Self-flowing pipeline transportation, mechanical properties and mechanisms of full-tailings cemented backfill materials

In mine cemented backfill, the pipeline transportation and mechanical properties of backfill materials are pivotal for the successful application of the backfill system. This study therefore investigates the self-flowing pipeline transportation and mechanical properties of full-tailings cemented backfill materials through L-pipe and strength tests. The variation patterns and microscopic mechanisms of backfill properties were analyzed and the feasibility of its industrial applications was discussed. Results show that increasing binder content and slurry mass concentration led to decreasing yield stress and increasing pipeline transportation resistance. As the viscosity and strength of backfill body increased, the maximum filling gradient was negatively correlated with pipeline transportation resistance. Intensified interparticle attraction and exacerbated interparticle friction were the intrinsic causes for the rise in yield stress and viscosity, as yield stress exerted a dominant influence on pipeline transportation resistance than viscosity. Individual or simultaneous increase in test factors leads to increased quantity of hydration products, reduced pore area, improved structural compactness and strength. With binder content of 210 kg/m³ and slurry mass concentration of 68 %, the system exhibited both industrial adaptability and economic efficiency, achieving a 4.11 % surplus in maximum filling gradient and 28 d strength of 2.08 %. This study offers references for self-flowing transportation theories and technologies of cemented backfill materials.