposits. One of the most interesting features of known uranium deposits of the world is the wide variation, see Table I, in character and geologic environment. It should be noted that many types became prominent during 1953. The davidite-bearing veins of Radium Hill, South Australia, are almost unique, although the same mineral occurs in a different kind of deposit in Mozambique. Recent studies indicate that brannerite disseminated in the granite near Cracker&apos;s Well, South Australia, may soon constitute uranium ore. Basalt has been added to the list of favorable host rocks in the Northern Territory of Australia. Basalt is also the host of the pitchblende veins of the Martin Lake deposit, Beaverlodge district, Saskatchewan. The truly remarkable rich and extensive Steen deposit near Moab, Utah, is of the uraninite-vanadium oxide type. Secondary hydrous uranium arsenates and phosphates constitute the uranium minerals in the disseminated deposits of the Wind River Basin, Wyo., a new district discovered in the summer of 1953. Uranium minerals in shales adjacent to fractures were newly reported in New Mexico and several other parts of the world during the year. The well-known important uraninite dissemination in the Rand conglomerates of South Africa has a counterpart, as discovered in the summer of 1953, in the Mississagi quartzite and conglomerate of the Blind River district, Ontario. Gunnar deposit of the Lake Athabaska district, Saskatchewan, consists of uraninite in both granite and sedimentary gneiss beneath a granite cap, and large new orebody of the Eldorado Co. in the same general area follows a preferred stratigraphic horizon in schists. Uranium is, generally speaking, a very soluble and ubiquitous element. It occurs in at least two valency states and for this reason is not easily tied down in natural solutions. As Gruner&apos; has pointed out, it is probable that uranium starts in the hexava-lent state in nearly all solutions instrumental in its transfer. It is believed that under oxidizing conditions the uranium moves in solution as the uranyl ion, UO. In solutions ranging in pH from 1 to 5, the uranyl ion is most commonly in association with

Jan 1, 1955

By Rick A. Croote

The objective of the Cerrejon Coal Project is to mine and export a minimum of 15 million metric tons per year of bituminous coal from the Guajira Pennisula in Colombia, South America. Major components of the project will include an open pit mine, 150 km railroad, marine terminal for storage and shipping, and accommodations for the support personnel. This paper primarily reviews the coal handling facilities at the mine and port which will include crushers, conveyors, silos, stacker/reclaimers, and a shiploader. Of special interest is the design concept for unloading bottom-dump railcars, a programmable controller control system with automatic stacking and reclaiming, a linear-type shiploader, and 2.4m wide conveyors running at 5 m/sec.

Jan 1, 1983

By F. du Breuil

BCR National Laboratory (formerly Bituminous Coal Research, Inc.), under a USBM con­tract (originally with the Department of Energy), monitored the installation and operation of a computer-based belt-monitoring and control system at the Barnes & Tucker Coal Co. Mine No. 20, Ebensburg, PA. The system installed was the National Coal Board&apos;s Mine Operating System (MINOS) coal transport monitoring and control system. The program objec­tive was to document (1) the installation requirements for a conveyor control system, (2) the operating experience with the system, and (3) the impact of monitoring and control on mine operation. Analysis of the system operation indicates that monitoring and control did improve belt availability significantly, and reduced downtime associated with belt delays. Economic analysis showed the increased belt availability would potentially result in significant production increase, and, therefore, excellent payback on the initial investment. The system performed satisfactorily, was well accepted by the work force, and did not increase the maintenance workload.

Jan 1, 1987

By AIME AIME

THE first meeting" of the Iron and Steel Division was held Tuesday afternoon, Feb. 17, with nearly 100 men present and C. B. Murray as chairman. This was a round table discussion of iron ore beneficiation and of its relation to blast-furnace operations, and only one paper was presented, by Clyde E. Williams. Mr. Williams discussed the future of the Lake Superior district in its relation to the iron and steel industry. He stated that although estimates had shown that the total life of the present known iron ore reserves of the Lake Superior district was 20 to 30 years and that many believed that as a result of this depletion foreign ores would be brought to the Atlantic Seaboard, thus causing a displacement of the steel industry to the East, he believed that the Lake Superior district would continue to be the important producer of iron ore used in this country for decades beyond the predicted time before the exhaustion of the present known reserves. He described the three general types of ores that required concentration and pointed out the needs for research and the proper methods to be used in processes for the beneficiation of these low-grade materials. He discussed the effects of fine concentrates and the use of agglomerated ores in the blast furnace. This general summary led to interesting and valuable discussion on the various economic, ore-dressing, and blast-furnace problems in large-scale development of beneficiation. Perry Harrison described recent developments in sintering and the properties of iron ore sinter. T. B. Counselman and W. H. Coghill discussed the merits of classification of iron ore previous to tabling. Robert Faulkner and J. E. Little described the beneficiation plant of the Bethlehem Steel Corporation.

Jan 1, 1931

By Erik Álan de Arruda Vieira

O início de operação da companhia Siderúrgica do Pecém foi um grande marco para a tecnologia e economia do estado do Ceará. O alto-forno é parte principal da área denominada “Redução”, onde ocorre o processo de transformação das matérias primas (carvão, coque e minério de ferro) no produto ferro-gusa que é a principal matéria prima para o processo de fabricação de aço. A robustez dos equipamentos permite larga capacidade produtiva e por isso ainda é a melhor tecnologia capaz de atender à demanda mundial no consumo de aço. Este trabalho apresenta o plano de início de operação e estabilização do processo do alto-forno, denominado “Início de Sopro”, apresenta os parâmetros definidos para o direcionamento operacional, os índices de performances que balizaram a assertividade no atendimento às metas planejadas. Neste trabalho é possível visualizar os procedimentos para as etapas de comissionamento dos principais equipamentos, a curva de elevação de produção, o atendimento às especificações conforme mensuradas no projeto e os resultados obtidos que sustentaram o sucesso do evento.

Oct 30, 2017

By Mohini Patel, Jahnavi Parmar, Pranav R. T Peddinti

Expansive clays pose a variety of geotechnical problems. Although the admixture stabilization is proven to address their problematic swelling and shrinkage characteristics, the influence of unsaturated condition on the engineering performance of these soils needs further research attention. In addition, highly saline soils with high organic content would further alter their performance. A similar soil stratum was encountered at the Gulf of Cambay, Bhavnagar district, India. High salinity in the in-situ expansive soil of basaltic origin and the prevailing unsaturated condition, enforces the engineers to look out for possible soil treatment methods. In this regard, the present work attempts to analyze the unsaturated behaviour of this soil when fly ash is used as an admixture. A comparative study for stabilized and unstabilized mixes is performed in terms of their unconfined compressive strength, electrical conductivity, swell characteristics and California Bearing Ratio.

May 1, 2022

Nine case studies are presented to illustrate how risks can be, minimised or quantified during pit optimisation, utilising Whittle Four-D software. Each case study covers a specific problem that has been encountered from a wide variety of pit optimisations. Case A: Maximising profits when the tenement owner is paid a royalty on tonnes processed. Case B: Allocating product prices, rather than a single commodity price during optimisation. Case C: Quantifying processing costs that are affected by penalty elements in the ore. Case D: Exploration expenditures below current pits can be quantified through the use of simulation techniques. Case E: Alternative strategies can be quantified when pits are restricted by tenement boundaries. Case F: Relocation of mine infrastructure that requires large capital expenditures, can be simulated by allocating costs to an area during optimisation. Case G: Evaluating alternative corporate strategies during pit optimisation. Case H: Sensitivity analysis for price, processing cost and mining cost. Case I: Quantifying the advantages of using additional mining capacity during the early periods of mining.

Jan 1, 1994