The Research On Stope Stability And Operational Safety Evaluation For Kangjiawan Deep Deposits

Kangjiawan deep deposits have the major technical problems such as unreasonable mining method, unsafe stope, mining under the river and surface which does not allow collapse. Field research, literature search, numerical simulation and mathematical calculation methods were taken to choose the reasonable mining method, analysis stope stability, optimize stope structural parameters and study stope operational safety for Kangjiawan deep deposits. At the main time, the fuzzy hierarchy evaluation model of stope structure parameters and fuzzy network model of deep stope operational safety were established. The research has the very important heoretical and practical significance for safe and efficient mining of deep mines. The main research works are as follows:(1) According to on-site surveys and data collection of Kangjiawan deep deposits geological and mining technology conditions, sublevel open stoping afterwards filling mining method was carried out. Moreover, block of mining method was designed; ore production capacity and mining filling direct costs were estimated. The method is security, economic and efficient.(2) The numerical simulation and stope stability analysis for the nine kinds of orthogonal design scheme by using ANSYS software. The results show that scheme 1,4,7,9 are unsafe and scheme 2,3,5,6,8 are safe; the vertical displacement of broken roof and top-pillar are affected by stope's span of significantly, the roof instability form is very likely with the interface between the rib-pillar occurs at split-level, leading two sides of the roof to fall. Besides, stope excavation has little effect on top-pillar, and its damage is not serious. The rib-pillar is most likely to destroy and the instability form is very likely shear failure which happens at the junction of the silicified breccias zone.(3) The research on stope structure parameters optimization based on the analytical hierarchy process (AHP) and the fuzzy mathematic theory. The weighting vector of the factors was figured out by AHP method, and the adapted membership degrees function was founded according to the fuzzy mathematic theory. With the weighting vector and the matrix of the membership degrees, the fuzzy synthetic judge model was established, which was used to optimize five steady combinations structural parameters of the stope. At last, according to the sort of each scheme synthetic superior degree, the fifth scheme is the best and structural parameters are stope's span:20m, rib-pillar's width:4m, top-pillar's thickness 4m.(4) The stope operational safety comprehensive evaluation method based on analytic network process and fuzzy mathematics theory was proposed. And then, fuzzy network analysis safety comprehensive evaluation model was constructed. By calculating the overall weight vector and find that internal factors of the people are the most important. Take the stope NO.8,9,10 of Kangjiawan deep deposits 12 middle section for example; the stope composite score of safety evaluation is 62.3%,69.4% and 72.8% respectively. The results show that the safety of stope No.8 is relatively low, but all the stopes are under the safe condition.