| China’s metal mines and nonmetal mines posses slowly inclined medium thick ore body, the Angle is about 5 °~30 °,the thickness is about 5m ~ 15 m.Slowly inclined medium thick difficult mining body is characterized by mining technology in stope mining process, ore handling, stability of stope roof and selection of mining method. Due to the differences in their respective mining technical condition, there is no fixed suitable mining method for this kind of orebody stoping, which hadn’t been also formed a fixed way of extraction. So there exists a certain problem in ground pressure control, ore handling in such aspects as the cutting ratio and cost in mining. In general, common room and pillar mining method is used for slowly inclined medium thick ore body in underground mining, but because of stope surrounding rock pressure of surrounding rock stress field change easily spread to the surface, open stoping method easily causes the surface subsidence, environmental damage caused by subsidence, serious when even cause casualties.To seriously explore complex slowly inclined medium thick orebody mining, with Cangshan iron ore as the research object instance, absorbing the advantages of various mining methods and the mining technology for slowly inclined medium thick ore body condition are studied on the basis of safety, and the reasonable, economical and efficient mining method is seeked. The main research contents of this thesis are as follows:(1) The Cangshan iron ore mining technical conditions of instructions is analyzed, this is the basic conditions for the mining method study of mining method selection and parameter optimization, which provides the original and fundamental conditions for the follow-up study.(2) Many primary mining methods are put forward according to the ore deposit, the occurrence conditions, ore body mining conditions and in combination with Cangshan iron mine’s actual situation and refer to the experience of similar mines at home and abroad. The economic and technical indexs of primary scheme are obtained through the preliminary comparison of economic and technical aspects among various mining methods.(3) According to preliminary analysis of the economic and technical indexes and characteristics of mining method, the fuzzy mathematical evaluation method is used to quantize the quantitative index and qualitative indexes influencing the mining method selection. The membership value and index weight of each index is got for quantitative evaluation, and the safe, economic, reasonable and efficient mining methods are put forward.(4) The three-dimensional finite difference analysis model is established according to the mining method. The numerical simulation analysis software is used for multi-parameter numerical simulation analysis of mining method. The largest exposure area of a single stope roof is simulated, and the optimal point pillar size is obtained through multi-parameter numerical simulation on the basis of largest exposure area of a single stope roof.(5) The surface deformation caused by this kind of mining method operation is analyzed according to the mining method result of fuzzy mathematical analysis and the pointed pillar size result of numerical simulation., The rationality of this mining method is determined according to "three under" mining surface allowing deformation value and analysis of the application.Finally, the optimization minging method is put forward. The result of research has been in successful application at-40 mRL of Cangshan iron mine, which goes well. |
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