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By William C. York-Feirn, Jeffrey H. Kravitz, David Stalfort

"Mining is an inherently risky business. Over the years, major mine disasters have resulted in the deaths and injuries of thousands of miners in the United States. These disasters also resulted in innovations in approaches to mine design, operations and the training of miners and mine rescue teams. The U.S. Congress responded to these disasters with new laws designed to create mandatory safety and health standards as a means to eliminate fatal accidents; to reduce the frequency and severity of nonfatal accidents; to minimize health hazards and to promote improved safety and health conditions in the nation’s mines.Following a mine emergency preparedness and response holistic gap analysis in 2012, the U.S. Mine Safety and Health Administration (MSHA) identified the need for the development of risk and readiness assessment models for MSHA and the mining industry. MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the mining industry for use at operational levels. In 2012, MSHA hired ABS Group, a recognized industry leader in safety risk management and a wholly owned subsidiary of the American Bureau of Shipping, to develop self-assessment models to help meet this objective.In September 2012, MSHA chartered a project to supply the coal mining industry with a pro-active toolset for mine operators to:1. Self-assess the risks associated with underground coal mining operations in order to prevent major mine emergencies.2. Assess the preparedness of mine operators to respond to an emergency.3. Measure the readiness of mine rescue teams and responsible persons to execute emergency plans.MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the coal mining industry for use at operational levels."

Jan 10, 2018

By T. J. Malterer

Peat has unique physical, chemical, and biological properties. These include high porosity and water retention, high absorption and adsorption properties, high buffering capacity, and it is a rich medium for microorganism activity. Peat has traditionally been used for horticultural purposes. However, in recent years, peat is increasingly being used for waste treatment purposes. This paper reviews North American literature on the use of peat for waste treatment applications. The literature indicates promising use of peat in treating municipal and on-site effluent, removal of low concentrations of heavy metals from wastewaters, and adsorption of liquid and gaseous hydrocarbon pollutants.

Jan 1, 1995

By Walfrid Been

There are no particular nor unique features of iron mining that are not shared in some degree by all mining ventures everywhere. There are, however, at least three problems that have acquired a special emphasis from a unique cause. That cause is the embarrassment of riches under which the industry is suffering. The most obvious' feature of iron mining today is the copious abundance of usable ore and its almost universal distribution over the face of the earth. By the term "usable ore" is meant ore that is amenable to reduction by the usual and conventional processes. Amidst this plenty, three problems become acutely emphasized: 1. The geographic location that will provide a mine with the best market opportunity. 2. The size of the orebody that will be required to' return the preproduction investment. 3. The geometry and configuration of the orebody that will permit quality control measures to be effectively executed.

Jan 1, 1964

By Frank W. Pereira

The Montana Talc ore body was discovered in 1983 in Montana's Gravelly Range, about 40 km (25 miles) south of Ennis. Initial drilling indicated a 910-kt (1-million st) ore body of high purity talc. Preliminary analyses on ore cuttings included chemical analysis, brightness measurements, and microscopic evaluations of the structure of the talc. Results indicated it was similar to talc currently being marketed from Montana and it would probably have good commercial value. Based on the positive test results, a test pit was made and a 180-t (200-st) sample of ore was mined. A portion of the ore was ground to various particle sizes and evaluated to determine its strengths, weaknesses, and other characteristics. The deposit is located close to the Cyprus Yellowstone deposit. It was therefore believed that Montana Talc ore may possess many of the same characteristics. Testing and analyses showed the talc to have a high purity and an extremely large surface area, even for Montanatype tales. The ore was also situated in a massive deposit, indicating low cost mining. While the lab analyses were encouraging, the true evidence would be obtained from commercial tests in the marketplace. About 91 t (100 st) of ore were ground to product specifications for pitch control, paint filler, and plastics filler. Consumers were contacted and requested to evaluate the sample talc products. A major trial for the talc as a pitch control agent was arranged at a Northeast paper mill. The trial indicated the new Montana Talc product performed as well or better than the current standard in the industry. In fact, due to a minor modification in the compaction process to make the transport of the talc easier, the product had substantially less dust than the currently used product. The operating people at the paper mill requested that management purchase this talc. Trials were also run at paint plants for use as a pigment filler. And the talc was fabricated into a number of plastics compounds. The initial product tests were largely positive and provided encouragement to proceed with the project. Different grinding mills were used and their performance evaluated. Significant data were generated by the custom grinders. They indicated how the Montana Talc ore ground and the particle size distributions produced at different grinding settings. Encouraged by the positive marketing tests, a prefeasibility study was commissioned. A talc grinding plant and mine plans were designed and capital and operating costs estimated. Initial economics showed an attractive return. The operating costs were among the lowest in the industry. The positive economics, along with the excellent results by the products in the marketing tests to the paper, paint, and plastics industries, led to the recommendation to proceed with the project. Plant construction began in June of 1985. The Montana Talc Co. (MTC) analyzed the data from the commercial tests. Based on the product's outstanding performance and the uniqueness of its high purity and platy structure, a strategy was developed to position the company as a premium talc supplier.

Jan 1, 1989

By Dan Mackie

Commissioning of a 150 tpd continuous vat leaching pilot plant at Ariel Resource's San Martin Mine began in October, 1995. Functioning of the systems proved to be as designed. Initial tri­als, however, were besieged with problems associated with clay fractions that were much higher than in the ore originally tested. Nevertheless, leach rates were good in the initial and subsequent trials. Difficulties with the viscous solutions generated by the clay fraction continued, requiring modifications to the solution collection methods and investigation of flocculant types and mixing points. Trials with deslimed ore and sand feed demon­strated continuous flow. Current modifications will be tried in late May, 1996, along with selected flocculants, with the objec­tive of leaching continuously without the need to deslime.

Jan 1, 1996

By Yousef Ghorbani, Abolfazl Danesh, Fatemeh Kazemi, Ataallah Bahrami, Morteza Abdollahi, Mohammad Raouf Hosseini

This study aims to investigate the effects of the operational variables on the concentrate grade, recovery, separation efficiency and kinetic parameters of the copper flotation process. The results indicate that concentrate collecting time and pulp density were the parameters with the greatest effects on the concentrate grade. Considering copper recovery, the concentrate collecting time, collector dosage and pulp density were the most significant variables, in decreasing order of importance. The separation efficiency was found to be mainly influenced by the concentrate collecting time. This study can be helpful in identifying the parameters with the most effects on flotation performance and, consequently, the overall process efficiency, including recovery and separation efficiency. Such an outcome can be used as a decision-based tool to apply the necessary changes in a real-life industrial operation in a more effective way to improve the quality and quantity of the flotation concentration.

By Nelson R. Shaffer

Implementation of the Clean Air Act Amendments of 1990 is negatively affecting production of coal used for generating electric power in Indiana and elsewhere in the Midwest. Required reduction of sulfur compounds from gas streams, or flue gas desulfurization (FGD), as mandated by these laws has encouraged installation of wet limestone scrubbers at many generating plants. Increasingly stringent requirements that will begin in 2000 are expected to necessitate even more extensive use of such scrubbers. Indiana has large deposits of limestone-the major consumable alkaline raw material for scrubbers-that can meet an expected demand of several million tons per year. Limestones are not, however, all the same. Different limestone units behave quite differently when used as scrubbing agents under differing conditions in actual practice. Decisions about FGD scrubber details would be more meaningful if made with thorough knowledge of which rock units contain the most efficient FGD limestones and which sites of suitable stone are located nearest to power plants. Even though abundant carbonate rocks occur in Indiana, their suitability in scrubbing systems has received little attention, and few attempts have been made to match details of stone resources to the needs of various utility scrubbing systems. Optimization of the fit between geologic characteristics of the existing limestones and prospective scrubber systems should allow for greatly improved planning and operation of FGD systems with attendant lower overall costs. Electric utilities have developed computer models to predict FGD system operations (i.e., the FGD-PRISM model of the Electric Power Research Institute). These models require geologic data such as reactivity that are commonly unavailable. We generated data needed for the model during a cooperative effort among the Indiana Department of Commerce, the Indiana Geological Survey (IGS), The Indianapolis Power & Light Company (IP&L), and the Indiana Mineral Aggregates Association. Our goal was to provide missing geologic details of Indiana scrubber-stone raw materials and apply them to the FGD-PRISM model to provide general guidance to determine which geologic units can provide stone for most efficient sulfur removal. Results of the model for selected limestones and parameters specific to one IP&L generating plant were calculated. Geologic data generated may be applied to other generating operations, and our examples should help other utilities optimize their FGD strategies. Several hundred samples from more than 30 active quarries were collected and their physical properties determined. Grindability values ranged from 7.2 to 21.7 for 50 selected samples. Acid-insoluble residues of less than 1% to 13% were found. Dissolution rates as an index of reactivity varied over two orders of magnitude for the selected set of samples. These data plus chemical analyses and Ca/Mg ratios were entered into a generic scrubber model to determine rates of stone use and scrubber efficiency for various stone. Removal of SO2 was projected by this model to range from 89% to 98% with stone utilization rates from 91% to 93%. Excellent scrubber stone sources were found in Mississippian rocks in central and southern Indiana. Rocks of the Ste. Genevieve and Salem Limestones were especially efficient. Even small amounts of dolomite, clay minerals, and quartz diminished a stone's usefulness for FGD scrubbing.

Jan 1, 1999

By Britta Schoesser, Zdenek Zizka, Markus Thewes

"The support pressure of a slurry shield corresponds to the in situ earth and groundwater pressure to ensure the stability of the tunnel face. The support fluid (bentonite suspension) penetrates from the excavation chamber into the pore space and transfers the support pressure to the granular structure of the soil within this zone. At the same time, the cutting tools rotate periodically with the cutting wheel and remove the penetrated soil up to a certain cutting depth at the face. Shortly after the tool passing, the penetration process starts again. Both, the support pressure and the soil excavation, act in the same direction at the tunnel face, but they are subject to different cyclic intervals. This relationship between the time needed for the transient penetration process and the interval of the cyclic passage of the cutting tools at a local point at the face is examined and the impact onto the global face stability is discussed. INTRODUCTION Slurry shields are usually deployed for excavations in soft ground. The main application range is in non-cohesive soils (DAUB Recommendations 2010). In non-cohesive granular soils, the tunnel face stability is one of the key design issues. The slurry shields make use of pressurized bentonite suspension (slurry) to support the unstable tunnel face. To support the tunnel face effectively, the slurry pressure has not only to counter the groundwater pressure, but also has to be transferred into an effective stress to support the soil grains. In general, the pressure transfer can be achieved in two ways: (1) with a thin flexible membrane or (2) a penetration zone. The membrane (1), called filter cake, creates a thin impermeable layer from bentonite particles directly on the tunnel face, and enables a transformation of excess slurry pressure into effective stress. In case of penetration zone formation (2), the excess slurry pressure is transferred onto the soil skeleton along the entire penetration depth by shear stresses between slurry and soil grains. These theories, presently applied to assess the pressure transfer on the grains within slurry shield tunnelling, are originating from diaphragm wall technology, e.g. Müller-Kirchenbauer (1977), Kilchert and Karstedt (1984). They assume that the support pressure transfer mechanism is built-up instantaneously on the whole tunnel face and is not damaged or influenced by the interaction with excavation tools. These assumptions are valid for conditions during the excavation of diaphragm wall trenches whose bottom is excavated and the walls of the trench are supported. At the tunnel face of a slurry shield, the support suspension acts on the same area as the soil excavation. Hence, the conditions on the tunnel face are transient (time dependent) due to the time period needed for the penetration process of the slurry and the periodical damage of the pressure transfer mechanism by excavation tools (Fig. 1a)."

Jan 1, 2016

By Saman Khaleghparast, Naj Aziz, Jan Nemcik, Guanyu Yang

"More than 25 years of uninterrupted research on ground support technology for underground mines has been undertaken at the University of Wollongong. This research has resulted in significant findings on tendon characteristics and strength properties. The paper focuses on the development of the fourth generation of cylindrically shaped shear test apparatus for assessing tendon performance in shear. This shear apparatus is known as the MK-IV Double Shear Box or Naj Aziz Double Shear Box (NADSB), and is based on the experience gained from the development of previous versions of rectangular double shear boxes. The new NADSB is circular in shape and is fitted with a truss system, which permits friction free shear testing of tendons across joint planes. A series of double shear tests were carried out on a number of cable bolts commonly used in Australian mines, both plain and indented wires, under varied pretension loads. The results were compared with similar test results using rectangular shaped double shear apparatus, with and without friction across joint faces. The significance of wire surface roughness and increased initial pretension loads are discussed and conclusions made, suggesting that indented wires are inferior in shear compared with plain cable bolts. The general test procedure of the NADSB is described and different concrete reinforcement techniques are reported. The influence of external and internal confinement of the concrete medium blocks in a circular double shear box contributed to consistent test results with a minimum of lateral and axial cracks occurring in the host medium.INTRODUCTIONThe use of long tendon ground support elements (cable bolts) is now a common practice in modern underground coal mines, hard rock mines, tunnels and other underground structures. Due to their material properties cable bolts contribute significantly to the overall ground reinforcement provided by a support system. Cable properties in tension and shear are in many cases vital to maintaining a safe and productive underground environment. Accordingly, tension and shear properties must be assessed accurately using both valid and reliable methods.Load transfer property testing of tendons has been studied over several decades with much of the early research focused on the pull and shear testing of solid rock bolts and hollow bolts (like Swellex and split set tube bolts), as these elements were used extensively at this time. It was not until the 1970’s that the use of cables for ground reinforcement developed, and as such highlighted the need to extend load transfer property testing to include shear strength of cable bolts. Initially, the discarded hoisting ropes were used for ground support in metal mines, particularly in stopping wall support and then late in 1980’s cable tendons began to use in coal mines."

Jan 1, 2019

By John K. Hammes

This paper has been written as one of a group of papers dealing with the subject "Cost Elements in Mining". What are cost elements in mining? The mine operator thinks of direct mining costs in terms of labor, materials, supplies and power, and we might define cost more generally as the price paid to acquire or produce something. Economic theory also has its concepts of cost. From one point of view, that of the consumer, the cost of mineral commodities might be viewed as the total price industry pays for mine output. Similarly, the mining company engaged in the on-going business of finding, developing and operating new mines is concerned very much today with the distribution of all the revenue paid for mine output and not just with its direct or controllable cash costs. In other words, what will the labor force, the supplier of energy, explosives, and reagents, and the supplier of government services, management, capital and the ore reserves receive for their contribution to production.

Jan 1, 1974

By Richard M. Tinlin

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

Jan 1, 1973

By Vivas

Goldcorp is one of the largest gold producers in the world with projects in South, Central and North America. Goldcorp?s flagship operation is Peñasquito, a world class, polymetallic deposit that started production in 2010 and is one of the largest mines in Mexico. Since the early stages of the project, Goldcorp has used the most advanced technologies available to maximize its value. However, the implementation of optimum mine plans has been challenging to put into practice. This is due to the fact that the mine operation involves more complexity than the plans usually reflect. This challenge is an industry-wide issue that presents opportunities for improvement. This article discusses the mine planning methodologies and procedures used to connect long-, medium- and short-term planning strategies in order to bridge the gap and produce optimum mine plans that can be practically implemented in the field.

By B. D. Hong

The Coal supply and demand review arrived too late to appear in the May issue. In 1991, the US coal industry produced 902 Mt (994 million st) of coal, according to preliminary data compiled by the Energy Information Administration (EIA) (Table 1). This amount was 32 Mt (35 million st) less than the record 933.5 Mt (1 billion st) produced in 1990. Most of the decrease in coal production occurred east of the Mississippi River. The substantial stock buildup that stimulated production in 1990 was not repeated in 1991. In addition, coal consumption by electric utilities and coke plants dropped by about 1.8 Mt and 4.5 Mt (2 million and 5 million st), respectively. Moreover, a higher level of coal exports failed to bolster the 1991 production. Production Surface mines accounted for about 59% of the 902 Mt (994 million st) of coal produced in 1991. Underground mines produced for 41%. More than one-fourth of the total coal output was from federal and Indian coal leases. Production of all ranks of coal, except subbituminous, declined in 1991. Bituminous coal is produced mainly in the East. It totaled an estimated 590 Mt (651 million st), a 6% decrease. Production of subbituminous coal, mostly in the West, rose 3% to a record 228 Mt (252 million st). Lignite output was from Texas and North Dakota. It decreased by 1 % to 79 Mt (87 million st). Anthracite production, all from eastern Pennsylvania, fell by 17% to 2.7 Mt (3 million st).

Jan 1, 1992

By S. K. MONDAL, K. K. K. SINGH, S. Singh, R. K. TIWARY, S. K. Chaulya, G. C. MONDAL, R. S. Singh, T. B. SINGH

In this work, a comprehensive field study was carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling was conducted to envisage dust concentration due to existing and closed mines in the region. The air quality modeling exercise predicted that particulate-matter levels of PM10 and PM2.5 might increase in the ranges of 3.2 to 23.1 and 2.1 to 8.9 μg/m3, respectively, due to mining activities when some of the closed mines will be operated in the region without controlled emission. The predicted total PM10 and PM2.5 at the selected receptor locations were in the ranges of 86.39 to 194.89 and 34.82 to 99.55 μg/m3, respectively. Adequate measures were suggested to control air pollution from mining activities, and an intelligent dry fog system was designed to suppress dust emission efficiently from mineral processing plants and opencast mines. The developed system has special features for facilitating eco-friendly mining.

By Brendan Demich, MAHIYAR F. NASARWANJI, Alan G. Mayton

During dusk, nighttime and dawn operations, effective illumination is a crucial component of safety for getting on/off mobile surface mining equipment and for preshift inspections. U.S. National Institute for Occupational Safety and Health (NIOSH) researchers examined whether illuminance levels could be improved for ingress/egress systems and preshift walkaround inspections of equipment using light-emitting diode (LED) area luminaires. Illumination and glare were key metrics evaluated. Although headlamps provided adequate illumination, LED area luminaires illuminated a much broader area compared to the narrow spot lighting of the headlamp. Hence, the use of additional area luminaires can increase slip-trip-fall (STF) hazard awareness and detection. Furthermore, a commercially available luminaire demonstrated better results than a custom LED luminaire relative to discomfort and disability glare.

By T. W. Lloyd

Accurately predicting coal seam discontinuities is an important part of modern underground coal mining. Conventional methods of coal exploration sometimes fail to identify rapid variations that may seriously impact mining and quality. Radio Imaging Method (RIM), a geophysical approach to mapping longwall panels, has been developed where electromagnetic signals are transmitted and received though the coal block. The amount of signal loss for a given distance, when compared to the coal seam characteristics, identifies anomalous areas. A comparison of RIM predictions with actual geologic conditions encountered during longwall mining demonstrates the accuracy and usefulness of the data.

Jan 1, 1986

By D. J. Sweet, B. Seymour, T. M. Emery, M. Armatys, J. P. Bourgeois, W. Johnson

The Spokane Mining Research Division (SMRD) of the National Institute for Occupational Safety and Health (NIOSH) has partnered with a narrow vein, hard rock underground mine to research the effects of the binder content on the elasticity and post-peak ductility of cemented hydraulic backfill (CHB). This is part of a larger study to enhance the long-term integrity of ground support in underground mines. As mining advances deeper and stresses increase, CHB mix designs will benefit if they can be modified to handle higher levels of strain which are induced by an increased stope closure, typically affected by a reduction in stope width and increased mining depth, or through dynamic loading resulting from a local seismic event. This portion of the research examined the impact of reductions in binder and their impact on Young’s modulus, peak strength, and post-peak ductility.

Mar 2, 2022

By J. Stowe

"While there has been continual improvement in the models for predicting deposition velocity and pipeline friction losses, the fundamental design philosophy for tailings pipelines has remained the same over the previous three or four decades: design the tailings pipeline to operate in turbulent flow without a deposit on the pipe invert for all expected process conditions. Recent improvements in the understanding of slurry pipeline flows allows for the design of pipelines operating with a deposit on the pipe invert, allowing the system to operate at moderate velocities for high flow rates, optimizing system energy requirements and maximizing pipeline wear life.Tailings pipelines are increasingly operated at higher solids concentrations when there is a greater likelihood the pipeline will operate in laminar flow due to the higher tailings slurry rheology. Historically, slurry pipelines have been operated in turbulent flow. We now know that laminar-flow pipeline operation is possible as there are several operational laminar-flow tailings pipelines. While our understanding of laminar-flow slurry pipelines is not complete, recent research provides guidance on how to approach the design of these pipelines.New sensor technology has led to the development of an instrument that provides reliable indication of bed-deposit height within a pipeline. This technology is particularly helpful in operating pipelines with a deposit and has application in better understanding the operation of laminar-flow pipelines. Failure of tailings pipelines can result in consequent damage to surrounding structures and unacceptable spillage into the environment. Modern pipeline leak detection technology allows operators to better manage this risk by ensuring safe and reliable operation of tailings pipelines.This article provides an overview of the each of the above advances in the design and operation of tailings pipelines.Operating tailings pipelines with a depositTailings pipelines, and slurry pipelines in general, are typically designed to operate without a deposit on the pipeline invert. Meaning, the minimum operating velocity exceeds the turbulent deposition velocity. This approach has been adopted due to concerns regarding potential blockage of a pipeline operating with a deposit."

Jun 1, 2019

By Eugene L. Foster

The engineering profession has traditionally devoted its efforts to understanding and modifying the Earth's environment in order to adapt it to man's needs. In appraising our overall performance, I would have to say it has been a mixed bag. In many areas, notably communications taken in the broadest sense, and development of creature comforts, we have done a good job. In others, we have failed, particularly in our assessment of the effect of our work on the environment. Our failures have been due in part to a lack of understanding or foresight, and in part to a disproportionate emphasis on lowest first cost. Now, with an increasingly large number of people living in a finite environment, there is an urgent need for reassessment. It is no longer possible to pursue a single objective without regard to its side effects. Our projects are too large, and there are too many of them. Environmental impacts must be taken into account in all important engineering decisions of the future. There are forces at work which will help to bring this about. Thinking people everywhere have realized that adverse alteration of our environment eventually affects every one of us. The majority of our citizens, who now live in cities, are beginning to appreciate the advantages of a good natural environment in a way which others who have been closer to the soil have appreciated for years. Our people have flocked to the cities because they wanted to be "where the action is." At the same time, there is a strong desire for what we have come to call the quality of life. Today, we all want the standard creature comforts. We want to be able to move freely

Jan 1, 1974

By Yuting Xue

The classification of rock and coal will assist in automated coal rib rating and shearer horizon control, and is studied with machine learning techniques in this work. A database of rock and coal images is created by filtering photographs taken by researchers from the National Institute for Occupational Safety and Health (NIOSH). The classifier was trained with patches extracted from the coal and rock images, and an accuracy score of 0.9 was obtained. The trained classifier was then applied to classify rock from a new coal rib image with three rock layers of different thicknesses, and good agreement was achieved. The results demonstrate that it is promising to use machine learning techniques and rib images for rock and coal classification.