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By D. K. Sitler

Continuing advancements in manufactured diamond materials as used in rock cutting tools have created a new generation of high production tools for mining. This paper reviews the three major manufactured diamond product types available in the mining industry as supplied by General Electric Co., Specialty Materials Dept., and examines the ways these materials are used. As an integral part of this examination, the economic impact of manufactured diamond tools is evaluuted. Time and again, one will find that the premium price for these tools is economically justified when compared to traditional tools.

Jan 1, 1988

By J. H. Desautels

The modern coal mining industry is subject to a vast array of regulations affecting virtually all aspects of its operations. Probably the most significant over-sight role involves the Office of Surface Mining Reclamation and Enforcement (OSH) established by the Surface Mining Control and Reclamation Act, or SHCRA.1 Although complying and coping with SHCRA can be difficult for coal operators, this complex regulatory process has helped insulate the industry from ongoing efforts to extend regulation under the Resource Conservation and Recovery Act, or RCRA, 2 to aspects of the mining industry in general. The Environ-mental Protection Agency (EPA) has struggled with regulation of mining wastes under RCRA since the mid-1970's, but RCRA itself places most coal mining wastes firmly under the control of OSH and SHCRA. Despite the general exemption from RCRA regulation for waste materials that result from extraction and processing of coal itself, there may be circumstances under which coal mining operators could find themselves subject to regulation under RCRA or a number of other statutes administered by EPA. This paper will review briefly the history of mine waste regulation under RCRA, as well as touch on the policy decisions that led to the exemptions from RCRA regulation. The paper will summarize coal waste requirements under SHCRA, and also will review what operations at coal mines need to be controlled, in order to avoid potential liability under RCRA. In addition, it will mention requirements under other federal laws, including CERCLA, or the "Superfund" law,3 and describe how they may impose restrictions or liability on coal operations for waste or other materials commonly found at surface and underground coal mines.

Jan 1, 1993

By Raphael G. Kazmann

The predicted warming of the earth's surface, presently the subject of much debate, controversy and legislation, is based on what is termed "the greenhouse effect." This is the result of the property of certain atmospheric gases. These gases allow the passage of radiant energy to the earth's surface and reflect back, to the earth, the infrared radiation given out by the heated surface. Physicists have computed that if there were no greenhouse effect the average temperature of the earth, now about 15° C (60T), would be close to -18° C (OT). Just what gases have produced this salubrious effect? Water vapor is the most important. Then come carbon dioxide, methane and a number of minor constituents of the atmosphere, both natural and man-made. Climate change, its cause and its impact on human activities have been the subject of scientific and historical study for more than a century. Recently, some scientists have concluded that if the man-made increase in the carbon dioxide and other greenhouse gases continues, by the late 21st century the earth's global average temperature will rise between 2° to 8° F. This temperature rise would cause the water in the oceans to expand and the massive polar glaciers to melt. In 1980, it was predicted that the sea level would rise 7.6 m (25 ft) by the late 21st century. By 1985, the predicted rise was 1 m (3 ft); and by 1989, it was 0.3 m (1 ft) (Jastrow, Nierenberg and Seitz, 1990). Agricultural scientists have pointed out that an increase in atmospheric carbon dioxide would enhance biological growth including the production of foodstuffs.

Jan 1, 1992

By John A. Herbst

In recent years, diminishing supplies of high grade ores and increasing consumption of mineral and metal products have demanded high efficiencies in extraction processes. The rising cost of energy has influenced plant operating policies. Rather than merely processing as much ore as possible, other process factors are being considered in process analysis, with energy consumed per ton of product produced taking on increased importance. Alternate processes and more efficient plant design may satisfy part of the demand placed on the mineral processing industries. However it is expected that the improvement of existing operatives will be responsible for most of the gains in efficiency in the short term. Even slight improvements in process efficiency lead to significant cost saving. Grinding, for example, is an inherently energy-intensive process. Grinding circuit capital and operating costs are high and it is essential that circuits run as efficiently as possible. In flotation plants, low-grade ores demand optimum recovery of valuables to maintain overall metallurgical efficiency. The use of modern data, treatment methods and systems analysis provide the means to achieve many goals, previously beyond reach. The design of more efficient plants and the evaluation and. improvement of existing plant operations constitute the general area of process analysis. Process analysis can be used to identify the capacity available in a process unit in some cases. In other cases, the goal may be to investigate alternative equipment configurations for an existing plant for possible improvement in efficiency. This goal is virtually impossible to achieve using plant data alone. A simulator of the process units involved can provide an excellent basis for performing the required process analysis.

Jan 1, 1979

By Gary Krix

The Amdel Thickener Interface Gauge (TIG) provides continuous on-line measurement of the level of the liquid/solid interface in thickeners and Counter Current Decantation (CCD) washers. Unlike other interface level measurement systems, the TIG also determines the span of the transition zone. The transition zone is the region between the clear liquid overflow zone and the compressed solids zone. The Thickener Interface Gauge determines the level of the interface by measuring the natural radioactivity of the solids in the thickener tank using an array of up to twelve detectors mounted vertically in a stainless steel probe. All solids contain low levels of natural radioactivity while the liquid phase generally does not. The concentration of natural radioactivity at each level in the thickener therefore depends on the concentration of solids. The radiation emitted by the solids is converted to electrical pulses by the detectors in the probe and the pulse-rate provides an accurate measurement of the density. A typical count-rate profile is presented in Figure 1. The vertical axis indicates the depth in the tank referenced to the surface of the liquid. The horizontal axis indicates the count-rate measured by the TIG probe, this count-rate is proportional to the density and can be used to determine the settling rate. The count-rate at the top of the graph is relatively low, this region corresponds to the clear overflow zone which contains virtually no solids. Moving down the vertical axis the count-rate increases dramatically at the level of the transition zone where the solids content increases with the depth in the tank. In this region the settling conditions of the solid particles change from free settling to compression. Moving further down the vertical axis the count-rate reaches a plateau where the count-rate remains relatively constant although there are often small fluctuations, this region corresponds to the solids compression zone. The liquid/solid interface as measured by the TIG corresponds to the depth at which the count-rate crosses the target count-rate which is generally selected to be midway between the liquid count-rate and the compressed solids count-rate. The length of the TIG probe is selected to cover the typical operating range of the liquid/solid interface in the thickener or washer. If, for example, the minimum bed level is 3.0 metres below the surface of the liquid then the probe length is selected to extend 30 metres below the surface. The TIG probe can include up to twelve detectors and the se are spaced over the measurement range. For small measurement ranges of around one metre 4 to 6 detectors would normally be used while for larger measurement ranges of three metres or more twelve detectors would be supplied.

Jan 1, 1993

By Taghi Sherizadeh, Paul Brooks, Dogukan Guner, Samuel Nowak

Large excavations are well known to result in rock mass deformations which can present challenging situations for mine personnel. Most of the currently available ground movement monitoring devices fail to adequately provide mine operators with highly accurate and meaningful insights into rock mass deformation or displacement. The use of distributed fiber optic sensors (DFOS) in industries such as oil and gas and civil engineering has shown the potential of these sensors to deliver real-time, highly accurate, and long-range distributed strain measurements with great success. However, the use of these sensors in underground mining is limited to a few case studies.

By R. J. Piniazkiewicz

Talc orebodies are mined in Asia, Australia, Europe, North America, and South America. Operators in North America must be efficient quality suppliers to thrive in a talc market in which many overseas suppliers have advantages such as lower hourly wages, shorter distances to ports, and less government regulation and intervention. Continuous improvement through teamwork and innovation is needed in the following areas to thrive amidst worldwide competition: 1) Maximization of the in-place value of ore. 2) Research and development to yield new processes and products. 3) Safe productivity. 4) Involvement in legislative processes. 5) Wellness programs to lower health care costs.

Jan 1, 1993

By Olivier Martin

In busy and historic cities, traditional open box metro stations are becoming outrageously difficult, unacceptable for the citizen and uneconomical. Hybrid stations provide an interesting alternative. In-house experience of Gautrain (South Africa), West bay (Qatar), Cairo line 3A (Egypt), and Melbourne (Australia) all aim to reduce disturbance to the city and its inhabitants during construction. Constructed in rock or in deep soil under water table, they take advantages of the latest construction techniques from cement grouting to freezing, and from traditional excavation of cavern to large tunnels constructed by sophisticated tunnel boring machines (TBM). Today, they form the ultimate construction challenge.

Jun 13, 2021

By S. S. Szoke

The concrete masonry industry, represented by the National Concrete Masonry Association has significantly expanded its markets since the industry's inception. The concrete masonry industry has developed and refined concrete masonry units by producing a variety of quality products on automated machines. In the sixties, architectural concrete masonry units gained popularity. In the seventies, the concrete paver market expanded. In the eighties, segmental retaining wall units became popular. The industry continues to research and develop new products and applications for concrete masonry to satisfy the needs of designers, specifiers, installers and owners. Both existing and innovative technologies in the concrete masonry industry are discussed.

Jan 1, 1993

By Nico Sutmoller, Rich Palladino

Underground voids present a unique geotechnical engineering challenge. This paper will address materials and transportation mediums that are typically used for backfilling underground voids with native material. After reviewing traditional backfill and transportation methods, this paper will explore the advancing technology of foam transportation and the advantages of using this technology for transporting fill materials into underground voids to backfill them with Liquid-Sand. The paper will also review the benefits that Liquid-Sand brings to these applications and highlight specific case studies in which foam transportation has proven effective and provided cost-effective, environmental benefits.

Feb 1, 2025

By M. L. Clark

Advances in the recovery of gold from heap leaching are being made daily, but of all the systems vital to the maximum recovery of gold from a leach pile, none is more important than the methods used to construct the pile in preparation for the leaching operation. The technology described in this paper illustrates the latest systems developed to minimize compaction in the pile during its construction and reduce the cost of placement of ore on the pile. The Florida Canyon Mine of Pegasus is evaluated in detail to show reasons for its high degree of success to date.

Jan 1, 1988

By D. C. McIntire

The Homer City Station, jointly owned by New York State Electric and Gas Corporation and Pennsylvania Electric Company is a three unit coal fired station. The first two units were put into commercial operation in 1969; the third unit became commercial in 1977. Units 1 and 2 are subject to the Pennsylvania State Implementation Plan (SIP) emission limit of 3.7 pounds of S02 per million BTU. Unit 3, having started construction later, is subject to the Clean Air Act, New Source Performance Standards emission levels of 1.2 pounds of 50-2 per million BTU.

Jan 1, 1988

Research has determined that ground control interaction problems in mining over a previously mined seam occur primarily in the tension zone created at the edge of the subsidence trough, and in areas above lower seam remnant pillars. Based on empirical and analytical studies, planning options for improving conditions on the upper seam have been developed to optimize extraction while minimizing the negative effects of seam interactions. These options include prediction of potential upper seam damage, guidelines for minimizing inevitable negative interaction effects, and recommended opening and pillar sizes, shape, and orientations, as well as design and planning procedures.

Jan 1, 1988

By D. L. Kuck

Water ice pillars far underground mine roof support can be frozen and/or maintained and/or melted on demand. The system to do this consists of a refrigeration brine chiller, brine circulation system and disposable plastic containers. Fusion expansion, resilience to dynamic loads, plastic deformation under stress, and non-contamination of coal or ore are unique properties of ice. Lower labor and material costs are economic advantages of ice far mine structural support. Ice brattices can become ice pillars on retreat. For safety, ice pillars can be placed (by remote control, if necessary) in hazardous sites without human entry.

Jan 1, 1988

By Daniel R. Hack

Mine planning software companies have recently focused some resources on the development of industrial minerals packages useful in the aggregate industry, which is years behind other mining industry sectors in the use of computer-based planning techniques. This paper presents and compares characteristics of aggregate / quarrying software packages currently on the market, each product having strengths beneficial under different circumstances. To be successful, the developers must confront the limitations of their packages under a variety of situations, address the unique characteristics of the aggregate industry, and pay particular attention to the applicability of their products in real situations.

Jan 1, 2002

By S. K. Mishra, R. L. Lytton, D. Sinn, D. Saylak

Calcium chloride is widely used for dust control on unpaved roadway surfaces, in base course stabilization, full depth reclamation and for total reconstruction of asphalt roads. Fly ash produced from coal-burning electric power plants have also been used in road construction. This paper examines the synergistic effect of calcium chloride and fly ash on compaction density and strength development of unpaved roadways. A mathematical model has been developed which provides excellent agreement with the experimental data. Based on these results, the potential of calcium chloride - fly ash treatments for typical mine road construction is discussed.

Jan 1, 2004

By D. M. Bodily, R. Jin, W. Hu

Four methods to assess the relative floatability of fine coal have been tested: flotation with frother only, salt flotation, timed-release analysis, and flotation with frother and collector. A practical and simple criterion that combines the separation efficiency (capacity factor) and kinetic rate constant (intensity factor) has been suggested. Five coal Samples from Utah were tested. Based on test results, it was concluded that the floatability test with collector and frother is closer to practice, and according to the suggested floatability criterion, coal fines can be classified into four categories of relative floatability: very easy, easy, moderate, and difficult.

Jan 1, 1988

By V. K. Karra

Research by various workers has shown compressive comminution to be significantly more efficient than impact comminution. Based on the work being done at Nordberg, wet compressive crushing in cone crushers producing finer and finer products, shows the feasibility for partial substitution of conventional tumbling mills. For further substitution, major challenges are processing of fine feed slurries in cone crushers to realize a significant size reduction of the particles, and understanding the limitation of the gyratory type units in terms of finest product achievable. The paper addresses the challenges involved, efforts at Nordberg, and the implications to conventional comminution flowsheets.

Jan 1, 1989

By Andy W. Stephens, William H. Langer

In Australia and America, encroachment by conflicting land uses, zoning restrictions, and the "not in my backyard" syndrome make it increasingly difficult to access high-quality aggregate resources located near the market areas. Attempts by government agencies in America to protect aggregate resources for future development have met with varying degrees of success. The State of Queensland, Australia, designates aggregate resource areas as Key Resource Areas, which protect the resource and the routes to transport the resource, provide a separation area from incompatible land uses, and indicate the likelihood that the area is free from conflicting social or environmental issues.

Jan 1, 2005

By M. J. Sapko

The US Bureau of Mines conducted, through joint funding with the Colorado Mining Association, large scale oil shale rubble fire tests to investigate flammability characteristics and different methods of extinguishment. Ignition of large rubble piles was easily accomplished. Foam blankets could he used to control surface flames. The results of these large scale tests confirmed that water was effective but not particularly efficient in extinguishing deep seated oil shale fires. It took up to 1.7 times as much water to extinguish afire as anticipated on the basis of a simple cooling model, assuming 100% utilization.

Jan 1, 1990