Design of roof-contacted filling ratio and filling holes in the sublevel open stoping with subsequent filling method

The major influence factors to control the cost of filling mining method are the design about the roof-contacted filling ratio and the number of filling holes. Firstly, taking the typical mine with subsequent filling sublevel open stoping method as engineering background, the distribution law of backfill strength and the final flowing track of filling slurry in the stope were obtained by three dimensional laser scanner and laboratory mechanics tests. Based on which, the three dimensional numerical optimised model on roof-contacted filling ratio and the number of filling holes in subsequent filling sublevel open stoping method were established. Then, the distribution characteristics on maximum principal stress and the stable state of backfill with different roof-contacted filling ratios were revealed by calculating and analysing of the model. Finally, the number and location of filling holes in the stope were optimised according to the suggested roof-contacted filling ratio.