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By Kunzo Amano

Fully-bonded rock bolts have been widely used in construction sites and mines in recent years. The purpose of this investigation is to prove the effectiveness of rock bolt supports in unstable ground through in-situ tests and numerical analysis. 2. MEASUREMENTS AND PROCEDURES OF IN-SITU TESTS The fully-bonded rock bolts as the mine road¬way supports were tested in the Fukasawa mine which is located in the northeast district of Japan (Fig. 1). The Fukasawa mine (one of the Kuroko mines) started the production in 1973, and the present monthly production is slightly less than 20,000 tons. The ore deposit which exsists at about 400 m depth is divided into several small lenticular shaped bodies. They are distributed apporiximately 1500 m in NW-SE direction and 700 m in NE-SW direction. The hanging wall is basaltic lava and the footwall is tuff. The rocks surrounding the ore bodies are soft but relatively intact, so the trackless mining system has been adopted from the beginning of the development.

Jan 1, 1982

By M. Peters, P. Schmäh

The development of renewable energies and a sustainable power grid are the challenges for future energy supply. Underground cables will replace the vulnerable overhead lines, because of their safety benefits. Due to the public environmental awareness, smart tunnelling and trenchless solutions are required for inner-city and cross-country installations of underground cables, as well as for crossings and the landfall sections to connect offshore wind farms to the transmission grid. Methods from the tunnelling and pipeline industry provide a high flexibility in the planning of alignments, including versatile tunnel concepts and the installation of protective pipes with E-Power Pipe and Direct Pipe.

Jun 13, 2023

By E. Poeck, R. Garvey, U. Ozbay, K. Zhang

"A coal bump is characterized by the sudden failure of one or more pillars and an associated release of kinetic energy. Although the geologic conditions surrounding coal bumps are often similar, their occurrence and magnitude are difficult to predict. This paper presents the development of an approach to assess the potential for coal bumps in room and pillar mines through the use of energy concepts and special consideration of the interface properties between the coal and overlying rock. Back analyses were performed on the widespread collapse of a room and pillar mine with an associated 3.9 local magnitude seismic event. Pillar and mine-scale models were constructed using the distinct element method to simulate the mining stages leading up to the collapse. A variety of loading conditions, material properties, and interface properties were evaluated for their effect on unstable failure of single pillars, and the mine-scale model was used to study the evolution of failure during progressive mining. The extent of unstable failure was quantified in these models by calculating the total kinetic energy released during each mining stage. Through the parametric analysis of single pillar models, it was found that softening parameters in either the coal or the coal/rock interface can individually facilitate unstable failure of pillars, but the combination of the two in a single model produced a much higher release of energy during failure. The results of the mine-scale model further illustrated the trend as the combination of softening parameters in the coal and coal/rock interface produced a series of failures which most accurately reflected the collapse event at the mine. The method of room and pillar stability analysis demonstrated in this study effectively explores the potential for large coal bumps. INTRODUCTION The analysis of coal pillar behavior is challenging because natural variability in geologic conditions requires estimation of material strengths and predicted loads for a given mining situation. Large width-to-height (w/h) ratio pillars and deep overburden present an additional challenge, as the failure behavior of such pillars is more complex and may involve unstable, sudden collapse. Empirical methods have improved the success of coal pillar design for a wide range of conditions, but for deep cover and squat pillar geometries, less accuracy has been achieved in predicting pillar performance (Mark 2000). As with any empirical approach, more back analysis and the consideration of new variables may help improve understanding and accuracy of future designs. This paper presents a study of pillar stability through the back analysis of the Crandall Canyon Mine collapse, which occurred in August of 2007. Pillar-scale models are utilized for the calibration of material properties and assessment of potential instability under varying conditions, and mine-scale models are constructed in an attempt to reproduce widespread failure and correlate with observations at the mine. Special consideration is given to the properties of the coal and the coal/rock interface, and kinetic energy is calculated throughout the course of the simulations to gauge the level of instability when pillar failure occurs. Models were constructed using the Universal Distinct Element Code (UDEC) (Itasca, 2014)."

Jan 1, 2016

By J. David Gunn, Richard W. Lawrence

Gold and silver often occur finely disseminated in sulphide minerals such as pyrite. The use of biological leaching to dissolve pyrite and liberate gold has been extensively studied for a concentrate from the Porgera deposit, Papua New Guinea. The successful operation of a continuous bioleach circuit has been demonstrated. Bioleach residues were cyanide leached to extract gold and silver, and unreacted pyrite recovered for recycle to the bioleach. A 26 day steady state continuous bioleach test on a concentrate assaying 14.3 g/tonne Au and 87.0 g/tonne Ag produced residues with an average 73.5% weight loss and a pyrite oxidation of 88%. Cyanidation and recovery of pyrite from the cyanide residues for recycle gave overall recoveries of 92.1% gold and 74.6% silver. A proportion of the remaining precious metals was found in the bioleach solutions and may be recoverable. Losses to tails were 3.0% gold and 8.1% silver. Final tails represented 14.3% of the feed weight and averaged 1.84 g/tonne Au. A description of the continuous bioleach circuit and bioleach residue handling procedures, and the results of the study are presented. The features and advantages of biological oxidation as a pretreatment for refractory precious metal ores and concentrates are discussed.

Jan 1, 1985

By A. L. Miller, A. J. Chambers, P. R. Griffiths, D. A. Parks

"Diesel engines are one of the primary contributors to the presence of nano and ultrafine aerosols in ambient air and occupational environments. Exposure to diesel emissions has been shown to contribute to various adverse health outcomes of the pulmonary system and cardiovascular system. Currently diesel emissions in the workplace are monitored by way of collecting the aerosol onto filters, which are then sent to a lab for thermal-optical analysis using the NIOSH 5040 method, which measures elemental and organic carbon explicitly. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of diesel particulate matter (DPM) before the problem is identified. To remedy this, researchers from the National Institute for Occupational Safety and Health (NIOSH) are seeking to develop a field-portable method for measuring elemental and organic carbon in DPM aerosols. In the current study, we investigated the use of Fourier transform mid-infrared (FT-IR) spectrometry, which lends itself more readily to implementation in a real-time system than do the thermal-optical analysis methods. We have demonstrated a method for measuring organic and elemental carbon in DPM for a broad range of organic carbon (OC) to elemental carbon (EC) ratios (from 50.3 to 0.8). The ability to handle a wide range of OC to EC ratios is critical given the evolving diesel technology. INTRODUCTION Respiratory illnesses are common in mining industry workers [1] and exposures to toxic aerosols such as DPM can result in serious respiratory illness [2]. Health studies show a correlation between workplace exposure to diesel exhaust and an increased risk of lung cancer [3-8]. The International Agency for Research on Cancer (IARC) has characterized diesel exhaust as a human carcinogen [9], and similar classifications have been made by the World Health Organization and the California Air Resource Board. A recent study [10] suggests that the risk of lung cancer is approximately three times greater for heavily exposed workers. When compared to other aerosols in the mine environment, the settling time of DPM is significantly longer than that of dust due to their small particle size (typically < 1 µm) [11]. Additionally, submicron particles (such as DPM) are deposited in the lungs much more efficiently than their larger counterparts such as dust [12]. Previous studies focusing on particle morphology [13] show that the largest mass contributor to lung disease in mining is elemental carbon, which provides a solid core onto which hydrocarbons are adsorbed. In accord with those findings the Mine Safety and Health Administration (MSHA) decided on submicron total carbon as a surrogate for monitoring diesel particulate matter in the mining environment."

Jan 1, 2018

By Jerry Wang, Greg Bold, Mahmood Khwaja, Rebecca Caldon, William Simcoe

Phase III and Phase IV of the Beaver Creek Clean River Project, Albany, NY, includes microtunnel construction of 2,320 feet of 48-inch/36-inch internal diameter (ID) conveyance pipe and a 525 foot long 9.5-ft horseshoe shape roadheader excavated tunnel. Notable challenges were encountered during the construction including mixed face tunnel conditions, undocumented existing fill ground conditions that resulted in settlement during shaft construction, and unstable tunnel face conditions. This paper discusses several of the key challenges encountered during construction and selected solutions to construction sequencing and methodology to successfully complete Phase III and Phase IV of the Beaver Creek Clean River Project.

Dec 1, 2022

By P. M. Soupios

There is an increasing requirement for geophysical surveys carried out during geotechnical investigations to provide direct information about rock quality or other geotechnical parameters. With the paucity of information to correlate geophysical results with actual rock properties, this is still difficult to achieve and additional research effort needs to be performed to address this issue. Nowadays, several researchers have been described detailed studies which designed specifically to investigate this matter. Generally, geophysical techniques which are used to estimate seismic velocities in the subsurface focus on the low strain levels that are not large enough to induce significant nonlinear, nonelastic stress-strain behavior (Luna and Jadi, 2000), which is normally evaluated when addressing liquefaction potential of soils in the shallow subsurface. Soil parameters relevant to seismic ground response (Rechtien, 1996) are density, relative density and void ratio, permeability, shear modulus, water saturation, soil fabric and stress history. Detailed characterization of elastic properties near a major construction site (e.g. a bridge) is useful for near field dynamic analysis of soil-structure interaction (SSI) effects. The coupled effect of the bridge foundation (piles, piers or abutments) and the soil immediately surrounding these substructure elements is essential for dynamic SSI analysis of these critical bridge structures. This paper presents a geophysical investigation performed along the under construction highway of Egnatia Odos, approximately 13 km west from the town of Xanthi in N. Greece. Twelve geotechnical boreholes, drilled at the maximum depth of 75 m, approximately located 20 m from the Nestos River. The objective of the survey was to obtain the high-resolution compressional and shear wave velocities of the shallow subsurface for computation of elastic engineering properties of the unconsolidated material interposed between the investigated boreholes. Joint interpretation of borehole logs and velocity images obtained by P- and S-wave traveltime inversions outlined shallow geological anomalies.

Jan 1, 2005

By William E. Mead

The process of selecting a building site for a major structure is a complex procedure involving the consideration of a multitude of factors. The approximate geographic location for a structure is usually fixed by its intended function, though often there may be several site alternatives. Socio-economic, logistic, marketing and political factors are the primary site determinants. Also critical in site planning, however, are the environmental factors, both natural and man-made. These factors will influence the precise siting location within the limits allowed by the primary determinants and will dictate some of the basic design criteria. This paper discusses environmental factors, principally those which are natural conditions, that must be analyzed for five different groups of structures. The importance of thorough site environmental analysis based upon the principles of applied earth science is described. Significant elements to be considered in an appraisal of the geology, hydrology, seismology and meteorology are outlined.

Jan 1, 1968

By L. Yuan, C. Brown, N. Rayyan, J. Soles, T. H. Dubaniewicz

As lithium-ion batteries (LIBs) become more prevalent in the mining industry, new hazards of battery fire and explosion are emerging. Efforts must be taken to ensure that workers are safe from these new hazards, such as batteries undergoing thermal runaway in underground areas that may have explosive methane-air mixtures. Researchers at the National Institute for Occupational Safety and Health (NIOSH) investigated overpressures generated within a sealed battery enclosure filled with an explosive methane-air mixture and a single cell lithium-ion battery driven into thermal runaway using an accelerating rate calorimeter (ARC). For both iron phosphate (LFP) and nickel manganese cobalt (NMC) lithium-ion cells, the explosion overpressures remained unchanged with varying percentages of methane concentration in the atmosphere surrounding the cell. It’s likely that the gases released from the battery undergoing thermal runaway caused an inert atmosphere within the sealed canister. The results from this study will help mining equipment manufacturers develop proper measures to keep miners safe while working with lithium-ion batteries in underground gassy mines

Mar 2, 2022

By Alan J. Solomon

The function of advertising is communication. Viewing the advertisements of mineral suppliers exposes the reader to a broad spectrum of purposes: announcements of new products, availability and supply, departmental services, company image, etc. It is the advertiser&apos;s hope that the message being conveyed is the same message being perceived by the viewer. To maximize this probability, the advertiser at least must carefully construct precise copy, identify the target audience and select the appropriate advertising medium. A truly successful and efficient ad, however, also must accurately reflect a product&apos;s life cycle, i.e., the rise and fall in demand for a product. Buggy whips and radio tubes are classic examples of items formerly in high demand. Industrial minerals are similarly affected by occurrences of product life cycles.

Jan 1, 1983

By T. Gupta, T. Ghosh

Rare earth elements (REEs) and their compounds are essential in a multitude of mundane and sophisticated applications such as renewable energy technologies, catalysts, medicine, and defense applications. The global supply deficit could be attributed to the destabilization of REE market that has, as a result, incentivized indigenous production of REEs. Cost-effective and environmentally benign opportunities are being explored for the production of REEs from non-conventional mineral sources including coal and coal by-products to stabilize the supply chain. Coal from Healy coal mine and Wishbone Hill deposits in Alaska have been quantified for REEs and were found to possess elevated total REE concentrations as compared to world average levels (60– 70 ppm). The objective of the study was to concentrate the REEs in the froth phase by froth-flotation of the fine size fraction (< 75 μm). A Box-Behnken design of experiment was employed to ascertain the main and interaction effects of operational parameters on response variable by analyzing 3D response surfaces. Experiments were carried out to maximize REE recovery and concentration by modeling and optimization of three operating variables (frother dosage, pulp density (% solids), and collector dosage). Based on the results, the optimum flotation conditions for maximum recovery at an elevated concentration of REEs in the froth fraction was obtained at 4.2% solids and 32.7 ppm of frother dosage for Healy sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic relationship between the input and response variable was found to be independent of collector dosage suggesting good surface hydrophobicity and floatability of the two coal samples.

By Peter W. Lipman

In the Rocky Mountain region, variations in Tertiary mineralization correlate with changes in tectonic setting and associated igneous activity that can largely be related to tectonics along the west boundary of the American plate. Successive settings include compressional tectonics and associated continental-arc igneous activity; transitional igneous types associated with intra- and back-arc extension; and basaltic or bimodal basalt-rhyolite assemblages associated with Basin and Range extension in- ward of a growing transform boundary between Pacific and American plates.

Jan 1, 2013

By Sheldon P. Wimpfen

Back in 1970 Congress passed the National Mining and Minerals policy Act, which had as one of its basic tenets to rely on a strong and stable private minerals industry for the development and production of our mineral resources. Since then, a substantial amount of legislation has been introduced that impacts on the minerals industry. Although most of the bills proposed are not passed into law, each bill affecting minerals and mining is given careful review by the Bureau of Mines. Comment is forwarded with the object of being helpful to legislators by providing our assessment of the probable impact of each bill proposed along with suggestions to improve them. Actually few bills introduced become law. For example, in the 93rd Congress 4,260 bills were introduced in the Senate and 17,690 in the House. In the final accounting there were passed 123 private laws and 649 public, 3 percent of the bills introduced. There would be little merit here in attempting to analyze each mineral-related bill that was proposed. Many are similar and aim at making a certain aspect of our minerals activity fit needs. So, to simplify the task the many bills have been grouped by subjects. Slide 1 shows the principal topics and the number of related bills introduced. Putting it altogether, there are 26 principal subjects and almost 200 bills. And these numbers are probably off somewhat, as this accounting was made early in December.

Jan 1, 1976

By T. B. Szwilski

ISO 14000 series are voluntary international standards that address environmental management system standards, environmental auditing, environmental labeling, environmental performance evaluation, and life-cycle assessment. An environmental management system (EMS) is a facet of an organization&apos;s structure that addresses the immediate and long-term impact of a company&apos;s products, services, and processes on the environment. Many companies in the United States are taking a cautious wait-and-see approach before embracing ISO 14000. A few mining companies are reviewing the standards and using them as guidelines. The paper outlines the status, possible benefits to the mining industry, and options available to a company wanting to become involved in the ISO 14000 standards.

Jan 1, 1997

By M. L. Matt

The Pittsburgh Safety and Health Technology Center of the Mine Safety and Health Administration has developed the Mine Emergency Responsiveness Development (MERD) program to improve the reaction and response of mine personnel in mine emergency situations. The MERD program simulates problems that may be encountered in underground mine fires, underground mine explosions or surface mine accidents. Since its inception in 1982, the MERD program has been presented to MSHA, Industry, Labor and State Government Personnel. The program is extremely versatile and is easily adapted to suit various training requirements. It gives the participants the opportunity to experience some of the emotions, frustrations and successes of a mine emergency in a controlled environment without having to be involved in one. Past participants have indicated that this training has better prepared them in actual emergency situations through increased awareness and advanced preparation of plans and resources. In 1992, a Mine Simulation Laboratory, which simulates a coal mine and metal/nonmetal mine, was built to improve training for mine emergencies and prevention and fighting of mine fires. This facility has been included in the MERD Program to provide realistic and practical training for mine rescue teams and MERD participants in advanced mine emergency operations. This paper presents an overview of the MERD program.

Jan 1, 1993

By Ihsan Berk Tulu, Gaobo Zhao, Deniz Tuncay, Syd S. Peng

Longwall mine instrumentation for measuring abutment stress distribution, mining induced immediate roof stress change and deformation, and primary/secondary support loads and deformations provides critical guidance for the design of gateroad chain pillars and roof support. Field measurement results are also recognized as the best way to calibrate numerical models that have been used to study the failure and support mechanisms. International Conference on Ground Control in Mining (ICGCM) started in 1981 and since then, there were 26 papers published in the proceedings discussing the stress and load measurements as the face advanced using various field instrumentation techniques. The focus of this paper is on summarizing the analyses of the data published in these papers. Stress/load change monitoring included the following categories: gateroad chain pillar, abutment pressure, bolt load, and pre-driven recovery room. The data shows that the magnitude of stress changes as the face advances varies considerably from panel to panel and mine to mine. However, regardless of types of stress changes, pillar stress, abutment pressure, and bolt load, there exists a rough trend of stress increase as the face advances, generally consisting of three stages, i.e., stress/load (1) initially increases steady or slowly, (2) increases rapidly, and (3) increases reaching the peaks and dropping down slowly or sharply. The stress/load increases start earlier during the second panel mining and are larger than the first panel mining. This review makes it easy for the interested persons to find valuable data for other similar projects.

By D. L. McCain

In considering slurry transportation for Consolidation Coal Company&apos;s Loveridge Mine in Northern West Virginia, many things were taken into account. The advantages of slurry transportation in comparison to shuttle car, belt and rail transport have been given in previous publications." These include increased safety and the potential for increased productivity. In addition to these considerations, the slurry transport system installed in an existing mine provides an alternate or additional transportation mode to the one already existing. In the Loveridge Mine, this is rail haulage. Since the rail system is a single track system and the distances involved are several kilometers, it is not always possible to provide for haulage of loaded cars, return of empties, supplies and maintenance in an efficient manner. Slurry transport of the coal from the production faces to the preparation plant allows the rail system to fulfill the remaining transportation needs in an efficient manner. Consol initiated development work in slurry transportation in the early fifties leading to the construction and operation of the 174-km (108-mile) Cadiz-to-Cleveland pipeline which carried 1,200,000 metric t/y (1,300,000 t/y) from 1957 to 1963. Development work on coarse coal slurry transportation for underground mines started in 1970 with feasibility tests on coarse coal at Conoco&apos;s Ponca City, Oklahoma, slurry test facility. A series of tests were conducted in several locations as development work proceeded on the various subsystems, mechanical equipment and controls required to produce a working system to follow a continuous miner in a room-and-pillar type mine, then to combine the coal production from several mine faces for mainline transportation to the preparation plant. The face system, including the crusher-pump vehicle, hose hauler vehicle, slurry booster pump units, return water unit and 900 to 1,200 m (3,000 to 4,000 feet) of pipeline was brought together for the first time and tested as a system at Consol&apos;s Robinson Run Mine in northern West Virginia in 1975. A pipeline wear test at the Loveridge Mine where 300,000 tonnes (330,000 tons) of minus 127-mm (5-inch) run-of-mine coal were pumped from the raw coal bin into the preparation plant and a large scale test in Ponca City on a multiple feed sump where several slurry flows could be combined to provide surge capacity and a constant reclaim rate for mainline transportation completed the preliminary testing for a complete system. A decision was made to commit the system to a mine, and the south half of the Loveridge Mine was chosen. This site required the transporting of coal from one longwall and two continuous miner development faces. To prevent startup and unexpected problems in the slurry system from shutting down production of coal from the longwall face, the rail car loading point from the main section belt was chosen as the feed point for the slurry system and the design would allow for rapidly switching from one transport mode to the other. Scheduling of required development entry work and the developmental nature of the system led to a decision to install only one continuous miner face slurry transport system rather than two for this first system. The type of continuous miner in use at the mine for the foreseeable future was the Joy 2BT6 twin boring machine. This machine cuts a stable, arch-shaped entry and was therefore allowed to mine about 26 m (85 feet) of entry before roof bolting was re¬quired. Since peak production from this type of machine was not high, a smaller transport system could be used with it.

Jan 1, 1981

Exploration for SX-EW copper deposits and plant operation depend largely on the copper and gangue mineralogy inasmuch as? they govern the feasibility of leaching. Mineralogical parameters are pivotal in identifying if an ore is suitable to dump, heap, thin layer, vat or agitated leaching and/or if the ore requires curing, bioleaching or alternate lixiviants. Problems in metallurgical testing, production leaching and recovery forecasting are very often related to lack of mineralogical data. This presentation will illustrate the use of quantitative mineralogical analysis for exploration, acquisition assessment and optimization of copper leach operations.

Jan 1, 1996

By Jonathan M. Pachter

The Bailey mining complex is located in Greene County, PA in the valley of Talley Run, a small stream tributary to the Enlow Fork of Wheeling Creek as shown on the location map insert found on Figure 1. The Bailey complex includes two Pittsburgh No. 8 Seam deep mines (Bailey and Bailey #2), a coal preparation plant, and two refuse areas (for disposal of coarse and fine processing waste). Clean coal is shipped from the complex via a 24.15 km (15 mile) rail spur, which connects to the Monongahela Railroad in Waynesburg, PA. In early 1981, Consolidation Coal Company (Consol) began a permitting effort aimed at beginning construction of Bailey, the largest underground coal mining complex to be built to date in the United States. Construction of the Bailey Mine began in December, 1981, less than six (6) months following the first application submittal. Clean coal was produced by the Bailey Preparation Plant in September, 1984. Effective project planning, including early formulation of a project planning team, identification of "red flag" issues, innovative responses to environmental questions and development of environmentally sound project designs, all contributed to the relatively quick permitting at Bailey.

Jan 1, 1985

By W. A. Haley

Wheel loaders became important bulk materials handling tools in the early fifties. As they grew in stature, productivity, reliability, and acceptance, the demand for larger, more rugged machines evolved. In the early sixties, the introduction of a 6-yard model by a major equipment manufacturer led quickly to widespread experimenting and rapid worldwide acceptance in loading blasted rock in stone quarries and smaller metal mines. As the wheel loaders grew in popularity for shot rock loading, larger models, 12- to 15-yard size were developed and saw widespread use by 1970. In the past 20 years, at most quarries and small to medium size mines, most cable operated power shovels have been replaced by large wheel loaders and more recently, hydraulic excavators as the primary loading tool. Wheel loaders larger than the 15-yard class are not used widely. Until about 1970, very few overburden haulage trucks were used in domestic coal mines. About that time, many states started enforcing stringent mine relcamation regulations and in 1977, even more stringent federal legislation was passed. These controls brought about drastic changes in coal surface mining methods in the mountainous areas of Appalachia, in smaller midwestern mines and in the large mines of the western states. Basically, simple material casting methods were replaced at most eastern mines by "haul-back" and "mountain top mining" methods using controlled placement of overburden as it is removed from the coal. These methods dictated much more extensive use of loaders/ shovels and trucks to the point that most coal mining in those areas is now by loader/shovel trucks methods. And those areas have become the home of the country&apos;s largest population of large wheel loaders and trucks in the 35- to 85-ton size class with a trend to even larger trucks and shovels. To maintain equal production or provide for growth, the new methods have caused a sharp increase in machine intensity to the extent that at some mines, up to three times as many machines were required to mine a million tons of coal in the late seventies as compared to the machine needs in the sixties. Mining costs and coal prices also took a big jump in the mid-seventies, paralleling the drastic price increases in oil and other forms of energy.

Jan 1, 1984