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By Thomas Fliess, Klaus-Christof Ritter, John R. Sturgul

The optimum flow of materials through a smelter is an extremely important phase of the mining cycle. A typical copper smelter will have up to $US 1,000,000 per day of copper being processed. The motion of the overhead cranes in moving the ladles filled with copper matte and slag from furnace to furnace is prescribed but there can be numerous variables to consider. Some of these variables to the system can be: the speed of the overhead cranes, the number of cranes, the size of the ladles, the size of the furnaces, the number of furnaces and the sequence in loading the furnaces. A simulation model was constructed of a working smelter in the SW of the United States. The model has been used to study the effect of varying parameters of the system. The program runs as follows: an input menu appears on the PC screen and the user can navigate through it and change any of the data; the simulation takes place and the results of the simulation sent to a data file. Animation of the system then is shown on the screen in "cartoon" fashion. The software chosen for the simulation was GPSSI H (') and PROOF Professional (') for the animation. The model presented here is believed to be the first reported simulation and animation model for a complete, working smelter.

Jan 1, 1996

By T. T. Chen, J. L. Jambor, J. E. Dutrizac

A reconnaissance study of the neutralization potential of 30 diverse minerals, 28 of which are silicates and aluminosilicates, has shown that most of these minerals contribute minimally to the neutralization potential (NP) in standard static tests. Feldspars in particular give low NP values and would not be expected to attenuate the acidity to any significant extent in acid rock drainage settings. The BET-determined surface areas of the minerals vary considerably, and the large surface areas of some of the pulverized samples have clearly affected the NP values even though the standard static-test protocol was used for the preparation of the samples. The low NP values of most silicates and aluminosilicates are in general agreement with the laboratory-determined slow dissolution rates for these minerals. The results suggest that, in the prediction of whether rocks will be acid-producing, the most realistic measure is that of the carbonate content. In mine wastes from metalliferous ore deposits, the contribution to the NP by the non-carbonate gangue assemblage is unlikely to be more than a token amount until well after the establishment of an acid rock drainage situation.

Jan 1, 2000

By Changwoo Lee

Under drastically deteriorated situations, diesel equipment was introduced to some of local coal mines, aiming at higher productivity and better safety. To accommodate various diesel equipment in conventionally developed mines, mining system itself had to be modified; much larger trackless haulage ways were excavated. Possible health hazards of diesel not taken into account at the beginning become a serious concern and effective control measures are being searched for. The purpose of this paper is to study the diffusion characteristics of diesel exhaust in local coal mines. One of the parameters affecting dispersion of diesel contaminants is the coefficient of turbulent diffusion. Since CO2 is known to be closely correlated with other contaminants such as CO, NO, NQ, SO2 and RCD, it was chosen as a tracer gas in a series of dispersion experiments. A large diesel passage as well as a conventional track haulage way were the sites for the experiments. Rectangular dispersion pulses were generated for 30 ~60 seconds and CO2 concentrations were recorded at several locations 50~190 m downwind. The diffusion coefficients calculated graphically vary between 0.10~0.48 m2/s at both haulage ways. The results are analyzed to find any correlation with the air velocity and the distance from the disperser. Skobunov's empirical formula is applied to the experimental data for comparison and the relationship between Reynolds number and Ex/Dp/sci0.4 Sc1…

Jan 1, 1995

By R. V. Ramani, R. Bhaskar

While the National Academy of Sciences has stated that gravimetric sampling technology for compliance purposes is adequate, research into various aspects of respirable dust control require data on many other parameters of airborne dust. These, in turn, have created the need to use many instruments, other than personal gravimetric samplers, in mine environments for dust measurement. There is a need to evaluate the performance of these instruments under conditions of potential use. As part of research in the Generic Technology Center for Respirable Dust, cascade impactors, gravimetric personal samplers and gravimetric samplers collecting dust using isokinetic sampling principles were employed for dust measurements under identical conditions in a mine airway. During the course of the experiments, 8-stage cascade impactors and gravimetric samplers drawing air isokinetically were located in the center of a mine airway at various stations. Two types of data were examined - concentration of dust and size distribution of the dust collected in the samplers. The data show that the amount of dust collected by an impactor is less than half the amount collected isokinetically. The size distributions of the dusts collected from the two instruments, though comparable, show a consistent difference in median diameters. The cause for this bias is examined. The paper presents and discusses the results of the tests, including the concentrations and size distributions obtained from the two instruments for different experimental conditions. There is a need to document the performance of various dust measuring devices in mine airflow conditions.

Jan 1, 1987

By Fred W. Stuart

Microprocessor technology has revolutionized the business community by placing tremendous computing power in the hands of the end-user for a very inexpensive price tag. The range of applications covers process control, to office automation, to personal computing capabilities. With the influx of this new technology, which these systems have to offer, also comes some unique operational and control considerations. But before we address these items, let us lay a foundation of common terms to be used throughout this presentation. Due to the rapid advances in microprocessor technology, where a new generation of computers is announced every two or three years, it becomes difficult to define a microprocessor system and have it valid for an extended period of time! Therefore, for this presentation, we will be dealing with a subset of microprocessors called Personal Computers or PC's. At the heart of a PC is a Central Processing Unit or CPU. The CPU performs the actual program and command execution. The programs dealing with driving the various peripheral equipment is referred to as the Operating System (for example: DOS : Disk Operating System, CP/M - Control Program/Microcomputers, etc.). The CPU is normally housed in an enclosure which contains power regulators, peripheral equipment interfacing 'cards', and expansion 'slots' to enlarge the capabilities of the PC system.

Jan 1, 1989

By Robert A. Haney, Scott G. Vail, Kenneth G. Fields

The Mine Safety and Health Administration, in cooperation with IMC Global Operations, Inc., conducted a joint study to determine the effectiveness of the technology currently in use at the mine to control diesel particulate exposures. IMC Global operates an underground potash mine using diesel-powered equipment to extract minerals. IMC uses a variety of technologies to control worker exposures to diesel particulate. These technologies include: ventilation, low sulfur fuel, oxidation catalytic converters (OCC), maintenance and work practices. The study was conducted over a two-week period, two shifts per day. During the first week (six shifts), baseline data on exposures and diesel particulate emissions were obtained. New OCC's were installed over the weekend on all equipment on the test section. During the second week (six shifts), data were collected to assess the effectiveness of the new OCC devices. In addition to exposure and diesel particulate emissions data, mine ventilation, engine exhaust temperatures and mine operational data were obtained. The primary means of determining diesel particulate concentrations was the respirable combustible dust (RCD) method. Gas concentrations carbon monoxide (CO), carbon dioxide (CO,), and nitrogen dioxide (NO,) were measured using passive dosimeter badges and gas bottles. Results of measurements of diesel particulate, gases, and air- flows were analyzed to determine the effectiveness of airflow and oxidation catalytic converters for controlling diesel particulate exposures. The use of oxidation catalytic converters resulted in reductions of both workers' exposures and diesel emissions.

Jan 1, 1997

By Robert F. Randolph

New technologies confront mining organizations with unprecedented human factors challenges. Likely problem areas range from the design of the human- machine interface to the design of work groups and mine organizational structures. However, these human design considerations are commonly ignored in most industries, resulting in a failure rate of 75% for advanced technology programs. The U.S. Bureau of Mines is addressing these concerns through a program of research on the human side of high technology mining systems. Interviews with mining industry participants and researchers have identified concern in several areas, including training and equipment design. Although new mining technologies promise to improve overall safety by relocating miners away from hazardous areas, data from MHSA accident reports and other sources suggest that certain types of new hazards may be created. Many of these new hazards can be reduced though a systems approach to ergonomic design of equipment, tasks, and work processes. This evidence, combined with reviews of high technology human-machine systems in other industries. can help in the design of safe and efficient future mining technologies.

Jan 1, 1992

By David L. Bradfield

This paper covers the development of the Yeelirrie Uranium Project from the discovery of the Yeelirrie deposit in 1970 to the present time, with emphasis on the mining, processing, and environmental requirements of the project. The Yeelirrie Uranium Project is managed by the "Yeelirrie Uranium Joint Venture Partnership", which, when formed, consisted of Yeelirrie Development Company Pty., Ltd., Urangesellschaft, Australia Pty. Ltd. and Esso Exploration and Production Australia Inc. The Yeelirrie Uranium Joint Venture Partnership holds mineral claims over the Yeelirrie uranium ore deposit in Western Australia. This deposit encompasses some 35 million tonnes of ore containing in excess of 50,000 tonnes of uranium as U308. Agreement has been reached with the State of Western Australia to mine and process the ore to produce uranium ore concentrate. The Project scope provides for an open-cut mine, alkaline leach hydrometallurgy plant, power plant, township, airstrip, access roads, community services and utilities. The Yeelirrie Uranium Project described herein has progressed through the stages of exploration, mine evaluation, process testing, project scope definition, environmental approval, Pilot Plant operation, preliminary engineering and the publishing of a definitive Project Feasibility Study. This article summarizes the project development through the above stages.

Jan 1, 1984

By J. M. Dean, R. L. Grayson, N. P. Reddy, Y. J. Wang

This 1988 survey provided a cross section of computer software use by the US coal industry. From 1250 mailed questionnaires, 171 responses were received, representing a 4.9% sampling of the 3496 US coal mines. Since the distribution of responses by regional stratum matched well with the distribution of mines by stratum, the survey was given statistical validity. A statistical description details the computer use by region, mining type, organizational size, the level of application within the organization, the type of software application used, the variety of computers on which the software was used and the percent of users within engineering, management and general applications categories. Overall, 63.5% of the respondents use computers at some level in their organizations. All of the mines producing more than 454 kt/a (500,000 stpy) used computers. However, for those producing more than 9 kt/a (10,000 stpy) but less than 91 kt/a (100,000stpy), only 44% used computers. Generally, the software applications were still data-processing oriented. The application sophistication grew with increasing mine size. Computer system models and configurations for different sized organizations are recommended based on the configurations used in the industry at the time of the survey.

Jan 1, 1994

By M. S. Prasad, K. J. Reid, M. P. Katsoulis

The State of Minnesota is interested in stimulating the development of clay resources and recently supported a two-year project to collect data on geological, mineralogical, processing, economic and environmental aspects of such potential developments. This paper presents the various process options adopted on bulk samples collected from the Minnesota River Valley area, which is a primary deposit and contains a major silica fraction. A standard test flowsheet involving degritting, dispersion. HGMS and cycloning was developed and for some samples yielded an acceptable filler grade product. Secondary streams containing relatively high grade kaolin but of coarse size were also obtained. Improvement in particle size distribution and in physical properties related to paper product specifications (brightness, viscosity) were obtained by size-reduction processes. Market and economic considerations for kaolin consumption in the upper Midwest are analyzed. Current markets for paper grade kaolin in Minnesota are briefly discussed.

Jan 1, 1992

By L. Tondo, W. Lim

The high pressure grinding rolls (HPGR) is a relatively new technology which offers the potential benefits in energy savings, circuit simplicity and improved product characteristics in minerals processing applications. Over 300 machines are now operating world-wide, but most of these are used for grinding cement clinker, and relatively few are used in conventional mineral processing. One of the rea- sons for its current limited use in the minerals processing industry is that design, scale-up and flowsheet assessment procedures are seen to be relatively immature and untested. This has reduced confidence in the potential application of the technology. To help rectify this situation an industry funded research project was undertaken, one of whose aims was to develop and prove a mathematical model of the HPGR and a scale-up procedure. Data were collected from tests using laboratory, pilot and in one case a full scale unit (2.2m diameter). A range of feed types were tested including quartz, limestone, kimberlite, bauxite, iron ore and gold ore. These data were then used to develop models of the size reduction performance, power draw, throughput and operating gap for a wide range of pressures, feed sizes, and roll speeds. This paper describes the models that have been initially developed and illustrates their accuracy using some of these data.

Jan 1, 1998

By N. A. Frazier

The technology for using limestone or lime to scrub SO2 from power-plant flue gas has significant implications to the limestone industry. A brief status report on these processes will be made, possible process requirements on the limestone properties will be reviewed, and projections on the buildup of demand with respect to time will be reviewed. Disposal problems inherent with the use of these throwaway processes will also be summarized. Given a viable technology, relations among (1) distance of power plants from low- and high-sulfur coal and limestone deposits, (2) modes of handling and transporting immense tonnages of bulk material-coal and/or limestone, and (3) regional air-quality standards are some of the factors which will ultimately determine the demand for limestone. A discussion of these factors will be presented, with the intent of identifying geographic regions where significant increases in production can reasonably be expected.

Jan 1, 1974

By R. V. Ramani, K. V. K. Prasad, M. Swaminathan

Engineering design involves, in addition to numerical calculations, considerable amount of expertise and judgement. The expertise and judgement is required to conceptualize and idealize the problem, select a suitable mathematical model for the problem and to interpret the model results in terms of stipulated design constraints. In recent years, knowledge based systems (KBS) have provided the capability to integrate the qualitative experiential and expert knowledge with the quantitative knowledge for improved analysis and design of systems. A possible KBS architecture for mine ventilation system design was discussed by Ramani and Prasad (1987). The expert system (ES) component of the KBS supports the analysis and interpretation phases of the ventilation design process with an algorithmic program used for the solution of alternate designs. The purpose of this paper is to discuss the data and knowledge needs for developing such a system and a formal means of their representation on the computer. A number of ES shells were evaluated to explore possible development and delivery environments for the system. A brief summary of this evaluation is also provided.

Jan 1, 1989

Traditional fine-grinding mills in mineral processing rely on the use of steel medium for particle size reduction. The IsaMill (a horizontal stirred mill with a 3, 000-L net chamber volume and a rated motor power of 1,120 kW) has successfully adopted a novel product-separator design, which has led to a major revision of medium use in fine grinding. The IsaMill separator has successfully operated with a wide variety of medium types, such as silica sands, river gravel, smelter slag, run-of-mine ore fractions and steel shots, with sizes ranging from 0.5 to 10 mm. Great flexibility in the IsaMill operations has been achieved for processing feed as coarse as 120 µm to a product as fine as 5 µm. This paper discusses the performance of two inert grinding media in the IsaMills that are used at Mount Isa Mines Ltd. for the processing of galena- and sphaleritebearing ores to below 10 µm. They are the copper reverberatory furnace slag (CRFS) and the heavy-medium plant rejects (HMPR). A methodology was also demonstrated for comparing the medium performance and for scaling up the IsaMills from a 1.5-L laboratory batch mill to a full-scale 3,000-L mill.

Jan 1, 2002

By R. D. Schmidt, S. E. Follin

Introduction Mineral recovery from an in situ leaching operation is determined by the often complex interaction of hydrology, mass transport, and chemical kinetics. The operating conditions of many pilot and production scale uranium leaching operations involve heterogeneities in aquifer permeability. Differences in permeability may be naturally occurring, the result of differences in main size or cementation, or they may be induced by leaching activity. Variations in permeability directly affect the fluid flow streamline pattern, fluid flux, and so also leaching geochemistry and uranium recovery. An in situ leaching hydrology model (ISL) and a mass transport-oxidation rate model (ISLGC) have been developed for use in making site specific predictions of the leachability and productive potential of heterogeneous ore deposits, and for the optimal design of leachant injection and recovery operations. The two models are linked by output and input requirements. The ISL hydrology model generates a leachant flow streamline pattern between injection and recovery points in a flow domain incorporating regions of arbitrary permeability. The ISLGC transport model describes the changing solution concentrations of uranium and oxygen and the changing mineral concentrations of uranium and pyrite resulting from convection, longitudinal dispersion, and oxidation reactions. ISL hydrology model Basic equations The differential equation for steady-state two- dimensional flow in an isotropic porous medium is

Jan 1, 1988

By Van Zyl Brink

A longwall-based coal mine in Australia, referred to in this paper as AusMine Colliery, experienced windblasts resulting from goaf falls. Windblasts were the cause of serious injuries and threatened the continued operation of the mine. A microseismic early warning system was installed and a significant success rate in providing early warning of large roof instability resulting in high velocity windblasts, has been achieved. Early warning of goafing is accepted as an operational tool on the mine. Severe demands are placed on the operator in terms of 'real time' interpretation. The development of an expert system allowed for a probabilistic approach to achieve automatic alarms. This paper will quantify the success, failure and false alarm rates achieved by manual operation and automatic expert system-based decisions making, respectively.

Jan 1, 2002

By M. Polat, G. Ahuja, S. Chander, M. S. Klima

A study was conducted to investigate the use of flotation in combination with dense-medium cycloning utilizing ultrafine (-10 um) magnetite, as an integrated process for high-efficiency cleaning of fine coal. The objective was to produce a high-quality (low-ash, low-sulfur) coal, while reducing the amount of non-magnetic material that would need to be removed by magnetic separation. Three dense-medium cyclone tests were performed using different underflow diameters to produce feed material for the flotation separations The use of different underflow configurations caused a variation in the pulp and solids splits, which changed the clean-coal yield and the magnetite-to-coal ratio of the cyclone products, and hence, the composition of the flotation feed. Flotation was used to separate the clean coal and to recover the magnetite contained in the cyclone overflow stream. Any ultrafine refuse material, which may have reported to the cyclone overflow stream, was also removed in this step, further upgrading the product. In addition, flotation was used to improve the overall yield by recovering a middlings fraction from the cyclone underflow stream. It was found that flotation was very effective in separating the coal (or middlings) from the ultrafine magnetite, even under variable feed conditions. Magnetite recoveries approaching 99% were possible using rougher-cleaner separations in a laboratory flotation cell. This paper presents the results from this study.

Jan 1, 1995

By Nico Bezuidenhout, André M. van Niekerk, Jan J. G. Vermaak

This paper documents empirical evaluations of geochemical data that was recorded during a seven year pilot scale experiment. The experiment was aimed at assessing the effectiveness of natural soil covers for rehabilitation of coal discard facilities. Ten test cells were constructed using different natural soil cover materials and configurations. Results of the evaluation indicate that, although a pH breakthrough was not recorded for the single layer soil cover cells as was the case with the uncovered cells, single soil covers were not effective in preventing ARD oxidation processes. Multi layered soil covers were found to be able to create anaerobic conditions leading to a reduction in ARD oxidation processes and an improvement in leachate quality.

Jan 1, 2000

By M. Misra, I. Anazia

The dispersion of oily collector has a significant effect on the flotation recovery of ultrafine coal. Generally, reagent dispersion is accomplished by mechanical mixing and/or ultrasonic agitation, followed by direct addition of dispersed collector into the flotation cell. Such dispersion and reagent addition techniques are invariably inadequate and nonselective. A new collector addition technique involving gas phase transport of atomized collector has shown improved results when compared to conventional reagent addition techniques. This technique involves atomization of the collector into the air stream. Under these circumstances, an aerosol is introduced into the flotation cell. Initially, the oil is dispersed within the air phase (continuous with respect to oil), and the air phase is dispersed within the pulp (continuous with respect to aerosol). In the flotation cell, the atomized oil droplets coalesce on the bubble's surface and create a de facto oil-encapsulated bubble. This approach provides excellent dispersion, increases selectivity, and, most significantly, increases the flotation rate of ultrafine coal. Atomization of collector/frother combinations yielded improved flotation recovery and maintained near uniform froth levels, which is a desirable feature in coal flotation. Microscopic examinations of the attachment of oil- coated bubbles at a coal surface were conducted by attachment time and contact angle measurements. Oil-coated bubbles attach at significantly faster rates and with a higher contact angle than oil-free bubbles.

Jan 1, 1988

By J. B. Hiskey, S. Chander, B. J. Scheiner

The use of selected iron complexing agents in preventing or ameliorating acid mine drainage was investigated. The experiments were conducted in weathering columns using refuse samples from a coal cleaning plant. It was observed that the treatment with iron complexing agents significantly altered the rate of oxidation. Some of the reagents tested reduced the rate of oxidation whereas the others even enhanced it. The results showed that a commercial reagent containing oleyl imidazoline was most effective in retarding the oxidation rate. In addition, a simple treatment with this reagent substantially decreased the rate of oxidation of pyrite in a column that was generating acid at a high rate. The effect of this reagent on the surface properties of pyrite was studied by cyclic voltammetry and zeta potential measurements. The decrease in the rate of oxidation resulted from suppression of both anodic and cathodic reactions at the surface of pyrite.

Jan 1, 1993