Mix proportioning of underground cemented tailings backfill

The usage of cemented tailings backfill (cemented paste backfill) in the underground by mining industry is becoming increasingly important. However, until now, the mix proportioning of CTB has been mainly based on the realization of extensive laboratory tests on a large number of CTB mixes. Therefore, this paper presents a design method for mix proportioning of CTB to minimize the number of trial mixes and provide an appropriate mix proportion. This method is based on the pairing of the response surface method (RSM) and the desirability approach. First, the RSM was used to develop predictive models for the performance properties of CTB. The predicted properties in question are the uniaxial compression strength (UCS), the slump, the solid concentration (solid percent, %Solid) and the cost (based on cement cost) of the CTB. The predictive models that were developed were able to accurately represent the relationships between the physical and chemical characteristics of the CTB components (tailings, binder, water) and the above properties. The results of the modeling phase were then used as input data in the optimization phase (based on desirability approach) to develop optimal recipes for the studied CTBs. This study has demonstrated that the combination of the RSM and desirability approach represents an effective tool for CTB mix proportioning. It has also shown that the mix parameters (cement content, water-to-cement ratio, tailings fineness and density) affect the performance properties of CTB. The results of this research provide a more comprehensive engineering approach to CTB mix proportioning. The developed design method can be useful in reducing the laboratory test protocol needed for the determination of the optimal mix composition. (c) 2006 Elsevier Ltd. All rights reserved.