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Groundwater and coal mining
254A
866313 Design and construction of the Soudan 2 detector laboratory Nelson. C R: Petersen, D L: Marshak. M Proc of the 1985 Rapid Excavation and Tunneling Conference, New York. 16-20 June 1985 VI. P135-154. Publ New York: .4IME 1985 Construction of a laboratory cavern 713m below surface at the Soudan Mine,in northeastern Minnesota. is underway. The location and planned usage (research in physics with greatly reduced interference from cosmic radiation) for the cavern present special excavation, lining, and outfitting requirements. The geologic conditions are proving as anticipated from the field investigation plan. Support needs are within the range expected in design and are being met with rock bolting and shotcrete designs.
Groundwater problems See also." 866221 866314 Groundwater and coal mining Brawner. C O 1Win Sei Technol V3. N3. April 1986. P187-198 Typical problems created by water during mining -environmental, operational and stability - are described. Water also causes stability problems with dams. dykes and spoil piles. particularly on dragline mining projects, Recommendations to deal with water-related difficulties are presented. Examples worldwide are referred to. Special consideration is given to methods of drainage and dewatering.
866315 Application of geophysical exploring methods for observing rock failure in the mining of coal seams menaced by waterbodies Liu Zongcai: Sun Zhengpcng; Gao Hang; Li Baiying; Yu Shijian: Li Jiaxiang: Zeng Ruihua In: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Alechanics. Rapid City, 26-28 June 1985) V2. P985-992. Publ Rotterdam: A. A. Balkema. 1985 Floor-water irruption has led to many regions of Ordivician karst-containing limestone in China being considered unmineable, The one man-made factor - mining effects - which can affect irruption was examined for two faces at mine 3 of the Jingxing Mining Bureau. The changes in floor and roof stress, convergence, the depth of damage to the floor and water irruption were monitored, at the face and away from it, whilst extraction by shortwall mining was taking place. Both geophysical and mechanical monitoring methods were used. Results suggested that little rock pressure was generated by mining, and model tests using simulated rock materials confirmed site data. It was concluded that shortwall mining may be safely used in these areas.
Surface subsidence, caving and rockbursts 866316 Analysis of field performance - the Thunder Bay tunnel Ng, R M C: Lo, K Y: Rowe, R K Can Geotech J V23 .VI. Feb 1986. P30-50 A numerical method for the calculation of the distribution of displacements for tunnelling in clays has been developed, The method employs an orthotropic elastic-perfectly plastic soil
model that takes into account various sources of ground loss and soil-lining interaction. Both undrained and drained analyses have been cart'ied out and the results are compared with the measured soil displacements of two instrumented arrays at the Thunder Bay tunnel. It is shown that the range of maximum settlements, the shape of settlement troughs, and the pore pressure change, as well as the magnitude and direction of spatial displacements obtained from the analyses, compare reasonably well with the results of field measurements for both short- and long-term conditions
866317 Potential for rock bursting and slabbing in deep caverns Dowding. C H: Andersson. C A Engng Geol V22. N3. April 1986. P265-279 An investigation is presented of the potential for rock bursts in deep, multiple caverns excavated in brittle, crystalline rock. Five case histories were uncovered where stresses and rock strength were either measured or could be inferred. These observations enabled a calculation of the ratio of maximum tangential stress at the opening to the unconfined compressive strength for each case. Stress concentrations around multiple storage caverns were calculated from two-dimensional, linear elastic, finite element models. The case histories and model studies were synthesized to develop a design recommendation and an understanding of the mechanisms causmg rock bursts.
866318 Subsidence prediction in shallow room-and pillar mines Missavage, R J; Chugh, Y P; Roscetti. T Int J Min Geol Engng 1/4. NI. March 1986. P39-46 A mathematical model was developed utilizing the relative flexural strength of the strata overlying a coal seam to predict the vulnerability of shallow room and pillar mined areas to subsidence. The model assumes the failure of the immediate roof as the precursor of a subsidence event, After the roof fails, either a sink hole subsidence event develops, if the unconsolidated material is thin and dry, or a subsidence trough forms if the unconsolidated material is thick and wet. The use of the model requires a knowledge of the local stratigraphy and approximate geotechnical properties of various roof layers. The model can be a significant mine planning tool to orient mine layout, for location of long life and short life workings, and for selection of safe extraction ratios in different areas of the mine.
866319 Mine subsidence hazard detection technique for Pennsylvania's anthracite coalfields Bhattacharya, S; Singh. M M; Moebs, N M In: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Mechanics, Rapid City, 26-28 June 1985) V2. P977-984. Publ Rotterdam." A. A. Balkema, 1985 The method adopted for screening sites and determining which sites it would be most appropriate to monitor for impending subsidence is described, together with the integrated monitoring plan for subsidence detection. The subsidence risk is determined by assessing the probability of subsidence, based on geological and mining procedure variables, and its consequences. The monitoring system adopted to locate anomalous activities used electromagnetic and ground penetrating radar surveys to identify near surface indicators of imminent collapse and the installation of tiltmeters to enable continuous momtoring.
~3 1986 Pergamon Journals Ltd. Reproduction not permitted
866313 Design and construction of the Soudan 2 detector laboratory Nelson. C R: Petersen, D L: Marshak. M Proc of the 1985 Rapid Excavation and Tunneling Conference, New York. 16-20 June 1985 VI. P135-154. Publ New York: .4IME 1985 Construction of a laboratory cavern 713m below surface at the Soudan Mine,in northeastern Minnesota. is underway. The location and planned usage (research in physics with greatly reduced interference from cosmic radiation) for the cavern present special excavation, lining, and outfitting requirements. The geologic conditions are proving as anticipated from the field investigation plan. Support needs are within the range expected in design and are being met with rock bolting and shotcrete designs.
Groundwater problems See also." 866221 866314 Groundwater and coal mining Brawner. C O 1Win Sei Technol V3. N3. April 1986. P187-198 Typical problems created by water during mining -environmental, operational and stability - are described. Water also causes stability problems with dams. dykes and spoil piles. particularly on dragline mining projects, Recommendations to deal with water-related difficulties are presented. Examples worldwide are referred to. Special consideration is given to methods of drainage and dewatering.
866315 Application of geophysical exploring methods for observing rock failure in the mining of coal seams menaced by waterbodies Liu Zongcai: Sun Zhengpcng; Gao Hang; Li Baiying; Yu Shijian: Li Jiaxiang: Zeng Ruihua In: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Alechanics. Rapid City, 26-28 June 1985) V2. P985-992. Publ Rotterdam: A. A. Balkema. 1985 Floor-water irruption has led to many regions of Ordivician karst-containing limestone in China being considered unmineable, The one man-made factor - mining effects - which can affect irruption was examined for two faces at mine 3 of the Jingxing Mining Bureau. The changes in floor and roof stress, convergence, the depth of damage to the floor and water irruption were monitored, at the face and away from it, whilst extraction by shortwall mining was taking place. Both geophysical and mechanical monitoring methods were used. Results suggested that little rock pressure was generated by mining, and model tests using simulated rock materials confirmed site data. It was concluded that shortwall mining may be safely used in these areas.
Surface subsidence, caving and rockbursts 866316 Analysis of field performance - the Thunder Bay tunnel Ng, R M C: Lo, K Y: Rowe, R K Can Geotech J V23 .VI. Feb 1986. P30-50 A numerical method for the calculation of the distribution of displacements for tunnelling in clays has been developed, The method employs an orthotropic elastic-perfectly plastic soil
model that takes into account various sources of ground loss and soil-lining interaction. Both undrained and drained analyses have been cart'ied out and the results are compared with the measured soil displacements of two instrumented arrays at the Thunder Bay tunnel. It is shown that the range of maximum settlements, the shape of settlement troughs, and the pore pressure change, as well as the magnitude and direction of spatial displacements obtained from the analyses, compare reasonably well with the results of field measurements for both short- and long-term conditions
866317 Potential for rock bursting and slabbing in deep caverns Dowding. C H: Andersson. C A Engng Geol V22. N3. April 1986. P265-279 An investigation is presented of the potential for rock bursts in deep, multiple caverns excavated in brittle, crystalline rock. Five case histories were uncovered where stresses and rock strength were either measured or could be inferred. These observations enabled a calculation of the ratio of maximum tangential stress at the opening to the unconfined compressive strength for each case. Stress concentrations around multiple storage caverns were calculated from two-dimensional, linear elastic, finite element models. The case histories and model studies were synthesized to develop a design recommendation and an understanding of the mechanisms causmg rock bursts.
866318 Subsidence prediction in shallow room-and pillar mines Missavage, R J; Chugh, Y P; Roscetti. T Int J Min Geol Engng 1/4. NI. March 1986. P39-46 A mathematical model was developed utilizing the relative flexural strength of the strata overlying a coal seam to predict the vulnerability of shallow room and pillar mined areas to subsidence. The model assumes the failure of the immediate roof as the precursor of a subsidence event, After the roof fails, either a sink hole subsidence event develops, if the unconsolidated material is thin and dry, or a subsidence trough forms if the unconsolidated material is thick and wet. The use of the model requires a knowledge of the local stratigraphy and approximate geotechnical properties of various roof layers. The model can be a significant mine planning tool to orient mine layout, for location of long life and short life workings, and for selection of safe extraction ratios in different areas of the mine.
866319 Mine subsidence hazard detection technique for Pennsylvania's anthracite coalfields Bhattacharya, S; Singh. M M; Moebs, N M In: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Mechanics, Rapid City, 26-28 June 1985) V2. P977-984. Publ Rotterdam." A. A. Balkema, 1985 The method adopted for screening sites and determining which sites it would be most appropriate to monitor for impending subsidence is described, together with the integrated monitoring plan for subsidence detection. The subsidence risk is determined by assessing the probability of subsidence, based on geological and mining procedure variables, and its consequences. The monitoring system adopted to locate anomalous activities used electromagnetic and ground penetrating radar surveys to identify near surface indicators of imminent collapse and the installation of tiltmeters to enable continuous momtoring.
~3 1986 Pergamon Journals Ltd. Reproduction not permitted