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By James S. Goff, Stephen J. Navin, Wesley W. Moulton

The White River Shale Oil Corporation (WRSOC) is developing a prototype oil shale facility on Federal Lease Tracts Ua and Ub located in northeastern Utah. This paper covers the successful driving of 1,525 m (5,000 ft) of dogleg downgrade decline with a 70-ton Paurat Roadheader mining machine and a conveyor muck-handling system. Ground support is with rock bolt and shotcrete; welded wire mesh is optional. The Upper Decline of 3.89 m by 8.69 m (12.75 ft by 28.5 ft) was mined through the Uinta Formation sandstones and shales in 210 days. The sandstones have a compressive strength in the 48 MPa (7,000 psi) range with a few bands of shale up to 137.8 MPa (20,000 psi). Green River Formation dolomitic marlstone with some sandstone lenses was mined in the Lower Decline 3.89 m by 5.64 m (12.75 ft by 18.5 ft) in 175 days. The Green River marlstones are tough massive formations ranging up to 206.8 MPa (30,000 psi). Roadheaders for use on steep slopes must be modified to accommodate the particular problems associated with mining downdip. The paper concentrates on the application of Roadheaders to steep slopes and the problems of mining tough materials such as marlstone. The paper also shows the advantage of using the method of excavation on long drives.

Jan 1, 1985

By Richard Jr. Ray, Richard Druesedow

The Virginia Operations of Consolidation Coal Co. include a diversity of mine fan configurations which have been tested to quantify pressure losses through the inlet ductwork. Airflow and pressure measurements were taken at four shaft sites to calculate losses for the 90-degree bend at the top of the shaft and the self-closing dampers or closing doors located between the shaft and fan. Velocity contours were then developed from the test data to determine flow patterns in each fan system component. In addition, yaw and pitch angles of airflow through the fan annulus were measured to evaluate turbulence levels created by various inlet ductwork designs. The test results indicate that proper design of the shaft collar and ductwork arrangement for main mine fans can substantially reduce system pressure losses and air turbulence. BY minimizing the pressure drop experienced on the surface, these design improvements enable the bulk of the total pressure developed by the fan(s) to be utilized in the mine.

Jan 1, 1995

By S. A. K. Forson, Newton A. Amegbey

In order to investigate production decline in Tarkwa Goldfields Ltd., located in a tropical rain forest, amongst other areas, a health survey was conducted with the aim to see 1. The health status of the workers. 2. Which parameters carry the most information about the health situation and which of them can be applied easily during screening programmes. 3. What steps could be taken to improve the situation. In all 249 workers were investigated. A non-invasive method involving taking of body weight and arterial blood pressure was used. All subjects were required to answer a questionaire. Emphasis was placed on the history of malaria and diarrhoea within the last six months. Both management and workers co-operated fully. Another set of 110 workers from a neighbouring tyre factory were also investigated for control. Among the underground workers, the percentage body weight loss during a shift increased with decreasing body weight. Dehydration levels could be as much as 4 to 5% of body weight. This could be attributed to the fact that workers took insufficient or no water during the shift. The health status of the mine workers was generally poor and in our opinion malnutrition combined with malaria severely threatens the health and well-being of the workers. Hypertension is also a problem. An improvement in production is intimately linked with the well-being of the workers.

Jan 1, 1989

By Cheryl M. McInnes, Graham J. Sparrow, James T. Woodcock

Three composites, assaying about 3 g/t Au and 0.75% Cu, were investigated. Each contained oxide copper minerals, iron oxides, and silicates. One composite also contained copper and iron sulphides. Maximum gold extractions by thiourea leaching were obtained after copper removal by acid pre¬leaching at pH 1.5 and redox potentials of 400 mV (Pt versus SCE). Best thiourea leaching conditions were pH 1.5, redox potentials over 200 mV, and 0.4% thiourea. This gave 90% gold extraction in 2 h with thiourea consumptions of 25 kg/t. Lower potentials gave poorer extractions. Ferrous iron additions before leaching halved thiourea consumptions. Longer leach times and the presence of sulphide minerals sometimes resulted in reprecipitation of gold.

Jan 1, 1989

By Peter J. Conroy

Introduction Most subsidence monitoring to date has been surface monitoring to develop empirical relationships of the magnitude and extent of subsidence effects. Federal regulations are forcing a better understanding of subsidence. Empirical methods of subsidence prediction may not be adequate, since the empirical relationships may not be valid between or even within coal fields. A better understanding of the mechanics of subsidence is required in order to develop and verify analytical models. This paper presents some of the results of surface and underground monitoring in longwall faces of a coal mine. The seam thickness in these mines ranges from 5 feet to 6 feet at depths of 600 to 1100 feet.

Jan 1, 1982

By Anthony D. Hammond, Charles A. Kliche

A slope stability study for the Annie Creek and Foley Ridge Mines was undertaken to provide Wharf Resources, Inc. with a technical assessment of the stability of the slope for an overall pit slope angle of 60°. A rock analysis of the most critical and persistent combination of discontinuities was carried out using probabilistic methods. A detailed discontinuity mapping and assessment of the rock mass provided the orientation data used in this study. The orientation data were reduced and analyzed to identify the discontinuity sets. A statistical analysis provided information about the distribution of the data. A deterministic wedge stability analysis identified the critical combination of discontinuities; those with a low factor of safety were further studied using probabilistic kinematic and kinetic stability analyses. The results from this approach were used to obtain the reliability or probability of failure of the slopes.

Jan 1, 1988

By Robert A. Jankowski, Ellsworth R. Spencer, Jay F. Colinet

Longwall mining is the most productive method of under- ground coal mining in the United States (US.), and record levels of production have been reached in recent years. These ever-improving production levels have the potential to generate significantly higher quantities of respirable dust. Consequently, the longwall industry continues to struggle with controlling dust liberation and maintaining compliance with the federally-mandated respirable dust standard. In response, longwall operators have in- creased the application of primary dust controls, airflow and water flow, in an effort to improve respirable dust control and reduce worker exposure. Pittsburgh Research Center (PRC) personnel conducted dust surveys at 13 longwalls operating throughout the U.S. and collected information to: identify current operating practices on these longwalls, identify the types of dust controls in use, document the levels at which these controls are being applied, and measure the respirable dust levels present. This data was analyzed to quantify the dust levels generated by the major sources on the longwall section and to evaluate the relative effectiveness of the control technologies in use.

Jan 1, 1997

By Malcolm J. McPherson

Mine shafts that are used as primary ventilation routes are different in their airflow characteristics to other subsurface openings because of the aerodynamic effects of guide rails, buntons, pipes, cables, ropes, and shape, size and velocity of conveyances. As many shafts contribute heavily to the overall resistance of a mine ventilation circuit, it is important to be able to predict the resistance of a planned shaft with reasonable accuracy. This paper describes part of a study on the ventilation characteristics of hoisting shafts, conducted for the Basalt (Nuclear) Waste Isolation Program (BWIP). Methods of quantifying each of the four components of shaft resistance are developed; namely the shaft walls, fittings (buntons, pipes, etc.), the skips or conveyances, including the dynamic effects of their motion, and shaft stations. Practical guidance is given on ways of reducing the shaft resistance. The paper concludes by giving a step by step procedure for the ventilation aspects involved in the design of combined hoisting/ventilation shafts.

Jan 1, 1987

By V. R. Degner

Given: the process tonnage, performance objectives, and plant floor area, the paper will outline the metallurgical and machine hydrodynamic scale-up procedures for translating the lab flotation test results to the design of a full size flotation machine installation, including the machine number, size, and arrangement. Machine selection considerations for rougher, scavenger and cleaner duty, and special considerations relative to specific applications, will be summarized where appropriate. The value of kinetic modeling in quantitative metallurgical (lab to full size machine) scale-up will be reviewed considering a coal installation, and design information for additional applications such as copper, molybdenum, iron, phosphate, and potash will be discussed.

Jan 1, 1986

By N. L. Piret, R. J. Wesely, A. E. Melin, A. D. Zunkel

At the end of the sixties new iron precipitation techniques as jarosite, goethite or hematite brought about the new generation of electrolytic zinc plants, thereby terminating the multitude of existing neutral leach residue treatment schemes. Since the eighties, increasing environmental impact considerations urge the conversion of these contaminated waste generating precipitation processes to techniques which either produce environmentally acceptable residues or minimize their formation thereby generating iron-bearing byproducts. Technologies identified and economically assessed include the hematite process either suitably improved or with subsequent upgrading, the iron extraction process and the direct smelting of neutral leach residue to slag and fumed zinc oxide.

Jan 1, 1993

By A. E. Reisenauer, R. W. Nelson, G. W. Gee

A model assessment was made to evaluate contaminant transport to ground water from clay-lined and unlined tailings pits. The input hydrologic soil characteristics were measured on materials typical of those found at the Morton Ranch uranium mill site in central Wyoming. The assessment involved combined saturated and partially saturated flow and contaminant transport models for two-dimensional cross-sections typical of the proposed Morton Ranch burial pits. Specifically obtained from the models were contaminant flow paths, the advancing contaminant flow fronts for sorbed and non-sorbed constituents, and travel times of contaminants along flow paths. Such results enable evaluation of the environmental consequences for the alternative control methods.

Jan 1, 1980

By Osvaldo Bascur

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. This results in significant deterioration in the ability to maintain a "smart" operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. This paper describes the use of Internet technologies with plant data. Examples are drawn from existing industrial sites. Users must project where this technology will lead - standing still is the most dangerous philosophy and the only one guaranteed to be obsolete. These examples show the way to leverage existing workers with information technology.

Jan 1, 2000

By Allan E. Hall

The use of full face boring machines in underground mining has increased considerably in recent years and over 200 raise-boring machines are now in use in the Western World. Several tunnel-boring machines have been tested notably in America, West Germany, Britain and South Africa. A relatively new concept is the blindhole borer, where the machine stands on the lower level and bores a full diameter raise upwards without the use of a pilot hole. Four of these machines have been tested to date in South African quartzites with varying degrees of success. The development of boring technology has created new problems for ventilation engineers and exacerbated several existing ones. This challenge has been met in many varying ways and this paper attempts to provide a review of the current state of the art. Technology and methods are developing at great speed in this field and therefore no final and absolute solutions can be proposed, since each machine and site pose individual problems which are best handled by local knowledge and experience.

Jan 1, 1980

By Steven J. Schafrik, Michael Karmis, Zacharias Agioutantis

3-D or pseudo 3-D visualization of orebodies and mining related processes such as loading and tramming, are now commonly used by the mining industry. An approach is presented that can aid the engineer in creating the visualizations necessary for accurate presentations for use in public relations, safety training, production projections, reclamation plans, etc. It is shown that the creation of such digital representations of mining environments are independent of the mining package used to create the original mine design. Once a proper model has been created, any view of the areas is possible. These views can be taken from any number of stationary points or entered into an animation showing the progress of a mining construction. The paper focuses on the presentation of the steps used to accomplish the visualization and an example is for a quarry fill placement project.

Jan 1, 2002

Surface characterization techniques, i.e. contact angle measurement, atomic force microscopy (AFM) surface force and surface imaging measurement, were applied to investigate the molybdenite surface in aqueous solution. It was shown that the cleaved basal surface of molybdenite was very hydrophobic with a 92 degree water contact angle. The non-polar component of the solid surface free energy is 50.52 mJ/m2 while the polar components are almost zero. The solid surface was not reactive and was only weakly charged at the pH 6. When the aqueous media changes from water to 1×10-4 M KEX solution, the measured contact angle, adhesion force and surface roughness all increase slightly. However, ethanol rinsing made the surface change back to the bare substrate. It was suggested that the hydrophobic chemical, i.e. dixanthogen, which was shown in the morphology of patches by the AFM image, physically adsorbed on the hydrophobic molybdenite surface through the hydrophobic interaction.

Jan 1, 2009

By Michael G. Nelson

Underground coal mining practice often requires that some coal be left in place at the seam boundaries after mining, for purposes of ground control, quality control, machine guidance, or good operating practice. Many methods for measuring the thickness of boundary coal have been developed, but only the natural % R gamma background method as bee used in routine operations. Use of this method is constrained by the level and consistency of the natural gamma background in the bordering strata, the accuracy of the gamma detection instrument, and the elevation profile of the seam boundary being detected. Computer simulations for three commercially available gamma detection instruments, designed for mine use, showed that measurement of boundary coal thickness by the natural gamma method can provide satisfactory input for horizon control systems when the gamma detector is large, when the sensor is mounted on the mining machine, and when the elevation profile of the seam boundary does not change rapidly in the direction of advance.

Jan 1, 1993

?Energy-related systems: wind, solar, electric are typically materials intensive. As new technologies are widely deployed, significant quantities of the elements required to manufacture them will be needed. However, many of these unfamiliar elements are not presently mined, refined or traded in large quantities, and, as a result, their availability might be constrained by many complex factors. A shortage of these ?energy-critical elements? could significantly inhibit the adoption of otherwise game-changing energy technologies. This, in turn, would limit the competitiveness of the U.S. industries and the domestic scientific enterprises and, eventually, diminish the quality of life in the US.? -Energy Critical Elements: Securing Materials for Emerging Technologies?- American Physical Society, 2011.

Jan 1, 2012

By Richard D. Harvey

Relative quantitative analyses of certain mineralogical and textural properties of carbonate rocks were made with an image analysis computer. The instrument, referred to by its manufacturer as a Quantimet; consists of a petrographic microscope, a television camera and monitor, a detector, an electronic computer, and a read-out meter. Measurements were made on polished and etched specimens, standard thin sections, and on scanning electron micrographs of carbonate rocks. Critical to the success of the analysis is the preparation of the specimen in such a way that good optical contrast is obtained between the various petrographic components. The dolomite content, the pore volume, pore boundary projection, and pore size distribution of high-purity carbonate rocks were measured by image analysis methods. The frequency and size distribution of void inclusions in dolomites were determined by image analysis of scanning electron micrographs of cleaved surfaces. Image analysis methods permit rapid and quantitative assessment of various microscopic properties. The results are of reasonable accuracy and certainly are relative quantities that may be used to characterize carbonate rock materials.

Jan 1, 1972

By Kadri Dagdelen

Production scheduling of an open pit mine is one of the most important steps in open pit mine planning. The production schedule of a mine defines the distribution of cash flows and as a result directly influences the net present value and overall economic feasibility of a project. It is becoming more and more critical to obtain an exploitation schedule of a deposit such that highest possible returns are achieved from a project. As the mining industry mines lower and lower grade ores, production scheduling is becoming a key item which can make or break a project. Although the need to plan and operate a mine with an optimum production schedule has been obvious for some time, the methods used to obtain such a schedule have not been. There is not a single, mathematically proven, optimum mine production scheduling algorithm which is widely accepted and used today. In an attempt to determine a production schedule which is optimum, a new algorithm was developed. This algorithm, in theory, is based on the lagrangian concepts of mathematics and in practice is based on the parameterization concept of mining. This paper describes the fundamentals of this newly developed algorithm.

Jan 1, 1986

By Randal J. Barnes

In, any open pit mine the ability to make accurate production estimations for the shovel-truck system is an important asset. This is true in an operating mine wishing to estimate production under a set of system modifications (i.e. more trucks, fewer loaders, change in roads, etc.), as well as in the pre- mining planning stages of a property. Many different methods have been proposed for solving this problem; some of the methods rely heavily on "rules of thumb" while others are highly mathematical and require access to a high speed digital computer. Analysis of shovel-truck systems with the use of simulation models is a widely accepted technique within the industry. Through the use of such models it is possible to account for much of the inherent variability of the system and thus produce meaningful results. However, simulation studies are expensive. Formulation and setup of the actual simulation model requires a significant commitment of time and energy. In addition, the cost of the necessary computer runs is often of considerable magnitude.

Jan 1, 1979