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Cutter roof and its causes
162A channeling, and later overwash crevasse splay deposits. A four-phase exploratory drilling program was initiated to confirm and further refine the depositional model. This resulted in a modification of the mining plan so that a more efficient and safer exploitation scheme for the coal reserves would be realized.
Stresses around underground openings See also." 874155, 874182 874265 Theoretical model examination of strata pressure distribution during winning On German) Kose, H Gluekauf-forschungsh V4& N1, Feb 1987. Pl7-22
described. This method is formulated by the three dimensional boundary element method, so that the three dimensional state of initial stress can be obtained. A case Study is presented here to demonstrate the applicability of this method. Auth. 874269 Loading on underground mine structures influenced by multiple seam interaction Kripakov, N P; Beckett, L A; Donato, D A Proc Symposium on Application o f Rock Characterization Techniques in Mine Design, New Orleans, March 1986 P225236. Publ Littleton: AIME, 1986
Strata pressure distributions around a face were computed using finite element analysis, and compared with in situ measurements, Vertical faults were taken into account in the calculations. Results agreed with the theory of the plastic trough (Jacobi, 1981). Additional pressure was seen at the face, but not on the seam. The magnitude of the additional pressure is influenced by stowing, panel length, and vertical faults.
A design procedure to estimate the continually changing load distributions that occur on underground support structures as mining advances is presented. The effects of seam interaction and the influence of a gob model are included. The technical approach incorporates two numerical modelling techniques: the displacement-discontinuity approach and the finite e!e, ment method. Five face positions are modelled representing mining of two adjacent longwall panels affected by multi-seam interaction. The resulting change in loading on a chain pil!a r separating the panels is determined analytically and by field instrumentation. The modelling results Compare favourabty to the field measurements.
874266 Stress distribution and parameter optimization during undercutting of a block caving m i n ~ method (In Chinese) Wang Yongguang; Song Xiaotian Nonferrous Metals I,'38, Nov 1986, PI-IO
874270 Three dimensional stress changes in pillars during Iongwall mining at Etlalong colliery Wold, M B; Pala, J CSIRO Division of Geomechanics report N65, Aug t986, 44P
Stress distribution during undercutting at the Tonkuangyu Copper Mine was studied by boundary element analysis. The influence of undercut dimensions, height of the production level, and drawpoint spacing on stress concentration around a production level are discussed. The influence of the undercut parameter on the cavabitity index and opening stability is analysed. Linear programming is used to optimise the caving parameter, taking into account rock cavability, stope stability and the cost of drilling and support.
In an attempt to clarify the mechanism of load transfer for the strong sandstone roof overlying the:caving z0ne. stress conditions in pillars and roadway closures were monitored as mining progressed. Three dimensional stress changes were measured using the CSIRO hollow inclusion cell and vertical stresses measured using I R A D gauges~ Results are compared with two and three dimensional numerical modelling. Good agreement was found between field measurements and three dimensional modelling in the early stages, until passage of the longwall face. Reasons for the divergence of predicted and observed behaviour, and design implications for longwalt mining at Ellalong are discussed.
874267 Stress changes near the face of underground excavations Kaiser, P K; Korpach, D Proc International Symposium on Rock Stress and Rock Stress Measurement, Stockholm, 1-3 Sept 1986 P635.645. Publ Lulea." Centek, 1986 An innovative approach for the determination of the in situ stress field during the construction of a shaft and a tunnel is evaluated. The stress changes that resulted during face advance were recorded by stiff inclusions measuring uniaxial stress changes. From these stress change measurements it was possible to calculate the in situ stress field. Two case histories and the data interpretatio n are discussed, together with an evaluation of the optimum instrument locations. Some long term measurements are also presented. Auth.
874268 Initial stress back analyzed from displacements due to underground excavations Sakurai, S; Shimizu, N Proc International Symposium on Rock Stress and Rock Stress Measurement, Stockholm, 1-3 Sept 1986 P679-686. Publ Lulea: Centek, 1986 A back analysis method for determining the initial stress and elastic constants of the ground, using the displacements measured during the excavation of underground openings, is
Avail: CSIRO Division of Geomechanics, PO Box 54, Mt Waverley, Vic 3149, Australia
Underground excavation failure mechanisms 874271 Cutter roof and its causes Su, W H; Peng, S S Min Sci Technol V4, N2, Jan 1987, Pl13-132 The intrinsic mechanisms of cutter roof failures are examined using data from field investigations, laboratory' tests, underground instrumentation, and numerical modeltingi Cutter roof occurred during the development of a set of tongwaii panel entries in a West Virginia coal mine, and this is presented as a case study. Mining alternatives applicable to the mine are rec, ommended. Cutter roof occurrences in two other West Virginia coal mines were also investigated. Comparisons were made between the three cases. Three dimensional finite element analyses were used to validate the cutter roof mechanisms. As a result of the investigation, intrinsic mechanisms Of cutter roof failures under various conditions are presented and mining alternatives for controlling cutter roof are recommended.
© 1987 Pergamon Journals Ltd. Reproduction not permitted
Stresses around underground openings See also." 874155, 874182 874265 Theoretical model examination of strata pressure distribution during winning On German) Kose, H Gluekauf-forschungsh V4& N1, Feb 1987. Pl7-22
described. This method is formulated by the three dimensional boundary element method, so that the three dimensional state of initial stress can be obtained. A case Study is presented here to demonstrate the applicability of this method. Auth. 874269 Loading on underground mine structures influenced by multiple seam interaction Kripakov, N P; Beckett, L A; Donato, D A Proc Symposium on Application o f Rock Characterization Techniques in Mine Design, New Orleans, March 1986 P225236. Publ Littleton: AIME, 1986
Strata pressure distributions around a face were computed using finite element analysis, and compared with in situ measurements, Vertical faults were taken into account in the calculations. Results agreed with the theory of the plastic trough (Jacobi, 1981). Additional pressure was seen at the face, but not on the seam. The magnitude of the additional pressure is influenced by stowing, panel length, and vertical faults.
A design procedure to estimate the continually changing load distributions that occur on underground support structures as mining advances is presented. The effects of seam interaction and the influence of a gob model are included. The technical approach incorporates two numerical modelling techniques: the displacement-discontinuity approach and the finite e!e, ment method. Five face positions are modelled representing mining of two adjacent longwall panels affected by multi-seam interaction. The resulting change in loading on a chain pil!a r separating the panels is determined analytically and by field instrumentation. The modelling results Compare favourabty to the field measurements.
874266 Stress distribution and parameter optimization during undercutting of a block caving m i n ~ method (In Chinese) Wang Yongguang; Song Xiaotian Nonferrous Metals I,'38, Nov 1986, PI-IO
874270 Three dimensional stress changes in pillars during Iongwall mining at Etlalong colliery Wold, M B; Pala, J CSIRO Division of Geomechanics report N65, Aug t986, 44P
Stress distribution during undercutting at the Tonkuangyu Copper Mine was studied by boundary element analysis. The influence of undercut dimensions, height of the production level, and drawpoint spacing on stress concentration around a production level are discussed. The influence of the undercut parameter on the cavabitity index and opening stability is analysed. Linear programming is used to optimise the caving parameter, taking into account rock cavability, stope stability and the cost of drilling and support.
In an attempt to clarify the mechanism of load transfer for the strong sandstone roof overlying the:caving z0ne. stress conditions in pillars and roadway closures were monitored as mining progressed. Three dimensional stress changes were measured using the CSIRO hollow inclusion cell and vertical stresses measured using I R A D gauges~ Results are compared with two and three dimensional numerical modelling. Good agreement was found between field measurements and three dimensional modelling in the early stages, until passage of the longwall face. Reasons for the divergence of predicted and observed behaviour, and design implications for longwalt mining at Ellalong are discussed.
874267 Stress changes near the face of underground excavations Kaiser, P K; Korpach, D Proc International Symposium on Rock Stress and Rock Stress Measurement, Stockholm, 1-3 Sept 1986 P635.645. Publ Lulea." Centek, 1986 An innovative approach for the determination of the in situ stress field during the construction of a shaft and a tunnel is evaluated. The stress changes that resulted during face advance were recorded by stiff inclusions measuring uniaxial stress changes. From these stress change measurements it was possible to calculate the in situ stress field. Two case histories and the data interpretatio n are discussed, together with an evaluation of the optimum instrument locations. Some long term measurements are also presented. Auth.
874268 Initial stress back analyzed from displacements due to underground excavations Sakurai, S; Shimizu, N Proc International Symposium on Rock Stress and Rock Stress Measurement, Stockholm, 1-3 Sept 1986 P679-686. Publ Lulea: Centek, 1986 A back analysis method for determining the initial stress and elastic constants of the ground, using the displacements measured during the excavation of underground openings, is
Avail: CSIRO Division of Geomechanics, PO Box 54, Mt Waverley, Vic 3149, Australia
Underground excavation failure mechanisms 874271 Cutter roof and its causes Su, W H; Peng, S S Min Sci Technol V4, N2, Jan 1987, Pl13-132 The intrinsic mechanisms of cutter roof failures are examined using data from field investigations, laboratory' tests, underground instrumentation, and numerical modeltingi Cutter roof occurred during the development of a set of tongwaii panel entries in a West Virginia coal mine, and this is presented as a case study. Mining alternatives applicable to the mine are rec, ommended. Cutter roof occurrences in two other West Virginia coal mines were also investigated. Comparisons were made between the three cases. Three dimensional finite element analyses were used to validate the cutter roof mechanisms. As a result of the investigation, intrinsic mechanisms Of cutter roof failures under various conditions are presented and mining alternatives for controlling cutter roof are recommended.
© 1987 Pergamon Journals Ltd. Reproduction not permitted