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By RAYMOND C. HARTVIKSEN

The Drumbo Mine is located near Highway 401 between Woodstock and Kitchener in southwest Ontario. The tabular flat-lying gypsum bed is between 1.5 to 2.4 m thick and is situated near the base of the Salina Formation, about 116 m below surface. The mine is owned and operated by Westroc Industries Limited. The 3.8 m diameter shaft was drilled using a Hughes CSD 820 drilling rig and a liner sinking technique new to the North American continent. The shaft was completed in the fall of 1977, and remaining facilities were finished in the fall of 1978. Gypsum production started in December 1978, employing the conventional room-and-pillar method of mining.

Jan 1, 1984

By Y. Chino

Cross-rolling, in which the roll axis is tilted by 7.5 degrees against the transverse direction, was carried out on a commercial magnesium alloy. The (0002) texture intensity of the cross-rolled specimen was lower than that of the unidirectionally rolled specimen. Also, the grain size of the cross-rolled specimen was smaller than that of the unidirectionally rolled specimen. As a result of the Erichsen tests at 433 ? 493 K, the press formability of the cross-rolled specimen was higher than that of the unidirectionally rolled specimen. The high formability of the cross-rolled specimen is attributed to both the reduction in (0002) texture intensity and the enhancement of grain refinement by the cross-rolling.

Jan 1, 2006

By R. Roufail

Mineral exploration is in a race to employ drilling technology that can perform the exploration and drilling investigation in a fast and inexpensive manner. After an extensive study of the available drilling technologies in the market, coiled tubing was chosen as a tool to be employed for mineral exploration due to its flexible mobility and ease of operation with a minimum number of personnel. Since coiled tubing technology is primarily used in the oil and gas industry, it was important to re-design the coiled tube rig to drill hard rocks in a fast and feasible manner. The main requirements were to drill the smallest feasible hole diameter and go as deep in the ground as possible, in the shortest reasonable time. The drilled rock particles, cuttings, are to be collected and analysed at the surface for their metal mineral contents. The process also needs to be repeated multiple times at different locations for mapping, without the need to change the tube on the rig due to failure or potential failure. The focus of the new designed coiled tube, for drilling and mineral exploration, is three fold. First is to increase the rate of penetration in drilling by designing a small high speed turbo motor. Second is to determine the controlling parameters of cuttings transport to effectively lift the cuttings to the surface for analysis and third is to minimize the overall weight of the rig for manoeuvring and prolong the life span of the coiled tube string. In this paper, a small downhole turbo motor, 5cm outer diameter, is designed to achieve a rotation speed of up to 10,000 rpm to fit on a small bit, coiled tube drilling assembly. The motor design utilised multiple finite volume and finite element analysis softwares for fluid flow study and fluid structural interaction analysis. The paper is also introducing the concept of a flow slurry loop that is designed to lift the cutting particles to the surface for mineralisation analysis. The controlling parameters of the cuttings transportation are the particle?s physical properties such as size, density, concentration and shape, as well as the rheological properties of the carrying fluid, drilled hole angle, as well as the fluid flow rate and flow dynamics within the annulus gap between the coiled tube and drilled hole. Such parameters are addressed via experimental work as well as numerical analysis. The paper is also presenting the selection and testing procedure of the material type for the coiled tube string. The tube needs to be light in weight for overall rig weight and its transportability. The tube is also required to drill several dozens of investigation holes before failing due to fatigue. A fatigue bending machine is designed to test the endurance limit of candidate materials for coiled tube strings and a performance index methodology is followed for material selection of the optimum material. The coiled tube rig is designed to be light in weight for transportation and relocation. It is also required to speed the drilling operation with the minimum footprint and reclaim the drilled rock particles for mineral composition analysis at the surface.

Aug 1, 2013

By Q. F. Wang, M. H. Lai, T. Q. Liu, G. G. Dong

Compared with the traditional pre-treatment process, biological oxidation process has many advantages including higher gold recovery, less cost, easier operation. The bio-oxidation reactor is the most important equipment for biological oxidation process. In this paper, the characteristics of biological oxidation are investigated, and the design principles are proposed based on laboratory tests. Both increasing the tank height and taking new inflation system can enhance higher dissolved oxygen. The new type of large-scale industrial bio-oxidation reactor is designed, which is 9.5 m in diameter and 10 m in height. The bio-oxidation reactor metallurgical performance has been tested by industrial-scale experiment. The slurry of flotation concentrate is divided into two parts to feed two bio-oxidation reactors. The feeding rates of two reactors are adjusted on the basis of getting the same content of S, Fe, As in overflow. The result shows that the feeding rate of the new type of 700 m3 bio-oxidation reactor is 3.72 m3 per hour, and the feed rate of the conventional 700 m3 bio-oxidation reactor was 3.23 m3 per hour. The processing capacity of the former is 15.2% higher than that of the later, which demonstrates the new type of bio-oxidation reactor has higher oxidation rate.

Jan 1, 2015

By A. J. Rigby

Computer generated, actual-scale furnace models have been imported into a rendering software application to provide for impressively realistic surface features and lighting. When these models are imported into a 3D engine framework, it is possible to create content-rich virtual environments allowing for complete interactivity and could provide for a powerful tool to conceptualize refractory lining designs. This technology has been applied to illustrate the optimized design concept of an anode-refining vessel, which can be expected to be completely relined in six days and to last for 4-5 years with minimal partial relining. This technology could easily be applied to other smelter furnace, converter and refining vessel designs.

Jan 1, 2007

By N. J. Shackleton, N. A. Chapman, V. Malysiak, C. T. O’Connor

In this study, the effect of using conventional crushing and high-pressure grinding rolls (HPGR) in combination with dry or wet milling was investigated using a base-metal sulphide (BMS) sphalerite and a platinum group mineral (PGM) ore to determine how these processes affect the flotation performance. In sphalerite, irrespective of the crushing procedure (HPGR or conventional), dry milling resulted in the highest grades and recoveries of zinc, whereas in PGMs, similar treatment produced the poorest results. The results were investigated further by the effect of factors such as percentage liberation and particle size on the flotation results.

Jan 1, 2012

By A. Bascetin

The mining industry in Turkey has been developing in the last 10 years. Mine wastes and tailings have thus been increasing, depending on the rising production rates. There are many problems related to accidents that occur in tailings damps. In this study, the applicability of the surface paste disposal (SPD) method for a Pb-Zn mine in western Turkey was examined. Density was 3.084 and specific surface area was 0.899 m2/g. The mill tailings have very low plasticity and show characteristics of clays and silts in terms of the Unified Soil Classification System. The particle size distribution of the tailings was 39.2% particles finer than 20 µm. The results of this study showed that the physical and chemical properties of mill tailings make them suitable for SPD.

Aug 1, 2013

By A. Grimod

The European Guideline ETAG 027 - 2008 (?Guideline for European Technical Approval of Falling Rock Protection Kits?) defines the procedures to test rock fall barriers. Nowadays, this guideline is essentially the only test and construction framework utilized by manufacturers and it is also starting to enter in the mentality of designer who can clearly specify the performances of rockfall barriers. ETAG 27 (and the related European Technical Approval and the CE marking) represents a milestone for the rockfall barrier market, because it gives the possibility to compare the performances of different fences and it ensures the quality of the certified product. For these reasons ETAG 27 presently constitutes the base for tenders all around the world. Although rockfall barriers are in common use, designers and consultants do not have a clear overview of the real performances and the technological limits of these structures. The first problem can be solved using ETAG 27 criteria, which allow designing rockfall barriers at ultimate and serviceability limit state. Even though ETAG 27 uses crash tests performed with the Service Energy Level (SEL) and Maximum Energy Level (MEL), design with these concepts is not obvious or in common acceptance. Some preliminary questions must be solved. When can these energy levels be correctly applied? In the case of rockfall simulations, what probabilistic approach must be used for the evaluation of the barrier? Unfortunately ETAG 27 does not give any information or tests relating to the technological limits of the fences. Therefore some important questions arise. How do the site specific aspects of installation affect the barrier performance? What is the behaviour of the barriers under extreme conditions? And finally, the main question lies in the background: what is the functional reliability of ETAG 27? All of the above questions require comprehensive answers, which is consistent with the experience of designers, installers and producers. Officine Maccaferri S.p.A., with its 130 year experience in the field of rockfall protection, collected a large number of case histories with barriers impacted by single or multiple blocks, debris flows, and snow avalanches. Throughout these case histories and in accordance with a recent Italian standard code, it has been possible to implement a reasonable design approach that considers the efficiency of the barrier, the uncertainties of the input data, and the fore

Aug 1, 2013

By G. Stenning

The paper outlines the need for high-volume ventilation in a uranium mining operation based on the design to meet environmental requirements for dust, radiation and diesel equipment. Mining methods in a highly mechanized operation, a key factor in design, are discussed. The construction and installation of major intake and exhaust fans are described briefly, together with the development of the mine airways and distribution system. Controls in the form of doors and bulkheads are important considerations in planning. Finally, the need to lower ventilation requirements in response to increasing power costs will result in future improvements.

Jan 1, 1979

By Bern Klein, Tichang Sun, Daozhen Gong, University of Science and Technology Beijing, Chunbao Sun, Stefan Nadolski

"This paper is focused on the effect of modifying the SAG mill/ball mill transfer size on the energy efficiency of SABC circuits. The transfer size is considered to be a parameter which provides operators with the opportunity to improve comminution circuit performance. In this study, the Moly-Cop tools package was employed to predict the energy consumption of SAG mill and ball mill circuits under different operating conditions. An Energy Benchmarking model was adopted to calculate grinding energy efficiency. The SABC circuit at the Huckleberry mine was selected for this case study. It was observed that after increasing circuit transfer size (T80) from the existing 3.3 mm to 4.8 mm, the Benchmark Energy Factor (BEF) of the SABC circuit decreased from 4.30 to 4.05. In terms of energy consumption of the SABC circuit, 1.17 kWh/t of specific energy saving was achieved through the transfer size optimization.It was also observed that when a transfer size was selected such that both SAG mill and ball mill circuits operated at their highest energy efficient states, the entire SABC circuit was the most energy efficient. The maximum energy efficiencies of these three circuits were all approximately 25% when compared to the minimum practical energy required to carry out an equivalent comminution duty. Single-particle compression breakage testing was used to determine the minimum practical energy associated with the Huckleberry mill feed. In combination with geo-metallurgical data, this study also provides an opportunity to perform dynamic optimization of SABC circuits."

Jan 1, 2016

By Martin Lebeuf

The phenomena occurring in the cathode and at the cathode surface of aluminum electrolysis cells are very important in regards to cathode voltage drop and cathode wear. In the current study, laboratory-scale aluminum electrolysis cell cathodes were analyzed by X-ray microtomography. This technique allows an excellent visualization of the distribution of different substances, if their respective X-ray attenuation coefficients are different enough. In the current case, the important difference in the mean atomic number between cryolitic bath and graphitic carbon results in good contrasts. The volumetric bath penetration profile, porosity and impurities distribution in the cathode were thus obtained. Furthermore, metallic impurities and bath heterogeneities were observed at the cathode surface. Observations were also made with Scanning Electron Microscopy - Energy Dispersive Spectroscopy (SEM-EDS).

Jan 1, 2011

By M. A. Gomez, V. Yahorava, J. A. Strauss

"It is accepted widely that pressure oxidation (POX) is the most appropriate technology for processing of arsenic containing refractory gold ores. However, studies on the stability of various iron-arsenic precipitates formed during POX are limited. Since the behaviour of these phases could have significant practical implications for gold processing plants, it is important to study them in isolation. This paper compares two synthetic precipitates, basic ferric arsenate sulphate (BFAS) and basic ferric sulphate (BFS) in terms of their formation, behaviour during hot curing and cyanidation, as well as their environmental stability. BFS and BFAS were synthesised hydrothermally at 205°C and their mineralogy was confirmed using various techniques. During synthesis, the addition of H3AsO4 into an aqueous Fe2(SO4)3-H2SO4 mixture significantly decreased the iron yield to BFAS in comparison to BFS under equimolar initial iron and acid concentrations. The BFAS dissolution kinetics was slightly faster, as compared to BFS, during subsequent hot curing. Cyanidation test work on the washed synthetic precipitates indicated that the lime consumption of BFAS was three times lower in comparison to BFS, while cyanide consumptions were comparable. Fresh BFS and BFAS precipitates, as well as their cyanidation residues, were found to pass the respective environmental tests in terms of arsenic release.INTRODUCTION Pressure oxidation (POX) is generally viewed as the most appropriate technology for the processing of arsenic-containing refractory gold ores due to the stabilisation of arsenic in the leach residue (Dutrizac & Jambor, 2007; Gomez et al., 2008; Harris, 2003; Collins, Berezowsky, & Weir, 1988). Detailed laboratory studies indicated that several Fe(III)-arsenate type compounds may be formed under typical conditions of autoclave treatment of refractory gold ores (Swash & Monhemius, 1994; Dutrizac & Jambor, 2007; Gomez et al., 2008, 2010; Gomez, Becze, Cutler, & Demopoulos, 2011). The basic ferric arsenate sulphate (BFAS) phase (Gomez et al., 2008), also known as Type II ferric arsenate (Swash & Monhemius, 1994) or Phase 3 (Dutrizac & Jambor, 2007), is one of the most common arsenic-bearing products (Harris, 2003; Dutrizac & Jambor, 2007). BFAS precipitation is viewed as one of the best routes for arsenic stabilisation and performed equally well to scorodite during environmental stability tests (Harris, 2003; Swash & Monhemius, 1994; Dutrizac & Jambor, 2007; Gomez et al., 2008, 2011)."

Jan 1, 2017

By M. Li, T. H. Dubaniewicz, H. N. Dougherty

"INTRODUCTION Underground mines have the risk of accumulation of gases if not ventilated properly or during and after emergency situations when ventilation controls become damaged or stop working. Common gases that are monitored in underground coal are carbon monoxide (CO), oxygen (O2), and methane (CH4). Methane is a gas found in coal and released through mining; its explosive range is between 5% and 15%. Methane is commonly monitored on all mining equipment and with handheld gas sensors carried by most underground coal miners. Fiber optics (FO) is a popular technology applied in underground mining, particularly for its electric isolation. Many miners are familiar with FO cables hung throughout the mine, which are primarily used in the communication of voice and data (Taylor et al. 2010). Advancements in laser and fiber optics have made this technology well suited for gas sensing the harsh environment of mining applications. The work of the U.S. Bureau of Mines on the use of fiber optic monitoring of gases in mines started in 1992. Dubaniewicz et al. (1992, 1993, 1995, 1999, 2003) developed prototype gas sensors, including methane gas sensors, for research purposes. Previous research (Dubaniewicz & Chilton 1992) identified potential fiber optic gas detection cross-sensitivities associated with the index of refraction of various gases. Index of refraction effects was noted for carbon dioxide (CO2), which is produced in significant quantities by mine fires or explosions. NIOSH released a broad agency announcement (BAA) for the development and demonstration of mine safety and health technology (CDC NIOSH 2017). The objective of this announcement was to validate a sensor, specifically fiber optic, for the mine environment and test it in an actual working mine. The RSL FO sensor “OptoSniff” provided from this work is capable of hundreds of sensing points over distances of up to 20 km, has a measurement range of 0.05% to 100%, senses in an oxygen- deficient environment, and has no gas cross-sensitivity (RSL, 2014). The RSL system is totally electrically passive outside the central control unit (CCU), which can be housed in an MSHA-approved explosion-proof (XP) enclosure or in a control room outside of the permissive area. The sensor was tested in dusty and signal loss situations, showing it is tolerant of dust, has functioned at signal losses up to 90%, and was successfully tested in a mine environment for a five-month period (Walsh et al. 2014). This paper describes how the RSL FO sensor is used for testing using smoke and its contaminants for applicability in emergency situations. The testing investigates individual contaminants such as CO2, temperature, and smoke. Each test was performed separately and methane concentration, laser power, and response time data were collected."

Jan 1, 2019

By D. J. Zuliani

A mass and energy balance for a modern electric arc furnace ("EAF") indicates that about 70% of the process energy losses are contained in the off-gas as chemical energy in the form of uncombusted CO and H2 and as thermal energy. Given the magnitude of the off-gas energy losses, improved EAF energy efficiency needs to focus first on controlling furnace practice to maximize "in-EAF" energy utilization and second, on recovering residual energy in the off-gas existing in the fume system. This paper focuses on the application of off-gas analyzers, sensors and process models to control and optimize "in-EAF" energy utilization efficiency. The paper will also discuss the application of heat recovery technology to EAF steelmaking.

Jan 1, 2015

By A. Warczok, T. A. Utigard

"Slags from smelting of copper concentrates contains from 1 to 15% of copper. Copper is present in the form of copper or copper matte inclusions of size from 2 to 1000 micro, and as dissolved cuprous oxide. Removal of the copper requires the slag reduction, primarily reduction of magnetite and co-reduction of cuprous oxide. Thus, the kinetics of the slag reduction play an important role in copper recovery. Instantaneously, at the contact of carbon and a slag the gaseous film is formed. The magnetite and cuprous oxide reduction is going through a gaseous film, separating the slag and carbon of a coke or electrodes. The thickness of a gaseous film grows to a critical value and gas bubbles, containing CO and CO2, are created and rise up in the slag. Results of measurements of kinetic of the slag reduction with graphite showed high value of activation energy, close to the value of activation energy of Boudouard reaction. Strong temperature dependence of the reaction rate points out the thermal instability of the reacting system. It was found that the slowest process in the reduction stages determines the loop of CO and CO2 transfer and magnetite diffusion to the slag/gas film boundary. Strongly endothermic Boudouard reaction seems to cause thermal instability on the reaction surface. So, heat transfer to the reaction surface is very important. Due to low thermal conductivity of a slag the convection dominates in the heat transfer. So, any slag stirring accelerates the rate of reduction and coalescence of metallic copper or copper matte inclusions."

Jan 1, 2015

By H. R. Stoger

"In 1994 world trade grew by 9%, the fastest annual increase since 1976. Dry cargo shipping rates are at an all time high.Panamax size bulk carriers are receiving19 000 US dollars per day for trans Atlantic round trip voyages. This is good news for the ship owners but not such good news for the industrial users of ocean shipping.The main emphasis of this paper will be on bulk carriers, the charter market and what industrial companies can do to reduce their costs of ocean transportation which is critical to Canadian exporters. Let us look at the charter market in general.Bulk carriers come in four main sizes:1.The Capesize bulk carriers of 110 000 to160 000 tons that are primarily used to transport iron ore and coal;2.the Panamax bulk carriers of about 70 000tons dwt. This is the largest size (with a beam of 105 ft) that can transit the Panama Canal.3.the Handymax bulk carriers of 40/45 000tons dwt; and4.the Handysize bulk carriers of 20/35 000tons dwt.The handysize vessels are usually craned or geared and carry a variety of bulk cargoes including steel. Ship sizes have increased over the years and the mining industry now uses primarily capesize or Panamax bulk carriers.International chartering is conducted through an international network of shipbrokers. There is usually one broker representing the ship owner and another broker who represents the charterer. The major chartering centers are London and New York but a great deal of chartering activity is conducted in regional markets such as Hongkong, Oslo, Montreal and Hamburg.The Biffex Index or Baltic Freight Index is a good measure of dry bulk freight rates. The Biffex is composed of ten major routes. In May1995, the Biffex was at 2310 points. A year earlier it was at 1354, an increase of about 56%."

Jan 1, 1996

By J. H. Morrish

"The delivered price of any mineral is the determining factor in converting untapped resources into economic resources. Transporting the minerals from the mine to the market plays a significant part in the total package. The expansion of the Western minerals industry in the last ten years has been paralleled by improved transportation systems to reduce cost, increase accessibility of resources and get the minerals to market in the shortest time possible. A review is made of developments, such as unit trains, complex multi-modal systems and containerized transport, over the last ten years, with specific movement outlined. The total transportation package of land transport, port and terminal facilities, and water transport, where needed, is stressed. As the volume of minerals movement expands, increasingly sophisticated and integrated transportation systems will have to be utilized. The development of solids pipelines and other possibilities is outlined."

Jan 1, 1973

By M. Al Mukhtar, D. Hoxha, X. Brunetaud, D. P. Do, C. Auvray, L. Michel

"Mechanical behavior of rock joints is often the key factor governing the response of complex structures constructed in fractured rock masses such as underground openings or of objects assembling various stones blocks such as historical building walls or damaged marble statues. This paper aims at developing a theoretical model to describe the behavior of fresh joints based on the description of their morphology. The main idea of the model is to establish a link between the effective contact surface of joints and the frictional coefficient. Beginning from a chosen level of joint surface description where a joint is considered as “smooth”, the model describes the added friction with respect to the increase of the contact surface of the joints and the distribution of stress in these contacts. The model developed initially for asperities with regular geometry is firstly compared with existing models and then applied on fresh artificial joints. For that, healthy artificial joints have been characterised using in one hand classical CNL shearing tests and in another hand the morphology of joints. The joints surfaces are digitized before testing using a high resolution laser scanner (Konica Minelota Vivid 910) allowing to obtain a precision up to 10µm. From these scanned surfaces the morphology of joints is characterised on the profiles running in the direction of shearing and a mean value of friction is calculated using the developed model. This calculated value is then compared with that obtained from CNL shearing test and a good approximation is notedINTRODUCTIONThe role of the mechanical behavior of rock joints on the overall response of fractured rock masses is well established in many fields of engineering activity going from the stability of underground constructions (Souley M, Hoxha D, Homand F 1999), rock slope stability (Einstein H.H. Veneziano D., Baecher GB., O’Reilly K.J, 1983, Jaeger 1971), various rehabilitation of masonry construction, damaged stone artworks restoration (Michel L., Do D.P, Coignard B, Hoxha, 2014) and so on. In the same time the characterisation of the behavior of joints and their modeling is nowadays a dynamic field of research or/and investigations and many alternative approaches have been proposed (Barton, N.R. and Choubey, V. 1977, Tatone, S.A. Bryan, Grasselli Giovanni 2010, William C E. 2007). While empirical relations of shear strength with various parameters of the joint morphology are the most used in practice because of their simplicity (Barton. and Choubey, 1977, Barton 1973, Bandis S., Lumsden A. C. and Barton N. R. 1983) many other models of joint strength are developed based on mechanistic considerations (Haberfield CM, Johnston IW. 1994), multiscale approaches (Yang Z.Y., Di C.C., Yen K.C. 2001, Fardin N., O. Stephansson, Lanru Jing 2001) or micromechanical ones (A. Serrano, C. Olalla, R.A. Galindo 2014) to mention just a few of research trends on rock joints modeling."

Jan 1, 2015

By A. Ghirian

Once cemented paste backfill (CPB) is transferred and placed into a mine stope, various coupled mechanisms will take place in the CPB material or structure. It will be subjected to strong coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes. Field studies have shown that the in-situ properties and performance of CPB differ from those obtained in the laboratory. This is mainly due to effects of the aforementioned coupled THMC mechanisms or processes. For a reliable and cost-effective design of a CPB structure and barricade, it is crucial to have a proper understanding of the THMC behaviour and evolution of CPB. Also, it is important to consider the effect of coupled THMC factors (e.g., self-weight pressure, drained/undrained and thermal conditions, pore pressure) while curing the CPB specimens. For this purpose, a laboratory setup is developed to investigate the properties of CPB materials. The setup is capable of curing CPB specimens (10 cm in diameter and 20 cm in height) under controlled vertical pressure (curing under stress) and various coupled THMC conditions, while continuously monitoring the evolution of total stress, pore pressure, suction, temperature, water drainage, chemical composition of the pore water and vertical deformation. Once the required curing time is achieved, the specimen can be extracted and then subjected to experimental tests of interest, such as those that determine the Unconfined Compressive Strength (UCS), shear strength parameters, saturated hydraulic conductivity and thermal properties. In this paper, we describe the developed experimental setup and present some results of the THMC behaviour of CPB under various curing stresses and rates of backfilling. The obtained results show that the THMC properties of CPB are strongly coupled due to several mechanisms, such as self-weight pressure, heat of hydration and suction development as a result of self-desiccation. The findings can assist researchers and practitioners to better understand THMC behaviour and thus design more cost-effective CPB structures.

Aug 1, 2013

By Laura Steeves, Inoka Eranda Perera, Jhon Silva, Arend Spaeth

"This paper reviews the main concepts ruling the design, implementation and performance of active explosion barrier systems for underground coal mines in the USA. The document examines the parameters needed for the design of this type of system, such as overpressure and flame speed, suppressant deployment speed and duration time of the active barrier. The document also discusses the available solutions for gassy mines and the concepts behind the selection of machined mounted and roadway active explosion barrier systems. The paper includes a review of active explosion barrier systems developed in the USA and South Africa. The paper provides an overview of the current status of this technology in the underground coal mining industry in the USA, and the possible implementation of such systems. The paper concludes with the identification of the future work needed for the successful implementation of the systems in several conditions to enhance the safety of underground coal mine operations and to provide more tools to the miners for their safety.INTRODUCTIONUnderground coal mine explosions can be addressed in two ways, through prevention or mitigation. The United States mining industry practices have emphasized the prevention of explosions in underground coal mines, with little being done to mitigate the explosion once it occurs. Despite successful practices for the prevention of underground coal mine explosions in the US, the threat of an explosion does still exist. Other mining countries around the world have developed and implemented mitigation systems such as active explosion barriers in their underground mines. In the 1970s, the United States Bureau of Mines (USBM) carried out extensive research on the use of active or triggered explosion barrier systems in the US; however, they are not currently used.Explosion barrier systems do not prevent explosions but mitigate the propagation of the shockwave and flame to other areas of the mine. The use of active explosion barrier systems enhance the safety of underground coal mines. Active or triggered explosion barriers will detect the arrival of the shockwave or flame front of the explosion and release inert material to suppress or extinguish the flame. The technology required for active barrier systems is readily available based on their presence in other mining countries and must be adapted for their use in US coal mines. The adaption must consider the coal dust and methane concentrations in US coal mines, the mine geometry, and the mining equipment used."

Jan 1, 2019