Characterizing Dynamic Segregation Behavior in Cement Paste Backfill During Pipeline Transport Through Electrical Resistance Tomography

Cement paste backfill technology is a key method for mine waste treatment, with pipeline transport being critical for safe and efficient waste transfer. Variations in raw material properties can cause slurry segregation, increasing pipeline wear, resistance, and risks of blockages or bursts, disrupting operations. To study cement paste backfill slurry (CPB) segregation during transport, we prepared CPB using cement as cementitious material and unclassified-tailings as inert material. A small-sized annular tube device using an electrical resistance tomography (ERT) system was developed to analyze its flow characteristics, and a quantitative bias assessment method was proposed, and a quantitative segregation assessment method is also proposed. Results indicate that CPB conductivity increases with transport time but decreases with higher solid mass content, with the latter having a greater impact. At low solids content, solid particles migrate towards the bottom of the pipe as the conveying time increases, and the migratory behavior of the particles diminishes as the solids content rises. At a flow rate of 1.25 m/s, the heterogeneity index text (HIT) for CPB with 58wt% solid content rose by 1.24 in 20 minutes, while CPB with 62wt% solid content saw a 2.17 increase. Longer transport times and higher solid content exacerbate dynamic segregation, emphasizing the need to balance these factors to minimize segregation. These insights can guide the optimization of mine pipeline transport systems.