Physical model investigation on effects of drainage condition and cement addition on consolidation behavior of tailings slurry within backfilled stopes

Abstract

Estimation of stressses within the tailings slurry during self-weight consolidation is a critical issue for cost-effective barricade design and efficient backfill planning in underground mine stopes. This process requires a good understanding of self-weight consolidation behaviors of the tailings slurry within practical stopes, where many factors can have significant effects on the consolidation, including drainage condition and cement addition. In this paper, the prepared tailings slurry with different cement contents (0, 4.76wt%, and 6.25wt%) was poured into 1.2 m-high columns, which allowed three drainage scenarios (undrained, partial lateral drainage near the bottom part, and full lateral drainage boundaries) to investigate the effects of drainage condition and cement addition on the consolidation behavior of the tailings slurry. The consolidation behavior was analyzed in terms of pore water pressure (PWP), settlement, volume of drainage water, and residual water content. The results indicate that increasing the length of the drainage boundary or cement content aids in PWP dissipation. In addition, constructing an efficient drainage boundary was more favorable to PWP dissipation than increasing cement addition. The final stable PWP on the column floor was not sensitive to cement addition. The final settlement of uncemented tailings slurry was independent of drainage conditions, and that of cemented tailings slurry decreased with the increase in cement addition. Notably, more pore water can drain out from the cemented tailings slurry than the uncemented tailings slurry during consolidation.