Research on the Parameters of Tailings Cemented Filling for Mined-out Open Pits

Taking the treatment project of tailings cemented filling for mined-out open pits in typical metal mines as background, using theoretical analysis and numerical simulation research method, the cement-sand ratio and concentration of filling slurry, the total filling height, level height, stratification height and the methods to determine the structure parameter of cement-sand ratio at different stages were provided. And then through the calculation and analysis, it is concluded that the cement-sand ratios of filling slurry of mined-out open pits are classified into three different grades: 1:8, 1:10, 1:20; the slurry concentration is 70%; the filling height is 80m; the level height is 20m; the stratification height is 1.5m; the cement-sand ratios of filling slurry of four stages are 1:8, 1:8, 1:10, 1:20. Introduction With the gradual depletion of shallow resources, many mines face a specific period of the transition from open pit to underground mining. At present the mining-out area at the bottom of open pit has great influence on the slope stability by the method of open stope mining after the transition from open pit to underground mining. At the same time the catchment of open pit penetrates into underground through the joints and fissures of surrounding rocks during the rainy season, which not only increases drainage costs, but also causes deterioration of surrounding rock, and it has a significant impact on mine safety. Whether can solve the open mining pit legacy security problems reasonably has become the guarantee for mining safety production [1-4]. Fig.1. The spatial distribution In the early years, open-pit mining is adopted in Shirengou Iron Mine, the bottom of open pit is ended in 0m level. The first phase construction from open pit to underground was began in 2000. The shallow hole shrinkage mining method was used to mine the orebody of south area at the medium stage of 0~-60m. In 2003, The second phase construction was began and the shallow hole 7th International Conference on Mechatronics, Control and Materials (ICMCM 2016) Copyright © 2016, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Engineering Research, volume 104