Abstract:
Paste backfill is made of tailing,cement and water with optimum combination,to make mixture like the toothpaste cementing body,and conveying the plunger flow through the pipeline to the filling stope.In comparison with the previous slurry mine fills,there are number of advantages,such as,the early strength of paste backfill can contribute to shortening of the cycle time of backfilling operation,the advantages of minimal requirement or no bulkhead together with less cement content which contributes to reduction of the mining cost.Paste fill is favored by most of the modern mining companies around the world.This paper based on the review of the historical development of paste backfill and it focuses on highlighting of the development of technologies developed around the world in the last three decades.The conclusions are as follows:Frist,The material composition and particle size distribution of paste have a significant effect on the flow and mechanical properties of the paste,the content of-20μm in the paste mixture must be greater than 15%.Second,The paste is a structural fluid with high yield stress and viscosity,and the pipeline conveying speed is less than 1m/s,clear the flow characteristics of paste and how to reduce the yield stress is the key to the conveying system of paste.Third,The internal stress of the stope is complicated and the arch effect is produced,the strength of filling is greatly increased due to the arch effect,arch effect should be considered in the design of filling to reduce the filling cost.