A study of the ground control effects of mining longwall faces into open or backfilled entries

被引:10
作者
Oyler D.C. [1 ]
Mark C. [1 ]
Dolinar D.R. [1 ]
Frith R.C. [2 ]
机构
[1] Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA
[2] Strata Engineering (Australia) Pty Ltd., Teralba, NSW
关键词
Coal mining; Ground control; Longwall; Recovery room;
D O I
10.1023/A:1016784325954
中图分类号
学科分类号
摘要
Unusual circumstances may require that a longwall retreat into or through a previously driven room. The operation can be completed successfully, but there have been a number of spectacular failures. To help determine what factors contribute to such failures, a comprehensive international database of 131 case histories has been compiled. The cases include six failures where major rock falls occurred in front of the shields, and seven even more serious failures involving major overburden weighting. The case studies suggest two types of room failure mechanism. The first is a roof fall type failure caused by loading of the immediate roof at the face as the fender or remnant longwall panel narrows. The second is an overburden weighting type failure caused by the inability of the roof to bridge the recovery room and face area, and affecting rock well above the immediate roof. The data indicate that the roof fall type of failure is less likely when intensive roof reinforcement (bolts, cables and trusses) is employed together with higher-capacity shields. The overburden weighting failures, in contrast, occured when the roof was weak and little standing support was used. Weighting failures were not greatly affected by the density of roof reinforcement. In one of the overburden weighting cases, in a Pittsburgh coalbed mine, stress cell, convergence, bolt load and extensometer data have been used to analyze the failure in detail.
引用
收藏
页码:137 / 168
页数:31
相关论文
共 21 条
  • [1] Bauer E.R., Listak J.M., Berdine M., Bookshar W., Raab D., Mucho T.P., Longwall recovery utilizing the open entry method and various cement-concrete supports, Proceedings of the 7th International Conference on Ground Control in Mining, pp. 30-42, (1988)
  • [2] Bauer E.R., Listak J.M., Berdine M., Assessment of Experimental Longwall Recovery Rooms for Increasing Productivity and Expediting Equipment Removal Operations, (1989)
  • [3] Bauer E.R., Listak J.M., Productivity and equipment removal enhancement using predriven longwall recovery rooms, Proceedings of the 1989 Multinational Conference on Mine Planning and Design, pp. 119-124, (1989)
  • [4] Bookshar W.B., Simpson P., Campoli A.A., Amick M.R., Stafford III F., Cuttable, variable yield, cement cribbing successfully support 84 mine longwall cut through entries, Proceedings of Longwall USA International Exhibition and Conference, pp. 69-89, (1998)
  • [5] Chen J., Mishra M., Cario S., DeMichiei J., Longwall mining-through the backfilled in-panel entries at Cyprus Emerald Mine, Proceedings of the 16th International Conference on Ground Control in Mining, pp. 1-8, (1997)
  • [6] Hendon G., Gateroad pillar extraction experience at Jim Walter resources, Proceedings of the 17th International Conference on Ground Control in Mining, pp. 1-10, (1998)
  • [7] Klenowski G., Philips R.N., Ward B., Strata control techniques for chock salvage, German Creek Mines, Queensland, Proceedings of the Bowen Basin Symposium, (1990)
  • [8] Listak J.M., Bauer E.R., Front abutment effects on supplemental support in predriven longwall equipment recovery rooms, Proceedings of the 30th US Symposium on Rock Mechanics, pp. 809-816, (1989)
  • [9] Minney D., Amcoal experience of longwalling through dykes, Proceedings of the 2nd International Underground Coal Conference, pp. 85-90, (1999)
  • [10] Molinda G.M., Mark C., Coal Mine Roof Rating (CMRR): A Practical Rock Mass Classification for Coal Mines, (1994)