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By P. H. Williams

Experiences gained using computers in the mining and geological environment have shown that it is quite rare for a system or the data it stores to be truly stand alone. Just as the mining enterprise aims to have a smooth integration of operations from exploration through mining and extraction to sales, so it should develop all its information systems within an overall framework or architecture which covers the applications and data as well as the computer hardware and communications. This paper discusses methods of achieving such an architecture, and describes some of the benefits it can have on the development and implementation of information systems. The key aspects are the identification of the business functions and the data that they use, and ensuring that the IS plan supports the overall objectives of the enterprise. Hardware and communications policies should be based on the plans for the applications and data, rather than the reverse.

Jan 1, 1986

By J. F. Cuderman

In situ experiments at the Department of Energy's Nevada Test Site (NTS) have extended the technology of propellant-based fracturing to include liquid- filled, uncased boreholes. Previous work had developed the technology for liquid-free, uncased wellbores. Test results show that fracturing behavior is considerably more complex in liquid- filled boreholes than in the liquid-free case. Compared to liquid-free boreholes, liquid-filled boreholes have faster pressure risetimes and lower peak pressures, large hydraulic-type fractures propagating several meters beyond the end of the test zone, numerous oscillations in the pressure history, and variable types of fracturing within a single test region. Multiple fracturing is initiated in the wellbore of a fluid-filled borehole when the proper propellant mixture is used but, unlike fluid-free wellbores where up to eight fractures propagate, only one to three hydraulic- and/or shear-type fractures propagate. Hydrodynamic effects involving liquid compression during borehole pressurization appear to be responsible for the differing phenomena observed in fluid- filled boreholes.

Jan 1, 1986

By A. D. Davis, C. J. Webb

Brohm Mining Co.'s Gilt Edge Mine in the northern Black Hills was a surface heap-leach operation that was active from the 1980s until 1999. Financing problems and acid drainage concerns at the mine were reported in the late 1990s. In February 1999 the Governor of South Dakota announced plans to request the US Environmental Protection Agency to help clean up acidic water at the mine and reclaim the site. In July 1999 the parent company of Brohm, Dakota Mining, filed for bankruptcy in Canada. Because of the bankruptcy and environmental problems, the State of South Dakota intervened and began water treatment. The mine was declared a Superfund site in 2000. Hydrologic issues include the potential for acidic drainage from the site. The mine is at the headwaters of Strawberry Creek, which drains into Bear Butte Creek. About four miles downstream, Bear Butte Creek loses its discharge to swallow holes in the karstic Madison Limestone aquifer, a regionally extensive and valuable groundwater reservoir. Other concerns at the site include treatment of acidic water in mine pits and a waste rock dump.

Jan 1, 2003

By H. Bernatowicz

The Nucoalyzer (On-Line Nuclear Analyzer) is a new method recently made comercially available for monitoring the elemental composition of a process stream. Applications for the Nucoalyzer include grading ore on a conveyor belt before or after it has gone through primary crushing, monitoring the slurry being transported in a pipe to the concentrator, and monitoring the stream of concentrate or the tailings from the concentrator. The Nucoalyzer may also be used at the smelter to monitor elements in the feed that include copper, sulfur, iron and silicon where a uniform feed is desired. The advantage of the Nucoalyzer over most other techniques are (a) it performs the measurement directly on the process with no sampling necessary, (b) the analysis can be performed on streams of particulate and slurries, and (c) the system does not have to make contact with the material it measures. These Nucoalyzers are operating at coal fired power plants and several more are about to be placed in service. This paper discusses the principles of operation of the Nucoalyzer, our experience in the field, application of minicomputers to data reduction, and potential applications in the ferrous and non-ferrous industries.

Jan 1, 1982

By S. W. Beckman, L. Williams, A. E. Seep, R. Fischer, J. Hubbard

Introduction The Summitville Mine located in southwestern Colorado was added to the National Priorities List in June of 1994. Summitville was the site of mining operations that began in 1873 with the discovery and development of gold placer and lode deposits in the late 1800's. The mine site is located about 25 miles south of Del Norte, Colorado in the San Juan Mountains adjacent to the Rio Grande National Forest at an approximate altitude of 11,600 feet. The site was mined for gold, silver and copper between 1873 and 1947. The Summitville Consolidated Mining Corporation, Inc. (SCMCI), a wholly-owned subsidiary of Galactic Resources, Ltd of Vancouver, Canada ran a large tonnage open-pit mine and cyanide heap leach operation from 1986 to 1992 (Pendleton and Posey, 1992) During the mine operation by SCMCI, approximately 10 million tons of gold ore was mined, crushed and stacked on a lined leach pad. Heap leach operations experienced water balance and unplanned solution discharges from the start of the mine life. Despite the production of 249,000 troy ounces of gold during the mine operation, SCMCI was unable to meet remedial requirements and notified the state of Colorado of its intention to file a Chapter VII bankruptcy in December 1992. The EPA Region VIII Emergency Response Branch took over site operations on December 16, 1992 to prevent a catastrophic release of hazardous substances to the environment. The multiple contamination sources at the mine site are due to both historic and SCMCI mining operations. Emergency response operations at the site have prevented releases of severely contaminated solution and a permanent treatment for all waste units at the site is under investigation. A Request for Proposal (RFP) was issued in October 1993 by Environmental Chemical Corporation (ECC) at the Request of EPA Region VIII, Department of the Interior and Bureau of Reclamation. The RFP requested that interested companies provide information on their ability to implement innovative treatment technologies to improve treatment efficiency and reduce treatment costs for remediation of the heap leach pad (HLP) spent ore and ore leachate solutions. Dames & Moore and Pintail Systems, Inc. (PSI) jointly submitted a proposal suggesting application of biotreatment processes for detoxification of cyanide in spent ore and HLP leachate solutions. The proposal was accepted for pilot and field demonstration under the SPA Superfund Innovative Technology Demonstration Program (SITE) with additional funding from EPA Region VIII. This report discusses the test program and results of a Focused Feasibility Study which demonstrated biotreatment processes for spent ore cyanide detoxification.

Jan 1, 1995

By R. M. Imhof, M. J. G. Battersby, J. V. Brown

There is a plethora of former industrial sites where coal mining operations have left large slurry impoundments. These contain raw washed fines, which have previously been too expensive to process to requisite grades for commercial use. New technology has been developed for fine material processing, namely the Imhoflot pneumatic flotation G-Cell. This froth flotation technique is a highly efficient means of concentrating coal and is particularly appropriate to the nature of materials encountered in tailings ponds. The high volumetric throughput resulting from the vastly reduced residence time in the cell allows for drastically reduced equipment sizes when compared to conventional flotation cells. This means the process, when combined with innovative pre treatment and filtration equipment can be developed as a mobile plant concept. This is seen as a minimum requirement when re-treating and rehabilitating fine coal ponds.

Jan 1, 2003

By P. Bevilacqua, G. Vallebuona

Empirical models are now used for predicting the performance of hydrocyclones in terms of capacity. cut size (d50.c), water split and partition curve. These models (such as the model by Lynch and Rao and the model he Plitt) were developed and checked for hydrocylones with diameters larger than 4 in. However, for smaller-diameter hydrocyclones, little empirical modeling has been done. This paper reports on an extended experimental research program on small hydrocyclones. For these cyclones, the suitability of existing empirical models was investigated and their accuracy was compared. To improve the predictive capability of these models to small cyclones modifications to the equations are proposed.

Jan 1, 1996

By David J. Hammel

This chapter will summarize some of the important applications in the geotechnical (pit slope, spoil pile and tailings stability, and hydrology), the environmental (including reclamation), and equipment selection and analysis areas. Virtually all aspects discussed are applicable both for planning of new mines and for evaluating existing operations. Probably the most influential item which has affected the areas discussed in this chapter and possibly most areas discussed in this book is and will continue to be, in the next decade, the myriad federal and state environmental, safety, and reclamation regulations affecting new mine development and continued operation of existing properties. Computer applications have been and will continue to be instrumental in assisting in planning to meet the challenges of the requirements dictated by these regulations.

Jan 1, 1979

By F. F. Peng, Y. Xia

In modeling of hindered-settling bed separators, the published separation mechanisms are based on differences of particle density and size distributions, without the details of complexity of particles-liquid interactions. A fluid dynamic model for the separator is developed using Euler-Lagrange approach of Computational Fluid Dynamics (CFD). Fluid motion is obtained from solving the movement of liquid governing equations. The damping effect on flow pat-terns caused by the movement of particles resulted in liquid-particle coupling is included in the model. Effects of particle size, and particle density compositions, feed rate, feed water flow rate, upward fluidizing water flow rate, etc., are simulated in the 2-D separation model. Flow pattern effects on the separation of fine particles in the separators with center downward-flow and side cross-flow feed systems are investigated.

Jan 1, 2004

By J. Launay

In order to control and dispatch the sewage water coming from 3 tunnels toward 2 downstream sewage tunnels, a large cavern has been excavated in a suburb of PARIS. Located at a depth of 47,00 m, it has been excavated using the NATM procedure through swelling clay, weathered sandstone, and marl and chalk. It is 16,50 m high, 12,40 m wide and 60, 00 m long, with an elliptical cross-section and its two ends are egg-shapped. The final lining of the cavern is composed of 30 to 40 cm of shotcrete, steel ribs and passive anchor bars. The excavation stages and related movements were surveyed by extensometers, pressure cells and convergence devices. The design, method of construction of the cavern and the results of the measurements made are commented.

Jan 1, 1989

By Frank W. Bowdish

During the early 1960's, a method was developed for refining sand from the Arkansas River to produce a feldspathic product that was proposed for use in making colorless glass. Because of the need for chemical uniformity, a cooperating glass manufacturer specified certain ranges of percentages for each chemical constituent of the sand. These specifications were met by fulfilling the single requirement that alumina vary by no more than 20.1 percent from the specified value. This translated to a total variation of only about 1 percent in the feldspar content of the mixed quartz-feldspar products. Because the feldspar was lighter than the quartz, the average density of refined sand varied depending on composition. Densities, determined to five significant figures, of several samples were correlated with their chemical analyses, and the correlation could then be used with density determinations to more reliably indicate compositions than by chemical analyses only. The effects of several variables on the composition of refined sands were studied. There was a regular variation in the proportion of feldspar with screen size. A series of samples with their natural size distributions were more nearly uniform in composition than the same sands after screening and recombination. The screening and recombination process was done so that the sands had identical size distributions. Variations in the refining showed little effect on composition. A pile of flow-back sand from a construction sand washer was found to be severely segregated. However, samples taken from many points in the river near the sand plant and from the flow-back discharge pipe over several weeks very nearly met the uniformity specification. If care was taken to avoid segregation either before or during processing, it should be possible to meet the uniformity specifications for a feldspathic glass sand.

Jan 1, 1978

By R. A. Metz, Ted H. Eyde, Dan T. Eyde

Industrial minerals deposits present sampling and grade control problems not normally encountered in metal mining operations. No longer are industrial minerals simply crude ground mineral products but are in fact high purity chemical raw materials. Operators of industrial minerals mines and processing plants now must meet increasingly stringent specifications established by the consumer of the final products. Meeting these stringent specifications requires not only sophisticated processing techniques but equally important careful sampling and grade or quality control at the mine. A well-trained geological staff can assure an adequate supply of uniformily high quality feed to the processing plant. In the final analysis this results in significantly higher operating profits.

Jan 1, 1992

By John A. Ames

Limestone for portland cement must be beneficiated to produce uniform raw material for the kiln. Careful quarrying and selective recovery are factors in this process, but the chief aspects of beneficiation are "in plant" processes, such as crushing and screening, washing, grinding, flotation, and heavy-media separation. Numerous technical and economic problems exist. Detailed studies of the limestone deposit and the stone itself are required for intelligent beneficiation. As used in this paper, beneficiation is defined as the improving of limestone composition so as to produce an economically usable raw material A limestone deposit is defined as a mass of limestone which can be recovered, by quarrying or mining, for sale or for use in a commercially profitable operation. The stone may require elaborate processing, or it may qualify with little or none. Obviously, the "commercially profitable" qualification may change as the economy changes. Potentially commercial deposits may be of much better quality than actually developed deposits, and yet may be denied development for various economic reasons.

Jan 1, 1966

By G. T. Lineberry, B. R. Yama

Artificial intelligence research has produced several tools for commercial application. Some of the techniques that are widely used today include neural networks, fuzzy logic and expert systems. Artificial neural networks (ANNs) are excellent predictive, pattern recognition and data analysis tools. In the mining industry, ANN techniques are being used commercially for real-time process-control applications. Modeling of spatial data, ore-reserve estimation, tunnel design, long wall-stability prediction and geologic roof classification are additional applications in which neural networks have been applied successfully. In this study, a standard back propagation algorithm was used to train a series of neural networks for a real-world predictive task. After training and optimizing the neural network architecture, the performance of the network is measured on an independent validation set. Results indicate a mean error of less than 1 % between the actual and predicted values. A neural network model was developed for learning the spatial continuity of a mineral field and, consequently, for predicting sulfur values for given coordinates. The neural network not only performed satisfactorily, but in some cases performed even better than the kriging model.

Jan 1, 2000

By Eugene L. Foster, Gilbert L. Butler

The successful demonstration of a precast segmented concrete liner in the Lexington Market Section of the Baltimore Regional Rapid Transit System (BRRTS) is an important step forward in our continuing efforts to control tunneling costs in the USA. In addition to its contribution to specific savings in future tunnels, this demonstration project has taught other lessons about the U.S. tunneling industry and about the process of "mainlining" new and improved technology into that industry. This paper will present an overview of the Lexington Market Demonstration Project from its beginnings to the present time. In addition, it will discuss other implications which have an important bearing on the extent to which tunnels will be used in future transportation systems in the USA. THE HISTORY Precast segmented concrete tunnel liners are not new. An unbolted version was reportedly used in New York City in the 1930's. The modern bolted configuration has been in use in foreign countries for more than 15 years. Indeed, consideration of the use of precast bolted segments below the water table in the USA dates back to the BART system in San Francisco in the 1960's. At that time, they were evaluated and it was concluded that the state of the art would not allow segments to be precast to the required tolerances. A secondary grinding operation would be required if water-tightness was to be assured, making them economically non-competitive with steel. Based

Jan 1, 1981

By K. Biswas

A finite-element algorithm was developed for an axisymmetric heat-transfer problem involving phase change. The finite-element treatment of the phase-change problem was dealt with by using the enthalpy method. The finite-element algorithm was subsequently applied to model the heat exchange between mine ventilation air and frozen ground in the presence of roof bolts in an underground mine with permafrost. This paper analyzes a single bolt in the problem domain with the convection boundaries at the roof level of the mine airway. A short-term study, comprising the evaluation of roof bolting (friction-anchored type), was conducted, and recommendations were made regarding the applicability of roof bolts as a support system for a given thermal condition.

Jan 1, 1996

By C. E. Jordan, B. J. Scheiner

The Bureau of Mines has developed a continuous ultrasonic flotation cell for the recovery of Florida phosphate ore. Within a small mixing chamber near the bottom of the flotation cell, an ultrasonic probe agitates an injected mixture of air, water, and phosphate ore and breaks the air into fine bubbles. Phosphate particles are preferentially attached to these fine bubbles and floated in the main chamber of the flotation cell. Over 94 pct of the phosphate was recovered, resulting in a 30 pct P205 concentrate. The ultrasonic energy consumption was less than 7 kW.h/mt of phosphate ore.

Jan 1, 1989

By G. Danko

Ventilation and refrigeration for mine climate modification, contributes significantly to the operating costs of a deep hot mine. Mine climate simulation programs can be used to minimize the impact of these costs. There are several computer codes available including CLIMSIM?, to assist in this work. Whichever simulation program is used, it is the mine ventilation engineer who must supply the input data. This paper raises and answers the following question, namely: what accuracy is required of the basic input parameters, in order for a certain precision to be obtained in the predicted air temperatures? In the first part of the paper a new approach is described to estimate the dry and wet bulb temperature of the airflow, either in a dry or wet roadway. The calculation procedure allows an arbitrary temperature change with time, using Duhamel's superposition solution. Matrix-vector representation is applied to simplify the computational structure. In the second part of the paper the sensitivities of the dry and wet bulb air temperatures are analyzed to the changes of the rock thermo-physical properties, the heat transfer coefficient and the wetness factor.

Jan 1, 1988

By S. Hicks

This technical note describes an alternative procedure that can be used in linear programming calculations where the compliance limit of lbs SO2/million Btu for the blending coal is subject to change. Dr. Mateer in his technical note titled "Coal blending for sulfur compliance" (ME, September 1994, p. 1103) defined an "excess sulfur" parameter that provides a valid constraint equation for a linear program optimization. The coals used by Dr. Mateer in his examples are shown in Table 1. To create the parameters for the constraint equations to blend to an SO2 content of 1.2 lbs SO2/million Btu, the excess sulfur for Coal A was defined as Sulfur excess% = 0.5 - 0.6*13,000/10,000 = -0.28 This equation was used to create the constraint equation -0.28A + 0.44B + 1.36C[<] 0.0 Another way to create the parameters for the constraint equation is given below. In these equations: •W is the total weight; •A, B and C are the fractional proportions of each potential blend stocks; •Sa, Sb and Sc represent the percent sulfur content of the blend stocks; •Ha, Hb and Hc represent the calorific content of the blend stocks in Btu/lb; and •H and S represent calorific and sulfur contents of the composite blend. The weight of blend to produce one million Btu is [ ]

Jan 1, 1998

By R. V. Ramani, W. Miola

The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of low-temperature, radio-frequency ashing (LTA) and infrared analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods. In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified.

Jan 1, 1996