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By S. K. Kawatra, T. C. Eisele

Production of highly-cleaned coal for advanced utilization schemes requires close control of the coal ash content at very low levels. For this purpose, a sensitive, low-cost, robust on-stream ash analyzer is needed. The development of such an instrument based on x-ray backscatter and fluorescence is described, including features to improve its sensitivity at low ash levels. The performance of the resulting device in testing a real coal sample is discussed.

Jan 1, 1990

By Patrick Ph. D. Kennedy, Osvaldo A. Ph. D. Bascur

With the revolutionary progress in information and computer technologies, applying the latest information technologies in metallurgical complexes has become a serious challenge to both a major opportunity and a serious challenge to both management and technical teams. The emerging component and object technologies are changing the way everyone can beneficially use their computer and networks to add to their corporate bottom lines. Most mining and metallurgical plants use predictive maintenance policies based on statistical analysis and special techniques, like vibration analysis and oil and lube analysis for critical equipment. Process control strategies are installed in several metallurgical sites. All process equipment and control strategies require maintenance from local personnel at the mine. Integrated use of existing and emerging technologies is making it possible to implement an overall process effectiveness control index. This index is based on key indices such as losses due to plant availability, performance efficiency and rate of quality. The availability of real time and process history to identify the most critical part of the processing system from mechanical integrity is highlighted. An emerging plant integration paradigm is described to simplify the implementation of business enterprise resources management and distributed plant management systems.

Jan 1, 1998

By B. N. Conley, K. D. Luxbacher

"The underground coal mining industry in the United States has recently seen the occurrences of several high profile, multi-fatality events. The explosions that occurred at the Sago Mine in 2006, the Darby Mine in 2006, and the Upper Big Branch Mine in 2010 have caused a ripple in an otherwise steadily improving safety record. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with a minimal decline of both fatal and non-fatal injuries over the past decade may signify that current safety practices have reached a level of diminishing returns. Risk management, a safety approach that has been successfully applied in various industries including mining across the world, may provide a means to surpass the safety plateau in the U.S. RISKGATE is an Australian risk management program for mines that shows great potential for application in the U.S. However, fundamental differences between the coal mining industries in Australia and in the U.S. prevent direct implementation. This paper discusses aspects of the RISKGATE body of knowledge that require some adaptation before this program may be applied to the U.S. mining industry. INTRODUCTION The underground coal mining industry in the United States has recently seen the occurrences of several high profile, multi-fatality events. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with a minimal decline of both fatal and non-fatal injuries over the past decade may signify that current safety practices have reach a level of diminishing returns. In order to combat this stagnation in performance, a modification to the manner in which the mining industry approaches worker safety may be warranted. The implementation of a risk management based approach presents a potential method for not only surmounting the current safety plateau but also for achieving the long desired objective of zero harm. RISKGATE a risk management body of knowledge designed for the Australian mining industry that shows great potential for application in the U.S. This paper discusses aspects of the RISKGATE body of knowledge that require adaptation before implementation in the U.S. mining industry. These adaptations are based on differences in operating practices and governmental regulations. This discussion will focus on the three major U.S. risk areas of explosion prevention, ground control, and moving equipment."

Jan 1, 2015

By J. S. Peterson

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Center (PRC), has conducted research to improve electrical fault detection on coal mine direct current (dc) trolley systems. Present circuit breaker protection systems are current-magnitude-based and cannot discern between normal traffic and high resistance electrical faults. Tests were conducted at cooperating mines to assist in developing a neural-network-based detection algorithm for distinguishing between electrical faults and normal operation. The Fast Fourier Transform of the trolley rectifier current signature served as baseline data for the neural network. During field tests, the algorithm performed with greater than 90% accuracy.

Jan 1, 1997

By J. A. Herbst, Y. C. Lo

An attempt has been made to parameterize the population balance model for a ball mill based on measurements of the elementary breakage process obtained using an ultrafast load cell device. Detailed insight obtained concerning the fragmentation of particle assemblies with the ultrafast load cell leads to a better understanding of ball mill grinding. The ball mill breakage function and specific selection function are derived from an average single event representing the multiple breakage events which occur in ball mill grinding. Since both the breakage function and the specific selection function depend on the loading mode in the mill, predictions of breakage mechanisms in ball mills are possible by using data obtained in various elementary loading modes. The application of this model to the description of batch ball milling behavior has resulted in reasonably accurate predictions of product size distributions for various energy inputs.

Jan 1, 1992

By D. R. Gehring

Effective project management is an excellent technique for meeting a goal through set, well-defined objectives. Even though project management is successfully used throughout the world in various construction projects, underground mining has unique characteristics that require approaches that vary from classical project management theory. Typically, a project includes four main stages: definition, planning, implementation and control. Definition and planning are often the most overlooked stages, but are arguably the most important. This paper addresses practical techniques for the definition and planning of projects for underground construction.

Jan 1, 1996

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite (Bayer Process) is known as red mud. Approximately one ton of red mud is produced for every two tons of bauxite mined. The red mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that more than 90% (by weight) alumina can be recovered from red mud by soda ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of more than 94%, resulting in attempts, for magnetic separation. These separations are desirable because there are no waste products generated. Consequently, there is an opportunity for complete utilization of the waste material. Conversely, the preseparated material could be charged through the tuyeres in an iron blast furnace, or it could be smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag would be high enough to justify its recovery by an established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red mud as an alternative to direct-reduced iron (DRI) is also discussed. A critical assessment of the recovery sequence chosen for the products is described based on economics. Key words: Red mud, Waste product utilization, Alumina recovery, Titanium oxide, Iron

Jan 1, 2003

By Wai Wu, C. Haycocks

The majority of Appalachian coal deposits lie in a multi-seam environment. Historically, the decision to extract a particular seam has been based on ease of access, ownership and economics rather than ground control considerations. As mining progresses and seams are being mined out, it is increasingly common to find working and abandoned mines in close vertical proximity to each other. Such contiguous operations can produce both positive and negative ground control situations in neighboring seams. These ground control problems, defined as interaction problems, are frequently reported, and their severity can range from minor roof problems that may require no additional support to complete loss of a large section of coal reserves (Stemple, 1955; Peng & Chandra, 1980; Haycocks & Karmis, 1983; Su et al, 1984). As a consequence, interaction problems are of growing concern to the Appalachian underground coal industry. Although interaction problems in multi-seam mining have been recognized for many years and many investigations have been conducted to study the problems, the ground control principles involved in their development are only partially understood. Previous research has identified four interaction mechanisms: pillar load transfer, innerburden shearing, arching effects and upper seam subsidence (Haycocks et al, 1982; Haycocks & Karmis, 1983). Pillar load transfer mechanisms and innerburden shearing have been successfuly used to explain interaction phenomena associated with undermining operations, while arching and subsidence have been used to assess problems during overmining. In addition, interaction-controlling factors such as cover, innerburden and seam thicknesses, extraction percentages on both seams, time delay between operations on two seams, and characteristics of innerburden rock have been identified and utilized in evaluation of interaction effects (Haycocks & Karmis, 1983; Webster et a1.,1984). As an example, Figure 1 shows the relation of innerburden layering and thickness to interaction on the lower seam. The combination of such theoretical work and the analysis of case study information has made it possible to determine, with a certain degree of confidence, the interaction damage in undermining conditions. The results of such an approach have been sufficiently successful and complete to be incorporated into a software package to assist field engineers in estimating potential interaction effects when undermining a previously mined upper seam (Grenoble et al, 1984; Grenoble & Haycocks, 1985; Grenoble et al, 1985). Although the conventional finite element and photoelastic modeling techniques have been

Jan 1, 1986

By T. Ruff, J. Steele

The lack of visibility near earthmoving equipment results in an average of five fatalities in U.S. surface mines each year. These accidents occur when a piece of equipment either strikes another vehicle or worker, or travels over the edge of an embankment. Researchers at the National Institute for Occupational Safety and Health have evaluated off-the-shelf proximity warning systems that sense obstacles near the equipment and provide an alarm to the operator. Limitations of existing systems have necessitated the development of new systems designed specifically for mining equipment, including a GPS-based proximity warning system and a computer-assisted stereovision system.

Jan 1, 2004

By B. J. Arnold

With the passing of the 1990 Clean Air Act Amendments, many utilities are opting to switch to lower sulfur coal to meet new SO2 emissions requirements. This lower sulfur coal may be from new suppliers or it may be from current suppliers that modify existing cleaning plants or build new plants to produce this higher quality coal. New, sophisticated coal cleaning simulators are useful tools for optimizing cod cleaning circuit operating parameters to maximize the production of clean coal that meets more stringent specifications for SO2 emissions potential. The examples in this paper were developed using the Coal Cleaning Simulator (CCS), running under ASPEN PLUS™, that was developed under a Department of Energy project cosponsored by the Electric Power Research Institute. With advanced sensitivity analysis and optimization features, CCS allows a quick, efficient, cost-effective review of coal cleaning plant performance to meet current production goals and to plan future changes in plant operating parameters or circuitry configurations.

Jan 1, 1995

By Ron L. Schmiermund

The Ferris-Haggarty underground mine was abandoned circa 1910, and portal discharge has since resulted in degradation of a trout fishery in the receiving waters of Haggarty Creek. Although tunnel discharge varies dramatically in volume throughout the year due to infiltration of snowmelt, compositionally it is a nearly constant low-TDS, pH-neutral, low-sulfate, copper-silicate dominated water. Between infiltration events, components of ARD accumulate in unsaturated, oxygenated environments within upper workings and are delivered to the main haulage level by the subsequent annual snowmelt flush. Mixing with non-ARD mine waters results in neutralization, dilution, and precipitation of amorphous copper carbonate and silicate phases. These mechanisms, combined with variations in the water balance, control the composition of the portal discharge. Understanding the chemical and hydrologic control mechanisms was critical to the design of a passive treatment system to decrease effluent copper concentrations.

Jan 1, 2000

By W. M. Snoddy

The Montana Tunnels diatreme is a low-grade polymetallic ore body containing economically mineable quantities of gold, silver, lead, and zinc. Widely varying gold grades combined with the general erratic nature of the mineralization create a complex sampling, assaying, and ore control problem. In order to maximize productivity and profitability, a variety of procedures have been used. These include differing sample size, frequency and method. In addition, assay techniques have been adjusted and refined to fit specific requirements, the result of which is an accurate, functional sampling and ore control system.

Jan 1, 1991

By R. Singhal

Canada's coal production is approximately 65.4 million tonnes of which 95 % is produced by surface mining methods mostly from the three Western provinces (British Columbia, Alberta and Saskatchewan). The mines are highly mechanized; productivity gains during the past few years have ranged from 60 -80%. Truck/Shovel methods are common although Saskatchewan lignite is almost exclusively mined by draglines. This paper provides an overview of Canadian Coal mining industry vis a vis surface mining. Emphasis is on application and utilization of mining equipment and associated mining methods.

Jan 1, 1994

By Charles T. Ford

Limestone neutralization of acid mine drainage has been proposed and examined as a method of treatment. However, limestones differ greatly in composition and structure. The reactivity of 14 selected limestones was studied, both by chemical and physical properties and by relative effectiveness in neutralizing synthetic and actual mine waters, and several guidelines for the choice of limestones are given. The particle size should be at least as small as 74 microns and preferably smaller. The most effective limestones are most nearly pure calcium carbonate. Stones which have a relatively low calcium con- tent but which contain calcite and have a large surface area are also effective neutralizers. Magnesite and dolomitic limestones are much less reactive. Disadvantages in using even the most reactive lime- stones for neutralization are indicated.

Jan 1, 1974

By K. Morsy, S. S. Peng

A new method of pillar stability evaluation was proposed. The unique feature about the method is that it estimates two types of stability factors for the pillar. The first stability factor is to measure how much the applied stress at that point is smaller than its strength, and the second stability factor is to predict whether or not the pillar will fail violently. The strain-softening behavior of coal pillars was simulated by the Drucker-Prager yield criterion. A new algorithm that simulates the strain-hardening behavior of the gob was used. A numerical technique to estimate the local mine stiffness (LMS) was introduced and verified by both numerical and analytical methods. A case of massive pillar failure in a room-and-pillar mine was used to define the stability limits for the proposed method.

Jan 1, 2003

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

By III Kimball

Mining wastes have received individual attention under the Resource Conservation and Recovery Act (RCRA) since its inception, in recognition of the special characteristics that distinguish mining wastes from other solid wastes. The Environmental Protection Agency (EPA) has recognized that: - Mining wastes are generated in much larger volumes than other industrial wastes. Most material handled in mining is waste (over 99% in many cases) and not marketable product, whereas waste is a small portion of raw materials used in most industries. Consequently, controls used for hazardous wastes may be technically infeasible or economically impractical. - Nearly all mining waste is managed at the site of generation and is land-disposed. . - Mining wastes typically pose lower hazards than other industrial wastes. Mining operations are located predominantly in sparsely populated areas and in arid or semi-arid areas with little surface water runoff and deeper water tables.

Jan 1, 1990

By W. J. Garmoe

The Carr Fork mine is located approximately 50 kilometers southwest of Salt Lake City, Utah, in the Bingham or West Mountain District, adjacent to the Bingham open pit copper mine. Applied geology at Carr Fork, by Anaconda Minerals Company personnel, includes detailed geologic mapping and sampling of underground workings, logging and sampling of drill core and cuttings, and the preparation and posting of geologic maps and cross sections for geologic interpretation, ore reserve calculation, mine operations, and long range planning. Accurate and easily understood graphic recording of Carr Fork geology is essential for optimum use by operating and engineering personnel. The design and implementation of exploration, development and definition drilling programs, research into geological spatial relationships, and analysis of structural complexities of the Carr Fork deposit are also integral parts of the applied geology program.

Jan 1, 1992

By E. K. H. Goh

A reliability-based engineering design approach for the effective design of reshaped spoil dumps was developed with the aim of obtaining structurally reliable spoil dumps at optimum reshaping costs. The aim was also to satisfy environmental erosion standards and community expectations. This approach encompasses the linking up of three major components: erosion appraisal of spoil dump designs, reliability-based engineering design of spoil dumps and costing of spoil dump reshaping practices. This paper addresses the application of the reliability-based engineering- design approach to the assessment of spoil dump designs for erosion control. Included are various types of erosion prediction models and reliability-based engineering-design analytical techniques. Also included is a case study that demonstrates the application of this approach.

Jan 1, 2000

By Prasannarao Dontula, Kal V. S. Sastry

Advances are made in the field of mineral processing on a continuing basis both in the industry and the academia. These advances do not always get used fully because of the inherent difficulties in the transfer of knowledge and reduction to practice. In recent years, knowledge engineering is being increasingly employed in other fields to overcome some of these difficulties. This paper presents a vision of how knowledge engineering can be applied to the benefit of the mineral processing industry and includes a discussion of associated principles, techniques, and advantages.

Jan 1, 1993