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The trend in the U.S. coal industry in recent years has been a continuous increase in the percentage of coal produced by surface mining methods. Though the predicted energy demands promise a good market for coal, growing legal and environmental issues make the exploitation of a coal deposit by surface methods a difficult and challenging task. Major emphasis has to be placed on the development of integrated mining and reclamation schemes which enhance the possibilities of post mining land uses. Since no major breakthroughs are foreseen in the near future in surface mining equipment, innovative applications of current equipment must be developed. Draglines have been and are expected to continue as the primary earthmovers in surface mining of coal. A dragline simulation model has been developed which has the capability to analyze various deployment schemes such as conventional side casting, advance benching, and extended benching. The mathematical aspects of the model, the input data, and the output results are discussed with reference to an application in an operating mine. The model can be used to select a suitable dragline for given geological and mining conditions and to study the effect of alternative mining layouts and spoiling plans on machine production.

Jan 1, 1979

By A. C. Noble, D. E. Ranta, J. W. Mustard

Skarn deposits present many unique problems in estimating ore reserves, including difficulties arising from the complex character of the mineralization and intricate ore body shapes resulting from structural complexity. Mineralization within skarns occurs in metasomatically altered carbonate horizons produced by magmatic hydrothermal fluids emanating from intrusive stocks. Deposit formation is controlled by both the presence of favorable host rocks and by proximity of these host rocks to a mineralizing intrusion. Ore controls must be defined to account for abrupt changes in grade that occur between miner- alized and unmineralized horizons. Gradational grade changes within the mineralized zones must also be defined in terms of skarn type and included barren rock to assist in reserve estimation. Defining mineralized limits can be further complicated by faulted, rotated, or folded strata affecting the morphology of an ore body. The MacTung copper-tungsten exoskarn deposit, located along the Yukon-Northwest Territories border in Northwestern Canada exhibits a number of unique properties that preclude a simple mathematical approach to ore re- serve estimation. This deposit is used to demonstrate methods for modeling geologic controls and geostatistical properties for a skarn deposit.

Jan 1, 1992

By Edehran Lotfi, Terrence Stobbe

INTRODUCTION Mobile excavating and handling equipment are important 'tools of trade' in the mining and construction industries. The handling of this equipment must be mastered so that its limitations are learned and its harmonic use with other pieces of equipment is practiced. he sudden growth in mobile excavating and handling equipment type, size, complexity, and application started after the Second World War. This growth has not been accompanied by pertinent human factors research. Investigations into the proper and safe handling of such equipment with due regard for human and machine limitations are lacking. One such piece of equipment is the front-end loader (FEL), which during one cycle of operation excavates, loads, and hauls, (Lotfi and Adler, 1981). The diversity of action by FEL is archetypical among excavating and handling equipment. Front-end loaders are the most rapidly proliferating type of equipment in the industry. Also, front-end loaders are involved in the highest number of accidents involving mobile excavating and handling equipment. In the period 1970 to 1978, FEL's were involved in 27% of all mobile equipment accidents in surface mining (Adkins, 1980). Improving operational safety and efficiency will reduce the frequency of accidents. The performance of the operators can be evaluated and improved by the following steps: first, define the operating conditions and the operator workload intensity (Adler and Lotfi, 1983), second, monitor the operator to evaluate his task performance, and third, make recommendations based on the findings. The stressful nature of the equipment operating task is an acknowledged fact (Field, 1980). However, a systematic measurement of stress evaluation is lacking. In this paper, methods for measuring mental stress and fatigue, are defined, the mental load which caused the stress is outlined, and stress measurement methods are proposed. MENTAL STRESS Mental stress has been described as a "specific somatic response to damage or the threat of damage by several environmental agents"

Jan 1, 1986

By James Warren Andrews, Philip C. Nyberg

The regulation of exposure of underground personnel to radon and its daughter products has significantly changed since the 1950's. The U.S. Bureau of Mines - Mining Enforcement and Safety Administration (MESA) - Mine Safety and Health Administration (MSHA) sequence of standards and regulations have lowered the maximum allowable occupational exposure and now the new Environmental Protection Agency (EPA) National Emission Standards for Hazardous Air Pollutants, effective in 1990, have further regulated uranium mine emissions. Under the authority of Section 112 of the Clean Air Act (42 U.S.C. 7401), the EPA has set regulations for the control of radon (Rn-222) emissions from underground uranium mines as well as other sources. Since the venting of radon from the mine atmosphere to the outside air is a major component of the miner's protection, and since this is the first quantitative effort to limit gaseous mine emissions to the environment, it was felt that it would be useful to examine the implementation of the EPA regulation at working mines. The concern was not only for determining compliance with the regulation but also for observing what effect the rule might have on mine air quality and thus on worker exposure. The regulation is stated in terms of the maximum permitted radiation dose to the closest potentially exposed individual, which is calculated from a computer program supplied by EPA and radon emission rates measured by the mine operator. Relative proximity to nearby populations determines the allowable magnitude of mine exhaust ventilation emissions. For some mines this is a serious operational constraint.

Jan 1, 1991

By Feida Wu, Yuhang Liu, Huimin Gao, Yuhan Song, Zhi Liu, Zijie Ren

In the process of quartz purification by calcination water quenching, the different expansion rates of gangue minerals and quartz were used to produce cracks or remove fluid inclusions, which is conducive to subsequent purification. However, the role and mechanism of calcination-water quenching are still lacking in research. In this paper, the position of calcinationwater quenching in gangue quartz purification process was adjusted and the removal effect of calcination-water quenching process at different nodes in the process was explored. The results show that the purification effects of grinding-calcinationwater quenching-classification-acid leaching process and grinding-classification-acid leaching-calcination-water quenching process were relatively good. The main reason is that calcined water quenching can make quartz produce cracks, which are more rough. At the same time, calcined water quenching is located after grinding, which has a larger specific surface area, pore volume and pore diameter, and has a strong adsorption capacity for acid solutions.

Nov 2, 2023

By P. W. Conrad, C. Todd, N. West, R. Kramer

"Surface subsidence caused by both underground room-and-pillar mining operations and solution mining operations have each been studied separately, but never combined. In 2008, FMC Minerals began using solution mining at its Westvaco Mine as a secondary extraction method in an area that had been previously mined using the room-and-pillar mining method. Mining regulations require that subsidence associated with underground mining activities be monitored and measured annually. Researchers at Montana Tech were able to develop a relationship between measured surface mine subsidence and solution mining that can be used at the Westvaco Mine to estimate the production of trona from solution mining operations. PROJECT BACKGROUND FMC Minerals (FMC) has increased the production of trona from its Westvaco Mine near Green River, Wyoming, using solution mining as a secondary extraction method in an area previously mined using the room-and-pillar method. The area of interest was mined until 2001 with the use of a borer miner at a depth of approximately 1,600 feet. Currently, FMC determines the amount of trona produced using its solution mining operations by measuring the dissolved solids pumped from the mine. This approach, however, does not account for the location from which the trona was removed. The location from which the trona was removed and the size of the cavern created by the solution mining operations is important to FMC’s mine planning. FMC believed that with proper investigation of the subsidence at the Westvaco test site, a correlation might be found that would allow for the use of surface subsidence measurements to estimate the amount and location of trona production from the solution mining activities. The primary goal of this project, conducted by Montana Tech, was to find a relationship between the measured subsidence and the solution mining activities. The project attempted to model the relationship between the measured subsidence and the solution cavern using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI), to determine the program’s usefulness for locating and developing the cavern created by solution mining activities. The project also attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The data used in this study were collected over a seven year period, 2008 through 2014."

Jan 1, 2016

By Robert C. Freas

Over the past twenty years people throughout the world, but particularly in the United States, have been taking an increasing interest in the environment, sources and causes of pollution, and pollution abatement. Air quality in the United States has been and continues to be an area of primary emphasis. In 1970, the US Congress passed the Clean Air Act and subsequently revised and strengthened it in 1977 with the issuance of the New Source Performance Standards. The Act has been further strengthened with the passage of the 1990 Amendments. By far the largest single source of sulfur dioxide (SO,) pollutants are coal fued electric generating power stations. Hence, a substantial portion of the flue gas desulfurization (FGD) research and equipment installation has been geared to the utility industry. Several competing FGD technologies were touted during the period 1970 to 1990 with varying degrees of success. Subsequently, the more successful technologies have been accepted, revised, and improved to the point that by 1991 third and fourth generation technology is available. A second area of emphasis for FGD has been coal fired industrial boilers. While individually they are much smaller than any electric utility generating station, they do represent a significant source of sulfur pollution. However, due to the size of industrial boilers and their location within industrial and educational complexes, the wet scrubber technology being employed by the utilities is not appropriate for these applications. Hence, fluidized bed combustion (FBC) technology has been developed for the industrial boilers. Since the installation of the first full scale test unit at Georgetown University, several equipment vendors have come forward with an increasing array of more sophisticated FBC units. Currently, FBC technology has matured to the point that the Tennessee Valley Authority (TVA), in cooperation with the Electric Power Research Institute (EPRI), has installed an FBC system on a 250 MW test unit at the Shawnee Power Station in Kentucky.

Jan 1, 1994

By D. N. Thompson, R. L. Sayer, K. S. Noah

Economical remediation of acid rock drainage (ARD) at secluded high-altitude western ore mines is difficult given the current treatment technology. Several passive-engineered systems that are based on wetland technology were tested in the laboratory with three western ore mine ARDs (Co, Cu and Fe mines) and with a copper leachate effluent. These systems used well-weathered lodgepole pine sawdust as the sole carbon source and mud from a pond at one of the mine sites as the source of sulfate-reducing bacteria (SRB). Simple one-pass flow-through systems removed 44% to 99% of the vari¬ous heavy metals front the Co and Cu mine ARDs and increased the pH from 3 to 7 after 28 days of SRB acclimation with a five-day residence time. Carbohydrate utilization rates were generally low, except for one 437-day run, which consumed 25%, 30% and 21 % of the cellulose, hemicellulose and lignin, respectively. Initial pH, amounts of toxic heavy metals and the degree of predegradation of the sawdust were found to significantly affect both remediation potential and acclimation time. Engineered SRB systems, alone or in combination with other passive technologies, offer promise for the economical remediation of western US ore mine ARDs.

Jan 1, 2000

By M. P. Evans, Rainer Kahrger

During the last decade or so great advances were made in the solvent extraction, electro winning technologies. They, combined with heap leaching, made it viable to exploit large, relatively low grade oxide copper deposits. The El Abra mine is a good example for such a deposit. Situated in Northern Chile at an elevation of about 4000m (14000 feet), 70 krn north of Calama, the El Abra deposit has been known for many years. In the early 1990's Codelco decided to sell a major holding in the deposit to international mining companies. After lengthy negotiations Cyprus Minerals finalized in June 1994 the purchase of 51% of the deposit with Codelco retaining the balance. lance. Already in 1993 Cyprus and the engineer on the project, began discussions with international materials handling companies with regards to the materials handling system required for the project. These early discussions were considered critical for this fast track project. Immediately after the notice to proceed with the project, several companies were invited to submit competitive conceptual proposals for that portion of the material handling system which was to transport crushed and treated ore from the plant to the leach pad and build the leaching heaps at a rate of up to 150 000 tons per day. A supplier was selected. Additional studies were made for the conveyor system from the mine to the fine crushing plant. Due to the extremely rugged terrain and high altitude at the mine, a decision was made to locate the plant and the leaching operations 15 km east of the mine at an elevation of 3400m. In July 1994 the supplier started the conceptual engineering with a design team at the engineer's San Francisco office. The undertaking was unique in the sense that the supplier's engineering team was integrated into the project for the duration of the conceptual engineering. The open and continuous communication greatly contributed to the success of the design work.

Jan 1, 1996

By William H. Sutherland

INTRODUCTION Coal workers' pneumoconiosis and sili- cosis are only two of several diseases which are rlassed as pneumoconiosis. These are respiratory diseases caused by dusts which are inhaled and accumulated in the lungs. The individual particles of dust cannot be seen by the human eye. They are so small that they escape the natural cleansing mechanism of the nose and air passages and make their way down to the terminal air sacs of the lung where they injure the cells and cause the formation of scar tissue. Consequently, if there is exposure to high concentrations of dust over a period of time - usually, a number of years - the amount of scar tissue increases and begins to impair breathing. As a result, the miner develops shortness of breath, coughing and wheezing ad-if exposure continues - this progresses to permanent disability and frequently to death. Death is often due to pulmonary heart disease, the effect of stress on the heart 2s it tries to compensate for the weakened lungs. Specifically, silicosis is an occupational lung disease caused by the accumulation of free silica (quartz) in the lungs. Silicosis is considered the most important form of pneumoconiosis, not only because of its seriousness as a respiratory crippler, but also because of the large number of workers who risk contracting it in a variety of occupations. Quartz is one of the most common substances of the earth's crust, estimated at about 60 percent. Silicosis has been found in coal, metal and granite miners, as well as in other workers, such as sandblasters and pottery makers. Silicosis is also known to predispose the lung to tuberculosis and to increase the chances that a worker will contract chronic bronchitis and emphysema. The seriousness of silicosis was tragically brought to public attention about 50 years ago. During 1932-34, workers were involved in digging a tunnel through rock at Gauley Bridge, West Virginia. While their exposure time was relatively short, they developed silicosis because of the high concentrations of quartz. By 1936, 476 workers had died of silicosis and about 1500 were believed to have the disease (Washington Post, 1982). It is difficult to tell how many coal miners have silicosis. Because x-rays and breathing function tests do not show the difference the type of pneumoconiosis is generally diagnosed by the miner's work history. For example, if a worker

Jan 1, 1986

By J. Mark Richardson

Steady-state flowsheet simulators for mineral processing plants have evolved to a current high level of utility and accuracy. Reliable, general-purpose, semi-empirical models now exist in nearly all unit operations categories particularly in the areas of comminution and classification. .These models, installed as user-selectable functions within the integrated frame- work of flowsheet balance-solver software systems, can be strung together to represent any plant configuration. In addition, CAD-like graphics, data reconciliation and model parameterization functions have become standard features of the current generation of integrated plant simulators. These advances have given engineers the capability to investigate many different plant scenarios while requiring a minimum of actual plant testwork. This paper describes a methodology and an integrated software package which are being successfully applied in a number of operating plants worldwide to predict plant performance under changing conditions. Those conditions which can be changed include effect-of ore type, feed size, water addition rates, equipment geometries and flowsheet modifications. By using data from actual plant optimization exercises in real mills, the paper illustrates and out- lines a technique which includes plant data collection, ore breakage testing, flowsheet simulation, model-fitting (parameterization), data adjustment and model experimentation. Brief descriptions of some unit operations models, such as autogenous mills and cyclones, are provided as examples of the current state of such models. Ore breakage testing and its relation to certain models is also discussed. Computer- generated size-distribution graphs, along with tabular data generated by the simulator, round out the presentation and serve to demonstrate the real- ism and accuracy of the models. The paper concludes with a partial list of cases where this technology has been successfully applied.

Jan 1, 1992

By K. V. Raj, A. Miller

"Workers at mineral processing facilities are often exposed to high levels of dust generated when ores are processed. Crushing, grinding, screening, and other processes generate large quantities of dust, which can exceed the threshold VALUES (prescribed by the Mine Safety and Health Administration (MSHA). Many ores contain quartz (silica), which has been known to cause serious health problems in workers over time. Given the structure of mineral processing plants, the airflow regime is not coherent inside the building, which may lead to multiple recirculation zones. These recirculation zones can trap dust, and concentrations of dust can then rise over time. Therefore, there is a need to understand the airflow phenomenon that occur inside of mineral processing facilities and how these occurrences interact with the dust generation processes to identify zones of potentially high dust concentration. Computational fluid dynamics (CFD) modeling can give a better understanding of the airflow and help recommend designs and methods to mitigate the high dust concentrations in a mineral processing plant. This paper presents the CFD modeling of airflow inside of a mill building to demonstrate airflow patterns that will affect the generation and subsequent dispersion of dust due to crushing, grinding, and other activities. This study was conducted by researchers from the National Institute for Occupational Safety and Health (NIOSH). INTRODUCTION In a mineral processing facility, minerals go through various mechanical processes in order to reduce their size for separation of economic minerals from gangue minerals to produce a final marketable product. This research, conducted by the National Institute for Occupational Safety and Health (NIOSH), focuses on ore mills in metal and nonmetal mining (MNM) operations, but the applicability of the approach will be valid for any large structure where workers are exposed to airborne contaminants. The processes of crushing, grinding, cleaning, drying, and product sizing in these facilities generate a large amount of dust, creating hazardous conditions for the workers in these facilities. This is highlighted by the fact that MSHA sampling data for the years 1997–2012 indicate that 12.3% and 15.9% of the gathered samples were over 100 µg/m3 for silica for metal and nonmetal mills, respectively [1]. Mineral processing operations typically use some type of engineering control to address their most significant dust sources. Engineering controls include such approaches as bag-house-type dust collectors, scrubbers, and electrostatic precipitation [2]."

Jan 1, 2018

The Henderson Mine is a large underground panel cave molybdenum mine located near Empire, Colorado. Secondary blasting requirements have varied from one shot per 27 tonnes (30 tons) to one shot per 900 tonnes (1,000 tons) of ore. Geology, structure, cave abutment loads, and location of the ore in the column all affect the amount of oversize boulders (greater than three-fourths cubic meter or one cubic yard) that require secondary breakage. The primary method of breakage utilizes cone charges (plastic funnels filled with an emulsion) placed on accessible oversize rocks. Hangups in the brow area of the drawpoint are drilled with a self contained diesel hydraulic drill and loaded with gelatin dynamite. High hang-ups located beyond the reach of the secondary drill are "bombed" in with strategically placed emulsion bundles or ANFO bags loaded in place though a sectioned aluminum pipe.

Jan 1, 1994

By w. Chruscielewski, T. Domanski

INTRODUCTION Concentration of radon 222Rn and its decay products occuring in the Polish mines of metal-ores call for the necessity of systematic radiation control /Do8la/ both of the working environment and of the miners' personal exposure. The attempts at introducing a system of radiological protection in mines, similar to the ones existing in X-ray or isotope laboratories, took several years and consisted of development of the methods for control of concentration of radon and its progeny in the air, as well as the methods for measuring individual exposure. It was accepted that the assessment of both transient concentration in the air and of personal exposure are basic elements of the control system, which should be implemented independently of each other. Concentration measurement serves to detect and to determine those areas in mines where there is intensive radon emanation, and where current control of the effectiveness of technology introduced to deacrease the concentrations is necessary; personal dosimetry results in the assessment of the actual exposure of miners to radiation. PRINCIPLES OF THE SYSTEM The assessment of working environment is based on concentration measurements of the potential radiation energy of radon alpha decay products. Decentralized assessment is carried out by the special dosimetric service operating in each mine. Dosimetrists are equipped with portable radiometers, type RGR-11, made by the institute of Nuclear Research, Warsaw. The radiometer is presented in Fig. 1. Measurement of filter activity is performed automatically according to Markov's method /Ma62/ or any other method. Simultaneously to potential energy measurement the dosimetrists are measuring the dust concentration in the air and ventilation rate. Ventilation service looks for correlation between those indices and the concentration of radon daughters in the air. Derived Air Concentration /DAC/ for concentration assessment was accepted to be 6.25 10-6 Jm-3 /0.3 WL/ according to ICRP recommendation /Publication No. 24/ /ICRP77/. If environmental measurements reveal potential energy concentration exceeding the value of 0.3 DAC at working places, the miners employed there are subject to individual control of personal exposure. Individual exposure measurement is carried out centrally by the Institute of Occupational Medicine in [Lodz] for all metal-ore mines. Miners who are to be included in the control scheme are referred by a mine management to the Institute where they are registered and assigned a dosimeter. A passive dosimeter with

Jan 1, 1981

By J. Duran

Mining at Newmont Mining?s Phoenix?s Mine is currently done by surface operation in the Fortitude and Bonanza pits at a combined rate of approximately 100 kt/d (110,000 stpd). A portion of the orebodies targeted by these pits was mined previously by underground mining methods, dating back to the mid-to late-1800s. Most of the underground workings (voids) are located in the west central area of the Bonanza pit. The surface operation requires excavation through voids, and there is a risk of pit floor subsidence that has to be addressed. This article presents a review of the risk mitigation measures that were implemented to reduce risks to people and equipment working in the area.

By D. Antonov

The physical and mechanical properties of coal play a important role in the planing and design of coal mines. However, due to the complexity conditions in situ and the influence of unknown factors, it is hard for people to evaluate the physical and mechanical properties of coal directly. In this research, uniaxial compressive stress was used to change the attribute of coal samples, and the ultrasonic measure technique was used to evaluate the physical and mechanical properties of coal. The results of laboratory test showed that there was a strong relation between uniaxial stress and velocity of ultrasonic wave. Sensitivity analysis with numerical simulation was used to define the relation between the physical-mechanical parameters of coal and ultrasonoc wave. With the dynamic analysis module of FLAC, three elastic and plastic models were built to model the coal samples. The modeling parameters were changed pro rata, and the correlation of coal and ultrasonic wave properties were summarized and presented. The result from this research will be base for further analysis of caving behavior of coal.

Jan 1, 2010

By Roland Hoet

Mine operators, conveyor system designers, consultants, and manufacturers have had opportunities over the past decade to utilize various actively controlled technologies to drive complex underground conveyor systems. These technologies included several electrical drive solutions, mechanical drive solutions, and hydromechanical (fluid coupling) drive solutions. All of these technologies have their inherent advantages and disadvantages, and only after several years of operation can mine operators fairly evaluate the overall benefits (short term performance and cost vs. longer term operational and maintenance costs) of any particular drive. Far too often in today's world, decisions for new equipment are made with inadequate regard to issues concerning serviceability and maintainability. Many of the newer electrical technologies (primarily AC variable speed drives) which have been used in recent years were selected based on the perceived desirable benefit from variable speed operation. This technology, however, which differs sign8cantly between various manufacturers, is in a constant state of evolution which puts into question the manufacturers' ability for long-term product support. In addition, various forms of this technology have also generated some undesirable operational issues, including reduced motor life, harmonics for the power system, and mine communications problems. This technology is also extremely current-limited, which results in problems handling overload conditions, a frequent occurrence often resulting from a decline in the coal recovery rate (conveying more rock than coal). The fluid coupling, however, is based on a technology which has been used successfully in underground conveyor applications for decades. Although the base hydrodynamic technology is well proven and has inherently beneficial characteristics on conveyor applications, Voith has continuously improved on this technology to meet the increasing demands of today's challenging conveyor haulage systems. Recognizing a need in the market for a reliable, actively controlled drive system, Voith Turbo began development in 1996 of a new, actively controlled coupling which was targeted specifically for the higher powered, complex underground conveyors. Voith introduced the new TPKL Fill Controlled coupling product to the market in 1997, and the first two applications for this new technology were on multiple drive mpper booster applications on longwall panel conveyors. Since the successful startup of these two conveyor systems in 1998, Voith has supplied over 200 TPKL couplings to the mining industry worldwide, with over 150 in US coal mining applications alone. This paper will provide an overview of the TPKL's capabilities, performance, and reliability based on the TPKL's impressive installation base and operational history.

Jan 1, 2004

By Rustyn Sherer

Curis, the name of a new Arizona-based mineral development company, is an acronym which stands for ?Cu? (elemental symbol for copper), ?r? (recovery), ?is? (in situ, the Latin for ?in place?). The company was created specifically to advance the development of the Florence Copper Project in Florence, AZ and to pursue other next generation copper development projects in progressive jurisdictions around the world. ?We are extremely excited about this project,? said Curis Resources president and chief executive officer Michael McPhie. ?We?re here to set the standard for Greenfield in situ copper recovery (ISCR) operations in Arizona and around the world. We believe in our people, our technology and our process; and we are passionate about our commitment to environmental stewardship and community development. We?re making a long-term investment in Florence, and in Arizona.?

Jan 1, 2011

By F. Segobia, M. Portal, F. Ysla, L. Goicochea

It is our responsibility to promote responsible and sustainable mining with new generations, promoting a culture of equality and respect. To fulfill this commitment, we are working with the SME UNC Student Chapter team, Newmont Yanacocha, BRG Women and Allies and the Museo de Agua y Tierra (MAT) to carry out the “Building our future” project. It is our responsibility to promote responsible and sustainable mining with new generations, promoting a culture of equality and respect. To fulfill this commitment, we are working with the UNC SME Student Chapter team, Newmont Yanacocha, BRG Women and Allies and the Museo de Agua y Tierra (MAT) to carry out the “Building our future” project. This project seeks to instill in new generations the importance of mining, integrating sustainable development objectives. We have the participation of Newmont Yanacocha and external professionals, who share their life stories and inspire participants from rural and urban educational institutions to pursue their dreams and aspirations. We believe that this project is important because it will help new generations understand the importance of mining and its role in the development of the country, covering the economic, environmental and social spheres. Since its inception in 2022, the project has positively impacted more than 500 participants.

Feb 1, 2024

By J. F. Brune

"Re-occurring face ignitions in U.S. coal mines are concerning and require a closer look at air quality monitoring systems and practices employed in these mines. The explosion disaster at the Upper Big Branch mine in West Virginia in 2010 caused 29 fatal injuries and was largely caused by inadequate water sprays and inadequate ventilation monitoring. In this comparison, the author compares ventilation system monitoring in Australian, German and U.S. underground coal mines and makes recommendations for improvements and best practices. Mines in Germany and Australia are adhering to more stringent requirements for monitoring air quality and quantity and for monitoring water spray systems on cutters to prevent frictional ignitions. Air quality should to be monitored for sufficient oxygen, toxic gases, explosibility and for fire gases indicating a potential fire. Ventilation monitors must also confirm that sufficient quantities of air are available. Fully automated, continuously recording atmospheric monitoring and alarm systems are established practices in Germany and Australia and should be mandated for U.S. mines as well, in addition to the current, regular spot inspections of the ventilation system by certified mine examiners. BACKGROUND: METHANE EXPLOSIONS, FACE IGNITIONS AND NEED FOR AIR QUALITY MONITORING Accumulations of methane in face areas of underground coal mines frequently lead to ignitions that can cause burns, traumatic injuries and, in the case of the 2010 Upper Big Branch disaster, cause major explosions with multiple fatalities. Table 1 shows the number of reported face ignitions in U.S. coal mines between 2010 and 2014, based on statistical data published by MSHA (MSHA 2010 – 2014). Although there appears to be a downward trend in such ignition incidents over time, ignitions continue to occur with some regularity; and each ignition may cause a potentially catastrophic mine explosion.Per regulation, all U.S. coal mining machinery, continuous miners and longwall equipment, is outfitted with continuously monitoring methane sensors wired to cut power to the equipment as the methane level exceeds 1%. Face ignitions keep occurring because these sensors are usually not positioned in sufficiently close proximity to the coal cutting drums or to the freshly exposed coal face where the methane is most likely released. Therefore, methane may accumulate in explosive concentrations near the coal face and the cutting drums long before the gas concentration reaches the 1% level near the monitor and creates an alarm."

Jan 1, 2016