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By Rollin A. Slater

The bulk materials handling industry has served silently for years as the skeleton structure and often the central system of nerves and nourishment for the body of basic production industries. During the past two decades, this body has undergone substantial growth and mutation to meet the surging demands of our national economy for more and better products. The steel industry has been prominent in this phenomena and plants of the sixties are as unlike the second war vintage as our current crop of basketball players differ from their fathers. Steel has kept pace with spiralling demand by innovation which has resulted in new processes and improved designs which generally yield greater production from fewer units. The supporting industry of materials handling has likewise improved its techniques and currently has a new stronger generation of equipment to perform its necessary supporting function. It has been my fortunate experience to have been instrumental in the creative stages of several new steel mills which are currently in conceptual design or actual construction. Drawing upon exerpts from this experience, this paper will describe a basic approach to the selection and application of modern bulk materials handling systems to an entirely new steel plant. Specific details of past work are not available for publication, therefore, the plant described herein is a composite of ideas and will be the new plant of the Hypothetical Steel Corporation which will be located on the lower shores of the Great Lakes.

Jan 1, 1967

By Jess W. Smith

The carbonaceous Monkemeyer sandstone member of the Creede Formation on Bachelor Mountain hosts alteration and mineralization which contrasts with other silver deposits of the Amethyst system. More than 20 million ounces of silver are contained in disseminated mineralization in the volcaniclastic conglomerates and sandstones. Hydrothermal fluids entered the Creede Formation directly from the Amethyst fault system and mixed with flowing meteoric ground waters trapped beneath the Monkemeyer sandstone. Portions of the basal rocks of the Creede Formation were argillically altered by more dense acidic fluids generated by boiling. The carbonaceous base of the Monkemeyer and much of the conglomerates below were mineralized and well silicified. Deposition of the mineralization resulted from two processes: (1) reduction by carbon in the Monkemeyer, and (2) fluid mixing in the conglomerates. Monkemeyer mineralization is confined to the carbonaceous basal material and silver content is relatively consistent. Silver is contained in acanthite which is commonly associated with traces of galena, chalcocite, covellite and sphalerite. Fluid mixing and mineral deposition in the poorly sorted conglomerates was controlled by the highly variable porosity and permeability. Anomalous silver contents are dispersed throughout a large volume of conglomerates but zones of higher silver content reflect the crude layering of the conglomerates. Acanthite is finely disseminated in pore spaces and partly replaces some detrital magnetite. other metallic minerals are rare in the main zone of mineralization.

Jan 1, 2013

By Barbara J. Arnold

A coal's size distribution, clay content and moisture content can affect its handling behavior, but the combined effects of these properties and the effects of other properties are not known. Research underway at CQ Inc.' s (formerly EPRI' S) Coal Quality Development Center (CQOC) and at Iowa State University (ISU) will answer these questions as part of a four-year project to develop a coal handleability index for utilities to use when specifying coals. This paper will present preliminary data from the first year of the project, which focused on obtaining data on the chemical and physical properties of various coals and their measured handling properties. Additionally, size, ash and moisture analyses and shear test data for several coals used at one power plant will be presented along with correlations between these physical and chemical properties and the measured handling properties. These data lead to the conclusion that, while moisture content-is the most important variable, the amount of -325M (-0.044 mm) coal fines is a significant factor in determining coal handling behavior.

Jan 1, 1990

By M. Leroux, S. R. Rao, J. Kim, V. Gervais, J. A. Finch, G. Labonté, N. Macminn, M. Ounpuu

Collectorless flotation of sulphide minerals from Lyon Lake ore (Mattabi Mines Ltd.) has been studied both in the laboratory and plant. Among the four major minerals chalcopyrite showed the greatest response to collectorless flotation, followed by galena. Flotation of sphalerite and pyrite was minimal. Collectorless flotation was influenced by pulp potential and pH. Experiments using different gas compositions showed collectorless flotation was promoted when the pulp potentials were greater than about 0 mV (SCE). The study of the effect of depressants showed that SO2 at pH < 8.0 depresses both galena and chalcopyrite but at pH 9.5 flotation of chalcopyrite recovers. Use of NaCN preferentially depressed chalcopyrite compared to galena. Preliminary results from plant tests at Mattabi Mines Ltd. confirm that collectorless flotation occurs and that it is preferential for chalcopyrite and to a lesser extent galena. Practical implications of collectorless flotation in plant practice are discussed. A critical factor will be silver recovery.

Jan 1, 1989

By A. J. Monhemius, R. G. Reddy, G. W. Warren, E. Peters

Thermodynamic solubility of chromium in pickling solutions (i.e., HF- HN03-H2O solutions) was determined as a function of HF and HNO3 acid concentrations at 298K. Pure Cr, AISI type 316 and 416 stainless steel were used in this study. The results showed that the solubility of Cr increased with increase in the concentrations of HF and HNO3 acids in solutions. The solubility of Cr increased in the order of pure Cr > 416 SS > 316 SS. The theoretically calculated Cr solubility data were in reasonable agreement with the experimental data.

Jan 1, 1993

By DEBASHISH MISHRA, SOMU MANDAL, ASFAR MOBIN KHAN, JAI KRISHNA PANDEY, NIROJ KUMAR MOHALIK, SANTOSH KUMAR RAY

Coal is a low-cost fuel with high calorific value. Statistically, the global coal mining industry suffered 12,489 fatalities in 104 reported mining accidents from coal dust explosions during 1900 to 2020. This review article discusses the occurrence, mechanism and explosibility parameters of coal dust explosions and presents a literature survey of the laboratory and computational fluid dynamics (CFD) simulation methods of studying them, as well as a comparison of the two methods.

Feb 1, 2023

By W. S. Sanner

Experiments were conducted to determine the quantity and purity of ultraclean anthracite that could be prepared in the laboratory, using conventional separating techniques. A low-, a medium-, and a high-volatile anthracite were studied. Specific gravity separation followed by grinding, screening, and refloating at lighter specific gravities yielded small quantities of material purified to 1.0 percent ash, as follows: From low-volatile anthracite, 0.7 percent; from medium-volatile coal, 1.0 percent; and from high-volatile coal, 2.3 percent. The reduction in ash had no appreciable effect on the volatile matter or sulfur content of the coal. The limited quantities of material containing 1.0 percent or less ash obtainable indicate that if ultraclean coal is desired, a practical approach should include the processing units as an integral part of a conventional dense-media washing plant.

Jan 1, 1968

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck, Y. Zheng

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control.

Jan 1, 2017

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck, Y. Zheng

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control.

Jan 1, 2018

By Sylvain Duchesne, Claude Bazin, Robert Grant

Grinding simulators are now widely available to assist in the selection of circuit operating conditions or flowsheet designs that yield a given product size distribution. These simulators do not inform of the impact of the grinding product size distribution on subsequent flotation stages. This paper presents a method to predict the effect of fineness of grind on a flotation bank operation. Application of the method is illustrated with data from two Canadian concentrators.

Jan 1, 1995

By M. Sengupta

Vast reserves of oil shale occur in the Green River formation in Colorado, Utah, and Wyoming. The room-and-pillar mining method is applied to flat-lying sedimentary deposits. Important elements in mine design include mine orientation, vertical location of the mining zone, selection of roof horizons, room span and pillar size, barrier pillar size, panel dimension, and layout of mains and submains.

Jan 1, 1988

By Lawrence K. Nordell

The selection of belt conveyor drive systems (*) is the subject of ongoing investigation. Frequently this choice has been governed by an incomplete perspective on the major considerations. A more comprehensive and objective approach is desirable. This paper presents additional factors which hopefully will broaden this perspective. BACKGROUND Conventional belt conveyors are powered by electric or electro-mechanical drives(*) mounted at the conveyor&apos;s head, tail, intermediate return span, or a combination of these (Fig. 1). A list of the drives reviewed is given in Table I. The following are main elements influencing the selection of the drive system: 1) dynamic characteristics, 2) economic factors such as capital cost, plant spares compatibility, reliability, availability, maintainability, and 3) environmental constraints. The principal dynamic characteristics of concern are the reactions of belt forces generated by the drive system during starting of the conveyor. Another attribute for consideration is the application of multiple driven pulleys used to 1) lower the conveyor&apos;s belt tension requirements, 2) increase the expected tonnage throughput, allowing for possible drive component failures, and 3) increase the plant spares flexibility related to the drive assembly.

Jan 1, 1977

By S. Nowosad, O. Langefeld, A. Godge

Pumped storage power plants are one of the options to store the fluctuating production of electric energy from renewable sources in a sustainable manner and is able to provide Europe with the opportunity to overcome the effects of climate change. However, due to the extensive land use required when planning the water reservoirs, several projects have been declined after social conflicts raised, even in Germany. Nonetheless, after the flooding and drought periods in northern Germany, the catastrophic floods of July 2021 in south west Germany, the country’s need to decrease its dependency on import of gas and energy supply, and the energy transition goals set for 2030 and 2050, it has become clear that the implementation for water reservoirs must increase in the coming years, whether above ground or underground. Furthermore, not only Germany is interested in the use of underground cavities for water and energy storage, other European countries as Sweden are currently developing studies and solutions to bring this concept soon to reality in Europe. This article introduces the systematic approach for planning and designing large underground cavities for water reservoirs as a sustainable energy transition approach and a climate change response by showcasing the process of selection and results of the “Energy and Water Storage Harz” (EWAZ) research project. Additionally, the results of the evaluation of the effect of implementing the selected underground and surface infrastructure into the current water management system in the region is presented. Finally, the different possibilities evaluated for the underground cavities within the project and the technical challenges involved are be discussed.

Feb 1, 2023

By Keh-Jian Shou

"This study adopts and analyzed a shield tunneling case in Taiwan, with a diameter from 5.25m to 6.70m and the smallest radius of curvature 100m, which was constructed in gravel formations as well as a vibration sensitive area. In this case study, a vibration monitoring plan, comprising the sensors inside the shield machine and on the surface, was proposed and performed to provide the vibration data during the construction. In this project, the major vibration reduction considerations were increasing the open ratio of the cutter head (to reduce the cutting function) and reducing the rotational speed of the cutter head. The results of the construction suggest the appropriateness of the above considerations. The findings could provide suggestions to the other similar shield tunneling cases. INTRODUCTION Underground vibrations during shield tunneling are typically isolated and absorbed by the soil. However, a portion of these vibrations may disseminate to the surface. These vibrations are considered micro-vibrations, which generally do not pose a threat to surface structures, and are thus seldom the focus of research. The present project was located in the Hsinchu Science Park where shield excavation bypassed numerous high technology manufacturing plants (e.g., wafer manufacturing plants). The vibrations generated by shield tunneling may affect the vibration-sensitive manufacturing equipment and instruments in these plants, and induce problems in manufacturing processes. Therefore, research to comprehensively understand the characteristics and potential influence of such vibrations is essential. To clarify the characteristics and potential influences of vibrations generated during shield tunneling, the vibration level in the excavation of the Taoyuan International Airport Access (TIAA) Metropolitan Rapid Transit (MRT) Project was examined, as it possesses similar excavation conditions to the present project. The parameters collected from relevant tests were provided as a reference to the firms along the excavation route of the present project to explain the effects of vibrations, and to relevant units for shield machine selection and project execution. No yield problems resulting from shield machine induced vibrations were reported by the firms, and the vibration levels measured in the present project were comparatively lower than those in the TIAA MRT Project. Because the related literature is scarce, this study aims to analyze the collected measurement data and provide suggestions on shield machine selection or designs. Such that we can more properly evaluate and control the impact of shield tunneling induced vibrations in similar projects."

Jan 1, 2016

By A. A. Zatout, G. H. Sedahmed, T. M. Zewail, M. H. Abdel-Aziz, B. S. Ibrahim, E-S. Z. El-Ashtoukhy

In this work, the possibility of intensifying the cementation process in stirred vessels was studied by using the perforated baffles as turbulence promoters; the cementation reaction of Cu+2 on Zn was selected as a model. Zn was used in the form of a sheet lining the inner wall of an agitated vessel. Parameters considered are initial concentration of Cu+2, solution temperature, impeller rotation speed, and impeller geometry. Within the present range of parameters studied, the rate of cementation was found to increase with increasing initial concentration of Cu+2, solution temperature, and impeller rotation speed. At the same rotational speed, a flat turbine gave a higher rate of cementation than a 45° pitched turbine. The present suggested that baffles’ geometry gave superior performance in terms of mass transfer of copper cementation compared to the conventional baffle geometry. All parameters that affect the rate of cementation were correlated in the form of dimensionless equations suitable for the design and performance prediction of the agitated vessel. Potential applications of the obtained results in the field of hydrometallurgical processes and wastewater treatment were discussed.

Jan 12, 2021

By J. W. C. Wong, T. A. Songberg, S. D. Miller, J. J. Jeffery

Natural degradation of cyanide has been widely used by the gold mining industry for removal of CN from cyanidation processing wastes. However, little documented study has addressed the decay and fate of cyanide within residue storage ponds. 'fhis paper describes a study on the cyanide behaviour in a residue storage pond at the Boddington Gold Mine in Western Australia. Depth profile samples were collected from the active residue storage to determine the distribution of CN forms and complexing metals throughout the settled residue.

Jan 1, 1991

By Daniel F. Meyer, William C. Paschen

INTRODUCTION The problems involved with moving millions of tons of rock are being addressed by nationally recognized tunnel contractors who have converged in Chicago over the past 5 years. This wealth of expertise has been needed to meet the risk and challenge of constructing the world&apos;s largest network of underground tunnels which in turn has required a dramatic advance in the art and science of tunneling. These pioneers, through innovation, adaptation, and hard work, have eliminated the one major concern of The Metropolitan Sanitary District of Greater Chicago - how to move 8 million tons of rock. The Metropolitan Sanitary District of Greater Chicago (MSDGC) serves 122 municipalities covering 866 square miles in Cook County, Illinois. Of these cities, towns, and villages, 53 have combined sewer systems. On an average of once every four days, these systems overflow about 4 million gallons of combined sewage and rainwater into the area&apos;s rivers and canals. The overflows occur at approximately 640 outfall locations of which 10% are owned by the MSDGC, with the remainder of the points belonging to various other municipal bodies. All those who own these "point" sources of pollution are in violation of Illinois State and Federal regulations. To enable its member municipalities to come into compliance with State and Federal law, the MSDGC is implementing its Tunnel And Reservoir Plan (TARP). TARP is a regional solution to the problem of combined sewer overflow in the metropolitan Chicago area. TARP will greatly reduce the pollution of area waterways by intercepting the combined sewage and rainwater carried in the existing sys-

Jan 1, 1981

By R. J. Andreini

Solvent extraction is widely used in hydrometallurgical processing of uranium for purification and upgrading leach solutions prior to recovery of metal values. Conventional solvent extraction processing utilizes mixer-settler units to achieve mixing of the aqueous and organic phases. Use of mixer-settlers permits continuous treatment of feed, but the processing rate is restricted by the time required for phase separation after mixing. Because of the high-shear type mixing used in a mixer settler a portion of the organic phase becomes mechanically entrained in the aqueous resulting in loss of extractant. For this reason application of mixer-settler units is often limited by the settling area required for phase separation, especially for systems where high volume throughputs are desirable or necessary. Several alternatives to mixer-settler operations involving the use of column extractors have been proposed. Packed columns (1-2), in which organic and aqueous phases are fed countercurrently, utilize packing materials similar to those used in gas absorption or distillation columns. Extraction columns utilizing rotating(3-5) or reciprocating elements(6-7) to achieve mixing have also been developed. Van Dijek(8) originated pulsed columns, in which mechanical or air pulsing of the phases enhances the mixing in the vessel. Each of the above column processes involve varying degrees of mechanical complexity which may lead to operational difficulties.

Jan 1, 1975

By J. B. Moritz

From the beginning, man has concerned himself with the task of controlling the elements and forces about him so as to provide a better and easier life. In the accomplishment of this task, he is required to utilize in the best way possible the resources which are available to him. In many cases, the available resources must bee refined before they are in a useable form. Many products in the mining industry fall into this category, as some form of refinement is generally needed to produce a saleable product. Over the years man developed more efficient ways of extracting the resources from earth through the use of electrical and mechanical devices. A reduction in manual labor, which is a by-product of increased efficiency through machines, has also been enjoyed. The combination of man&apos;s senses and new devices has also enabled man to reach a high level of control in the refinement process. Control of a process through machinery and man&apos;s senses has been termed an "art." Until recently man&apos;s senses (sight, feel) were the only method available for making measurements simply because suitable measurement devices (instruments) were not available. Even today some items cannot be measured and man&apos;s senses must be used. However, the development in our instrument laboratories tends to indicate that time will eliminate this. In recent years, control of many processes has been reduced to a science and part or all of the art eliminated. This does not imply that process art should be degraded; however, when a process is reduced to a science, uniformity of the product from day to day is attained. Decreased processing time and more efficient use of additives and raw materials are other benefits that result from control of a process when it is reduced to a science.

Jan 1, 1965

By A. Arik

The accurate estimation of mining-block grades continues to be a challenging task for ore reserve practitioners. The estimation method used and the variability of the mineralization in the deposit are two factors that affect the accuracy of the estimates. The objectives of this study are to determine how different estimation methods perform on a given deposit and to determine the impact that the nature of the mineralization has on the results. A comparison of several estimation methods for prediction accuracy is performed based on conditional simulation results.

Jan 1, 2002