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Some factors to consider when selecting mining equipment for a typical opencast coal mine in the Witbank area
42A 891334 Studies on passive resistance development in saturated expansive soil Katti, D R; Katti. R K Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 VI, P61-66. Publ Rotterdam: A A Balkema, 1988 Lateral pressure variation with depth under the passive condition was evaluated for air dried black cotton soil, placed by controlled pouring or compacted, and saturated black cotton soil. A large scale laboratory tank device, with a rigid wall which was rotated from 5 minutes to 7.5 degrees into the soil mass, was used. Results are presented and discussed. 891335 Effect of CNS on active pressure development in expansive soils Moza, K K; Katti, R K; Katti, D R Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 VI, P71-78. Publ Rotterdam: A A Balkema, 1988 The use of a cohesive non-swelling (CNS) soil layer between retaining wall and expansive backfill to mitigate effects of high lateral pressures developed in the fill has been investigated in large scale laboratory trials. Lateral pressure development on fill saturation was studied under various conditions of wall rotation away from the fill. The use of the CNS layer is seen to be helpful in preventing transmission of the high lateral pressures developed in the fill. Lateral pressure equations are developed, based on the self-equilibrating depth concept. 891336 Role of CNS on passive resistance of saturated expansive soil Katti, D R Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 VI, P83-89. Publ Rotterdam: A A Balkema, 1988 Large scale laboratory studies were used to investigate the use of a cohesive non-swelling (CNS) layer to counteract swelling and swelling pressure effects of expansive backfill under various conditions of rotation of the wall towards the fill. Passive resistance in saturated expansive soil was seen to be greater than the external force applied through the jacks. The CNS layer significantly reduced lateral pressure on the wall.
Construction methods 891337 Some factors to consider when selecting mining equipment for a typical opencast coal mine in the Witbank area Fourie, G A Proc International Conference of the South African Institute of Mining and Metallurgy: Planning and Operation of Openpit and Strip Mines, Pretoria, 9-13 April 1984 P351-361. Publ Johannesburg: South African Institute of Mining and Metallurgy, 1986 The geology of the Witbank area is first described: soft overburden underlain by sandstone and siltstone, and five seams split by sandstone partings. Suitable equipment for removal of soft overburden, overburden drilling, blasting, and stripping, and coal mining is described, the proposed equipment and mining methods being selected on geomechanical property and economic grounds.
Groundwater problems 891338 Modern ground failure in the Garlock fault zone, Fremont Valley, California Pampeyan, E H; Holzer, T L; Clark, M M Bull Geol Soc Am VIO0, ?/5. May 1988, P677-691 Modem ground failure, ranging from scarps to tension cracks, in the Fremont valley is restricted to an area underlain by unconsolidated alluvium from which large quantities of groundwater have been withdrawn. The relation between ground failure and groundwater withdrawal was investigated by mapping the failures and monitoring via repeated precise surveys of closely spaced permanent bench marks. Differential displacement across the failures and strain fields in the general vicinity of failures were monitored. Groundwater hydrology and subsidence are described. Results suggest that failures were caused by water level decline rather than natural tectonics. 891339 Modelling of flow through potash tailings piles Wong, D K H; Barbour, S L; Fredlund, D G Can Geotech J V25, N2, May 1988, P292-306 In situ infiltration tests and laboratory tests to determine index properties were undertaken to define the saturated and unsaturated properties of potash mine tailings. A numerical simulation of infiltration of brine through tailings during a trench infiltration test was performed using a transient saturatedunsaturated finite element flow model to verify the application of the model to flow of brine in tailings,and examine the applicability of measured fluid content versus suction curves and calculated permeability functions. Calculated and measured values show good agreement. 891340 Temporal model for landslide risk based on historical precipitation Miller, S M Math Geol V20, N5, July 1988, P529-542 Precipitation can be an important factor in short term slope stability. A method to obtain time based predictions of slope stability is presented. The method is developed from extreme value probability analysis, such as Monte Carlo simulation, which incorporates historical precipitation data into ground water response and geotechnical slope stability analyses. 891341 Griffin Coal's Muja Open Cut - multiple ~ seam mining over abandoned underground workings in severe hydrological systems Calnan, R T; Evans, A W Proc International Conference of the South African Institute of Mining and Metallurgy: Planning and Operntime of Openpit and Strip Mines, Pretoria, 9-13 April 1984 P283-292. Publ Johannesburg: South African Institute of Mining and Metallurgy, 1986 Mining in a fully charged artesian basin in an area formerly worked by deep mine methods is described. The geology and hydrology are illustrated. The program utilising production, dewatering, drainage, sump,and pressure relief wells to enable working in acceptably dry conditions is described. Mine operation, overburden and coal removal, and safety precautions related to the abandoned bord and pillar workings are also discussed.
© 1989 Pergamon Press plc. Reproduction not permitted
Construction methods 891337 Some factors to consider when selecting mining equipment for a typical opencast coal mine in the Witbank area Fourie, G A Proc International Conference of the South African Institute of Mining and Metallurgy: Planning and Operation of Openpit and Strip Mines, Pretoria, 9-13 April 1984 P351-361. Publ Johannesburg: South African Institute of Mining and Metallurgy, 1986 The geology of the Witbank area is first described: soft overburden underlain by sandstone and siltstone, and five seams split by sandstone partings. Suitable equipment for removal of soft overburden, overburden drilling, blasting, and stripping, and coal mining is described, the proposed equipment and mining methods being selected on geomechanical property and economic grounds.
Groundwater problems 891338 Modern ground failure in the Garlock fault zone, Fremont Valley, California Pampeyan, E H; Holzer, T L; Clark, M M Bull Geol Soc Am VIO0, ?/5. May 1988, P677-691 Modem ground failure, ranging from scarps to tension cracks, in the Fremont valley is restricted to an area underlain by unconsolidated alluvium from which large quantities of groundwater have been withdrawn. The relation between ground failure and groundwater withdrawal was investigated by mapping the failures and monitoring via repeated precise surveys of closely spaced permanent bench marks. Differential displacement across the failures and strain fields in the general vicinity of failures were monitored. Groundwater hydrology and subsidence are described. Results suggest that failures were caused by water level decline rather than natural tectonics. 891339 Modelling of flow through potash tailings piles Wong, D K H; Barbour, S L; Fredlund, D G Can Geotech J V25, N2, May 1988, P292-306 In situ infiltration tests and laboratory tests to determine index properties were undertaken to define the saturated and unsaturated properties of potash mine tailings. A numerical simulation of infiltration of brine through tailings during a trench infiltration test was performed using a transient saturatedunsaturated finite element flow model to verify the application of the model to flow of brine in tailings,and examine the applicability of measured fluid content versus suction curves and calculated permeability functions. Calculated and measured values show good agreement. 891340 Temporal model for landslide risk based on historical precipitation Miller, S M Math Geol V20, N5, July 1988, P529-542 Precipitation can be an important factor in short term slope stability. A method to obtain time based predictions of slope stability is presented. The method is developed from extreme value probability analysis, such as Monte Carlo simulation, which incorporates historical precipitation data into ground water response and geotechnical slope stability analyses. 891341 Griffin Coal's Muja Open Cut - multiple ~ seam mining over abandoned underground workings in severe hydrological systems Calnan, R T; Evans, A W Proc International Conference of the South African Institute of Mining and Metallurgy: Planning and Operntime of Openpit and Strip Mines, Pretoria, 9-13 April 1984 P283-292. Publ Johannesburg: South African Institute of Mining and Metallurgy, 1986 Mining in a fully charged artesian basin in an area formerly worked by deep mine methods is described. The geology and hydrology are illustrated. The program utilising production, dewatering, drainage, sump,and pressure relief wells to enable working in acceptably dry conditions is described. Mine operation, overburden and coal removal, and safety precautions related to the abandoned bord and pillar workings are also discussed.
© 1989 Pergamon Press plc. Reproduction not permitted