Mining Technologies Of Muddy Ore Body In Sublevel Caving With Non-pillar For Yingfangzi Silver Mine

Ore body of yingfangzi silver mine present irregular lenticular and vein output, the thickness of ore body is 2～40m, and the angle of it is 40°～60°, it has many branches, caved bulk would mud when meet water, it belongs to highly difficult mining. yingfangzi silver mine exist the production problem of high ore loss and dilution, low production capacity, poor safety conditions by original sublevel caving. By field investigation, point loading strength test, analysis of ore rock and stability, determination the flow parameters of granular, it found that rock and ore are softly, the jointing crevasse are growth, rock and ore belong extremely unstable to instability, flow ability of bulk is poor. Therefore, with application "three laws" (ground pressure law, the rock mass caving rule and the bulk flow rule) adaptive efficiency mining theory. The paper raise improvement program of sublevel caving mining by research.The structural parameters of sublevel height is 13 meters, sublevel drive interval is 12.5 meters of yingfangzi silver mine. The structural parameters not consistent with draw body from laboratory. From the analysis, the reason of high dilution and loss was mainly caused by unreasonable structural parameters. According to the ore conditions and recovery principle of three fragment draw conclusion that the best sublevel height is 10 meters. Based on the stochastic medium theory and the mine situation, the best sublevel drive interval is 10 meters. Because of roadway floor muddy serious and the chassis of scrapers is low, scrapers cannot move in the muddy roadway, and it leads transport ore slowly. Following demonstration, LW300K wheel loader with higher reinforcement can settle the problem. According to the equipment working conditions, the reasonable section size mining roadways was optimization. Production schedule was slow down, because chutes were blocked and damaged. Elevating capacity of main shaft and auxiliary shaft cannot meet the demand of the mining production. Because of mud ore with great viscosity, it fit carry by directly loading. Also, ore is close to the surface. The analysis showed that Ramp exploitation is reasonable. So, change hoisting system in vertical shaft for ramp hauling system. By analyzing the problem of surrounding rock weakening serious after exposure, roadway with large deformation, it found out a reasonable method to protect the roadway by combined support way which is timely closed exposed surrounding rock by concrete.It analysis indicates that improved mining equipment, modes of transportation, tunnel supporting can effective fit mud ore conditions in yingfangzi silver mine. It can effective enhances productivity. PFC3D software is applied for three-dimensional numerical simulation of ore drawing, it get higher ore extraction and has lower ore dilution rate by the improved structure parameters. The analysis shows that, sublevel caving mining technology which was changed can significantly control ore loss and dilution in mud ore of yingfangzi silver mine, increase the ability of mine production, and achieve the expected target of efficient exploitation.