1. Filling aggregates should be made of materials that have a certain strength, are not muddy, and are non-toxic and harmless. When conditions permit, the tailings of the mine and the excavation and stripping of the waste rock should be used as the filling aggregate.
2. When using pipeline hydraulic conveying, the selection of filling aggregates should meet the following requirements:
1 When using graded tailings as the filling aggregate, the classification limit of tailings should be 0.037mm , and the penetration speed should not be less than 80mm/h . When the amount of tailings is high, the classification limit can be reduced appropriately; When the body is cemented, full-grain tailings should be used;
2 For the sulfur-containing tailings used for cementation filling, the sulfur content in the tailings should not exceed 8% ;
3 When using bar scrub as the filling aggregate, the maximum particle size of the bar scrub should not exceed 3mm .
3. Dry filling materials can be used to dig underground waste rock, and the block size should meet the following requirements:
1 When using gravity filling, the maximum block size should not be greater than 300mm ;
2 When filling with a throwing machine, the maximum block size should not be greater than 80mm ;
3 When using wind power transmission, the maximum block size should be less than 1/4 of the pipe diameter , and should not be greater than 25mm .
Fourth, the cementitious material filling low-grade bulk cement should be used, coal ash can be employed powder, ground slag smelting, lime, gypsum and other portions of the active material in place of cement.
5. The pH of the filling water shall not be less than 5 .
2. When using pipeline hydraulic conveying, the selection of filling aggregates should meet the following requirements:
1 When using graded tailings as the filling aggregate, the classification limit of tailings should be 0.037mm , and the penetration speed should not be less than 80mm/h . When the amount of tailings is high, the classification limit can be reduced appropriately; When the body is cemented, full-grain tailings should be used;
2 For the sulfur-containing tailings used for cementation filling, the sulfur content in the tailings should not exceed 8% ;
3 When using bar scrub as the filling aggregate, the maximum particle size of the bar scrub should not exceed 3mm .
3. Dry filling materials can be used to dig underground waste rock, and the block size should meet the following requirements:
1 When using gravity filling, the maximum block size should not be greater than 300mm ;
2 When filling with a throwing machine, the maximum block size should not be greater than 80mm ;
3 When using wind power transmission, the maximum block size should be less than 1/4 of the pipe diameter , and should not be greater than 25mm .
Fourth, the cementitious material filling low-grade bulk cement should be used, coal ash can be employed powder, ground slag smelting, lime, gypsum and other portions of the active material in place of cement.
5. The pH of the filling water shall not be less than 5 .
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