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By Joseph A. Zupanick

Methane drainage is a mature technology, now commonly practiced in many highly productive underground coal mines throughout the world. Universally, the practice of pre-draining methane will continue to grow as near-surface coal seams become depleted and mining operations are forced to exploit deeper reserves. These deeper coal reserves inherently have higher gas contents. In addition, increases in productivity and extraction rates have caused higher methane liberations per unit of time. As the cost of providing ventilation air increases, the economic justification for implementing a methane drainage program becomes apparent.

Jan 1, 2005

By William J. Miles

From a historical perspective, bentonite is the common rock term for various uses and applications. Its name originates from water-based muds near Fort Benton used for lubrication of wagon wheels during the 19th century migration to western territories (which are presently part of the United States) when the pioneers ran out of axle grease. From a clay mineralogy perspective, bentonite is composed primarily of montmorillonite, an expandable magnesium aluminum silicate clay mineral. When magnesium occupies an octahedral structural site that usually contains an aluminum atom, a negative charge is created. In order to neutralize negative charges, cations are drawn to the interlayer surfaces between clay mineral sheet structures. Modem applications for bentonite depend on the sodium or calcium cation populations and other characteristics of the clay mineral. When sodium is the dominant cation, the material is called sodium bentonite, also known as swelling bentonite, western bentonite or Wyoming bentonite. When calcium or magnesium is the dominant cation, the material is called calcium bentonite, also known as non-swelling bentonite w southern bentonite.

Jan 1, 2012

By S. C. Gambrell

The practice of roof bolting in world-wide mining activities is very well known, having been used extensively for over 50 years. The theory of roof bolting, however, is extremely complicated, and only recently have investigators attempted to explain the theory. Discussions of the mechanics involved usually originate with actual experience gained in the use of roof bolts. The use of roof bolting in mines has grown dramatically during the period after World War II. Other scientific techniques have emerged in mining research in the same period. Included in these techniques is the study of rock mechanics, which has now developed into an impressive research effort. Various means of analysis have been utilized in rock mechanics, most of which reduce rock to an isotropic, homogeneous medium that could be easily analyzed. Because of the inherent nature of rock, direct research methods frequently are not certain to provide satisfactory results, whereas indirect methods must idealize a given set of conditions in order to be useful. One of the indirect research methods is the photoelastic technique, the theory of which is widely known and needs no elaboration. This technique has been used extensively to examine the state of stress around underground openings of various shapes in certain types of strata, and under various configurations (1,2,3,4,5). Much of the theory used now in the design of underground openings is based on photoelastic evaluation. Unless rigorously applied, how- ever, the photoelastic technique is at best a qualitative means of evaluation. It is useful, however, for unusual examples which can be more or less easily analyzed to obtain the overall state of stress which could not be determined by other means. Little work has been done in the photoelastic analysis of rock bolting, mainly because direct research techniques have proven useful.

Jan 1, 1970

By H. R. Manouchehri

The responses of calcite, feldspar, and quartz minerals In a laboratory free fall electrostatic separator, before and after tribocharging with stainless steel, PVC, and copper plates, have been investigated. The effect of H3BO3 and BaCl2 chemicals pre-treatment on the electrical properties of the minerals is examined. The changes in the electrical properties are discussed with the determined charge, dielectric constant, and electrical conductivity of the mineral samples. Electrical properties of the minerals and their responses to the electrical field during separation, after tribocharging and chemical pre-treatment, are explored for the need to characterize the electrical behaviour of the minerals.

Jan 1, 1998

By Byron C. Hardinge, Michael Sokaski, Paul F. Sands, W. Loring III Mc Morris, David J. Akers

INTRODUCTION In the early days of coarse-coal cleaning by the dense-medium process in Europe, loess was one of the materials used for medium solids. Newly developed cyclones were used to reclaim and thicken the loess suspension. On occasion, when the cyclone thickener at the Maurits mine in the Netherlands plugged, the overflow was found to be filled with clean coal free of impurity. From this observation stemmed the concept of the cyclone as a cleaning device. Development took place during World War II in the laboratory of the Dutch State Mines under the direction of M. G. Driessen. A 15-tph (13.6 t/h) pilot plant was in operation in the laboratory by 1945, when, in September, Driessen made the first public disclosure of the process in a paper presented to the Institute of Fuel in London.51 In April 1945, operation of this pilot plant was observed by H. F. Yancey, who was so impressed with the potential of the cyclone process that, on his return to the United States, a research program on the cyclone was immediately started by the US Bureau of Mines (USBM). This work led to an AIME paper in 1946 in which the first details of cyclone operation on American coals were made available.52 Commercial adoption of the cyclone proceeded in Europe, initially in the Netherlands, Germany, and France. In the United States, where coal is less costly and most of the coals are easy to clean and respond well to simpler cleaning processes, the first cyclone plant was not built until 1961.53 THEORY Before discussing the theory of a dense-medium cyclone, a brief description may be helpful to some readers who are not familiar with its basic operation. In a typical dense-medium cyclone, illustrated in Fig.7-51 a mixture of medium and raw coal enters tangentially near the top of the cylindrical section, thus forming a strong vortical flow. The refuse moves along the wall of the cyclone and is discharged through the underflow orifice. The washed coal moves toward the longitudinal axis of the cyclone and passes through the overflow orifice, or vortex finder, to the overflow chamber. Washed coal is discharged from this chamber, usually through a tangential outlet.

Jan 1, 1991

By Wei Bin, Liu Zhe, Liping Xiao, Jichi Bai

The Acid Mine Drainage has characteristics of low pH, high concentrations of heavy metal ions, such as Fe2+, Mn2+, Cu2+ and Zn2+. In this paper, the composite particles that consisted of bentonite and steel slags were used to dispose the Acid Mine Drainage. Bentonite is the mineral materials and can adsorb heavy metal ions excellently. The steel slags are alkaline and industrial solid waste for the treatment of the Acid Mine Drainage. The main influencing factors, such as adsorbent dosages, shaking rates, concentrations of heavy metal ions, temperatures, adsorption time and pH value were studied by the static experiment. Increasing the adsorbent dosages and the concentrations of the heavy metal ions, speeding up the shaking rates, raising the temperatures, extending the adsorption time and improving pH would improve the removal efficiencies of heavy metal ions. Through considering the removal efficiencies and the treatment costs, the optimum reaction conditions for the four kinds of heavy metal ions were obtained. The adsorbent dosage 21 mg/L, the rotational speed 120 r / min, the temperature 25?, adsorption time 100 min and the initial wastewater pH 7. The four kinds of heavy metal ions existed independently in the simulated mine wastewater. The highest initial concentrations of Fe2+, Mn2+, Cu2+ and Zn2+ were 150 mg/L, 100 mg/L, 170 mg/L and 140 mg/L respectively. The removal rates were 93.42%, 92.64%, 93.86% and 95.17% respectively. The determination of the particles’ SEM-EDS Microscopic characterization showed the composite particles could play a part in neutralizing, absorbing and the chemical precipitation. The acidity decreased notably and the heavy metal ions of Fe2+, Mn2+, Cu2+ and Zn2+were adsorbed and precipitated effectively. The research results can extend the practical engineering application of the composite particles.

Jan 1, 2017

By F. M. Doyle, C. V. Diniz, A. H. Martins

A proposed process for the direct production of battery¬grade Mn02 leaches manganese ore with HCl to remove heavy metals selectively. The acidic manganese chloride solution produced is contaminated with Cu, Ni, Co, Pb and Fe at levels that preclude immediate utilization. This paper reports on screening tests to measure the uptake of Cu, Ni, Co, Pb, Fe and Mn from acidic chloride solutions onto different chelating ion exchange resins. Dow M-4195, which contains the bis-picolylamine,functional group, showed promise for detoxifying manganese chloride process solutions. Column ion-exchange tests demonstrated the ability of this resin to produce pure manganese chloride solution from an acidic manganese chloride leach solution contaminated by Cu, Ni, Co, Pb and Fe.

Jan 1, 2000

By J. D. Allen

The Concord Mine Coal Preparation Plant of United States Steel Corporation, located near Bessemer, Alabama, began operations in June, 1950. The basic cleaning circuit consisted of a Chance Cone for cleaning the 2-inch x 3/8-inch fraction and concentrating tables for cleaning the minus 3/8-inch coal fraction. Dewatering of the final product was accomplished with 35-mesh vibrating screens. However, because Concord coal is very friable (Figure 1), 85 per cent passing three mesh and 25 per cent passing 28 mesh, there was a considerable amount of fines passing through the dewatering screens. To recover these fines, the dewatering screen effluent was sent to two 70-foot diameter hydro-separators with the underflow returning to the dewatering screens and the overflow going to a 175-foot diameter thickener for water clarification, (Figure 2). As might be expected, there was a considerable amount of recirculation of the minus 35-mesh coal in this system. This degraded the coal and led to higher moistures. It also resulted in a fines bleed-off of plant water and thickener underflow to a fine-coal settling pond. In 1961, vacuum filters were installed to supplement the screens and to recover the fine coal lost in the bleed-off. The above system resulted in a product moisture of about 20 per cent. Further reduction to approximately 11 per cent was accomplished by drainage from railroad cars during transit to the coke plant. Control of the moisture at unloading was poor because of variations in operating levels and railroad car availability, but since the Concord coal constituted a smaller percentage of the coal previously used at the coke plant, the high moisture and fluctuations did not seriously hamper coking operations.

Jan 1, 1966

By S. K. Kawatra, T. C. Eisele

To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of. Currently, the major markets for scrubber sludge are for manufacture of gypsum products, such as wallboard and plaster, and for cement. However, the quality of the raw sludge is often not high enough or consistent enough to satisfy manufacturers, and so the material is difficult to sell. Other markets, such as paper manufacture and plastics fillers, have even more stringent quality requirements and will not accept raw sludge at all. In the work described in this paper, several reagents have been examined to determine their ability to selectively improve the flotation of the unreacted limestone contaminant away from the desirable products (calcium sulfite and gypsum). The most success has been achieved using a cationic collector, which shows a higher selectivity between calcium sulfite and calcium carbonate than do the anionic collectors that were studied.

Jan 1, 1995

By S. Becker, M. Gruner

"Microstructure stabilized crushed rock salt is a newly developed backfill material for infrastructural openings in HAW repositories. The motivation for this research is based on the fact that the microstructure stabilized crushed rock salt is considered to be superior to the currently used crushed rock salt. The avoiding of settlements with a simultaneous 100% backfilling of openings, early stabilization of the geological barrier and low permeability (< 10-14 m²) are the main improvements. With the newly developed backfill material, the gap between the crushed rock salt and the saliniferous composite backfill materials is closed. Due to the minimized amount of a binding agent, the material will still be easy to handle like a bulk material, yet guarantees close to 100 % backfill success without any settlements. This is accomplished with a long-term stable re-mineralization that is formed by the components of the binding agent. INTRODUCTION The permanent storage of high active waste in underground geological formations (HAW-repository) is the labored method in Germany as well as internationally. Experiences have been made over the last decades, e.g. in the Waste Isolation Pilot Plant (USA) and the mines Morsleben and Asse (Germany). For this purpose salt formations are preferred as host rock due to the adequate heat conductivity, creep capability, and low permeability. In order to maintain the low permeability of the host rock and to avoid any contact of the stored waste with the biosphere, the formation of flow paths has to be prevented. The cavities which have been mined for the purpose of waste storage have to be backfilled with material that is alike to the host rock. Therefore crushed rock salt is considered as an appropriate backfill material. Crushed rock salt is a bulk material that is produced by mining saliniferous formations. This material is mainly used in underground repositories as a dry backfill that is brought into the cavities by the use of mechanical (loading machine, slinger machine or scraper) or pneumatic energy (pneumatic stowing). In Germany it is intended to use dry crushed rock salt with a maximal grain diameter < 64 mm for backfill in a future repository in saliniferous formations. With this method applied, the porosity of the backfill is up to 35 % [1]."

Jan 1, 2015

By R. Trottier, B. H. Kaye

Characterizing the structure of such open-structured dusts such as diesel soot and those present in welding fumes plus any other dusts which were initially formed by precipitation or agglomoration of subsidiary units in a flame process has always been a difficult task. Recently, scientists have been able to use the concepts of fractal geometry to model the growth of diesel soot and fume fine particles and characterize their structure using fractal dimensions. The measured fractal dimension of a diesel exhaust at various levels of scrutiny can be used to study the health hazards posed by the soot. Thus, the fractal dimensions of the overall structure can be related to the dynamics of the dust both empirically and theoretically. In this communication, the use of fractal dimensions to describe the structure of smoke and fine particles which pose a respirable hazard are reviewed. Experimental studies linking the measured fractal dimensions of the fine particles to dynamics of the fine particles in respirators and in the lung are outlined.

Jan 1, 1987

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (see Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By M. Ghiani, R. Peretti, A. Zucca

The paper deals with the experimental application of a pilot flotation column to baryte and fluorspar ores. The column has been installed in parallel with the cleaning stages of two different industrial flotation plants where the above ores are processed using conventional cells with mechanical impellers. The effect of several parameters, including froth height, wash water additions, pulp feedrate and air supply rate, has been investigated. It has been shown that by finely tuning the above parameters good flotation performances can be achieved. The experimental results demonstrate the greater versatility of the column flotation and its superior separation efficiency, especially for the fine particle size fractions, over conventional cells.

Jan 1, 1995

By W. Kennedy Gauger, Tim Oolman, Debra L. Bisson

Radian Corporation (Radian) has developed a process for treating Cr(V1)-contaminated soils that involves: 1) soil washing using an alkaline extractant, 2) biological reduction of Cr(V1) to Cr(II1) in the soil wash effluent, and 3) separation of Cr(II1) from the biologically treated effluent. Biological treatment has been demonstrated for immobilized cells in fluidized bed bioreactors and suspended cells in slurry bioreactors for Cr(V1) levels ranging from 30 to 600 mg/L which have been reduced to non-detectable levels (< 0.05 mg/L; method detection limit [MDL]) during hydraulic residence times as short as 12 hours. The resulting Cr(II1)-containing effluent stream was chemically treated to precipitate chromium hydroxide for removal by physical separation.

Jan 1, 1995

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By Yeonuk Choi, Patrick R. Taylor, Lyle Cunningham

Laboratory experiments have been performed to evaluate the potential for metal removal and recovery from river bed tailings by ferric chloride leaching. The lead, zinc, silver and other metals in the river bed occur due to the old method of dumping mill tailings into rivers. This was practiced prior to the introduction of tailings impoundments. The effects of the leaching method, leaching time, pulp density, ferric chloride concentration, and leaching temperature on the rates and recoveries of lead, zinc and silver were studied. The effects of pulp density and leaching temperature were significant on the extraction rates of lead, zinc and silver. The lead content in the leached tailing was reduced to 0.023 percent, when using an 353O K leaching temperature and 0.384 g of FeC13/1 g of sample.

Jan 1, 1992

By VIVEK KASHYAP, PATRICK TAYLOR

Zinc ferrite is the major phase component present in zinc refinery residue (ZRR) and electric arc furnace dust (EAFD). Up to 71 percent zinc ferrite has been reported to be present in ZRR, and in most studies zinc ferrite has been deemed the major phase in EAFD. In 2010, the global annual production of EAFD was 3.7 Mt, with 15.20 kg of EAFD generated per ton of recycled steel [1]. The generations of ZRR and EAFD have been growing over time, requiring a greener approach for the reutilization and extraction of valuable elements. ZRR can be a potential source of zinc, as its zinc content is as high as 30 percent [2,3]. The presence of zinc ferrite makes the extraction of zinc difficult because zinc ferrite is refractory to leaching, and direct leaching is inefficient. The Waelz process is currently employed to extract zinc from EAFD and other metallurgical wastes. The Waelz process operates in the temperature range of 1,100 to 1,500 °C and uses coke as reductant. This study explores a carbon-free and relatively low-temperature process for the selective extraction of zinc from pure zinc ferrite.

By Ralph E. Magnuson

The quality of our environment is of great importance to all of us. Today, there is a great public concern about the degradation of our air, land, and water and the resultant slow death of our planet Earth. The miner has always been concerned with his environment. Historically, mining has been a part of the frontier. As a result, the miner has pioneered and developed many parts of the world. In the beginning, he had to hack out a place for his mine, himself, and his family. He was given accolades and praise for his accomplishments. Now, however, he is attacked as a ravager of the landscape. It was and is no different on the Marquette Iron Range in Marquette County, located in the Upper Peninsula of Michigan. Iron ore was discovered in 1845 and mining was begun by 1848. Over nearly 1 ¼ centuries, a total of 379,197,000 tons have been shipped to market. Ports, docks, railroads, and towns all had to be built in order to get that tonnage out to iron and steel makers. In those early days the environment had to be mastered, not pampered.

Jan 1, 1970

By James D. Bennett

Relationships among mine and injured miner characteristics and HSAC&apos;s degrees of injury are examined for 91,404 injuries in under- ground bituminous coal mines in the United States from 1975 through 1982. Injury severity varies by the mining system, geographical region, circumstances surrounding the injury, the injured miner&apos;s age, whether the miner was using powered equipment, the year which the injury occurred, and the location in the mine where the injury happened. Injury severity is not related to the injured miner&apos;s total mining experience, job experience, and experience in the mine in which the injury occurred.

Jan 1, 1984

By H. Demirel

This paper deals with concentration of hematitic-limonitic iron ores. The ore sample obtained from Karakuz (Turkey) contain:. about 40-46 I Fe. First, a low intensity magnetic separation process was employed to separate the strongly magnetic particles cf "-10+2 mm" and "-2+0.075 mm" size fractions and magnetic concentrates with 59.1 % Fe aid % 58.0 Fe were obtained respectively. The non-magnetics of both fractions were then fed to a nigh intensity permanent magnetic separator. The Fe contents of "-10+2 nun" and "2+0.075 mm" size fractions were increased from 28.2 to 51.13 and from 35.4 7. to 43.25 respectively after single pass. Easing on these results, it was concluded that the high intensity permanent magnetic separator could he used as a pre-concentrator f.7.1- hematitic-limonitic Karakuz iron ore.

Jan 1, 1991