Abstract:

The filling mining method has the advantages of preventing and controlling the collapse of the empty area，slowing down or avoiding surface subsidence. However，when filling deep ore bodies，the requirements for filling quality are becoming higher and higher.Due to the difference between the filling processes，there are technical problems in the filling process of the mine，including the problem of the topping in the cement filling. The effect of the ceiling in the goaf or the empty area directly affects the supporting effect of the surrounding rock.Due to the poor filling and filling effect，there are still a few centimeters to several tens of centimeters of gaps between the upper cementing surface of the filling body and the top plate.Due to the existence of this gap，the surrounding rock may collapse and，in severe cases，may even cause the upper rock mass to collapse, forming a subsidence on the surface.In the test，the whole tailings were used as the filling material，according to the slurry concentration of 65%，70%，75%，80%，the bentonite content was 0，5%，10%，15%，and the ratio of lime to sand was 1∶4, 1∶6，1∶8，1∶10，design three factors and four levels，a total of 16 orthogonal experiments. From the experimental observation data，when the dosage is 0，the total bleeding rate of the slurry is 5.6%~24.3%； when the dosage is 5%，the total bleeding rate is 5.2%~23.8%； when the dosage is 10%，the total bleeding rate is 3.5%~15.3%； when the dosage reaches 15%，the total bleeding rate of the filling slurry is reduced to 1.1% to 9.0%.The results show that the influence of slurry concentration on total bleeding rate was the most influential，then bentonite was the second and cement-sand ratio was the least.The dynamic bleeding process of slurry have two stages with early rapid bleeding stage and late stable bleeding stage. And the duration of the two stages is different under different proportion conditions. From the dynamic bleeding process，the most important factor influencing is bentonite content，but the concentration of slurry and the cement-sand ratio are small than bentonite content at the dynamic bleeding rate.

Key words: fulling tailings, cemented filling, filling slurry, bentonite, bleeding performance, filling expansive agent, cement-sand ratio, orthogonal experiment