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SME-ICGCM (1801)
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TITLE Effect of High Horizontal Stress on Coal Mine Entry Intersection Stability
SUMMARY This manuscript describes an extensive ground control study at the Inland Steel No. 2 Mine near McLeansboro, IL, conducted by the U.S. Department of the Interior's Bureau of Mines (USEM) in cooperation with Inland Steel Coal Co. The mine experiences severe ground control problem primarily due tohigh horizontal stress, particularly at entry intersections. Mine experience has shown that reorienting mine entries, modifying the bolting pattern, and altering the mining sequence are effective in reduc...
AUTHOR Hanna, K.
TITLE A Case Study of Longwall Roof-Supports Interaction
SUMMARY During the last two decades many research projects were conducted to study the load requirements for the powered supported longwall faces (1-6). Significant results had been achieved by these researches. Most of the previous studies were rarely designed to understand the mechanisms of interaction between the supportsand the surrounding rock, or to correlate the stress conditions around longwall faces to the mining operations both in time and space. In case of the shield supported faces, the r...
AUTHOR Wang, Y. H.
TITLE Development of A Yielding Steel Post
SUMMARY Ground support continues to be the most important safety consideration in underground mining. The Bureau of Mines has developed a yielding steel post with a capacity of 45 tons and b c1osure allowance of 24 inches in a 6 to 7 foot seam height. The post mechanism in a three piece unit consisting of a top and bottom leg made from standard steel pipe and a separate foot bracket. It develops its load carrying ability when the lower pipe, with an attached interference ring, is forced into the larger ...
AUTHOR Dunford, John P.
TITLE Optimization of the Stress Control Method to Improve Productivity and Safety in Underground Coal Mining
SUMMARY The Stress Control Method improves productivity and safety in underground coal mining. The method stabilizes the roofs and floors of mine openings in both shallow and deep coal beds, regardless of whether or not there are ground stability problems. This paper describes the means by which a tapered pillar experiment is used to collect in situ data, which is then used as input for a computer model. The resulting computer model is then used to optimize Stress Control design for the mine under study...
AUTHOR Serata, Shosei
TITLE Empirical Approach to Calculate Rock Loads in Coal Mine Roadways
SUMMARY In order to define the support parameters, by use of empirical approaches, it is particularly important to analyze the rock-load height that should be controlled by supports. The controlling mechanism however, depends on the type of support used there- fore, the rock loads should be treated differently. In this paper, an empirical equation is introduced which relates the rock-load height (ht) to a quantitative rock quality index (REIR), and roof span (B) as fallows:
AUTHOR Unal, Erdal, Dr.
TITLE Assessment of the Rockburst Proneness in Hard Rock Coal Mines
SUMMARY Rockburst is a sudden manifestation of the release of elastic strain energy stored in the rock. Therefore the tendency of the rock to burst should depend upon its ability to accumulate elastic strain energy. The use of Burst Proneness Index as a simple and reliable indicator to recognize the burst prone situations in the mines has been advocated in this study. The Burst Proneness Index exhibited a strong dependence upon the brittleness, compressional and shear wave velocities and the point l...
AUTHOR Singh, S. P.
TITLE A Study of Roof Caving in the Eastern U.S. Coalfields
SUMMARY Appropriate roof control is the most important requirement in underground coal mining and, in the case of longwall panels or second mining in room and pillar extractions, this can be simply expressed in terms of good and predictable roof caveability. Studies of roof caveability have been undertaken in many coalfields around the world. Most of their conclusions. however, are directly related to the mining and geological conditions experienced in these areas and as a result, may not be applica...
AUTHOR Agioutantis, Z.
TITLE Outburst Control in Underground Coal Mines,
SUMMARY Outbursts, the sudden and violent out- pouring of material into mine openings, is a ground control problem increasingly encountered in the United States as deeper seams are developed. Outbursts, caused by several mechanisms, are the result of the loading of ground support systems be- yond their designed capacity to failure, manifested in a violent release of stored energy. There are several types of outbursts typical to deep underground coal mines. - Outbursts ofthe coal face due to the ...
AUTHOR Varley, Floyd D.
TITLE A Simple Tool to Measure Stress in Mine Backfill
SUMMARY A cone penetrometer has been used to assess the level of stress existing in hydraulically placed mine backill. The test apparatus was fabricated at the mine and consisted of a steel cone, connector rods and a hydraulic jack. Testing was carried out from a manway passing through the centre of the stope. The cone was pushed horizontally into the fill, both at right angles and parallel to the orientation of the stope walls, and the resistance to penetration was measured. Corrections were made to al...
AUTHOR Robertson, A. MacG.
TITLE Designing for Upper Seam Stability in Multiple Seam Mining
SUMMARY Historically, the selection of mining sequence for multiple seam conditions has been based on many factors other than ground control considerations and minimization of interaction effects. Today, numerous operations are finding themselves mining above existing or abandoned operations, some of which exhibit large scale caving, pressure arches and subsidence troughs. Development of design criteria for the upper seam that would alleviate damage due to lower seam interaction effects can contribute s...