A Study About Downward Hexagonal Access Backfilling Mining Technology Under Crushing Ores In Jinchuan Mines

As a result of the decrease in mining area and the lower in ore grade, the production cannot be guaranteed in Longshou mine of JNMC. It’s necessary to research the downward hexagonal drift filling technology in weak crushing ores, for stabilizing and improving the ores and metal output. This paper discussed the access structure parameters、optimized the blasting parameters and researched the large section hexagonal access mining technology. Using theoretical analysis、 numerical simulation and local industrial experiments, we obtained some results as follows:Firstly, according to the mechanical properties of rock and the filling quality, this thesis simulated the mining sequence and the course of the downward large section hexagonal access backfilling mining using finite element software, summarized the bearing law, and then determined the best section size:top and bottom width3.5m, waist7.0m, high6.0m, section area31.5m2.Secondly, in order to improve mining intensity, based on the blasting mechanism analysis and blasting parameters optimum research, this paper summarized the access blast hole arrangement、ut way、explosive selection、 charging and initiation way of explosive and so on under different conditions. Applying linear cut way、reamer bit and second delay detonator can realize2.0m footage per blasting,110～130t blasted ore each time, explosive specific charge less than0.25～0.28kg/t, improving the footage per blasting in downward large section hexagonal access mining.Lastly, on the basis of the researches before, local industrial tests were carried out. Through the experiments, the continuance and reliability of large section access mining and mining system were proved. We also gained optimal stope structure parameters. Finally, production of technical standards suit for large section mining system was established.All of the above achievements solved the key technology of downward large section hexagonal access filling mining in Longshou mine. The industrial tests demonstrated its rationality. In conclusion, this study have finished intended target, improved production capacity、production intensity and efficiency, and guaranteed its stable output, providing reference for other similar ores.