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By S. L. Huang, J. D. Rockaway, N. B. Aughenbaugh

Shale has long been recognized for its tendency to swell when exposed to the atmosphere. Interaction of moisture with exposed shale strata can cause serious ground stabi1ity problems, since the initial strength of a shale is reduced if the material is sensitive to moisture variations. In this paper, the authors present a classification system to estimate the response of swelling generated within shales. This characterization of the swelling potential is based upon plasticity, susceptibility to moisture, mineralogical constituents of clay size particles, and fabric. Use of this classification system in conjunction with other existing rock properties tests will provide data for more rational engineering design.

Jan 1, 1986

By O. E. Brown

The measurement principle of the Coulter Counter for particle size analyses is described. The application of the Coulter Counter to cement particle content and size analysis and to the size distribution of clinker from standard grindability tests are described. Methods of calibration, sample preparation and data reduction are presented. The results of the analyses obtained are compared with characteristics associated with performance showing both concordance and non-concordance of test data., Future uses of the Coulter Counter for particle size analysis in research and plant control adaptations are indicated.

Jan 1, 1960

By Jan K. Wolski

This paper addresses jet fans used as booster fans within mine ventilation networks. The static pressure developed by the jet fan was determined using the momentum theory. The influence of various parameters on this pressure was analyzed. A method was proposed for determination of the jet fan characteristic curve . The distance between the jet fan and a point where the fully developed static pressure can be measured was determined. It was shown that a reduction cone can significantly improve the jet fan performance. Verification experiments conducted in the Waldo mine are described.

Jan 1, 1995

By A. H. Reitsema, Hans E. van Dam

In CIP, CIL, and Heap Leach gold recovery operations, a sub-optimal activated carbon performance invariably causes a significant loss of revenues. In this paper it is shown, how dedicated analyses of carbon samples can be used as a guide in plant performance optimiza­tion. Firstly, a brief outline is given of the most important methods of analyses, including the specialized methods not normally used by mining operations, but provided by carbon manufacturers. Then, a number of practical cases are discussed in which carbon sample analyses provided insight which allowed significant improvements.

Jan 1, 1995

By Richard R. Klimpel

This article introduces the basic definitions and philosophy behind process hazard evaluation procedures and the determination of risk as being a function of accident probabi1ity and accident consequence. The general concepts of good engineering practice and predictive hazard evaluation are discussed. The most commonly employed methods used in the processing industries are reviewed with an eye towards briefly presenting what each method offers as far as information, time and resources required, etc. Some initial references on the actual practical use of each technique in the processing industries are also given.

Jan 1, 1991

By E. R. Reeves

The mining industry has recognized the importance of engineering controls as a primary means of preventing hearing loss. The noise control treatments most commonly observed on drills and bolters during this study were windshields, sound absorbing material, and hydraulic motor covers. These controls were evaluated on machines at underground metal mines to determine the amount of noise reduction achieved by each control. The results indicate that absorbing material has very little effect on the noise level. The noise reduction attributable to the motor covers was dependent on the material used to create the cover. Properly installed windshields were the most consistent control.

Jan 1, 2004

By F. L. Jackson

When using perlite as an insulation, it is important to determine the requirements for different applications as this influences the processing of the perlite. In cryogenic application, perlite properties of low density and fine particle size are desirable, while loose fill insulation applications require similar properties and water repellency. However, in perlite insulating concrete applications, a coarser particle, of higher density, is required to provide improved compression strength. The essential properties of perlite including particle size, density, and surface treatment are discussed in relation to the various insulation applications. Also, typical mineral processing and manufacturing techniques are reviewed.

Jan 1, 1987

By Ian J. Corrans, Gary Johnson, John E. Angove

Activox® is a hydrometallurgical process used to oxidise sulphide concentrates. The process is based on two relatively simple, established unit operations; i.e. fine or ultra-fine milling (UFM) and pressure oxidation under mild conditions. An under-standing of, and ability to control the pulp chemistry during oxidation has resulted in the successful Activox® treatment ( on a batch scale) of a wide variety of sulphide flotation concentrates; • pyrite/arsenopyrite + gold • pyrite/chalcopyrite + gold • pyrite/chalcocite + gold • pyrite/enargite/tetrahedrite + gold Oxidation rates are rapid (1-2 hours retention time) and gold

Jan 1, 1995

By James Lonergan

This paper describes the application of the Graphics Assisted Under Ground Engineering (GAUGE) software to a 2-layered room and pillar hard rock mine. The graphics- assisted mine modeling and mine planning capabilities of GAUGE are demonstrated. The system uses polygons to model the room and pillar mine design and displays the model in plan view on the graphics screen,. The planning engineer interactively specifies areas to be mined in the medium or long term. The system calculates and accumulates tonnages and grades for the user-specified areas based on the layer being mined and the particular unit operation (drifting, widening or benching).

Jan 1, 1989

By Robert C. Schenk

The rapidly expanding, globally based mining industry provides many opportunities and challenges for the engineering construction business. This paper reviews some of the innovations that the industry is implementing to provide increased value in the design, construction, and successful start-up of new mine plant facilities. Approaches being taken to reduce installed-plant costs as well as related value-enhancement opportunities are discussed. Included are comments on new technology developments, use of automation and global communications networks, application of economic models as a project design tool, and management approaches being adopted to make the engineering construction process significantly more effective.

Jan 1, 1998

By A. D. Davis, D. J. Dixon, J. L. Sorenson, C. J. Webb, S. Dawadi

Limestone-based material appears to be an effective arsenic removal process that has great potential for source reduction in drinking water. Limestone-based material offers several benefits to the drinking water community: 1) reasonable removal efficiency as compared to material cost, 2) broad geographic and water system applicability, 3) compatibility with other water treatment processes, 4) ease of technical use, and 5) low-cost disposal in ordinary landfills. Batch and column experiments have evaluated the removal efficiency of several limestone types. Additives and material alteration have increased the removal efficiency. Granulation of powdered limestone as a filter media currently is being investigated.

Jan 1, 2006

By W. D. Mayercheck, A. G. Mayton, J. R. Bartels

Since 1982, the US Bureau of Mines has investigated improvements in protection for operators of thin seam shuttle cars. Due to working height restrictions in thin seam mines (=1.22 m or 48 in.). Federal mine regulations require that canopy protection on shuttle cars be provided only in mines =1.07 m (42 in.). However, court obtained variances are granted to mines =1 .22 m (48 in). This paper presents ongoing research to design and evaluate a uniquely positioned, ergonomic compartment for a shuttle car that provides the operator with full canopy protection in working heights of 1.02 m (40 in.).

Jan 1, 1990

By J. T. Gepford, K. A. Prisbrey, T. Scott, M. Spangler

Using neural networks for plant control is challenging. The objective was to show how to make a neural network effective, even with noise, lag times, and unmeasured disturbances in the plant. The procedure was to evaluate the neural network in a laboratory flotation vision system and in a plant refractory gold autoclave system. Although the resulting neural network easily conquered simple laboratory data, the noisy plant data was much more difficult, and adaptive linear models were equally effective. We concluded that the neural network needs support by combining it with other tools found in the best control packages.

Jan 1, 2000

By William J. Gregg

Mechanical testing results on oriented Devonian gas shale core throughout the Appalachian basin show a preferred fracture direction perpendicular to bedding. The preferred direction is generally parallel to the Allegheny Front, but is only coincidentally parallel with in-situ stresses in some areas of the basin. The strength of the preferred orientation of induced fractures decreases with distance from the Front. It is suggested that strain related to Paleozoic deformation is responsible for this mechanical fabric and thus the direction of induced fractures in laboratory tests may not be of use as indicators of in-situ stress orientations as previously suggested.

Jan 1, 1986

By James P. Rider, Charles D. Taylor, Edward D. Thimons

Research was conducted to investigate how ventilation of a mining face is affected when scrubber flow is greater or less than intake flow. Tests were conducted in a full-scale surface test gallery built to simulate a mining entry with a continuous mining ma- chine at the face. Methane gas was released at constant flow at the mining face. Gas measurements taken at six locations near the face were used to evaluate how well the face was being ventilated. Increasing scrubber flow resulted in lower methane levels even when scrubber flow was much greater than intake flow.

Jan 1, 1997

By Philip M. Rice, Paul Schmall, Peter W. Deming, Hugh S. Lacy

A groundwater cut-off is needed to provide a stable face of tunnels to be constructed by jacking precast rectangular tunnel segments beneath commuter rail tracks for the new I-90 extension in Boston, MA. Extensive obstructions are present within the path of the tunnels. This paper describes how the use of artificially frozen ground is being planned to provide a reliable groundwater cutoff and assure a stable tunnel face. Monitoring during freezing assures continuity of the cutoff. Laboratory testing of frozen soil samples aided the design of this frozen soil boundary. Logistics of installing vertical freeze pipes are described.

Jan 1, 1999

By G. H. Schnakenberg

In 1986, the US Bureau of Mines (USBM) embarked on a major research effort to develop technology that could substantially reduce worker exposure to face hazards by simply relocating the equipment operators to an area of relative safety. This reduced-exposure mining system (REMS) research effort enhances the USBM's ongoing health and safety efforts aimed at reducing and controlling dust and noise and reducing accidents through training and better mining practices. This paper reports on the progress made on the developing research and demonstrates the technologies required for the computer-assisted teleremote operation of continuous mining machines, haulage systems and roof bolting machines.

Jan 1, 1998

In addition to capital and operating costs, the accurate estimation of ore reserves is a key component to the successful outcome of any feasibility study. In recent years, there have been many project failures caused by the improper estimation of ore reserves. The accurate estimation of an ore reserve relies heavily on an understanding of the geology and the underlying assumptions unique to the estimation techniques being used. These assumptions are reviewed, and the shortcomings of the estimation techniques and their possible impact on a given project's economics are discussed. The latest developments in geostatistics in overcoming existing reserve-estimation problems are presented.

Jan 1, 1998

By G. H. Schnakenberg

In 1986, the US Bureau of Mines (USBM) embarked on a major research effort to develop technology that could substantially reduce worker exposure to face hazards by simply relocating the equipment operators to an area of relative safety. This reduced-exposure mining system (REMS) research effort enhances the USBM's ongoing health and safety efforts aimed at reducing and controlling dust and noise and reducing accidents through training and better mining practices. This paper reports on the progress made on the developing research and demonstrates the technologies required for the computer-assisted teleremote operation of continuous mining machines, haulage systems and roof bolting machines.

Jan 1, 1997

By J. M. Johnson, J. Vialpando, C. Lee

Since 1951, Molycorp has operated the Mountain Pass Mine in San Bernardino County, California to extract fourteen lanthanide elements, or rare earths, from a carbonate ore body. Wastes generated by the open pit mining operation consist of overburden and 1800 tpd of tailings. The tailings are classified as Group B mining wastes by California regulators. Paste tailings is one of several alternatives being considered during the permitting process for future mine operations. This paper presents the findings of study to assess the feasibility of using paste tailings to develop an unsaturated tailings stack instead of dilute slurry discharge behind a tailings dam.

Jan 1, 2004