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By Ross W. Smith, Xiapeng Zheng, Merrill P. Allen

The results of flotation of a primary desliming hydrosizer overflow material containing 14.6 wt.% P20, and 3.6 wt.% MgO are presented. The phosphate minerals were collophane and francolite and all minerals appeared to be liberated. The material had not been previously treated with flotation reagents. In the experimentation, various collectors were evaluated for effectiveness. The relative effectiveness of flotation in different flotation devices was determined. Finally a two-stage flotation scheme is proposed using column flotation of dolomite in the first stage and Denver cell flotation in the second.

Jan 1, 2002

By A. Pavlidis

This paper investigates variations of lignite quality attributes with geostatistical methods. The study focuses on lignite from the Southern Field in the Greek province of West Macedonia. The targeted quality variable is the ash water-free content (AWF). A geostatistical model is constructed based on data from 480 drillholes (approximate drill hole spacing of 250m). For each drillhole, the vertical average of the AWF is calculated. The coarse-grained AWF is then modeled as the superposition of a trend surface and fluctuations. The spatial dependence of the fluctuations is modeled by means of the experimental variogram. Kriging estimators are used to determine the AWF values on a rectangular grid, and the uncertainty of the estimates is calculated. Implications of the analysis for the variability of the produced lignite are discussed, and recommendations for additional drilling are proposed.

Jan 1, 2006

By P. Todd, K. Dever, P. S. Mills, A. A. Campoli

Resin bolt performance is dependent on the size of the resin annulus, i.e., the difference between the hole and bolt radii. The majority of the millions of resin roof bolts installed each year in the United States employ an annulus of 3.175 or 4.775 mm (0.125 or 0.188 in.). Short encapsulation pull tests with resin annuli of 3.175 and 2.413 mm (0.125 and 0.095 in.) resisted an average of 0.08 t/grouted mm (2.25 st/grouted in.) with no significant variation. Resin loses to simulated fractures increased as annulus size decreased.

Jan 1, 2003

By Otis M. Clarke

The 34th Forum on the Geology of Industrial Minerals gave members a chance to see the geology of various stone and ore deposits displayed graphically in quarry walls and also provided an opportunity to hear and see first-rate papers and posters on the geology of industrial minerals. Also, some field trips passed through areas of spectacular scenery. As a bonus, participants saw scenic mines, some of which are "pretty as a picture." Watercolor paintings prove it. At the Oklahoma Forum, the writer displayed a number of paintings of mines and other landscapes seen during previous Forum trips. These paintings and this brief article are part of a crusade to prove that some mines and geologic vistas are scenic wonders and belong in our visual heritage. It is a plea to save some of our best geologic exposures for future geologists, tourists, and artists.

Jan 1, 1999

By I. de Jong, G. Van Weert

Silver cyanide adsorbs extremely well on activated carbons. This suggests that the addition of soluble silver salts to trace cyanide containing waste streams should allow efficient cyanide removal with active carbon. Silver losses, however, would make this method expensive and also objectionable, since silver has biocidal effects. When silver impregnated carbon is used, these problems are overcome. Test work has shown that such silver remains on or in the active carbon, that cyanide concentrations can be reduced to the level of detection (< 5 ppb) and that the silver impregnated carbon can be reactivated with equipment similar to that now in use at gold milling operations. Initial results on the type of carbon, the impregnation procedure and the level of silver, and the effect of repeated regeneration are discussed.

Jan 1, 1992

By M. Spangler

FirstMiss Gold installed a supervisory control system that is based on Pavilion Technology&apos;s Process Insights neural-network software and Oil System&apos;s PI data historian. The first successful control loop involved controlling the limestone feed rate to the neutralization circuit. The resulting improvements in the control of the circuit resulted in savings of $31,000 per month. Although it was the primary goal of the system, supervisory control of the preconditioning circuit was not achieved. However, information gained during the modeling suggested process modifications that resulted in cost savings of $54,000 per month in the preconditioning circuit.

Jan 1, 1997

By D. W. Gentry

Introduction Until recently, there were many jobs for mineral engineering graduates. Traditionally, minerals-related career paths available to university graduates stem from rather standard offerings in the disciplines of mining, metallurgy, petroleum, geology, geophysical engineering, and mineral economics. Within each discipline, there exists many career opportunities. In fact, until fairly recently, the most difficult decision for most graduates was choosing among all the available alternatives. Unfortunately, this relative state of euphoria changed quickly and dramatically within the minerals sector. Within two or three years, graduates from minerals-related engineering disciplines found it exceedingly difficult - and then almost impossible - to secure employment in the minerals sector upon graduation. At the same time, there were dramatic reductions in production requirements and, ultimately, mine closings. This resulted in massive layoffs and often termination of professional personnel possessing significant and valuable industrial experience. Obviously, this worsened an already bad employment picture for those hoping to begin a career in minerals. Certainly, there is no universal agreement on what the future offers for the US minerals industry or the career opportunities associated with it. However, there are a number of considerations that deserve study by students, faculty, administrators, and industrial personnel before minerals-related career paths are chosen. Where Will the Jobs Be and How Many? Everyone is aware that the minerals industry is very cyclic. It is not surprising then that job opportunities for new graduates also fluctuate. Typically, there is a two-to-four year lag between industry&apos;s engineering manpower needs and the academic community&apos;s ability to produce this talent. Due to the response lag, there will necessarily be years when supply and demand do not match. Employment Projections It is extremely difficult to anticipate what the key career paths might be within the next few years. Considerable speculation remains with respect to whether activity in the US minerals sector over the short-, intermediate-, and long-term will improve, remain status quo, or further deteriorate. However, some information pertaining to the prospects for career opportunities in mining engineering was offered by Tingley and Ghose (ME, Sept. 1983, p. 1274) from a study performed by Fenvessy and Schwab. Results from this industry-sponsored survey suggest that the US will experience 700 more mining engineers than needed in 1985, 1300 in 1990, and 1800 in the year 2000. These conclusions were based on the assumptions that future graduate levels remain flat and demand increases 3.6% annually. Educators quickly argued that depressed job markets, coupled with university student mobility, would negate the assumption of flat mining graduate levels in the immediate future. Student Mobility Student mobility from one engineering discipline to another is high. This is perhaps best demonstrated by the tremendous growth in programs such as computer engineering and computer science at the expense of enrollments in the more traditional engineering programs. The ability and willingness of students to quickly change engineering disciplines in response to existing and perceived job market demands have created significant student, faculty, and resource dislocations within universities nationwide. This has resulted in problems for university faculty and administrators responsible for effective use of

Jan 2, 1985

By James H. Nulty, Joseph S. Roti

Wetting agents used for heap leach gold applications would appear to have technical merit in aiding in recovering higher levels of precious metal. Many questions, however, remain as to whether they will function in practice, on what type of ore are they effective and if there are any negative affects associated with their use. A series of experiments are conducted at Bateman Labs, Sparks, Nevada, to determine under what conditions reagents of this type are useful. Carbon kinetics test work was also performed to determine if there are negative aspects associated with carbon loading with the use of these treatment chemicals. This paper outlines the results of these research evaluations, the general chemistry associated with action of wetting agents on leach ores and future work which is planned to further determine the viability of these products in the mining industry.

Jan 1, 1998

By C. F. Bonney

Spherical or oil agglomeration has been recognised for many years as a possible process for the recovery of mineraVmetal values. BP has investigated the potential of spherical agglomeration for a number of minerals as have other workers. Testwork has also been carried out by both BP and others on the selective agglomeration of fine coal. The spherical agglomeration of both minerals and coal depends on the use of an immiscible liquid e.g. a hydrocarbon which is added to a suspension of the solids in water. On agitation the oil is distributed over oleophilic/hydrophobic surfaces and particle impact allows inter-particle liquid bridges to form causing agglomeration. It is also possible to enhance the oleophilicity of the material to be recovered by the use of collectors similar to those used in froth flotation.

Jan 1, 1998

By T. W. Mattioli

Restrictions on fugitive emissions and crushing operations continue to get tighter. Although fugitive dust control in the gold mining industry has historically been difficult, there are now several options that can make dust control both effective and efficient. Using new technology, mine operators can now design and maintain a dust control program that can reduce product losses, decrease equipment failure, cut cleaning costs, and meet air quality compliance standards as well as provide a better working environment. This paper discusses the sources of fugitive emissions related to the gold mining and crushing operations and describes effective new control methods.

Jan 1, 1998

By J. Duncan Wilkins

Introduction In difficult times such as these, there is a strong reaction to the current way of doing things. Typical reactions that we have all heard are "There has to be a better way," "We&apos;re pricing ourselves out of business," "We have to improve our productivity," and "We have to have more cooperation," between union and management and employees and management. All of these comments have at their roots one common factor - getting the maximum amount for your dollar. The other factor inherent in these statements is productivity. I have not yet met a person in our industry who has not expressed the opinion that we should, and that we can, improve our productivity. Reducing Labor Costs In light of these factors I suspect we have all spent a fair amount of time examining our labor costs. For some of us, labor costs are a high proportion of our total cost of doing business. To alleviate the impact of these costs, we have generally done four things. We have reduced our number of employees, shut down operations for appropriate periods, sought concessions from union employees, and placed freezes on wages, salaries, and other benefits on nonunion employees. These approaches have been made to improve current shortfalls in our cash positions - to tide us over, as it were - or to provide us with a chance for survival. These are short-term measures that help to bring immediate relief, but can pose significant problems (or challenges), for the longer term. For instance, what do we do when times improve? How much do things have to improve before we do anything? By seeking concessions from unions in bad times, what do we do when unions come to us in good times? It is a rather sad and critical fact that we have grown too fat during the good times and too thin during the bad. In the first case, we have failed to optimize our earnings. In the second, we have cut ourselves too far. Consequently, when good or better times have arrived, we have had to bulk up our requirements to meet production commitments. In mining, for example, when times become tough, we tend to reduce our development plans so that when times improve we have to really "sock it to &apos;em," so that we can maintain productive capacities. We should plan ahead a little more to reduce the amplitude of our cyclical wavelength, so that in good times profits are optimized and in bad time we are better able to take the strain. Of course, forecasting cycles is not a refined art, but if we properly control our work force levels and costs at all times, and therefore optimize our productivity, we would be more able to withstand the problems we face today. Unfortunately, it appears that it takes bad times to bring us to a realistic appraisal of our way of managing our businesses. Labor Practices Not all of the problems now faced are due to low metal prices. Inflation has played a major role in bringing costs to a frightening level. Trade unions alone can not be blamed for high inflation levels over the past several years, popular though that notion is. Contract negotiations, after all, require two parties. Indeed, our current levels of labor cost are due to two factors: • We have felt obliged to keep our employees whole, relative to the cost of living. • We have felt obliged to maintain our competitive position relative to our peers, in order to maintain our ability to attract and retain a skilled, efficient work force. In the first case, our felt obligation has been applied without due recognition of the factor of performance, either in individuals or groups. Average, even mediocre performers, have been amply rewarded for their average work and mediocrity, while the good performers, no doubt receiving more for their good work and effort, have not perhaps appreciated the slight premium for their effectiveness. The rather predictable result of this practice has been that the average and mediocre stay that way (why change?), while some (certainly not all) of the good performers have said "It&apos;s not worth it," and slipped into the warm, cosy pool of the average and mediocre. In the second case, that of maintaining competitiveness with other companies&apos; employees, we have compounded an already serious problem of lack of skilled tradesmen by paying higher and higher prices for the existing pool to maintain comparability without improving the flow of more skilled people through sound and sufficient training programs. We have the rather dubious pleasure of paying more and more for the same problems. Compensation is either mutually agreed, as with unions, or it is unilaterally applied, as with nonunion employees. Generally, there is more flexibility available to the employer when dealing with nonunionized groups than there is with unionized groups. Sometimes that flexibility has not been used well, most often be-

Jan 11, 1983

By J. Edwards

A new, world class dump leach, solvent extraction, electrowinning plant for the recovery of copper comes on line in Chile. CODELCO-Div. Chuquicamata has added a new facility to their operations located in northern Chile. The plant demonstrates many unusual features including: underground collection of leachate, high copper tenors, extensive use of plastics and special corrosion resistant alloys.

Jan 1, 1989

By Mark L. Munsell

In recent years, miners have tried many approaches to maintenance such as: - Highly sophisticated computerized programs. - large planning groups designed to preplan and schedule work. - Contract maintenance. - Break down maintenance. Each of these approaches has faced the added constraints: - High replacement cost of equipment necessitating longer useful equipment life - management?s increased scrutiny of all indirect costs such as maintenance. Faced with these factors, what system of maintenance control is right? After visiting many properties recently, it appears there is no right system. Maintenance programs need to be tailored to the people and production constraints that occur at an individual property.

Jan 1, 1976

By C. E. Jordan

The Bureau of Mines conducted research to determine the effect of fine bubbles on the flotation of fine-sized particles (minus 20-um size). Turbulent flow collision models for fine particles and fine bubbles were reviewed. Velocity distributions within the flotation cell along with measured bubble and particle size distributions were considered in the models to predict the flotation response. The models were corroborated with laboratory fine-bubble flotation tests to verify the expected increase in flotation efficiency.

Jan 1, 1988

By J. F. Mack, P. R. Michael, J. M. Shapaka, S. J. Self, M. W. Richmond

"On October 11, 2000, an estimated 306 million gallons of water and coal waste slurry drained from an impoundment in Martin County, eastern Kentucky into an adjacent underground mine. Approximately 230 million gallons of the water and slurry discharged from two underground mine portals and affected over 75 miles of streams in Kentucky and West Virginia. In response to this and several other similar events, the U.S. Office of Surface Mining Reclamation and Enforcement (OSMRE) commissioned an oversight study that evaluates how well state and federal regulatory programs established under the Surface Mining Control and Enforcement Act are ensuring that impoundment operators are minimizing the potential for impoundment-basin breakthroughs. The study focuses on slurry impoundments constructed in the hollows of Appalachia where numerous coal seams and steep topography combine to result in a large number of mined seams intersecting and underlying impounding facilities. Factors under consideration include: (1) full accounting of all mineable coal seams intersecting and underlying the impoundment; (2) identification and accurate location of underground mines close enough to the impoundment to potentially affect its stability; (3) assessment of the stability of coal barriers between the impoundment basin and adjacent mines, and stability of roof rock and pillars in mines subjacent to the structure; (4) determination of the flowability of the impounded slurry when expanding or undermining the facility are being considered; and (5) measures undertaken to reduce breakthrough potential when necessary. The oversight study began in 2012 after program-evaluation criteria were defined in an OSMRE technical position paper. The study is scheduled to be completed in 2017. BACKGROUND The Surface Mining Control and Reclamation Act (SMCRA) authorizes the disposal of coal mine waste by constructing a coarse coal mine waste embankment across a valley and pumping the fine coal mine waste (slurry) into the resulting basin (Figure 1). A concern shared by many engineers, geologists, and mine inspectors familiar with coal mine waste slurry impoundments is related to the common occurrence of underground mine workings adjacent to or beneath the impoundment: the potential for slurry “breakthroughs” into mine works and subsequent breakouts into the surface waterways (Figure 2). On October 11, 2000 a combination of coal refuse slurry and water from the Big Branch impoundment in Martin County, Kentucky broke through into an underground mine and subsequently discharged into the receiving streams. The location of the point of breakthrough, pathways of slurry/water flow within the mine workings, and two points where the liquid exited the mine are shown in Figure 3. An estimated 306 million gallons of water and coal refuse slurry drained from the impoundment into the adjacent underground mine. Approximately 230 million gallons subsequently discharged from the underground mine at two portals."

Jan 1, 2015

By C. S. Harman, C. A. Enright, J. F. Brune

"The mining environment presents challenging and complex situations for the application of medical care. The combination of remote locations, difficult access and longer response times may create an increase in morbidity and mortality in the event of serious accidents. The U.S Mine Safety and Health Administration (MSHA) has only minimal requirements of first aid training for mine workers. For mine rescue team members, MSHA requires medical training at the Emergency Medical Responder (EMR) level, as only prescribed by mine rescue contest rules. This paper examines, based on mine accident statistical information, whether a higher level of medical training, for example at the Emergency Medical Technician (EMT) or at the Advanced Life Support (ALS) level can better address injuries most commonly disabling or leading to the death of miners in the United States. BACKGROUND Prehospital emergency medical care for the sick and injured has evolved considerably from first inception. Ambulances used to be staffed by persons with little training and equipment and prehospital care was focused largely on the rapid transport of the injured person to a hospital and. The modern prehospital care model was initially developed in military applications, where medics were responsible for some treatment on the battlefield and rapid transport to the care of a physician. In 1965, the National Academy of Sciences and National Research Council Committees on Trauma and Shock published Accidental Death and Disability: The Neglected Disease of Modern Society (National Research Council Committees on Trauma and Shock, 1966). This white paper laid out the consequences of the insufficiency of the Emergency Medical System (EMS) in the United States at that time. According to this paper, in 1965, 107,000 people were killed from accidental injury, with another 400,000 injured with permanent disability. The authors estimated that approximately 50% of ambulance services were provided by local morticians that were not capable of rendering advanced life support. The paper states that, based on experiences in the Vietnam war, seriously wounded soldiers had a better chance of survival in the battle field compared to traffic accident victims with similar traumatic injuries because the military was capable of providing first aid and efficient transportation to emergency care facilities. The white paper states that death rates from battle injuries declined significantly from 8% in World War I to 2% in Vietnam. The publication of this white paper is credited for the broad evolution and rapid advance of the civilian EMS system after 1965. It eventually lead to the creation of the National Highway Transportation Safety Administration (NHTSA) National Standard Curricula (NSC) for emergency medical care in 1985. Training, and therefore required skill and knowledge for prehospital emergency care has continued to grow to reach the current standard."

Jan 1, 2016

By F. Calizaya, S. Bhattacharyya

"INTRODUCTION Mechanized underground mines often suffer from noise overexposure. Noise levels are usually above the Permissible Exposure Limit (PEL) where underground fans are used. Sound levels in active workings can reach 121 dB(A), especially when fans are not equipped with silencers. Use of silencers seldom ensure PEL for various reasons. Overexposure of noise induces permanent hearing loss among mine workers. Recent field studies by a NIOSH-funded research project at six coal and non-coal mines revalidated the findings. The University of Utah has undertaken laboratory studies to reduce fan noise at the source. A new silencer prototype with varying noise dampening material has been designed and tested. The silencer and an associated extension which can be repacked with different dampening materials were used in various configurations. Attempts were made to simulate field conditions where installations are quick and not perfect. The test results are presented here. NOISE IN UNDERGROUND MINES Noise induced hearing loss (NIHL) is a chronic problem in the mining industry. In spite of regulations being in place and elaborate hearing protection programs under way, hearing loss is prevalent among the mine workers (Bise, 2001). All production and support machinery in mining generate loud noise often beyond the approved exposure level. Researchers in the U.S. have identified auxiliary fans as one of the major sources of noise that can create noise exposure levels up to 121 dB(A), which is one of the highest in the mining operation (Bauer, 2006). Studies have demonstrated substantial reduction of noise level by using silencers. Adequate fan selection and proper utilization of silencers in auxiliary fans have great potential of abating the problem. In hard rock mines, auxiliary fans are used in blower configuration to ventilate development headings and large production stopes, and also to ventilate underground shops, crushers, conveyor transfer points, etc. Typical duct diameters in hard rock mines vary from 0.91 m to 1.21 m. Silencers are often omitted for cost reduction. In coal mines auxiliary fans are used in exhaust configuration with rigid ducts 0.61- 0.76 m in diameter (Hagood, 1982 and Moreby, 2009) to ventilate working faces in gate-roads and main entry developments. Sometimes, stone dusters are added at the discharge end to dust the roof, ribs and floor. AUXILIARY FANS AND SILENCERS Auxiliary fans are relatively smaller in size than the main fans and often have high rotational speeds (1800 -3000 rpm). Fans are selected based on pressure-quantity requirements and space restrictions only. Noise emissions are rarely considered during the selection stage. Installation of fans, ducts and other accessories is mainly based on best practices, which often do not include noise control. As a result, the operation of an auxiliary or local ventilation system normally produces excessive noise."

Jan 1, 2018

By N. Damiano, J. Noll, C. Zhou, J. DuCarme

"Preventing machine-related injuries is one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable were characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which cause little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects. INTRODUCTION An average of 250 injuries occur every year during operation of Continuous mining machines (CMMs), and 43 miners have been killed by striking or pinning accidents involving CMMs in the U.S. from 1984 to 2015 (Mine Safety and Health Administration, 2015). In addition, there have been 10 fatal accidents involving mobile haulage equipped with trailing cables from 2000 to 2015 (Noll et al., 2017). In response to these fatalities and injuries the Mine Safety and Health Administration (MSHA) promulgated a regulation in 2015 requiring the use of a proximity detection system (PDS) on all CMMs except full-face machines and proposed a regulation in 2016 which would require a PDS on other mobile underground equipment. Current PDSs approved for underground use are magnetic-field based. The PDS contains machine-mounted magnetic field generators that create fields around the machine. The other part of the PDS is a miner-wearable component (MWC) that reads the flux density of the generators. These systems use the magnetic field strength readings from the MWC to determine whether a miner is at a safe distance from the machine. A stable magnetic field is essential for the accuracy of the system."

Jan 1, 2018

By Andrew J. Regis

The methods of evaluation of industrial minerals occurring on Federal lands have different meanings if the evaluations are done by a company rather than a government agency. For example, when the Bureau of Land Management (BLM) conducts an examination of mining claims, this is commonly referred to as a "validity examination," whereas it is an "economic evaluation" when performed by a company. Not only is there a difference in nomenclature in these evaluations, but there is a general lack of expertise in the Federal government on industrial minerals in general. A metallic mentality still prevails in the U.S. Forest Service (USFS) and the BLM. Because of this, many validity exams on industrial-mineral deposits commonly just skim the surface concerning economics and marketability. The BLM and USFS place a high amount of emphasis on past administrative case law pertaining to the validity of industrial minerals under the 1872 Mining Law and, rightly so, on marketability, which also is heavily addressed in case law. When the BLM considers marketability, only the marketability of a particular industrial mineral for only the primary use for which it was located is considered and any value-added markets cannot be included. The BLM defines marketability based only on the value of the mineral material in its in situ or raw state, rather than value-added through processing. Another difference in the evaluation of industrial minerals by government and industry is the question of by-products. When a company evaluates a mineral material it looks at all the markets. The BLM looks only at that market for that locatable mineral for which the claim was located. In other words, sales from non-locatable by-products cannot be used to support marketability or the prudent-man rule (i.e., oversize silica sand from a glass-sand claim being sold for construction sand, road base, fill, etc.). The question of reserves also can present conflicts. An industrial-mineral company will often try to identify all the reserves available for a possible future development. They must do this for financial backing and support from upper management. The BLM, however, will limit their validity examination only to those reserves that meet the prudent-man rule and marketability tests. The BLM will validate reserves sufficient to last 25-30 years, based on available market. The development of industrial minerals on Federal lands is a difficult process, and, if the 1872 Mining Law is changed, it could become not only more challenging but also more costly. The industry must become more tolerant of the mineral specialists in the BLM and the USFS. On the other hand, the government mineral examiners must become more aware of the importance of industrial minerals in everyday living, and the economic evaluation of these materials.

Jan 1, 1999

By T. Rockley, B. Goertz, S. McDaniel, J. Brune, K. Bakhsh

"Researchers at the Colorado School of Mines, under a project funded by the Alpha Foundation, have developed a working prototype of a dust sample collection device designed to determine if sufficient rock dust has been placed in an underground coal mine to prevent coal dust explosions. When used in conjunction with the Coal Dust Explosibility Meter (CDEM), the device will provide near instantaneous results on the quality of rock dusting at the tested location. The sampling device applies a pulse of air to a testing surface and collect a representative sample of mine dust based on the pneumatic entrainment process during a mine explosion. The use of both physical testing and Computational Fluid Dynamics (CFD) modeling has allowed researchers to refine the design to accurately represent the particle entrainment and optimize the sample size collected for the CDEM. The prototype is being tested in a mine environment to produce information of usability and practical aspects of mine dust sampling. This paper is a progress report summarizing the current status of sampler development. Researchers expect to have a fully developed and tested sampler in early 2016. INTRODUCTION Underground coal mines face the danger of methane and coal dust explosions. The disaster at Upper Big Branch mine (2010) has demonstrated the impact of a violent coal dust explosion that fatally injured 29 miners. Reviewing the history of coal dust explosions, researchers found that that mine operators and mine inspectors do not have a reliable method of collecting dust samples to assure that sufficient amounts of rock dust have been places to inertize the coal dust. This is a problem specifically with small mines that do not have dedicated safety departments to track rock dusting work. The aim of this research is to develop a simple, portable device that can help underground mine examiners collect dust samples from workings and test the explosibility of the sample near instantaneously. Researchers determined that the current brush-and-pan sampling method required by MSHA (MSHA 2013) is flawed in several aspects: Mechanical sampling with a brush exerts forces on the mine dust that may differ significantly from those present during an explosion. Also, U.S Bureau of Mines research (Nagy 1965) has determined that only the top 0.125 inches of the mine dust layer will be entrained in a coal dust explosion. Using a handheld pan and brush, it is difficult to correctly and repeatably sample a layer of this exact thickness. The following will describe the CFD modeling and experimental testing for the development of the prototype sampler. Researchers analyze the accuracy and performance of the prototype during the course of the build process."

Jan 1, 2015