The effect of shear strength parameters on cemented paste backfill performance

Cemented paste backfill can be defined as a pumpable, fluid, high density and composite material of filtered tailings of the milling operation of mine with water and hydraulic binders. Cemented paste backfill is a method increasingly used by mines throughout the world due to increasingly stringent environmental regulations opposita to sulfur-rich tailings. Physical, chemical and mineralogical properties of the materials composing backfill are the crucial factors affecting the quality of cemented paste backfill. Quantity of binder is one of the most important physical factors influencing the strength and stability of paste backfill. In this paper studies the mechanical behaviour of cemented paste backfill containing 15 wt% finer than 20 with short term and long term curing time. Mane tailings containing sulfur were used for making backfill samples with three different dosage of binder. Paste backfill samples containing 5 wt% cement were observed to no loss of strength until 56 days curing time.however lose their strenghts after 56 days. Strength of paste backfill had been dropped by 112 days and 224 days for binder composition with 6 % and 7 % respectively. By comparing , uniaxial compressive stress tests and shear stress parameters confirms the relation between them. Consequently, percentage of binder determines pass backfill performance in both shorth and long term.