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Li Y.-B.,Taiyuan University of Technology | Yang Y.-K.,Taiyuan University of Technology | Kang T.-H.,Taiyuan University of Technology | Chai Z.-Y.,Taiyuan University of Technology | Lan Y.,Shenhua Wuhai Energy Co.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011

Aimed at the problems of coal spontaneous combustion of working face by fully mechanized sub-level caving mining in shallow inflammable thick coal seam, the conditions of the shallow depth based on the fire prevention was proposed, the characteristics of the inflammable outcrop and the large space, the more residual coal, the serious air leakage and other other aspects of the fully mechanized top coal caving for the shallow thick coal seam have been studied, a new mining method adapted to the outcrop mining or open-cutting extension to underground mining was introduced, the positive pressure ventilation , the backfills in buries and the roller compaction were expounded, the spontaneous combustion hazard zone in the goaf was determined, the comprehensive technology of fire prevention and extinguishment was conducted mainly with injection of nitrogen in the goaf and secondarily stifling by water or grouting. This prevented coal spontaneous combustion and protected the safety of the mine rescue team members. After several successful engineering practices, research have been adopted in Haibowan mining area, showing great theoretical and practical values to similar conditions in mining method and safety production.

Yang Y.,Taiyuan University of Technology | Kang T.,Taiyuan University of Technology | Lan Y.,Shenhua Wuhai Energy Co. | Li Y.,Taiyuan University of Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

Based on the conditions of #16 coal seam of Lutian coal mine, a new mining method adopting the roadway layout with L-shape is proposed and carried out successfully. The caving characteristics of the top coal and roof, the working resistances of the powered support, the subsidence and collapse rules of the ground surface, the backfill and the roller compaction technology and the other aspects of the fully-mechanized top coal caving for the shallow-buried thick coal seam are studied by field observation. The evolution of the roof rupture and collapse is analyzed. The mechanical model of arch and step voussoir beam combination is established. The movement law of overlying strata and the crushing mechanism of the top coal are revealed; and the powered support resistance formula for controlling roof stability is put forward. The study results show as follows: (1) The mining method of L-shaped working face is a kind of method with high efficiency, safety and high recovery; it is a meaningful reference to outcrop mining or transition from open-pit to underground mining. (2) It is feasible in technology to use fully-mechanized sublevel caving mining for the shallow-buried thick coal seam under the appropriate mining conditions. (3) The periodic weighting step distance increases with the increasing thickness of overlying strata. (4) The periodic weighting is obvious in the middle of working face. (5) The subsidence and collapse of the ground surface can be divided into 4 stages; the backfills and the roller compaction should be divided into 2 stages. (6) In order to enhance the stabilities of the roof and the coal wall, it is essential to increase the initial supporting force of powered support. The results can be referred for further studies in similar conditions.

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