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By Thomas J. Feeley

The US Department of Energy (DOE) is supporting the engineering development of three advanced physical coal cleaning technologies: selective agglomeration, advanced flotation and advanced cycloning. Each is capable of significantly reducing the pyritic-sulfur content of US coals. The objective is to provide the coal and electric-utility industries with a cost-effective option for addressing the SO, emission reductions required by the 1990 Clean Air Act Amendments (CAA). A secondary objective is to evaluate the potential of advanced coal cleaning for removing trace elements that are precursors to the formation of hazardous air pollutants (HAS). The proposed National Energy Strategy (NEE) and the 1990 CAA lay a foundation for a more efficient and environmentally sustainable energy future (1991). The need to use energy resources in an environmentally sound manner presents critical challenges and opportunities for coal preparation during the next decade, particularly regarding the control of SOS and HAY emissions. The principal challenge is the development of cost-effective coal preparation approaches for sulfur and HAY precursor removal.

Jan 1, 1993

By H. D. Freeman

The Pacific Northwest Laboratory (PNL) is developing cover technology for uranium mill tailings that will inhibit the diffusion of radon to the atmosphere. As part of this cover program, an improved radon flux measurement system has been developed. The radon measurement system is a recirculating, pressure-balanced, flow-through system that uses activated carbon at ambient temperatures to collect the radon. With the system, an area of 0.93 m2 is sampled for periods ranging from 1 to 12 h. The activated carbon is removed from the radon trap and the collected radon is determined by counting the 214Bi daughter product. Development of the system included studies to determine the efficiency of activated carbon, relative calibration measurements and field measurements made during 1980 at the inactive tailings pile in Grand Junction, Colorado. Results of these studies are presented.

Jan 1, 1981

By Hajime Miki, Michael J. Nicol

Relatively simple techniques have been developed which enable the electrochemistry of sulfide minerals to be studied with particles varying in size from above 100 pm to less than 1 pm. Both oxidative and reductive processes have been studied wing the minerals pyrite, arsenopyrite and chalcopyrite. It has been shown that it is possible to completely oxidise or reduce the minerals during a single voltammetic sweep. The resulting voltammogram produces peaks which are characteristic of each mineral and can be used to qualitatively identify the minerals. In the case of chalcopyrite, it has been demonstrated that the charge involved in the anodic oxidation can be quantitatively related to the amount of copper dissolved. Quantitative information can be obtained using peak fitting techniques. Interesting differences in the behaviour of the minerals in sulfuric and hydrochloric acids have been observed, particularly in the case of pyrite for which a second major peak is obtained which has been attributed to the oxidation of elemental sulfur in the presence of chloride ions. The technique offers the possibility of providing mineralogical information of individual particles based on an electrochemical voltammetic finger print.

Jan 1, 2005

Many organisations, including those in the resources industry have Board-level endorsed principles on sustainability. A key challenge, however, is how to systematically integrate these high-level principles into the design and operation of mineral processing plants. In an effort to meet this challenge the Sustainable Operations framework, called SUSOP®, was conceived and developed through the Corporative Research Centre for Sustainable Resource Processing (CSRP) in Australia. Somewhat analogous to HAZOP (Hazard and Operability Studies) which is well entrenched in the resources industry, the key aim of SUSOP® is to produce a holistic, systematic and rigorous methodology for identifying and assessing sustainability opportunities and risks. This paper argues the need for such a sustainability framework, presents the key elements of SUSOP®, highlights how case studies enhanced its development and articulates the reasons why such a framework will have growing importance into the future.

Jan 1, 2011

By R. A. Haney

The Mine Safety and Health Administration (MSHA) has conducted studies both in coal and non-coal mines to evaluate methods for sampling diesel particulates in underground mines. The agency is investigating size separation techniques to distinguish between diesel particulate and respirable coal mine dust. Additionally, ashing techniques have been used to distinguish diesel particulate from mineral dust in metal and non-metal mines. As part of these studies, personal exposures to diesel particulate for various mining occupations have been measured. This paper describes the measurement techniques and summarizes the exposure levels for various underground mining operations.

Jan 1, 1993

By Richard M. Tinlin

The mining industry needs to assure compliance with the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500). Congress has enacted this legislation with the intent of preventing, reducing, and eliminating pollution of the nation' s surface and groundwaters. Recognized sources of pollution such as seepage from tailings ponds, waste dumps, and contaminated effluent from mine dewatering operations pose a serious threat to adjacent groundwaters. In addition, technological innovations being implemented by the industry such as in situ leaching of low grade ore deposits may also lead to ground- water contamination. An adequate monitoring methodology designed to meet the needs of the mining industry is needed. Monitoring and control methodology devised for other man- caused sources of ground- water pollution - e. g., landfills - offer considerable promise for adaptation to the problem. The prediction of deleterious effects on groundwater quality usually requires extensive geohydrological data in addition to a thorough analysis of the mining activity that is underway or projected. If the avail- able data are adequate, mathematical models of surface and groundwater flow can be constructed that will help to predict effects on water quality. Data are inadequate to allow a realistic interpretation of pollution potentials. These data can be supplemented by computer simulation as a method to explore a number of possible environmental effects and also to develop a minimum-cost approach to identifying and gathering the additional necessary supporting data. Incorrect assessment of the important environmental considerations may, in many instances, prove to be the weakest link in analyzing the financial feasibility of a mining operation.

Jan 1, 1973

By W. K. Pincock

Accident prevention can be portrayed as a science that deals with facts and natural phenomena and must be dealt with in the same manner as any other operating problem. Safety at the Copper Queen Branch dates back to 1913 when a Safety Organization was started and rules formulated for underground mining. Since then the mining industry has made substantial progress in the elimination of accidents and when the Lavender Pit was started in 1951, it adopted the general plan in use at all Phelps Dodge properties. Following is a brief description of the Pit Operations:

Jan 1, 1959

By W. E. Horst

Raw materials and mineral products are crushed, ground, or pulverized for a variety of reasons. Some of the most important reasons for size reduction are: to liberate marketable mineral species from a matrix of commercial minerals and gangue, to promote rapid chemical reaction through exposure of large surface area, and to produce a material with desirable size characteristics for handling, utilization, and storage. Comminution processes are currently used on vast tonnages of raw material annually. In the mineral industries where mineral products and other solids are processed, the various size-reduction unit operations represent a major portion of the manufacturing costs. The comminution process is an expensive unit operation from the stand- point of both capital and operating costs. Power consumption is large, and the energy conversion to useful work is very small regardless of the size-reduction system. In energy terms, about 1% of the all electricity generated throughout the world is expended in crushing and grinding operations by the cement industry alone. Comminution is a general term for size reduction that may be applied without regard to the actual breakage mechanism involved. General type of size-reduction equipment include crushers, tumbling mills of various type, impact mills, fixed-path mills such as a roller mill, and fluid-energy mills. Some comminution machines accomplish

Jan 1, 1985

By L. W. Saperstein

In this paper, a number of novel hypotheses that provide a fresh perspective on the characterization of strata movements associated with longwall mining are developed by analyzing subsidence measurements with an influence-function-based computer program. Using an inverse application of the traditional influence-function technique, easily obtained surface displacements are used to analyze some of the complicated, expensive, and difficult-to- measure movements of the intermediate roof strata in a longwall panel. The primary hypothesis developed by this analysis proposes the existence of an area of partial roof caving near the edge of a panel called the "edge effect." A secondary hypothesis, interrelated with the first, promotes the importance of the effect of gate-entry closure on the observed strata movements. Both the primary edge-effect hypothesis and the secondary hypothesis concerning gate-entry closure are justified and quantified in an extensive analysis of surface subsidence that uses supporting information from related theories, design criteria, and in situ measurements. Next, the edge effect and the gate closure hypotheses are extended further and used to provide an explanation of the complex subsidence interaction of adjacent longwall panels in what is termed a "redisturbed" effect. Finally, the importance of accurately understanding these longwall strata movements for proper subsidence prediction or gate design is stressed.

Jan 1, 1988

By Klimpel. R. R.

Acknowledgments I am honored to be named as a recipient of the Antoine M. Gaudin Award, and I would like to briefly single out four groups who deserve a special thank-you relative to this award. The first group consists of Professor Kawatra, the many international support references that he gathered and the Gaudin Committee itself. I know such things don't come without considerable effort by many individuals, and I'm grateful for their support. The second group consists of the management of The Dow Chemical Company, the managements of various mining companies and, in recent years, the management of G. S. Technologies, all of whom supported me, financially and otherwise, in my grinding, flotation and other particle-processing work. Operations people are the most overworked and under recognized people in the world, whether they be in the mining or chemical industry. Obviously, without extensive industrial support, especially from operating personnel in the mining industry, almost nothing about the work contained in this lecture would have, or could have, happened. The third group consists of a number of coworkers who have played key roles in specifically implementing the new flotation-product portion of this lecture. Of these, Bob Hansen, Don Leonard, Basil Fee, Simon Isherwood, Fernando Cones and Marty Meulendyke deserve special recognition. They have not only been dedicated, but they have been great to work with. Also in this third group are many members of the international academic community, especially those at Penn State. Professor Leonard Austin must be singled out because he took me as a young mathematically oriented chemist and taught me to be an effective process-oriented engineer. Without this experience, I would not have had the over 30-year career as an engineer, which I have loved. In addition, Len planted the size-reduction-research virus in my blood, which I can't seem to get rid of. I also need to mention Professor Frank Aplan, whose obvious love of mineral processing and froth flotation helped to create my interest in flotation. Thus, for those of you who don't like my approach to flotation, it's all Frank's fault. The fourth, and certainly not the least, group to thank is my wife, Charlene, and our two sons, Richard and Steven. No one could have a more supportive family. In every sense of the word, my wife has been my partner from the beginningwe were married at the end of my freshman year in college. She has sacrificed much for me, and I will never really be able to express the depth of my gratitude for Charlene's encouragement, loyalty and support over the past 36 years. General comments on froth flotation The industrial process of froth flotation: Where is it going? I'm here to tell you loud and clear that froth flotation is alive, well, and growing. The inherent characteristics of high mineral throughput per unit of capital, low operating cost per unit of feed, high mineral specificity and high operating flexibility have guaranteed froth flotation an important past and a growing future. As with any evolving technology, there are always trends at the industrial level that are primarily driven by economics. The current trends include: •the movement towards larger and larger equipment, •more alternative equipment designs (e.g., the column cell),

Jan 1, 1996

By W. Jacobi, K. Eisfeld

The primary objective of dosimetric modelling for the inhalation of radon daughters is the evaluation of the dose distribution and of the mean dose to sensitive cells or target tissues in the respiratory tract which are assumed to be responsible for the initiation of lung cancer. The results of such dosimetric models are influencing the practice of radiation protection in a twofold manner: Firstly, they enable us to identify appropriate operational quantities for air monitoring and for the surveillance of individual exposures to radon daughters. Secondly, they can be used to derive secondary and operational limits for these radionuclides from the basic dose limits. The dose to target tissues in the lung from inhaled radon daughters depends on various physical and biological parameters: The unattached fraction of daughter atoms, the AMAD of the carrier aerosol for attached atoms, the geometry of the respiratory airways, the breathing conditions, the parameters for the retention and translocation of daughter atoms in the different lung regions, and the location of the target cells or target tissues, respectively. Therefore, dosimetric modelling for radon daughters has to include a sensitivity analysis showing the influence of these parameters. To meet these objectives we have recently described in a comprehensive report an improved dosimetric model for the inhalation of 222Rn, 22ORn and their short lived daughters (Jacobi and Eisfeld, 1980). In the following this model is shortly described and the main results are summarized. DOSIMETRIC MODEL [Model Structure]. For the geometry of the bronchial airways the model A of Weibel (1963) was used. Each bronchial generation i (i =0.1 .... 16) was considered as a separate compartment i, for which the following transfer pathways for radon daughter atoms were taken into account (see fig. 1): (1) the uptake by deposition (deposition probability wi); (2) the translocation by ciliary clearance (rate constant [A]i); (3) the transfer to blood by diffusion through the bronchial epithelium (rate constant [A]b). To distinguish between attached (Index a) and free (index f) daughter atoms each bronchial generation was divided in two subcompartments (i.a and if) with a transfer rate constant [a]s (ia- if) characterizing the desorption or dissolution rate of attached atoms in the mucus fluid. Thus for daughter atoms primarily deposited in attached form the transfer to blood is a twostep process with the rate constants [a]s and [A]b which were assumed to be independent of the generation number i. [Deposition]. The deposition probabilities wi in each bronchial generation were calculated on the basis of the laminar diffusion model of Gormley et al. (1949); however the deposition in the upper airways was corrected for turbulent air flow, taking into account the results of our deposition experiments (Martin et al., 1972). Figure 2 shows the resulting deposition probabilities per unit surface area of the bronchial generations for nose breathing at a rate of 20 1/min. The values for attached daughter atoms refer to an AMAD of 0.2 - 0.3 µm ([O]g =3) for the carrier aerosol; the deposition values for free atoms were derived with a diffusion coefficient of 0.05 cm2/s, assuming a prefiltration of 50% in the naseopharyngeal region.

Jan 1, 1981

By Brian P. Stapleton, Bill M. Stewart, Joel R. Warneke, Curtis C. Clark

Of the 28 accident/injury classifications listed by the Mine Safety and Health Administration, handling materials is second only to roof falls in terms of generating the highest number of reportable accidents in active underground coal mines. Two materials-handling activities that cause numerous injuries each year are the categories of ‘handling supplies or material, load and unload’ and ‘moving power cables.’ Mechanization and mine worker activity training are two methods that can aid in preventing these injuries. This paper describes three mechanical methods – the mobile manipulator, the in-mine hoist, and a cable-handling system - being developed and tested at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Two of the devices are specifically designed for loading, unloading, and moving supplies and materials, and the third device is for handling trailing cables in the confined spaces of coal mines. Also described are safety solutions developed for underground coal mines geared to showing miners safe and unsafe ways of performing various materials-handling tasks.

Jan 1, 2005

By P. A. Anderson

Innovative solution management is being used at Coeur-Rochester, Inc. to increase bullion production and decrease overall costs. New operating programs call for reduced solution application rates to the heap to increase pregnant stream values at a lower and less costly plant flowrate because silver and gold extractions are equal regardless of leach solution application rate. Solar heating is used in the summer months to increase the core temperature of the heap for use in the winter months thus increasing silver extraction rate. This paper outlines the programs now in effect and the savings incurred because of them.

Jan 1, 1989

By L. W. Pommier

In the field of minerals processing the concentration of valuable minerals normally takes place in suspensions of ore particles in liquids. The fluid resistance offered by Newtonian liquids to the movement of free settling spheres for the limiting cases of creep flow and turbulent flow is well described by Stokes' and Newton's Laws. However, these equations are not applicable to non-Newtonian fluids, since the relationship between applied shearing stress and resulting rate of shear is a non-linear function, and more than one viscosity parameter is necessary to describe their rheological properties. For this reason, the term "apparent viscosity," which has been commonly used to explain the flow resistance of the non-Newtonian systems including suspensions, may be misleading. A rigorous analysis of the mechanisms of momentum transport of solid-liquid systems is complex indeed. There are many variables that affect the properties of such systems, and precise limitations and assumptions are necessary in order to produce quantitative relationships for predicting their behavior. Very dilute suspensions of spherical particles in Newtonian liquids of identical density as the solids have been examined in the past (12); however, the study of suspensions in which there is a considerable difference in density, between the liquid and the suspended solids has been neglected.

Jan 1, 1968

By K. G. Sutterer, P. T. Wang, R. Sweigard

One possible alternative for the disposal of flue gas desulfurization (FGD) by-products is to use it as backfilling support material in highwall mine adits. The finite element method was used to analyze the variation in stresses and displacements within and around a highwall adit backfilled with FGD materials. The engineering properties of the rock material and the optimum mix of the FGD materials were obtained from laboratory tests. Finite element analyses show that, for the case in question, the roof displacement would decrease about 48% and the peak stress could be decreased by about 58%. The study indicates that fairly weak FGD materials can eventually lead to the stability of backfilled highwall adits.

Jan 1, 1998

By R. V. Ramani, R. Bhaskar

The results of an experimental and theoretical research study into the spatial and temporal behavior of dust in mine airways is summarized. Experiments were performed in mine airways under both controlled and normal operating conditions. The controlled experiments included the documentation of the concentration and deposition patterns for two types of dust under three different velocities. Real-time dust concentration data were obtained using real-time aero- sol monitors (RAM-I) to determine the dispersion coefficient in a mine airway. On the theoretical font, a convection diffusion model of the dust flow phenomenon in mine airways was developed considering dominant mechanisms affecting dust transport and deposition in mine airways. Mechanisms modeled include turbulent and gravitational deposition, coagulation, and dispersion. In this paper, comparative analyses of results (8 the controlled experiments with the predictions of the mathematical model are presented. In addition to the overall validity, the adequacy of the individual components of the model, such as deposition in the total and respirable range, and dispersion are examined in light of the experimental observations. The experimental data from controlled experiments compared more favorably with model predicted results for similar conditions as opposed to the comparative analysis results for in-mine experiments. Specifically, the model predictions for an 800-m stretch of a mine airway reveal some significant differences from the behavior noticed in the mine. The deposition was lower than that predicted by the model. Consequently, concentrations were higher than those predicted by the model. The implications of these and other findings for further investigations are discussed in the paper.

Jan 1, 1987

By Sheldon P. Wimpfen

Sand and gravel has been, and will continue to be, our principal construction material. Most of us are familiar with the patterns of past growth. Today we will examine the present status of this vital industry. We shall also attempt to look into the future to see where it is going and to evaluate the constraints that are being imposed. Natural aggregates are among the lowest in value of all bulk industrial minerals. From the processing point of view, sand and gravel production is relatively simple since the products are sized materials obtained from a deposit of satisfactory physical soundness. They can be used either loose or bound to provide bulk, strength, or protection. One of the main uses of coarse aggregate is in concrete as a filling material. As a general rule, the coarse aggregate constitutes about three-quarters of the volume of concrete. The other main use for aggregate is as a roadstone or roadbase to provide protective and stabilizing bulk beneath the road surface. Also it is used in a mixture with petroleum products as the wearing course on top. The sand and gravel industry is geographically widespread. In general, the output of operations is directly proportional to the amount of construction in any area. A wide variety of other aggregates compete with sand and gravel, including crushed stone, blast-furnace slag, clinker, and artificial and natural lightweight materials.

Jan 1, 1972

By Feng Cai

"As a new method to support gate roadways, rock bolting has been widely used in the big coal enterprises for its superiority. The disturbed stress field of surrounding rock and anchor pre-stress field were divided into 3 areas in consideration of s1, s3. The surrounding rock failure form and characteristic were analyzed in combination with parameter f, the failure mechanism was explained using the slip line theory, furthermore, the rock bolting mechanism and its arrangement were studied. After roadway excavation, the tensile stress area appeared at the surface of the surrounding rock. The failure type changes from shallow tension-shear form into deep compression-shear form and the failure shape is an “incense burner”, surrounding by high risk failure area in butterfly shape. The maximum principle stress in roof appears discontinuous distribution because of layers separation. The failure type of surrounding rock is intensity-stress environment-weak plane control model. The internal reason of roadway macroscopic failure is the displacement between the surface plastic area and the deep elastic region along the tangential direction of slip line. In condition of rock bolt support, there is one-way tensile stress area in small range at the surface of surrounding rock, inside is the bidirectional compressive zone in uniform distribution form, stress environment is improved by the superposition of anchor pre-stress and disturbed stress field, anchor rock bolt arrangement and pre-tightening force distribution is decided according to the distribution of f parameter. Finally, supporting method and parameter reasonability was proved by the roadway deformation monitoring, damage depth drilling peep test in the 8101 transportation roadway in a mine.Introduction The stability of roadway support is very important to the safety and sustainable development of coal mine. In recent years, the focus of China's coal mining industry began to move to West China, the thick-extra thick coal seam is developed in the West. The latest technology and equipment have been put in to service, the occurrence condition of thick coal seam and the increasing of productivity lead to the cross section of the roadway increasing continually, hence, it is more difficult to control the surrounding rock. At present, the most common way to support the roadway is rock bolt (cable) support (Wang 2007); Scholars have been deeply studied on the mechanism of rock bolt. It is reported (Wang et al 2012, Gao 2007, Zhang and Yuan 2006) that the influence of rock bolt on physical and mechanical parameters of coal and rock mass in the anchorage zone, It is believed that the rock bolt can improve the peak strength of surrounding rock, especially the post peak strength, and the failure mode of rock mass under the rock bolt support is analyzed. It is reported (Wang et al 2014, Xiao et al 2013, Li et al 2007, Yan et al 2012), according to different geological conditions, the failure mechanism of surrounding rock and supporting technology of the whole coal roadway were studied. Focus on the failure mechanism of roadway surrounding rock, different forms of high strength support methods were proposed, which achieved good results. It is reported (Wang et al 2012a, Zhang et al 2011, Wang et al 2012b, Kang et al 2010, Zhang et al 2010, Kang et al 2007) that the supporting mechanism of pre-stressed anchor was analyzed from the point of the distribution of the maximum principal stress in the pre-stressed anchor field, and the influence of the rock bolt support parameters and surrounding rock characteristics on the supporting effects were studied. Based on the latest research results, this paper analyzed the failure mechanism of surrounding rock of coal roadway, proposed the high strength anchor net cable combined supporting technology based on the feature of stress zoning distribution of surrounding rock, to provide reference for the coal roadway rock bolt (cable) support technology."

Jan 1, 2017

By P. R. Wotruba

The Fortitude gold-silver deposit is related to a "wallrock" copper porphyry system developed within Middle Pennsylvanian to Permian Antler Sequence rocks adjacent to a Middle-Tertiary altered granodiorite intrusive stock at Copper Canyon. Gold-silver ores of the Fortitude deposit occur with disseminated and massive sulfide replacement mineralization of skarn-like or calc-silicated limy horizons of the Antler Sequence contact meta-sedimentary rocks. A major, north-trending, steeply westward dipping normal fault was important as a conduit for hydrothermal fluids responsible for the metallization in the Fortitude area. Gold-silver mineralization is best developed near a marble front where retro-grade chloritization and destruction of prograde calc-silicate mineral phases is most prevalent. Fluid-inclusion studies performed on the Copper Canyon system indicate a wide variation in fluid chemistry during several hydrosilicate stages that ranged in temperature from 500°C to 220°C.

Jan 1, 1986

By W. S. Sadik

This paper presents the ventilation design for an underground testing facility in a salt medium. The underground workings consist of two-12 ft. (3.66 m) diameter watertight shafts and approximately 6000 ft. (1830 m) plus of drifting. These facilities are designed for the purpose of providing access for an in-situ testing of a salt horizon in which a variety of hazardous and non-hazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1988