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Miner's Toolbox |
| Mine Backfill Engineering |
| Cemented Rockfill Preparation |
There are many methods in use today for producing cemented rockfill and the choice depends on the unique conditions at each site. Two systems that are common are:
1. Spraying cement slurry over rock in truck box 2. Batch mixing of cemented rockfill
Figure 1 is a simplified flowsheet of a cemented rockfill system that is suited to operations that use waste rock from development work as their aggregate source. In this system, cement and or other binder is pneumatically transported from surface through a pipe to another small silo at a cement slurry mixing station. A preset weight of cement is added to a weigh hopper and the preset amount is delivered to a colloidal mixer. Water is also added to the colloidal mixer and the slurry is rapidly mixed. The slurry is then discharged from the colloidal mixer and sprayed over the rock in a truck's box. The batching process can be completely automated and a batch can be prepared in under one minute. The cemented rockfill is then trucked to a stope where it is end dumped.
Figure 1: Spraying Cement Slurry over Aggregate in Truck Box
Cemented rockfill can also be prepared on surface in a process similar to a concrete batch plant (Figure 2). The prepared rock is loaded into a weigh hopper with a wheel loader. Cement and possibly fly ash or ground blast furnace slag is weighed into smaller hoppers and then each is discharged into a pan mixer. A quantity of water is added and the material is mixed. The cemented rockfill is then discharged into trucks and taken to the stope.
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