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"The 33rd annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Tucson Starr Pass Resort & Spa on Saturday, Dec. 5, 2015. Each year, one living Hall of Fame inductee, two Medal of Merit recipients, several honorees from Mining’s Past, an Industry Partnership Award and a Special Citation are recognized for their respective contributions to the mining industry.Conrad E. Huss, cofounder of M3 Engineering & Technology Corp. located in Tucson, AZ, will be honored as the 2015 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Huss has served his company as chairman of the board for its entire 30 years and guided M3 to become a full discipline firm. Now M3 offers complete project execution through engineering, procurement and construction management procedure and has become a major engineer of large observatories around the world. The company now has more than 1,000 employees with offices in Arizona, North Carolina, Mexico, Argentina and is incorporated in Guatemala, Peru and Canada.The Medal of Merit will be awarded to Charles Michael (Mick) Lownds, founder of his eponymous consulting firm in Salt Lake City, UT, for his 42 years in commercial explosives following tenure at Sasol and at Orica. Originally from South Africa, Lownds immigrated to the United States in 1998 and has made significant advancement on electronic initiation systems. Lownds has published numerous technical papers, is an inventor with 12 awarded United States patents and was also the recipient of the President’s Award from the International Society of Explosives Engineers in 2000.Medal of Merit for young professionals will be awarded to Fiorella Giana, Freeport- McMoRan Inc.’s (FCX) mine manager at Bagdad. Born in Buenos Aires, Argentina, Giana left the small cattle farm where she was raised in 2001 to pursue higher education in the United States. For the past decade at FCX, as a result of her extraordinary combination of technical skill, leadership and commitment to excellence, she has been given positions of progressively greater responsibility from an entry level engineer to senior mine engineer, to chief engineer and now as mine manager, a position rarely held by woman."

Jan 1, 2015

By J. C. Watts

Ball mill grinding circuit control has received increasing emphasis in the past few years due to such factors as declining ore grades, increasing production costs, and advances in analytical devices and minicomputer technology. Since ball mill circuits have been a traditional bottleneck in mineral processing plant throughput, control systems often improve through- put without requiring additional processing equipment. In addition, much of the variability of the grinding product size and consistency is often removed, allowing better process operation downstream. Among the problems which arise in designing and implementing a process control strategy for ball mill circuits are circuit constraints imposed by processing equipment and local management, proper instrument selection, installation and maintenance, and use of calculated or inferred variables for process measurements. This paper discusses these problems and attempts to identify valid approaches to their solution.

Jan 1, 1979

By David J. Kruse

Accurate field measurements are essential when validating a conveyor design. They are fundamental in determining a conveyor's behavior, its long-term maintenance requirements, and the life expectancy/ condition of the installed equipment. Field measurements are also invaluable in forensic engineering, particularly when vital equipment has failed This paper will discuss a wide variety of data acquisition equipment, field measurement techniques and accuracies achieved State-of-the-art, custom designed monitoring equipment, as well as, ''08-the-shely instruments and sensors, will be discussed.

Jan 1, 2004

By S. Henley

There is much in common between the requirements of open-pit mining and quarrying operations. Both involve the extraction of large volumes of material from surface excavations. The principal differences are of degree: open-pit mining of materials such as coal or gold generally involves the extraction of only small volumes of 'mineral' and large volumes of waste-they are operations with very high stripping ratios, and are made viable only because of the high unit value of the extracted mineral. In quarrying operations, the unit value of the mineral - sand, aggregate, limestone, or clay - is much lower, but stripping ration Are also lower. Thus the same techniques of geological modelling, reserve estimation, and pit planning are applicable, as is shown in two examples from the British quarrying industry. In each case, a primary requirement is the definition of production volume or tonnage. Sometimes, this need may be addressed simply by the use of a survey data processing package. However, in other cases, such as the two examples addressed in this paper, of sand and clay quarries, detailed assessment of the variation of mineral grades is a vital part of the exercise, and simple volumetric modelling cannot in itself be sufficient. In these cases, a block model approach using simple logical and numerical post-processing is also required to obtain required parameters for commercial classification of the products to be extracted. Pit designs themselves may be optimised by use of algorithms such as Lerchs-Grossmann, but the value of mineral produced can be dependent on factors other than its grade in any one part of a single pit, and the 'optimised' pit itself must be considered only a good sub-optimal. Given the right degree of healthy skepticism, and a software package with sufficient flexibility to be adapted readily to the rather different requirements of the quarrying industry, there is no reason why the quarrying industry should not benefit from the many years of investment in mining software technology.

Jan 1, 1989

By Anibal Gajardo

Clays for building bricks and roofing tiles in Chile are classified as common clays and ball clays, with deposits of sedimentary and residual origin, both Cenozoic in age. Deposits are known from north to south, through 11 of the 13 Chilean Administrative Regions, 18° to 39° South latitude, and from west to east, through three of Chile's main geomorphic features, namely the Coastal Plains, Coastal Range, and Intermediate Depression. Alluvial and lacustrine sedimentary common clay deposits are located in the northern and southern Intermediate Depression. The average chemical composition of clay deposits in I and I1 Regions, is 58 percent Si02, 16 percent A1203, and 4 percent Fe203 by weight; the primary minerals are sericite, quartz, feldspar, and albite. The average chemical composition of clays in Metropolitan, VI, and VIII Regions, is 52 percent Si02, 16 percent A1203, and 6 percent Fe203 by weight; the primary minerals are montmorillonite, quartz, and plagioclase. Residual common clay deposits occur in the Intermediate Depression and in the Coastal Range internal basins, VII, VLII, and IX Regions, and they represent surficial alteration of pumice beds and crystalline rocks. The average chemical composition of clay deposits derived from crystalline rocks is 58 percent SO2, 17 percent A1203, and 9 percent Fe203 by weight; the primary minerals are sericite, quartz, and clinochlore. Clay deposits formed from pumice beds contain 47 percent Si02, 24 percent A1203, and 10 percent Fe203 by weight; the primary minerals are kaolinite, feldspar, and cristobalite. Sedimentary ball clay deposits are located in the Coastal Plains and Coastal Range, VI, VII, VIII, and IX Regions, between 34" and 39" South latitude. The average chemical composition of the ball clay deposits is 51 percent ,902, 28 percent A1203, 5 percent Fe203 by weight; the primary minerals are kaolinite, quartz, and sericite (illite?). These clay deposits supply the Chilean building sector with over one million metric tons (mt) (1.1 million short tons [st]) of material per year. The average growth rate of clay consumption during the period 1993 through 1997 was 10 percent annually. The clays are used by both mechanized plants and handcraft facilities.

Jan 1, 2001

By G. Meiers, M. O’Kane

Dry cover systems as a closure option for management and decommissioning of waste rock and tailings is a common prevention and control technique used at numerous sites around the world. Numerous site-specific factors control the long-term performance of dry cover systems. Site-specific climate conditions are one of the key factors to consider when determining the objectives of a dry cover system because these conditions will significantly influence long-term performance. There are advantages and disadvantages of characterizing the site on an annual basis as generally a “dry” site (annual potential evaporation greatly exceeds annual precipitation), or generally a “wet” site (annual precipitation meets or exceeds annual potential evaporation). The field performance monitoring data and discussion presented herein illustrates the caution that is required when using these “annual” criteria for characterizing site climate conditions. Numerous sites exist where precipitation exceeds potential evaporation on an annual basis; however, the site typically experiences hot, dry summer months where evaporation greatly exceeds rainfall. These dry summer conditions have a strong influence on long-term performance. In contrast, sites where potential evaporation exceeds precipitation on annual basis, typically experience periods of the year when a moisture surplus occurs, which also impacts on long-term performance. This paper uses soil-atmosphere cover design modelling and field performance monitoring from sites in Canada, Australia, and the United States to demonstrate the importance of considering site-specific climate conditions when predicting long-term cover system performance.

Jan 1, 2003

By R. K. Mehta

An electrochemical coal oxidation model involving heterogeneous kinetics is presented. This model was tested by collecting current transient data on three coals assaying different ash content under varying operating conditions such as particle size, temperature, and % solids. In all cases, the model fitted the data very satisfactorily. Three intrinsic rate constants, namely mass transfer coefficient of Fe(II) Ions diffusing from solution to the anode (kma), mass transfer coefficient of Fe(II) Ions diffusing from solution to the coal surface (kmc), and chemical rate constant for coal oxidation with respect to Fe(III) at coal surface (k), were calculated. It was interesting to note that in this system, the mass transfer at anode was as important as the chemical reaction at the coal surface. The validity of this model was further demonstrated through a comparison of the activation energy of coal oxidation: firstly, by utilizing calculated chemical rate constant and assuming Arrhenius' type of relationship: secondly, by utilizing conventional approach using limiting current values. The comparison revealed that agreement was quite close. This kinetic analysis is useful because such a model can be used in predicting the intrinsic rate constants so that the relative importance of mass transport can be rationally analyzed.

Jan 1, 1991

By Robert A. Jankowski, Charles A. Babbitt, Natesa I. Jayaraman

Today, approximately 31% of underground coal mining operations have designated occupations or areas with more stringent (below 2.0 mg/m3) respirable dust standards in place. Many U.S. coal mines have been able to maintain compliance with very low dust levels, and the Bureau of Mines, in an effort to identify those factors contributing to low dust levels, completed a survey of twelve continuous miner sections which were able to maintain their dust levels at or below 0.5 mg/m3. The quantity and quality of face ventilation appeared to be the most important factor in controlling dust exposure. The results directed Bureau research towards identifying improved face ventilation techniques for reducing quartz dust levels on continuous mining operations. This research has involved the evaluation of a half-curtain face ventilation technique which reduces the cross-sectional area of the entry, thus increasing the air velocity over the operator. The Bureau has also conducted extensive laboratory studies to compare tubing versus brattice, including an evaluation of both systems in a crosscut turn. In an effort to improve ventilation and reduce dust exposures of roof bolter operators working downwind of the continuous mining machine, the Bureau has evaluated two novel face ventilation systems. The first system consists of a fan discharge tubing technique which routes dusty air away from the return entry being bolted. In a technique similar to the fan/tubing concept, exhaust air from the upwind continuous miner face can be scrubbed using a dust collector to capture a portion of the dusty air, clean it, and supply it to the bolter operators as a split of clean intake air. A better understanding of face ventilation techniques should lead to solutions to the problem of more stringent dust standards due to quartz.

Jan 1, 1989

By Bernard Amadei, Michael J. Robison

The purpose of this paper is to present the results of 102 mu1tiaxial tests conducted on cubical specimens of Indiana limestone using the mu1tiaxial apparatus available at the University of Colorado at Boulder. These tests include (1) uni-axia1 compression and tension, (2) bi-axial and tri-axial compression, (3) biaxial compression- tension and (4) tri-axial compression-compression- tension. The applicabi1ity of existing failure criteria to predict the strength of the tested materia1 is discussed.

Jan 1, 1986

By STEVEN J. SCHATZEL, Zoheir Khademian, KAYODE M. AJAYI

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine, creating safety concerns. To provide recommendations for developing guidelines that ensure a safe coexistence of longwall mining and unconventional shale gas production, this study uses a discrete fracture network (DFN) model to evaluate the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations are within values validated with field measurements.

Mar 1, 2023

By J. H. Calder, J. C. Hower

Three lithotypes of Phalen coal from Cape Breton County, Nova Scotia, Canada, were subjected to a modified Hardgrove grindability index (HGI) test. The testing scheme differed from conventional (ASTM D-409) Hardgrove testing by, in one case, repeating the test three times prior to removing the -200-mesh fine coal from the Hardgrove mill, and, in a second test, removing fines after each of three successive Hardgrove tests. Only the first stage of the latter testing scheme actually conforms to the standard HGI test. All processed samples were analyzed petrographically by a combined maceral/microlithotype analysis. The increase in the percentage of coal ground to -200 mesh increases through the 60- to 180-mesh fractions for each of the lithotypes for the following two apparent reasons. First, with progressive grinding, more of the oversize material is close to 200 mesh (75 µm), creating a "pool" of particles ready to be ground to -200 mesh, and, second, the removal of fines from the system at each step eases the grinding at the successive step. The fines retained system shows the influence of buffering of further grinding by the particles retained in the grinding mill. The Phalen lithotypes and the series of Central Appalachian coals, evaluated previously by Hower and Wild (1994), differ in that an increase in vitrite and a decrease in trimacerite is observed in successive -200-mesh fractions in two of the Phalen lithotypes. This is the opposite of the trend observed in the slightly lower-rank Central Appalachian coals.

Jan 1, 1998

By John Rushton

Surface mining, from ore extraction to processing, requires many types of equipment to obtain the final product. Mine equipment often includes shovels, drills and haul trucks. Ore processing equipment, including plants, mills and concentrators, are also part of surface mining operations. Surface mining operations emphasize production. Production is where the bills are paid and fortunes are made. However, there must be support to keep the equipment operational. To most production people, equipment maintenance is a necessary evil. Maintenance is not glamorous work. It is often neglected when praise is being passed around. It is easy to recognize higher production, greater capacities, faster cycle times or more loads hauled. But who cares if an engine is replaced in 12 hours instead of 48? The answer is, everyone should - from the hourly miner to the mine manager. Surface mining equipment needs constant maintenance work. It must be lubricated, components replaced, electrical problems repaired and other problems addressed. Repair work for any surface equipment takes time away from production. It costs money. Maintenance costs cannot be avoided. However, they can be minimized. Minewide communication should include operations cooperating with maintenance. Traditionally, operations resist surrendering equipment to maintenance if it can continue to produce. The rationale is, every load that can be hauled today is money in the bank. If the unit is taken down, the money is lost. This thinking is prevalent in many surface mining areas, including the mill. "Not on my shift," the operator thinks. "Let the next crew worry about it. The problem with this thinking is in probability and statistics. The longer equipment goes without maintenance work, the higher the probability of equipment failure. When the failure does occur, it is certain to cause the equipment to remain down longer than if the maintenance department had been allowed to take it down. Many mining operations have closed early in their lives because of poor maintenance practices. This has become the industry standard because substandard levels of performance are acceptable. Management believes it gets five to six hours of work from maintenance people during an eight-hour shift. Actually, the industry average is less than two hours of work per shift. Real productivity levels of less than one hour are not unusual. There are few exceptions. However, a daily work schedule (DWS) will increase productivity at many properties by 50% to 100%. A 200% improvement is not unusual. The DWS will work. Maintenance people are among the most intelligent and motivated people on the property. They deserve the chance to be productive. [ ] In preparing a DWS, management needs to understand two productivity principles - the productivity spread and the real maintenance workday.

Jan 1, 1997

By S. W. Beckman, L. Williams, A. E. Seep, R. Fischer, J. Hubbard

Introduction The Summitville Mine located in southwestern Colorado was added to the National Priorities List in June of 1994. Summitville was the site of mining operations that began in 1873 with the discovery and development of gold placer and lode deposits in the late 1800's. The mine site is located about 25 miles south of Del Norte, Colorado in the San Juan Mountains adjacent to the Rio Grande National Forest at an approximate altitude of 11,600 feet. The site was mined for gold, silver and copper between 1873 and 1947. The Summitville Consolidated Mining Corporation, Inc. (SCMCI), a wholly-owned subsidiary of Galactic Resources, Ltd of Vancouver, Canada ran a large tonnage open-pit mine and cyanide heap leach operation from 1986 to 1992 (Pendleton and Posey, 1992) During the mine operation by SCMCI, approximately 10 million tons of gold ore was mined, crushed and stacked on a lined leach pad. Heap leach operations experienced water balance and unplanned solution discharges from the start of the mine life. Despite the production of 249,000 troy ounces of gold during the mine operation, SCMCI was unable to meet remedial requirements and notified the state of Colorado of its intention to file a Chapter VII bankruptcy in December 1992. The EPA Region VIII Emergency Response Branch took over site operations on December 16, 1992 to prevent a catastrophic release of hazardous substances to the environment. The multiple contamination sources at the mine site are due to both historic and SCMCI mining operations. Emergency response operations at the site have prevented releases of severely contaminated solution and a permanent treatment for all waste units at the site is under investigation. A Request for Proposal (RFP) was issued in October 1993 by Environmental Chemical Corporation (ECC) at the Request of EPA Region VIII, Department of the Interior and Bureau of Reclamation. The RFP requested that interested companies provide information on their ability to implement innovative treatment technologies to improve treatment efficiency and reduce treatment costs for remediation of the heap leach pad (HLP) spent ore and ore leachate solutions. Dames & Moore and Pintail Systems, Inc. (PSI) jointly submitted a proposal suggesting application of biotreatment processes for detoxification of cyanide in spent ore and HLP leachate solutions. The proposal was accepted for pilot and field demonstration under the SPA Superfund Innovative Technology Demonstration Program (SITE) with additional funding from EPA Region VIII. This report discusses the test program and results of a Focused Feasibility Study which demonstrated biotreatment processes for spent ore cyanide detoxification.

Jan 1, 1995

By Jean-Michel M. Rendu

Increasingly, geologists use geostatistical methods to evaluate drilling programs. The complexity of the methods varies with the nature of the available sample information, the objective of the statistical analysis and the geologist's experience. Occasionally, estimating the average sample grade is all that is required. In other instances a semivariogram calculation may be considered. If sufficient data is available, the geologist may wish to estimate blocks or panels of complex shape, using the kriging method of evaluation. Historically, the use of geostatistics by geologists has been limited by a number of factors, most significant being the difficulty in accessing and using computer programs needed to complete the necessary studies. Geologists are often working in remote areas from which electronic communication is unreliable, if not impossible. Even when access to computer programs is technically possible, the costs incurred in accessing and using these programs are often considered prohibitive. In many instances using the programs requires an understanding of computer systems far beyond that which a field geologist can justifiably be interested in acquiring and maintaining.

Jan 1, 1984

By S. J. Schatzel, K. M. Ajayi, E. N. Rubinstein, Z. Khademian

This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities, and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72 × 10 m3/s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97 × 10 m3/s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16 × 10 m3/s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07 × 10 m3/s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover.

Feb 1, 2024

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 C. J. Pritchard, A. B. Cecala

An evaluation was performed on a district recirculation system at a trona mine in Granger, WY. A 1.52 m-diam (5 ft-diam), 37.3-kW (50-hp) vane axial fan was installed in a crosscut between the intake and return airways and recirculated about 31.4 m3/s (66,578 cfm) of air back into the intake. This amounted to a recirculation factor of about 20% of the return air. This air was part of the primary ventilation to three different continuous miner sections at operating distances of between 610 m (2000 ft) and 1829,m (6000 ft) from the recirculation fan. The mine environment was constantly monitored for respirable dust, methane and carbon monoxide in the operating sections and in the main intake and return entries. In addition, air samples were taken with and without the recirculation system during the evaluation and analyzed using gas chromatography. The results of this study showed only small increases in dust, while all other mine contaminants remained at such low levels that it was impossible to determine any relative changes from the recirculation system. Because of this, a brief SF6 tracer gas analysis study was subsequently performed to more precisely determine an increase in a mine contaminant with the recirculation system.

Jan 1, 1992

By Petr Salak, Adrian St. John, Angelos Gakis

"INTRODUCTIONCrossrail will provide London and the South East of England with a world class, high-capacity railway to ease congestion on London’s public transport system and enable better access between business, residential and entertainment districts. At the heart of this £14.8bn scheme lies Farringdon Station, which will form a major interchange between Crossrail, Thameslink and London Underground. The £400m Farringdon Crossrail station was awarded to a joint venture of BAM Ferrovial Kier (BFK) in 2011, and comprises two ticket halls, two platform tunnels and a multitude of connecting tunnels all constructed using open face sprayed concrete linings (SCL). BFK appointed Dr. Sauer & Partners (DSP) as their specialist SCL designer. As the main contractor for both C300/C410, the Western Running Tunnels and Station Caverns, and also for C435 Farringdon Station, BFK were in a unique position to develop strategies to reduce cost, time and risk for the Client. One such innovation involved the continuation of the TBM drives for the running tunnels right through the length of the new Farringdon platform caverns. This created large diameter precast concrete pilot tunnels for the subsequent platform enlargement using SCL. The benefits of such an approach are described in detail by St.John et al 2015. BFK also introduced another alternative strategy to reduce cost, time and risk, by proposing to abandon the TBMs in the ground (“Turn & Bury”) permanently rather than recovering them through the ticket hall shafts. This de-risked the programme, enabling critical ticket hall construction to proceed unhindered. However, one consequence of this revised strategy was an area of increased underground congestion, with two SCL tunnels (RTE2 and ES2) and a bored tunnel (complete with abandoned TBM) in close proximity to a ticket hall excavation (see Figure 1) and a sensitive, listed railway structure. Faced with this complex geometry, and combined with challenging geotechnical conditions (Gakis et al 2015), the team chose to install enhanced monitoring to study the behavior of tunnel RTE2 and provide additional assurance that the tunnels were performing as predicted. Applying advanced 3D numerical modelling and taking into account the residual tensile strength of the SCL helped avoid unnecessary reinforcement installation in primary lining and/or early installation of a secondary lining in RTE2 prior to ES2 construction."

Jan 1, 2016

By G. A. Rosario, G. Peach

Twin 8.5 m diameter, 10 km long headrace tunnels under overburdens of up to 1870 m were excavated for the neelum jhelum hydroelectric project in north-eastern pakistan using two main beam gripper tunnel boring machines (tbms). Rock bursts were encountered and presented a significant danger to personnel and equipment. Micro seismic monitoring was installed to analyze rock burst characteristics and to create a database for future reference. Correlation of rock burst characteristics improved the ability to predict the likelihood, location, severity, and number of rock burst events. This paper presents the analysis of the micro seismic data

Dec 1, 2022

By J. DuCarme, A. Smith, M. Reyes

"A magnetic proximity detection system is mounted on a mobile mining machine to prevent underground workers from being pinned or struck by machine motion. The system generates magnetic fields around the machine to determine safe working distances. The minerworn component measures the magnetic field in order to approximate location. Large masses of steel, such as those from mining equipment, can alter the magnetic field distribution. This affects the locational accuracy of the system, thus adversely impacting worker safety. To examine this problem, U.S. National Institute for Occupational Safety and Health researchers developed a method and test system to study the influence of a steel mass on the magnetic field distribution. The results show that a steel plate can strengthen the magnetic field perpendicular to the generator by up to 40 percent. Furthermore, they show that the degree of the influence on the field distribution is a function of distance. The results from this study can be used to further develop and improve the performance and reliability of electromagnetic proximity detection systems used in underground mining applications.IntroductionOn average, 250 miners are injured every year, and 43 miners were reported to be killed by striking or pinning accidents involving continuous mining machines in the United States between 1984 and 2015, according to the U.S. Mine Safety and Health Administration (MSHA, 2015). Continuous mining machines are large mobile machines used to mechanically cut coal in underground mines. These machines weigh approximately 60 t (132,000 lb) each. Although modern continuous mining machines can be remotely controlled, operators still need to be close to the machine primarily because of the low visibility and wide blind spots of the underground working environment.The MSHA promulgated a final regulation in 2015 that requires the use of proximity detection systems on all continuous mining machines except fullface machines. MSHA has approved five such systems to be intrinsically safe for use in underground coal mines: (1) Strata Worldwide’s HazardAvert System, (2) Frederick Mining’s Model 200 HazardAvert Detection System, (3) Nautilus International’s Coal-Buddy System, (4) Matrix Design Group’s M3- 1000/Joy Global SmartZone Gen 1 and (5) Matrix Design Group’s IntelliZone/ Joy Global SmartZone Gen 2."

Jan 6, 2018