Forecasting cemented backfill strength: Back calculation of cement dosage

Research was done to reduce the cost of filling and to increase the reliability of the slurry preparation system.Filling is important in large sized goafs as the second step of preparing the mining props.Mixture ratio tests and statistical analysis are used to form a model to predict the strength of the fill body.Sampling from the backfilled body gave material for field verification of the model.The actual amount of cement in the goaf and the cement analysis are used as predictors of deformation.The results showed that in early stages the cement fill is excessive,for example in the 52-8# and 52-10# stopes the amounts are 60.28%and 49.24% more than normal.As the technical proficiency of the filling operators increases checks of measuring instruments and the conveying equipment show reduced amounts of cement in large spaces.These results can provide a theoretical basis for reducing the cost of filling and provide guidance for additional research.