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By James Thompson

Mine planning at Consolidation Coal Company's (Consol) Glenharold Mine in North Dakota is being constrained by environ¬mental concerns that did not exist when the mine opened in 1965. One such concern which developed in the mid-1970's is the impact of mining on woodlands that are considered impor¬tant wildlife habitat. To better coordinate mine planning with permitting, a cooperative task force was created to evaluate woodlands for their wild¬life habitat potential. The task force included representatives from Consol and state and federal agencies. This cooperative process is seen as a method of communication between industry and government and as a way of developing decision-making tools for mine planners and regulatory agencies.

Jan 1, 1981

By Andrzej Wala, Henry P. Cole, Perry David Passaro

Cognitive representations and misconceptions of flow through circuits is an area which has received little attention from science educators, cognitive psychologists, or accident investigators. Misconceptions are also called Aristotelian thinking. They involve a person using primitive unscientific ways of reasoning to make decisions about events (Piaget, 1929; Nussbaum & Novick, 1982; McCloskey, 1983). The use of such primitive concepts leads to errors in reasoning about scientific and technical problems. The existence of misconceptions is well documented among children, adolescents, and adults involved in learning science concepts (Piaget, 1929; Cole & Raven, 1969; Clement, 1982; Mistrell, 1982; McDermott, 1984; Richardson, 1987). Concepts of flow through circuits are important because miners' conceptual errors about these aspects may be, in part, responsible for two fatal mine disasters. On at least two separate occasions, methane gas explosions occurred in underground mines when separate ventilation systems were connected (Elam, Fuller, Carter, Cavanaugh, Fesak & Painter, 1983; Fesak & Cavanaugh, 1984). A review of these disasters indicates that conceptual errors made by miners may have resulted in the accidents (Cole, Wala, Haley, & Vaught, 1987). In this study, co-author Andrzej Wala, stated that his research had "identified conceptual errors that may have caused the miners in these disasters to make fatal mistakes" (Cole et al. 1987), p. 167. Further exploration of these conceptual errors by Wala has led to the hypothesis that misconceptions of basic aspects of flow distribution changes in mine ventilation circuits, are at least, in part, responsible for some mine disasters caused by errors in ventilation systems (Wala & Cole, 1987). Why should these conceptual errors occur? Ausubel (1963) suggested that students come to a new area of study with their own conceptions or preconceptions about how a process operates. Furthermore, these preconceptions may be in conflict with the empirical data from the discipline. In such cases, learning becomes a process in which new concepts must displace or be re-molded from stable concepts that the student has constructed over many years (Clement, 1982). Given the existing research with misconceptions and the work of Wala and Cole (1987), it was hypothesized that experienced miners; either working miners, students of mining engineering, or professional mining engineers, harbored misconceptions about the formal or conceptual aspects of mine ventilation circuits. The misconceptions hypothesized to exist involved flow distribution changes in complex mine ventilation circuits; specifically, how does flow distribution change when a ventilation circuit pathway is altered? Given this information, the following research questions were proposed. Research Questions 1. Do experienced miners and mining engineers harbor misconceptions about mine ventilation systems? This question was addressed by: A. The administration of the Cutthrough Ventilation Arrangements (CVA) exercise that measures subjects' performance level when making decisions about major ventilation changes when connecting two mine sections;

Jan 1, 1989

By Craig M. Sams

Dry grinding circuits and factors influencing the selection of the most appropriate grinding system for a given ore selection are discussed. Comparisons of the drying, grindability, installed costs and operating costs are presented for several grinding systems.

Jan 1, 1994

By Bradley V. Nelson

A number of improvements in the ventilation system at the Henderson Mine have been made during the past several years. A key to these improvements was the installation of a computerized monitoring and control system. Employees can determine the status of any of hundreds of devices in seconds through the use of this monitoring system. Mine dewatering pumps, the water treatment system, the ore haulage system, electric power usage as well as other devices are controlled and/or monitored. Ventilation parameters which are monitored include air flow volumes and carbon monoxide as well as the status of main surface fans, mine doors, and ventilation raise doors. Main underground fans are also constantly monitored and can be controlled remotely. These underground fans can be programmed to automatically start and stop to follow work schedules, optimizing air quality while reducing power cost. Mine air heating costs have been reduced by replacing an electrical resistance heating system with a direct fired natural gas heating system at the portal of the ore haulage tunnel.

Jan 1, 1995

By G. E. Erdman

The total attitude of the industrial minerals producing company is a most important factor in how they regard quality control, technical support for their customers, and procedures used in mining their minerals products. This philosophy of the producing organization directs their action along certain courses. For instance, one producer might see itself as a mining company with its major goal mining efficiency to make it exceedingly price competitive in the market place. Another producer might see itself as a wide spectrum multi-mineral producer that furnishes a reputation for a complete line of products. Another producer might see itself as a specialist in one specific industrial mineral and bet its whole bankroll on providing the very best of quality with the goal of becoming the largest producer of the mineral commodity. Each perception can have a different impact upon the producer's operations and its regard for quality control. Minerals Being Produced The specific markets being served will have their own influence on how mineral product quality is regarded. Ceramic raw materials, for instance, have a very low tolerance for iron which is the cause of low fired color. Thus, industrial minerals for use in glass and ceramic markets must be won from deposits with a very low iron content. A high iron silica sand might be sold to a manufacturer of good old beer bottles. That is a solution to one particular quality facet, but eliminates selling to a significant market in clear glass, porcelain enamel, ceramics whiteware bodies and hobby glazes. Thus, there is a need for sound research in the industries expected to be served before the product is brought to market.

Jan 1, 1987

By Jack Parker

Cycles of mine convergence coincide with annual cycles of temperature and humidity in the mine. Laboratory measurements confirm that the presence of moisture reduces rock strength and induces internal rock stress. Findings are used in the design of mine openings.

Jan 1, 1969

By Robert E. Jones

The barite industry shares with its associates in the minerals industry the impediments of excessive federal and state regulations. We have learned to exist with the Organic Act of 1976, the Mine Safety and Health Act of 1966, and the Multiple Use Act of 1955. I do not mean to imply by the above that all aspects of mining legislation have been detrimental, however, each of you has been subjected to interpretative restrictions by federal or state bureaucrats. As frustrating and costly as this is to the barite industry, it is not the primary problem facing our segment of the industry at the present time. Our major difficulty today deals not with too much government regulation, but with the lack of a cohesive and consistent government energy program. This administration and those that have preceded it have dealt with intermittent energy crises on an emergency basis. If we remove the political rhetoric which has surrounded each of the more recent major crises, we can liken the action of our federal government to that of a rural volunteer fire department which devotes its entire efforts toward extinguishing existing fires rather than the developing of programs designed to prevent future fires. The lack of a comprehensive energy program has created an environment in which long range planning is extremely difficult, if not impossible.

Jan 1, 1983

By Rami Abousleiman, Gabriel Walton, Sankhaneel Sinha

"Although conventional coal mine designs are conservative regarding pillar strength, local failures such as roof-falls and pillar bursts still affect mine safety and operations. Previous studies have identified that discontinuous, layered roof materials have some self-supporting capacity. This research is a preliminary step towards understanding these mechanics in coal-measure rocks. Although others have considered broad conceptual models and simplified analogs for mine roof behavior, this study presents a unique numerical model that more completely represents in-situ roof conditions. The discrete element method (DEM) is utilized to conduct a parametric analysis considering a range of in-situ stress ratios, material properties, and joint networks to determine the parameters controlling the stability of single-entries modeled in two-dimensions. Model results are compared to empirical observations of roof-support effectiveness (ARBS) in the context of the coal mine roof rating (CMRR) system. Results such as immediate roof displacement, overall stability, and statistical relationships between model parameters and outcomes are presented herein. Potential practical applications of this line of research include: (1) roof-support optimization for a range of coal-measure rocks, (2) establishment of a relationship between roof stability and pillar stress, and (3) determination of which parameters are most critical to roof stability and therefore require concentrated evaluation.INTRODUCTIONRecent studies on pillar design have suggested that the assumptions utilized in traditional methods such as tributary area theory (TAT) (i.e. overburden has no self-supporting capacity, infinite pillar array, and CHILE material properties) are invalid in many geo-mining conditions (Esterhuizen, Mark, and Murphy, 2010; Frith and Reed, 2017). Although TAT is conservative with respect to pillar loading, and mine fatalities have steadily decreased since 1990, roof-falls and pillar bursts still occur and injure hundreds of miners per year (Mark, Pappas, and Barczak, 2011). Even though large-scale global mine failure has not occurred in a US coal mine since 2007, the mechanics of global and local stability as governed by the relationship between geologic parameters, mine geometry, and engineering design are still not well-constrained.Numerical methods are a highly effective tool that can be used to gain further insight into these relationships. When using such an approach, calibration to existing empirical relationships is imperative to ensure that numerical model results are realistic. In this study, we utilize the discrete element method (DEM) approach in Itasca’s Universal Distinct Element Code (UDEC v. 6.0) (Itasca, 2010).DEM accounts for explicit separation and contact of individual deformable blocks (Jing, 2003) and captures how discontinuities can affect system behavior. Discontinuous and anisotropic rockmass properties are typical features in coal-measure rock which contain various horizontal (bedding) and sub-vertical (joints) fractures depending on their depositional environment, diagenesis, and historic and current stress states."

Jan 1, 2019

By A. D. Davis

Environmental impacts from acidic mine drainage are growing national concerns that are particularly acute in the headwaters of the Rocky Mountain region. In the Black Hills of South Dakota, approximately one thousand mines are inactive or abandoned, most of them in the headwaters of major drainages. This paper examines the Bear Butte Creek basin, a heavily mineralized watershed with significant historical mining impacts and a surface gold mine permitted in 1997. The watershed loses its surface discharge to swallow holes in the karstic Madison Limestone. The integrity of the aquatic ecosystem was monitored with a suite of site-specific bio-indicators. Stream surveys covered the entire reach of Bear Butte Creek from near its headwaters to the swallow holes in the Madison aquifer. Data from the stream surveys, water-quality sampling, and bio-indicator surveys clearly showed that water-quality impacts are limited mainly to Strawberry Creek and to the area of Bear Butte Creek near and downstream of the town of Galena.

Jan 1, 1999

By N. K. Dumakor-Dupey, K. J. Bansah

"We made site visits to determine potential environmental issues caused by artisanal and small-scale mining (ASM) in the Tarkwa Mining Area (TMA) of Ghana. Activities of the diggers were observed to degrade vegetation, land and water. Improper handling of mercury was also identified as a major threat to people and ecosystem. Large abandoned pits and trenches posed fall traps to farmers, hunters and wildlife. We argue that lack of adequate monitoring and regulatory enforcement by Ghanaian authorities, together with inappropriate mining processes, probably due to lack of technical expertise are contributing factors to the environmental issues of artisanal and small-scale mining in the TMA. INTRODUCTION Environmental degradation caused by artisanal and small-scale mining (ASM) has been a major concern to many people and governments around the world. ASM is often associated with health, safety and environmental issues in communities where it is practiced (Kitula, 2006; Asiedu, 2013; Sousa et al., 2010). Some of the environmental issues that have been reported include land degradation, mercury contamination, cyanide release, and pollution of rivers/streams. These issues have been attributed to improper mining methods, inefficient technology, lack of technical training and environmental awareness, and lack of regulatory enforcement (Serfor-Armah et al., 2005; Bansah et al., 2016a; Hentschel et al., 2002). In Ghana, ASM typically occurs in rural communities, providing jobs to many people and contributing towards socioeconomic growth of the country (Banchirigah & Hilson, 2010; Bansah et al., 2016b; Osei-Kojo & Andrews, 2016). As a result of the environmental issues, many people have called on government to develop drastic measures to control ASM operations. It is in this regard that this paper examines potential environmental issues caused by ASM in the Tarkwa Mining Area in Ghana, and suggests mitigation measures to ensure environmental sustainability. ASM in the area comprises of registered (licensed) and unregistered (unlicensed) operations that adopt surface or underground mining methods to exploit gold-bearing materials. Surface operations typically involve clearing of vegetation, removal of overburden, excavation of mineral deposit, washing/grinding of excavated gravels and processing with mercury. Except grinding, washing and mercury recovery, underground operations are conducted below ground with limited impact on the surface. Alluvial mining is also commonly practiced in streams and along river banks. These activities can have devastating impact on biodiversity of the ecosystem. To achieve the objective for this study, field visits were made to ASM sites to observe operations and interact with diggers. Visits were also made to host communities of ASM and government officials to obtain their perspectives on ASM in relation to environmental impact. The study area (Tarkwa Mining Area) is located in the Western Region of Ghana (see Figure 1). It is endowed with natural resources such as gold and manganese. Hence, mining is the major economic activity in the area. ASM is widespread, with 15 registered operations and several unregistered mines. The environmental issues observed in the study have been grouped into three main categories: vegetation and land depletion; water quality and pollution issues; and mercury contamination issues."

Jan 1, 2017

By Daniele Martinelli, Rodrigo Winderholler, Daniele Peila

"This paper presents a technical description of an experimental procedure developed for the geotechnical characterization of granular soils conditioned for EPB tunneling using a modified direct shear box. As the main concerning parameters of the conditioned soil mass were their undrained properties, in order to preserve its pseudo-fluid characteristics, a watertight direct shear apparatus was constructed. A comparison between the results obtained under dry, saturated and conditioned conditions is presented. INTRODUCTION EPB shield machines have been used for tunneling excavation in many different types of soils thanks to the use of soil conditioning agents. These modify the properties of the soil into that of a plastic paste, thus permitting the homogeneous flow of the excavated soil from the tunnel face through the bulk chamber, the screw conveyor and finally the conveyor belt. Moreover this technique allows controlling the face pressure and its regulation in the bulk chamber, preventing water inflow when tunneling below the water table. Further advantages are a drop of the cutter head and screw conveyor torque and reduction of the friction between metallic parts and the soil, consequently reducing wear phenomena (Merritt & Mair, 2006; Vinai et al., 2007; Borio et al., 2010; Thewes & Budach, 2010; Herrenknecht et al., 2011; Barbero et al., 2012; Peila, 2014). Several studies have investigated the possibility of conditioning and the chemical materials to be used in different types of soils, mainly subdivided into three groups: cohesionless soils (sand and gravel), silts and clays, and rock masses. This various researches have set up several laboratory procedures for these achievements before and after soil conditioning, as stated in Thewes & Budach (2010) and Peila (2014) (for cohesionless soils), in Thewes & Burger (2005), Hollmann & Thewes (2013), Zumsteg et al.(2012) (for clay), in Peila et al. (2013) and Martinelli et al. (2015a) (for rock mass). Such tests should be simple to execute, reliable and easy to interpret at the in-situ excavation step. The reduction of shear strength is necessary in EPB operations, since it allows an effective transmission of the pressure from the material itself to the front. In some cases the slump is not sufficient to return a reliable result on the shear strength reduction, as in some cases some materials are behaving differently. Therefore this research is aimed to study this aspect more in detail, in order to show the effectiveness of the soil conditioning process on the material to be excavated."

Jan 1, 2016

By Chee S. Theng

As the 2017 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2017 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 342. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2017 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH), a special review article on Heap Leach Modeling, and articles from two Special Issues on Rare Earths. The 2017 Transactions consists of a total of 54 technical papers, encompassing all 21 papers published in 2017 in the Technical Papers Section of Mining Engineering (Vol. 69) and all 24 papers published in 2017 in Minerals & Metallurgical Processing (Vol. 34). Additionally, this volume contains 9 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our Publications staff. As the 2017 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2017

By B. V. Cooper

The word "research" has been used in the title of my presentation somewhat against my better judgement. There are many definitions of the word. But the one I like best comes from Webster's New World Dictionary. It reads: "Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles. ..." I like that. In only 9 words, the definition conveys to me the very essence of what should be going on either in or for the coal industry. Unfortunately, not enough coal-related research is going on. And much of what is being done is, in my view, not really as effective as it might be.

Jan 1, 1983

By Syd S. Peng

The key design parameters of roof bolting using expansion - shell type support for underground coal mine roof support are bolt length, bolt spacing, installed load and anchorage capacity. Depending on the utilization of suspension effect or friction effect, the bolt length is dictated either by the distance between the roof surface and the first overlying strong strata encountered or the desired magnitude of reduction in bending stress at the roof surface, The current prevailing practices about the bolt spacing and installed load are that an initial torque of 125 - 170 ft-lbs is applied and the bolts are spaced at 4- or 5- ft. square grid pattern. This seems to be a rather broad generalization in view of the great geological variances which are expected in underground coal mines. A modest evaluation program to measure the effectiveness of current roof bolting practices is to monitor the load history of roof bolts during a complete mining cycle including the phases of room development and pillar robbing. The load history, when compared with the anchorage capacity of roof bolts determined by in-situ pull tests, will provide information for evaluating the installed load, the bolt spacing as well as the specifications for structural and anchorage characteristics of the bolt assemblies. This paper presents a case history of monitoring the complete load histories of roof bolts in an underground coal mine of Pittsburgh seam.

Jan 1, 1976

By Mark E. Gershon

Conventional methods of drillhole site selection are reviewed briefly. Two approaches using geostatistics are then discussed, both of which have been shown to yield improved results. Finally, a branch and bound algorithm is described which will select the best locations for drilling from a user specified number of possible drill sites. Two options are discussed. First, the user can specify a maximum drilling investment or a maximum number of drillholes and the program will select the locations yielding the minimum estimation variance. This amounts to getting the most for a given investment. Alternatively, a maximum tolerable estimation variance can be specified and the program will select the number and location of the drillholes to obtain the desired information at a minimum cost. Another benefit of the approach is the quantification of the tradeoffs between investment and information obtained.

Jan 1, 1983

By E. G. Loesche

Grinding mills in which the comminution takes place between rollers and the surface of a disc, table or ring are generally known as roller type mills. The Loesche Mill, also known as the Disc Roll Mill, is a special type of roller mill in which the grinding surfaces consist of two rollers assembled over a horizontal disc or table which rotates at a relatively low speed. This design is particularly applicable to industry's present day demand for large capacity grinding mills.

Jan 1, 1964

By D. H. Davidson

The basic principal in the ISL process involves the recovery of metal values by moving fluids through rock instead of moving rock. The process combines surface and sub-surface operations, with the economic performance controlled by four major factors; rates of fluid injection and production from wells; the rate of mineral solubilization; the volume of rock swept by the fluid; and the volume of solution processed through the system. This paper discusses various technical and economic parameters affecting these four factors and how they impact project costs.

Jan 1, 1985

By Jurgen Hahn

The paper reports on both, the design and decision making for the filters in a backfill plant in Europe as well as more then 10 years of operation and maintenance experience of the vacuum disc filters installed. It begins with the first step, the filter sizing based on a sample provided by the customer, followed by the commissioning of the filter units and reports on the development of the filter performance during the following 10 years of operation. Based on the physical properties of the sample and the process targets of the client for the backfill plant, the paper shows the logic steps taken in the laboratory to ensure the target moisture, determine the required filtration area and filter size as well as the selection of the ancillary units and the formulation of the performance guarantee. The paper discusses some issues with filter operation during the commissioning phase and the actions taken. Finally, the paper concludes by highlighting the gradual change over the more than 10 years of operation and how this change affected filter performance and operating costs.

Feb 1, 2024

By C. Konya, A. Konya

"INTRODUCTION Over the past twenty years this Linear-Regression Modeling has become widely accepted for ensuring limits are not exceeded at a site, using the Scaled-Distance variable. In today’s industry, numerous equations are present for different scenarios, geologic environments, hole sizes, and numerous other factors with an emphasis on site-specific equations developed for all major projects; however, underground blasting applications have not been analyzed to a great degree of detail. Without previous knowledge this puts underground blasting operations into a guessing-game to ensure that vibration levels are not exceeded. This paper will review two recent projects that have been worked on by the authors and linear-regression models that were used with both burn cuts and stope blasts. BLAST VIBRATIONS MODELING The first major research project conducted in the United States on blasting vibration was Bulletin 442 (Thoenen & Windes, 1942) which looked at the relationship between blasting and blast vibrations in the fall of 1940. This study examined numerous blasts and began the investigation into topics such as damping, structural damage from vibrations, frequency dependency on vibration, resonance vibration, delayed blasting, and numerous other factors. Bulletin 442 had two major conclusions which are: 1. The vibration from a blast can be predicted with a relationship of size of the shot and distance to the structure (now known as scaled distance) 2. “The vibration of a structure at resonance does not in itself cause damage because of the restraining effect of damping inherent in the building” (Thoenen & Windes, 1942) Due to the increase of blasting near homes and busier areas the USBM commissioned an additional study to further develop a few of the topics covered in Bulletin 442; this study would go on to be published as RI 6561 (Duvall, Johnson, Meyer, & Devine, 1963) with the study looking into delayed blasting and the relationship between charge weight, distance, and peak particle velocity of the blast. This relationship would be termed as the ‘scaled-distance’ and take the form of:"

Jan 1, 2018

By S. K. Sharma

The Bureau of Mines' rapid method of dewatering fine-particulate slurries uses extremely high molecular weight polymers. These polymers form large, strong flocs which can be dewatered by sieving or sedimentation. However, sometimes these flocs deteriorate rapidly if water is not removed immediately. During field tests, clay slurries have been encountered that could have been dewatered economically if it were not for the rapid floc deterioration. A kinetics study was conducted to determine the rate of kaolin-PED floc degradation in which polymer addition, to bring the flocs back to their original condition, was used to determine the extent of floc decay. Results showed that the amount of polymer added, to replace polymer lost by spreading, was less for the lower PEO concentrations. For this clay-polymer system, floc breakage as judged by polymer additions followed first order kinetics. It was also found that the addition of fluoride ion stabilized the kaolin flocs.

Jan 1, 1992