Response surface optimization and performance verification of cemented backfilling ratio for decyanided tailings

• Targets decyanided tailings, a challenging waste, for cemented backfill application. • Employs Response Surface Methodology to optimize backfill mixing ratios. • Determines optimal ratios: 1:4-70% for high-strength and 1:15-70% for low-strength. • Achieves prediction accuracy with less than 5% error between model and experiments. • Provides a reliable technical pathway for tailings resource utilization. In light of the need for tailings resource utilization and green mine construction, this study addressed the challenges posed by the fine particle size, poor gradation, and low backfill strength of decyanided tailings. Using decyanided tailings from the Suichang Gold Mine, experiments were conducted to characterize the properties of cemented backfill slurry and the mechanical performance of the cured backfill. By systematically testing the physical, chemical, and rheological properties of the tailings, the effects of cement-tailings ratio, slurry concentration, and curing age on the uniaxial compressive strength (UCS) and slump flow of the backfill were analyzed. The response surface methodology (RSM) was used to establish a multiple regression model for strength and fluidity, followed by optimization and verification. The results show that the cement-tailings ratio and slurry concentration are the main factors affecting backfill performance. The optimal ratio for high-strength backfilling is a cement-tailings ratio of 1:4 with a concentration of 70%, while the optimal ratio for low-strength backfilling is a cement-tailings ratio of 1:15 with a concentration of 70%. The error between the model’s predicted values and experimental measurements is less than 5%, confirming the reliability and practicality of RSM for optimizing the backfilling ratio of decyanided tailings. This study provides technical support for the safe disposal of tailings and green backfill mining.