Multiphase slurry flow regimes and its pipeline transportation of underground backfill in metal mine: Mini review

The underground cemented backfilling of tailings slurry in metal mines is an important guarantee for controlling goaf, reducing tailings storage, and ensuring mining safety. As a typical multiphase flow, the slurry and its pipeline flow transportation are important factors that affects mining efficiency and leads to poor pipeline wear. To better understand the flow regime and its pipeline transportation characteristics, this paper systemically reviews following aspects: 1) the non-full/full pipeline flow regimes, patterns, and key evaluating parameters (distribution of pressure drop, velocity, etc. of slurry flow); 2) the breakthroughs, findings and limitations by using the slurry rheology experimental (loop pipeline test, etc.), or undisturbed detections methods (electrical resistance tomography, magnetic resonance imaging, Micro-CT, etc.) of slurry pipeline transportation; 3) the computational fluid dynamic models and numerical simulations, and 4) the generating mechanism, major modes and its controlling methods of slurry pipeline wear and undesirable erosion are critically summarized. It conducts that the non-full pipeline transportation, slurry composition heterogeneity, coarse particles segregation/sedimentation, pipeline shapes and its layout, and even electrochemical corrosion caused by acidic/alkaline slurry could be key causes for the high resistance and poor effectiveness of slurry pipeline transportation. These discussions in this review paper will contribute to offering good supports to understand slurry pipeline flow behaviour and potential wearing controlling methods.