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By John Durkin, Steven Wirch, Fred N. Kissell, Steven Ruggieri

The Bureau of Mines has developed two expert systems to give advice on coal mine dust control, one for continuous miner sections, and another for longwalls. Prototype versions have been evaluated by coal operators and MSHA. Both systems query the user as to the nature and extent of the dust control problem. Typical questions asked deal with matters such as cutting sequence, current dust standards and characteristics of current dust control techniques. Advice given by the system generally does not focus on a single issue, but may suggest a variety of approaches consistent with the ability of the operator to practically implement what is suggested. Both were written using expert system development software called Insight 2+. The advantages of Insight 2+ for the user are: low cost, IBM-PC compatibility, and the fact that little prior experience with computers is required. For the developer, Insight offers an easy to use production rule language and goal driven structure as well as a wide variety of capabilities.

Jan 1, 1987

By P. R. A. Andrews, R. K. Collings

The beneficiation of barite has been the subject of many investigations at CANMET, thus reflecting barite's importance as an industrial mineral. Fifty-one studies relating to various aspects of beneficiation were conducted between 1920 and 1986, and a review of some of the more important studies is presented. The information, including mineralogy, beneficiation methods and results, flotation parameters, and reagent concentration data, is presented in tabular form. By so arranging the principal data, the research worker and production metallurgist will be assisted in the evaluation of barite ores from a variety of origins.

Jan 1, 1990

By John Rushton

Surface mining, from ore extraction to processing, requires many types of equipment to obtain the final product. Mine equipment often includes shovels, drills and haul trucks. Ore processing equipment, including plants, mills and concentrators, are also part of surface mining operations. Surface mining operations emphasize production. Production is where the bills are paid and fortunes are made. However, there must be support to keep the equipment operational. To most production people, equipment maintenance is a necessary evil. Maintenance is not glamorous work. It is often neglected when praise is being passed around. It is easy to recognize higher production, greater capacities, faster cycle times or more loads hauled. But who cares if an engine is replaced in 12 hours instead of 48? The answer is, everyone should - from the hourly miner to the mine manager. Surface mining equipment needs constant maintenance work. It must be lubricated, components replaced, electrical problems repaired and other problems addressed. Repair work for any surface equipment takes time away from production. It costs money. Maintenance costs cannot be avoided. However, they can be minimized. Minewide communication should include operations cooperating with maintenance. Traditionally, operations resist surrendering equipment to maintenance if it can continue to produce. The rationale is, every load that can be hauled today is money in the bank. If the unit is taken down, the money is lost. This thinking is prevalent in many surface mining areas, including the mill. "Not on my shift," the operator thinks. "Let the next crew worry about it. The problem with this thinking is in probability and statistics. The longer equipment goes without maintenance work, the higher the probability of equipment failure. When the failure does occur, it is certain to cause the equipment to remain down longer than if the maintenance department had been allowed to take it down. Many mining operations have closed early in their lives because of poor maintenance practices. This has become the industry standard because substandard levels of performance are acceptable. Management believes it gets five to six hours of work from maintenance people during an eight-hour shift. Actually, the industry average is less than two hours of work per shift. Real productivity levels of less than one hour are not unusual. There are few exceptions. However, a daily work schedule (DWS) will increase productivity at many properties by 50% to 100%. A 200% improvement is not unusual. The DWS will work. Maintenance people are among the most intelligent and motivated people on the property. They deserve the chance to be productive. [ ] In preparing a DWS, management needs to understand two productivity principles - the productivity spread and the real maintenance workday.

Jan 1, 1997

By W. Petruk, D. B. Sikka

Lithium-bearing lepidolites from three deposits in the province of Goias, Brazil, were investigated to determine whether there is a correlution between the lithium content of the mineral and the color of lepidolite and associated tourmaline. Such a correlation can be a useful guide to field geologists for outlining high-grade lithium ore zones. It was found that mauve-pink lepidolite associated with pink tour-maline, and brownish lepidolite associated with black tourmaline have high lithium contents, but that the color of lepidolite is not due to lithium. The pink color of lepidolite and tourmaline is likely due to Mn3+, and the brownish tint of lepidolite and black color of tourmaline to Fe3+. Lepidolites appear to be lithium- rich when the lepidolite and associated tourmaline contain relatively high amounts of Mn3+ and/or Fe3+.

Jan 1, 1988

By Lawrence J. Connelly

During the last decade, use of freeze conditioning agents (FCA) to ease unloading and handling of both run-of-mine and washed coal during periods of cold weather has become an accepted practice by the coal industry. This paper reviews some of the mechanical means of easing the handling of coal during periods of cold weather, as well as their use in conjunction with FCA's. Factors required to promote a successful cold weather handling program are also covered. Mechanisms by which FCA's function and the influence of various substrate characteristics on the ultimate response to freeze conditioning agent performance are discussed. A modified approach to freeze conditioning is presented.

Jan 1, 1986

By T. S. Mackey

The industrial types, sources, and quantities of US tin residues are identified and the methods of treatment reviewed. The effect of a lower tin price, due to a current major world surplus of tin metal, is mentioned and covered in some detail. The names and locations of over 100 US firms recovering tin residues are listed. Current smelting and refining charges are included to convert the residues into tin metal and alloy. The impact of the complete with-drawal of the LME daily tin price since Oct. 24, 1985, and the collapse of the International Tin Council, which at one time supported the Buffer Stock Manager, are reported with comments.

Jan 1, 1987

By A. G. Mayton

Bureau of Mines research has addressed improved operator protection for thin-seam shuttle cars. Because of working height restrictions in thin-seam mines (1.22 m or 48 in), MSHA regulations require that-canopy protection on shuttle cars be provided only in mines 1.07 m (42 in) and greater; however, variances are given to mines 1.22 m (48 in) and below. This paper reviews past Bureau efforts to develop protective structures for thin-seam shuttle car operators. The paper also discusses recent research leading to a novel method of protecting shuttle car operators, in mines as low as 1.02 m (40 in), through the use of a cross-car, end-mounted operator compartment.

Jan 1, 1989

By A. K. Bakshi

In cold regions, rinsing of spent cyanide from leach heaps is stopped during winter and is resumed again after the snow melts. The effect of this idle time on the overall removal process was studied in this experiment. Samples were collected for rinsing tests from one heap at a gold mine near Fairbanks, Alaska. Continuous and interrupted rinsing of this sample were carried out in test columns. The rinse solution was analyzed at regular intervals to determine the rate of cyanide removal from the solids. It was found that total cyanide concentration per rinse cycle for interrupted rinsing test was higher than for the corresponding continuous rinsing test. As a result, interrupted rinsing required less rinsing cycles than continuous rinsing.

Jan 1, 1995

By E. K. Albert

Title IV of the 1977 Surface Mining Control and Reclamation Act (SMCRA) provides for an abandoned mine reclamation fund. This fund, taken from fees collected from operating coal mines, provides capital for the reclamation process. The Act directs the Office of Surface Mining (OSM) to collect the fees based on coal production. Monies from the abandoned mine lands (AML) fund are distributed through two programs. The first provides OSM with capital to use in emergency situations resulting from abandoned mine sites and reclaiming high priority sites in states without established AML programs. The second distributes the money through a state's AML program in the form of grants. To provide for a flexible and customized selection procedure for AML projects, a management information system (MIS) that combines scientific selection procedures is being developed. This system employs objective and subjective methods developed in systems research in recent years. The MIS component is an essential part of any selection process involving large numbers of potential projects. It must contain all the necessary project parameters that can be applied to the selection of projects whether or not they are to be used in the immediate selection criteria. In addition, variable selection criteria will allow ‘what if’ types of inquiries for comparison of differing selections and benefits.

Jan 1, 1990

By Peter Zhang, Daniel Su, Bo Kim, Berk Tulu

This paper summarizes significant findings from the ongoing NIOSH Gas Well Stability research over the past decade; in particular, the important ground control engineering considerations. Longwall-induced surface and subsurface deformations may induce gas well casing deformations and stresses, depending on a few parameters such as overburden depth, overburden geology, topographic relief, strata dip, gas well setback distance, and a gas well casing cementing alternative. Overburden depth to the mining seam is one of the most influential factors; shallow overburden depth induces large horizontal displacement and resulting casing deformation and stress, while deep overburden depth induces large longwall-induced vertical pressure. Overburden geology is another important factor affecting the longwall- induced casing deformations and stresses; the large contrast of bending stiffness at the soft-to-hard rock interfaces tends to induce large casing deformations and stresses. Large surface topographic relief and the presence of soft-to-hard rock interfaces below the stream valley bottoms may shift longwall-induced subsurface gas well casing deformations closer to the surface, thus having less impact on underground. mining operations. Strata dip magnifies longwall-induced deformations by 20% per degree of strata dip for down dip longwall excavations. The gas well setback distance is also a critical geometric parameter; the effect of longwall-induced deformation decreases exponentially as the setback distance increases. Longwall-induced casing deformation and stress will be mitigated or totally uncoupled for uncemented production casing.

Jun 25, 2024

By R. Tanaskovic

The objective of study of climatic conditions in underground mines is to create a working environment suitable for normal development of operations. Disregarding the fact that the development of equipment and technology, especially during the past decade, made the work in underground mines much easier, it is observed, according to the number of professional publications, that increasing attention is devoted to the study of climatic operating conditions in mines of many countries. This indicates that the climatic operating conditions are closely connected with productivity, and in turn with mine production profitability, in addition to the protection of manpower health and working capabilities. Usually, the concept of unfavourable climatic conditions of operation implies increased mine air temperature and humidity and low air flow rate, resulting in impeded heat exhange between human organism and working environment. As known, above phenomena are present in deep underground mines where the heat problem exceeds the-problems related to other features of natural conditions of mining. On the contrary, unsuitability of climatic operating conditions in mines with shallower mining depths is manifested by inadequate heat, particularly during the cold winter period. The two stated aspects of unsuitable climatic operating conditions are not solvable only by mine ventilation, so the former case requires cooling and the later one heating of the air used to ventilate the pit, or part there of where the phenomena are manifested. Study of climatic operating conditions in mines is, due to the number of factors involved, a complex and time consuming task, and this was, among others, one of the reasons for inadequate study of these problems in many mines. However, it is evident that further development of mine production imposes the need to make the climatic operating conditions in mines similar to those existing in other activities, where increasing attention is being devoted to the improvement of these conditions. Development of mining industry in Yugoslavia, particularly over the past decades, caused several of our mines to approach mining depths where the heat regime has a major influence on climatic operating conditions. This imposed the need to determine and investigate heat regime parameters, especially those that cause unsuitable operating conditions. The results of such investigations in the case of the deep part of Lead and Zinc Mine "Trepca" - Stari Trg are briefly reported in this paper.

Jan 1, 1980

By M. M. Nash

Since the late 19th Century, scholars have been concerned about finding proper methods of managing business. The search seems to be taking us full-circle to the time and motion studies of Taylor (Horn, 1987). It wasn't until the late 1970's, however, that systematic investigations were made in the mining industry. One of the first was a study by Sanders, Patterson, and Peay (1976). That project explored the relationship of attitudes and safety. Peay, Atkin, and Goodman (1977, then reviewed the whole area of Organizational Development, including the so-called Rushton experiment.

Jan 1, 1988

By R. S. Scheetz

The search for a more effective means of coping with methane liberation has resulted in the expanded use of seam degasification. Its advantages are measured not only in reducing the hazards due to methane, but also in producing a marketable commodity: .the gas, itself. However, the success of a methane drainage system is the culmination of many complex factors, the most important being the coal seam permeability. The two most popular drainage techniques used mining today are the vertically simulated borehole method and the in-seam horizontal borehole method. The objective of this paper is to determine the permeability range in which the selection of the degasification technique is based primarily on equipment and economic analysis. A discussion of the equipment involved will be incorporated into examples evaluated by the Penn State coal methane simulation model.

Jan 1, 1989

By Feng Dingwu, Chen Jin, Sun Zhongyuan, Peng Shiying

The recent development of rare-earth permanent magnets has impacted the field of magnetic separation. The permanent magnets technology led to the advent of various magnetic separators particularly designed for application in mineral processing. In this paper, a new type of rare-earth PHGMS possessing a higher magnetic field strength in the working zone was developed using finite element analysis techniques. The NdFeB permanent magnets used had properties of 38 MGOe stored energy, and magnetic material flux levels exceed 1.2 T, The combination of scientific and engineering design and suitable matrices can offer an effective separation of industrial minerals, such as kaolin, feldspar, etc. Compared with conventional high intensity electromagnetic separators, the equipment can reduce electrical energy over 80% with lower operation and maintenance costs, and less installation space.

Jan 1, 1995

By J. Partyka, Trevor R. J. Kelly

This paper presents the results on noise testing of a fan only, as well as the results of a steel silencer and of flexible silencers that were connected directly to a fan. On-site facilities and free-field method set by the British Standards Institution were used to measure and then compare the fan only and different practical silencer configuration setups. In order to determine the fan-silencer combination that would give the maximum noise attenuation, total noise intensity, noise contributed to by the fan motor only, as well as aerodynamical noise created through air interacting with the fan parts were considered to obtain decibel readings for the octave bands. Subsequently, the optimal configuration found was the setup with flexible silencers on the fan inlet and the fan outlet. If only one silencer is used, it should be installed on the fan inlet. The aerodynamic noise affects the low frequencies. The flow noise is then overtaken at 1 kHz by the mechanical noise.

Jan 1, 1995

By R. W. Hagemeyer

By way of background. it is important to keep in mind that the information presented in this paper relates specifically to synthetically produced precipitated calcium carbonate (PCC) fillers. Natural calcium carbonate fillers manufactured by grinding limestone, marble and chalk, though having similar chemical and physical analyses to PCCs, normally contribute somewhat different performance properties in paint, paper and polymer systems. Many factors have been cited and numerous theories have been proposed for the observed differences. Particle size parameters, surface chemistry and particle morphology are the items most frequently mentioned. A discussion of this subject is beyond the scope of this paper.

Jan 1, 1989

By Stephen Hoffman

The Environmental Protection Agency (EPA) is investigating approaches to control non-coal mining wastes. In May 1988, the EPA's Office of Solid Waste (OSW) released a document that outlined an approach to manage non-coal mining wastes and materials. This document was called Strawman I. It was a staff-level approach designed to aid the continued participation of interested parties and to enhance EPA's understanding of mining waste issues. EPA has been working with states, public interest groups and the mining industry to gather information and to solicit input on waste management approaches. The involvement of the states in the Strawman process has been coordinated by the Mine Waste Task Force of the Western Governors' Association and the Interstate Mining Compact Commission. Involvement of public interest groups has been coordinated through Colorado Trout Unlimited. And the participation of the mining industry has been managed principally by the American Mining Congress. In May 1990, EPA released Strawman II. It was based on comments submitted to the EPA on Strawman I and on information given to the EPA by interested parties since 1988. Strawman II is again a staff-level approach to protect human health and the environment from wastes and other materials associated with non-coal mining. In September 1990, meetings were held with public interest groups and the mining industry to discuss their comments on Strawman II. By early 1991, the EPA expects to make a decision on how to proceed with program development.

Jan 1, 1990

By R. D. Grove

The control of Florida phosphate flotation plants is largely based on the visual observations of experienced operators, both in recognizing good and bad froth conditions and in making judgments about the composition of feed, concentrate and tailing streams. Chemical analyses lag the process by at least two hours and, therefore, only assist in recalibrating the operators' vision when major deviations occur. An image analysis system was developed by IMC Fertilizer to improve the accuracy and precision of the composition estimation process. It still relies on the operator taking a representative sample, but provides a measurement in about 15 minutes after that sample is obtained. Background The search for a quick and inexpensive technique for estimating phosphate flotation stream composition continues. There have been attempts at using "wet chemistry," nuclearmagnetic resonance, neutron activation, X-ray diffraction and other techniques reported on in the past several years. None of these have yet found its permanent place in the flotation plants of the Florida phosphate industry. IMC attempted to use wet chemistry to provide 7.5-minute estimates of final concentrate insol and tailings BPL. This was aborted after 36 months of plant operation due to the high operating costs for chemicals and an operator. There was also no significant economic improvement in the plant's operation. Another factor was the necessity to limit these crude analyses to only a few process streams, which were insufficient to achieve improved plant operation.

Jan 1, 1993

By Mark L. Blanford, Roger M. Zimmerman

INTRODUCTION Volcanic tuffs on and adjacent to the Nevada Test Site (NTS) are being considered by the Department of Energy (DOE) for the possible geo- logic disposal of high-level radioactive wastes. The Nevada Nuclear Waste Storage Investigations (NNWSI) project was established in 1977 to evaluate such disposal. Sandia National Laboratories (SNL), one of the participants in the NNWSI project, has as one of its responsibilities the development of a rock mechanics program for the Nevada site. SNL conducted three small-diameter heater experiments in welded and nonwelded tuffs in G-Tunnel on the NTS, to investigate the thermal (heat transfer) and hydrothermal (thermal- induced water migration) behavior as part of the rock mechanics program. These two aspects were investigated to increase knowledge about the behavior of tuff so that predictive capabilities are available for use by repository designers, waste-package designers, and performance analysts. Also, knowledge of the behavior of the tuff is invaluable for planning and designing future in situ experiments at Yucca Mountain, the candidate site for the repository. The evaluations of these three experiments is the subject of this paper. Designers, analysts, and experimenters are seeking a better understanding of the behavior of tuffs under the influence of thermal loads expected from radioactive-waste storage, because of two physical features peculiar to tuffs. First, tuffs are inherently porous because of the manner in which they are deposited (Smith, 1960). Tuffs utilized in G-Tunnel testing have porosities ranging from 15 to 46%, which cover the ranges of expected porosities in the target horizon at Yucca Mountain. It has been established that the G-Tunnel tuffs have similar bulk, thermal, and mechanical material properties to those at Yucca Mountain (Zimmerman et al., 1984), thus, G-Tunnel testing can be used to evaluate the effects of porosity on the thermal and mechanical behavior. The second feature is that tuffs above the water table contain pore water that influences the thermal properties of the rock; displacement of the water must be accounted for in repository designs and analyses. For example, G-Tunnel tuffs, located some 600 m above the static water level, have saturations in excess of 60%. Similar percentages are expected at the target horizon in Yucca Mountain (Zimmerman et al., 1984). The presence of and the removal of the pore water affects the thermal behavior of the tuffs, and these three experiments were designed first to determine the phenomenological behavior and then assess influences on predictive capabilities. The focus in this paper is to present the results and evaluations of the experiments as they apply to improving predictive capabilities. The thermal aspects are emphasized by comparing the measured temperatures (in and around heater emplacement holes) with calculations of predicted temperatures using numerical models, so that the effects of significant parameters can be evaluated and integrated into future predictive models. Observation of the hydrothermal aspects is needed to assess the effects of loss of pore water and subsequent migrations on the temperature fields during the heating, and also to define the expected environment in the vicinity of the outer metallic surface around the waste. The metallic boundary can be either the outer shell of the waste package system, which is the main engineered barrier for waste containment, or the borehole liner. A final decision has not been made as yet about the necessity for lining boreholes; thus, the emphasis is on predicting the characteristics of the environment around the outer metallic surface. Two aspects that limit the scope of this paper are (1) the experiments were performed at a smaller than canister scale for the purpose of

Jan 1, 1986

By E. M. Frizzell

This paper addresses the use of the microcomputer programs BACKONE and BACKWEDG for an estimation of rock mass strength characteristics by back analysis of plane and wedge failures. The artificial support requirements are also determined by the programs PLANE2, BOLTPAT, and BOLTWEDG in terms of rock anchor installation angles, tensions, and installation patterns. These programs have been combined into a package called BACKPACK, which can be applied in open pit mines where some failures have already occurred.

Jan 1, 1988