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By William L. Husk

Stockpiles have always been a necessary part of coal mining except, perhaps, when a person was mining only for the needs of his family from a seam on his home place or coal mined for the use of a small hamlet and carried to each man's house as it was mined. Then it may have been stockpiled at each man's place for several days or on the village common. Mining with this limited production required waste stockpiling. Stockpiling of the products of coal mining, both coal and waste material, has always been a necessity. Very little coal has ever been moved directly or immediately from the working face to the point of consumption and burned. It has always been expedient to stockpile the coal some- where and store the waste.

Jan 1, 1981

By J. D. Noll

An effective technique to minimize miners? respirable dust and diesel exposure on mobile mining equipment is to place mine operators in enclosed cabs with designed filtration and pressurization systems. Many factors affect the performance of these enclosed cab systems, and one of the most significant factors is the effectiveness of the filtration system. High-efficiency particulate air (HEPA)-type filters are typically used because they are highly efficient at capturing all types and sizes of particles, including those in the submicron range such as diesel particulate matter (DPM). However, in laboratory tests, minimum efficiency reporting value (MERV) 16 filters have proven to be highly efficient for capturing DPM and respirable dust. Also, MERV 16 filters can be less restrictive to cab airflow and less expensive than HEPA filters. To verify their effectiveness in the field, MERV 16 filters were used in the enclosed cab filtration system on a face drill and roof bolting mining machine and tested at an underground limestone mine. Test results showed that DPM and respirable dust concentrations were reduced by more than 90% when the cabs were properly sealed. However, when the cab door was opened periodically throughout the shift, the reduction efficiency of the MERV 16 filters was reduced to 80% on average.

Feb 1, 2014

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2010 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration for the year 2010: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia; 2) regional and site-specific exploration activities that took place in 2010, as compiled by the USGS, and 3) regional events including economic, social and political conditions that affected exploration activities. These were derived from published sources and unpublished discussions with USGS and industry specialists.

Jan 1, 2011

By Nawal Kishore, Nilesh Pratap Singh, Amit Kumar Verma, Vikram Seervi

In India, demand for coal exceeds its countrywide supply, despite its natural abundance, due to failure to achieve high production targets, especially in opencast mines, which are responsible for 94.98% of total raw coal production within the country. Employment of technological solutions, such as surface miners, is key to achieving higher coal production and productivity in an eco-friendly manner, especially in the populated areas adjacent to the mining zone and, hence, require restricted blasting operations. It eliminates blast hole drilling, blasting, and primary crushing units, thus reducing related environmental hazards like ground vibration and fly rocks. This paper encompasses the applicability, advantages, constructional features, and performance assessment models for each working mode of a surface miner. The current paper discusses the correlation between coal production and key productivity indicators, namely, machine shift-time, pick, and diesel consumption of surface miner in three different geo-mining conditions. Furthermore, relationships between machine shift-time, pick, and diesel consumption of surface miner and coal production were evaluated through bivariate regression analyses along with their coefficient of determination. These key productivity indicators of surface miner follow polynomial relationships with coal production on a daily and monthly basis, having Pearson correlation values from 0.774 to 0.907 and coefficient of determination, from 0.664 to 0.909 in opencast coal mines.

Jan 20, 2023

By C. Alexander

Stillwater Mining Company is developing a second underground palladium and platinum mine approximately 21 km (13 miles) west of their existing Nye operation in south central Montana. A 5650 meter (18,550-foot) tunnel is required to gain access to the ore bearing horizon (J-M Reef). Access and primary mine development can be accelerated through the use of two 4.6 meter (15-foot) diameter tunnel boring machines (TBM). One TBM was purchased new while the other was purchased used. Machine specifications, site support facilities, portal/launch chamber construction, TBM assembly, startup and operation are discussed in this paper.

Jan 1, 1999

By Evgueni Jak

Pyrometallurgy is an important sector of modern industrial society actively participating in solving current environmental, economic, materials scarcity and other challenges. Recent advances in analytical methods, experimental techniques, thermodynamic, phase equilibria and process modelling tools provide new opportunities to increase the productivity of pyrometallurgical reactors, the treatment of complex feeds and metal recoveries. Fundamental theoretical models can now be used to make a significant next step towards the development and implementation of computerised models describing real industrial processes—Virtual Reactors, and computer-aided smart-decision-making systems that may be called Pyro-GPS by analogy to GPS; these developments can facilitate knowledge-based improvement and optimization strategies. The implementation of these improvements require ongoing collaboration between researchers, industry and government

By Hakan Uyguçgil, Beril Bayraktar, Adnan Konuk

Mining is one of the industries with the highest risk of occupational accidents in Turkey and globally. The most important feature that distinguishes the mining industry from other sectors is the constantly changing working conditions. The risk of accidents is very high, especially in underground mining, and can happen for several reasons. Therefore, it is essential to carry out all necessary measures in coordination with other disciplines to adapt to changing workplace conditions. The dangers that might occur underground must be determined in advance, controlled at their source, or eliminated since it is critical to take the necessary precautions before the accident. Accident prevention will protect miners’ living conditions by contributing to the country’s economy through reduced labour and production losses. In this research, the data from 13,653 accidents reported in the Karadon Hard Coal Enterprise between 2000 and 2011 were analysed and compared using the Life Table and the Kaplan-Meier methods. Accident records were classified and analysed into four categories: environmentalrelated accidents, equipment-related accidents, person-related accidents, and other accidents. Findings in terms of survival time indicate that environment-related and person-related accidents had the highest risk in Karadon, with equipment-related accidents having the lowest. This study established the reliability of using survival analysis methods to investigate occupational accidents in the mining sector. Given that environment-related and person-related accidents occur in a relatively short period, such as 1 year after starting work, it has been recommended that research be done to improve workplace and occupational safety measures and broaden the training given to miners. Additionally, it has been determined that increasing the use of automation and mechanisation in underground coal mines, combined with developing a thorough equipment safety training programme to raise awareness of the danger, can help prevent person-related occupational accidents caused by the interaction between equipment.

Aug 5, 2023

By Irina Chernyshova, Erik Larsen, Hanumantha Rao Kota, Vladislav Slabov, Garima Jain

The mining industry faces pressure to provide metals for the green digital shift using sustainable technologies. This study evaluates biosurfactants as collectors for ultrafine and coarser particles of hematite and malachite, aiming to improve the flotation of ultrafine particles.

Jun 1, 2023

By Daniel Lakovic

"Mining operations can create a negative environmental impact, especially when considering the tailings that are produced through the processing of ores. Tailings are finely grained residues that form sludges. The tailings are deposited into giant basins, or sludge ponds, where they create a burden on the environmentby limiting the use of processed water.Tailings are one of the most important environmental liabilities for mining operations because of their large proportion in relation to the ore mined — generally 90 to 98 percent. To get to the valuable minerals, mining companies must move large amounts of rock. The rock is ground and then treated, usually with the addition of chemical solutions and large amounts of water. The lower the concentration of the valuable resources, the greater the proportion of accumulated excavated material sludge.Sustainable tailings management requires responsible handling, making it one of the mining industry’s greatest challenges. The proper technology should include consistent control of the environmental risks and impacts, as well as a proper relationship with the communities that surround the mining operations.The tailings, which can remain partly contaminated with chemicals, are pumped into the large sludge basins, which are secured by earthworks. During the mining operations, the basins must be stable enough to withstand the pressure of the stored excavated material. The storage option is still used, but it has failed on occasion. And when it does, it increases the risks to the environment and binds the unused process water. The more complex the availability of fresh water required for industrial use and for human consumption and their economic activities — for example, farming and agriculture — the more complex the conflicts that have the potential to shut down mining operations. With modern separation technology solutions, it’s possible to process the sludge and recover the processed water. However, the responsible use of the water is critical. Therefore, mining companies must rely on technologies that allow for proper reclamation of the water, whether re-using in their own processes or treating it to return it to the environment."

Dec 1, 2018

By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice pitwall profiles are often planar in crosssection and the profile in between ramps especially tend to be planar and defined by a constant inter-ramp angle. Sometimes rock layers exhibiting different strengths require the inclination of the profile to vary with depth, but the inclination across each layer is usually constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties and Factor of Safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e. the planar profiles exhibiting the same FoS) up to 8 degrees depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Mar 2, 2022

By Miguel Reyes, Bruce Whisner, Joseph Bickson, Lincan Yan, David Yantek, Justin Srednicki, Nicholas Damiano, Eric Bauer

Built-in-place (BIP) refuge alternatives (RAs) are designed to provide a secure space for miners who cannot escape during a mine emergency. Heat and humidity buildup within RAs may expose miners to physiological hazards such as heat stress. To minimize the risk of heat stress, Title 30 Code of Federal Regulations (CFR), or 30 CFR, mandates a maximum allowable apparent temperature (AT) for an occupied RA of 35 °C (95 °F). The National Institute for Occupational Safety and Health (NIOSH) has conducted extensive research on the thermal environment of occupied RAs intended for use in underground coal mines. NIOSH research has demonstrated that a fully occupied BIP RA can exceed the AT limit by more than 5.6 °C (10 °F) in mines with elevated mine strata and air temperatures. In this circumstance, an RA cooling system could provide a solution. This paper provides an overview of test methodology and findings as well as guidance on improving the performance of a cryogenic air system prototype by optimizing the flow rate, increasing the tank storage capacity, and improving the efficiency of the heat exchanger of the cryogenic system. This may enable BIP RAs to meet the 35 °C (95 °F) AT limit in mines with elevated temperatures. The information in this paper is useful for RA manufacturers and mines that may choose to implement a cryogenic air system as a heat mitigation strategy.

By P. I. James, M. R. Baker

Este artículo analiza la nueva producción de cobre a partir de "minerales de desecho" de baja ley usando la tecnología de Blue Planet Strategies DEMET™ (Dynamic Electrode Mining Effluent Treatment, por sus siglas en inglés), que tiene como objetivo salvar la brecha de procesamiento entre la solución débil de lixiviación en operaciones de extracción por solventes/electrowinning (SX/EW), removiendo electroquímicamente los metales a partir de corrientes débiles y a la vez generando productos concentrados en metales objetivo en un análogo funcional de extracción por solventes (SX). Se estudió el tratamiento de la débil solución de lixiviación pregnant (PLS por sus siglas en inglés) y se usó para estimar los impactos económicos y de producción para una hipotética lixiviación en pilas de cobre brownfield y una operación aumentada DEMET usando SX/EW para tratar el "mineral de desecho." Se presenta la remoción de cobre a un 86% de eficiencia en las placas por debajo de 0,1 g/L de cobre con un consumo de energía de 0.55 kWh/lb de cobre y una concentración del producto mayor a 10 g Cu/L. El modelamiento arrojó aproximadamente $2/ lb para la producción total de cobre y costos de tratamiento menores o iguales a $1/lb con un inmediato aumento del margen bruto de operación del 12% para el brownfield incrementado. Se indicó también un aumento de la vida de la mina con un margen bruto promedio de 38% en la producción aumentada de "mineral de desecho" con valores de cobre de $3.25/lb.

Jan 1, 2014

By P. I. James, M. R. Baker

This paper examines new copper production from waste-grade ore using Blue Planet Strategies’ DEMET™ (Dynamic Electrode Mining Effluent Treatment) technology, which aims to bridge the practical weak pregnant leach solution (PLS) processing gap in heap leach-solvent extraction/electrowinning (SX/EW) operations by electrochemically removing metals from weak streams and generating product streams strengthened in target metals in a functional analog to SX. Weak PLS treatment was studied and used to estimate the economic and production impacts for a representative hypothetical brownfield copper heap leaching and DEMET-augmented SX/ EW operation to utilize "waste ore." Copper removal at 86% plating efficiency to below 0.1 g/L copper with power consumption of 0.55 kWh/lb copper and product strengths of over 10 g/L copper are presented. Modeling yielded approximately $2/lb total copper production and = $1/lb treatment costs with an immediate operation gross margin increase of 12% for the augmented brownfield. Potential mine life extension with an average 38% gross margin on "waste ore" augmented production at copper values of $3.25/lb was also indicated.

Jan 1, 2014

By D. C. Dahlin, W. K. O’Connor, G. E. Rush, C. A. Summers, S. J. Gerdemann

The Albany Research Center (ARC) conducted studies of mechanical activation by conventional and ultra-fine grinding techniques to enhance olivine reactivity in mineral carbonation reactions. Activated olivine is one of several solid feed materials used at ARC in reactions with carbon dioxide to form carbonate minerals. This paper compares grinding techniques via energy demand data and product characteristics, including particle size distributions, surface areas, full width at half maximum (FWHM) XRD analyses, and particle morphology by SEM analyses. Reactivity was gauged by percent conversion to carbonate in subsequent carbonation tests.

Jan 1, 2004

By W. Hustrulid

"In recognition of his inspiring dedication to the mining industry through education, research contributions and dissemination of practical knowledge, exceptional leadership and excellence in mining engineering practice and for his lecture, “You can't make a silk purse out of a sow's ear.” Recipient of the 2002 D.C. Jackling Award Introduction It is always difficult to decide on the most appropriate title to give to a paper or talk. It is a particularly difficult decision in the case of the Jackling Lecture, because the title becomes part of the award citation. I hope that the significance of this unusual title will become crystal clear as you read the pages that follow. However, to assist you in this journey, I will provide the following few words of guidance. In making a cake, you need the proper ingredients. If one or more of them are missing, it will not be a cake. In addition, the quality of the cake depends on the quality of the ingredients. In my lecture, the "cake" is the U.S. mining industry of the future. A national perspective President George W. Bush in his State of the Union Address (Bush, 2002) delivered on January 29, 2002, defined three national objectives: •win the war on terrorism, •protect the homeland and •revitalize the economy. Under the heading "revitalize the economy," he indicated the importance of "good jobs" and "energy production" by saying: "Good jobs begin with good schools. Good jobs also depend on reliable and affordable energy. This Congress must act to encourage conservation, promote technology, build infrastructure and it must act to increase energy production at home so America is less dependent on foreign oil." I wish that he would have broadened his focus and stated instead that: "This Congress must act to encourage conservation, promote technology, build infrastructure, and it must act to increase materials production at home so America is less dependent on foreign sources." With regard to jobs, all jobs are not equal. To paraphrase John Reeves of MidContinent Resources (Reeves, 2002): "If our nation is to prosper, we all cannot make a living by doing each other's wash. Some of us, at least, must be actively engaged in the primary production of raw materials from the riches of the earth and other Americans must turn those materials into consumer products." The unfortunate trend in our country has been to neglect the primary production of basic materials, even those coming next in line. We have left those responsibilities to others while we concentrate instead on performing various services, i.e., doing each other's wash and flipping burgers. This cannot continue. It must be remembered, especially by those in leadership positions, that all "jobs" are not created equal. Some jobs are much more essential to the security and wellbeing of our country than others. We must be sure that the important ones are in place. We cannot produce the basic materials that our nation requires without access to those materials. This leads to my Proposition 1: You cannot have a viable mining industry without a clearly enunciated, positive U.S. materials policy. Background regarding U.S. materials policy Resources for freedom. In January 1951, President Truman created the President's Materials Policy Commission, with William S. Paley as chairman. As expressed in the invitation letter from the president to Paley: This commission, within the executive office of the president, is to study the broader and longer-range aspects of the nation's materials problems as distinct from the immediate defense needs. The task of the commission is to make an objective inquiry into all major aspects of the problem of assuring an adequate supply of production materials for our long-range needs and to make recommendations that will assist me in formulating a comprehensive policy on such materials. The commission should study, together with any other aspects deemed by it to be pertinent, such questions relating to production materials as: - the long-range requirements outlook; - the long-range supply outlook; - the prospect and estimated extent of shortages; - the consistency and adequacy of existing government policies, plans and programs; and - the consistency and adequacy of private industry practices.

Jan 1, 2003

By M. A. Reyes, L. Yan

Heat and humidity buildup withn refuge alternatives (RAs) may expose occupants to physiological hazards such as heat stress. The Mine Safety and Health Administration (MSHA) regulations require RAs in underground coal mines to provide a lifesustaining environment for miners trapped underground when escape is impossible. RAs are required to sustain life for 96 h while maintaining an apparent temperature (AT) below 95 °F (35 °C). The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type RA, a 23-person tent-type RA, and a 6-person metal-type RA in its underground coal mine facilities to investigate the thermal environment over a 96-h period. The test results showed that mine air and mine strata temperatures surrounding an RA occupied by simulated miners (SMs) increased over the 96-h test period. The test results suggest that RA manufacturers should consider this increase in temperatures when calculating and evaluating RA components during surface and laboratory tests. The findings can equip stakeholders with additional considerations for calculating the interior heat and humidity temperature profiles for occupied RAs not tested in situ.

By Barrie A. Wigmore

There are two aspects of financing western coal development -- whether there is going to be enough money to finance the prospective large development of the industry, and the specific techniques of raising money for that development. To take the first question of whether there is going to be enough money around to finance your industry, I think it is quite clear that the restrictions on the development of western coal are going to be non- financial. Environmental impact problems are creating the greatest delay in coal mine development, at the moment; but getting enough personnel, mining equipment, railroad equipment, and failure of the Department of Interior to act on leasing federal coal lands all appear likely to create significant bottle- necks in the development of western coal -- larger bottlenecks than financing. Financing appears straightforward for the industry. There are many projections of the financing required to meet Project Independence goals. The National Academy of Engineers estimated that development of 500 million tons per annum of western coal would be necessary by 1985 to meet the Project Independence goals which might require $20 billion of capital spending. It is generally agreed that 500 million tons a year is not a realistic possibility. Carl Bagge?s estimate of production of 250 million tons a year by 1983 appears a more reasonable projection. Development

Jan 1, 1976

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

This study level process design represents an economically viable method for extracting thorium dioxide and other rare earth elements from monazite ore. This paper incorporates results from the 2019 capstone project from the honors Design Internship in Green Engineering in Chemical and Biomolecular Engineering. In this activity, senior students in Chemical Engineering at the University of Tennessee (UT) focused on the development and study of a process for the recovery of thorium dioxide and P2O5 from monazite. While not mandated, the process offers rare earth oxides as attractive byproducts. The project focused on recovery of byproducts rather than the creation or addition to waste streams. Additionally, (1) the process economics relied heavily on recovery of rare earth byproducts, (2) thoriumhandling portions of the process could be effectively segregated from rare earth and phosphate handling portions of the process, and (3) thorium and uranium content of waste streams should be carefully managed and eliminated where possible.

May 29, 2020

By R. V. Ramani, C. J. Bise

INTRODUCTION Classification of coal seams as thin, medium, and thick is both subjective and relative and is more a reflection of the statistical mode of the thicknesses en- countered in a mining region. A geological factor more precisely understood as defined than thickness is the inclination of the seams to the horizontal, commonly referred to as the pitch or the dip of the seam. Thick and steeply pitching seams present far more challenges to the ingenuity of the mining men to devise methods for their extraction than the thick and less steeply inclined ones. In a marginal case, where a thick coal seam may be minable by surface or underground methods, the decision bears a close relationship to the technological developments in the mining scene. Near surface thick coal seams are a special gift of nature and are not as wide- spread as the ones that call for the application of under- ground methods. Recent advancements in surface mining equipment have made it possible to surface mine to great depths. Stripping ratios of 30: 1 (cu yd of over- burden removed per ton of coal) have been achieved. The extraction of thick seams which preclude the use of surface methods is the concern of this chapter. Specifically, the objective here is to outline the special technological factors in underground mining of thick coal seams and to illustrate through several case histories the methods that are practiced in the North American continent. For the purposes of this chapter, a thick seam is defined as one which is not readily minable with currently available equipment without modifications to the extraction method or the equipment. At the present time, a thickness of 4.8 m (16 ft) can be considered as the lower limit, although developments in equipment and methods can be expected to push this limit upwards. The data for the case histories were collected from two extended mine visits in 1975 and 1978, and from other published accounts of the mines visited. Reference is drawn particularly to reports by Bise, Ramani, and Stefanko (1976) and Rarnani and Kenzy (1979). THICK SEAM MINING METHODS The various methods of mining thick seams can generally be grouped into three major categories: full face methods, where the entire thickness of the seam is re- covered in a single pass; slicing methods, where the seam is extracted to its full thickness by horizontal or inclined slices either in an ascending or descending order; and caving methods, where the seam is undercut and the en- tire coal seam is recovered by caving the top coal into the excavated cut, or some variations of the basic sub- level caving method. As shown in Table 1, in each of these methods, the coal is removed by either room-and-pillar or longwall methods. Hydraulic mining and transport of the coal in open flumes or in pipelines are also practiced. Addition- ally, the void created by the removal of coal may be filled with a packing material (stowing) except in the caving methods. The pitch (dip) of the seam, particularly when it is greater than 0.26 rad (150), imposes severe operational limitations on mobile equipment. A more detailed general discussion of the methods can be found in Bise et al. (1976) and Vorobjev and Deshmukh (1964). Specific discussion on the many variations of the three basic methods can be found in the papers presented at the international symposia that were held in

Jan 1, 1982

By D. Brandt

The Dos Pobres Mine is a copper oxide heap-leach operation located near Safford, AZ. Mine production is 163 kt/d (180,000 stpd) with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority. The engineering department began a project to improve fragmentation through blasting and thus increase throughput in the crushing system. It soon became clear that input from other departments was going to be required to make this a safe and economical project. Therefore, the crush and convey and ore control departments worked together to evaluate all available data on blast patterns and explosive loads and tracked performance and results. Using image analysis, drill energy index and databases, improved fragmentation size has been achieved and results have been verified while controlling costs.

Jan 1, 2011