Study On Safety Mining Technology Of Fourth Segment In Makeng Iron Mine

At the second mining stage, the fourth segment of Makeng iron mine is the main ore body. As the first mining ore body is going to be depleted, in order to solve the mine production problem from the first mining to second mining, the mining operators designed and constructed stepping shaft on hanging wall of fourth segment. Because the stepping shaft is located in the range of safety mining, its safety must be taken into account in the process of mining, in addition, the ore body is close to F2huge Fault, so water prevention should be also taken into account during mining.In this study, the large-scale simulation software FLAC3D was used to probe the optimization of mining method selection, blasthole optimization study, recovery sequence, ore block structure parameters, the impact of mining goaf to stepping shaft as well as mining process to safety pillar of fourth segment. In this paper, the main research was as follows:(1)The fourth segment rock mechanics parameters were obtained by Makeng orebody geological conditions field investigation, data collection, rock mechanics parameters test.(2)Based on in situ mining conditions, the AHP(analytical hierarchy process) and the fuzzy mathematics method fundamental theory were used to comprehensive evaluation the mining methods and optimized a mining method with high production capacity, safety, economy, efficiency.(3)The stope stress and displacement were calculated and analyzed by using the FLAC3D simulation software. And the stope stability was investigated by calculation, thereby determining the reasonable stope structure parameters.(4)The FLAC3D numerical simulation based on the ANSYS interface used the confirmed stope structure parameters to obtain the effects of orebody excavation on1#stepping shaft. And the pillar size was obtained that can make sure the safety of shaft during mining process by setting four pillars by monitoring the maximum tensile stress, maximum compressive stress, safety factor of the stepping shaft and the displacement distribution near the shaft.(5)The blasting vibration may influence the safety of F2fault nearby, through simulation with ANSYS LS/DYNA, and the best distance between stope and safety pillar of fault was got.