Abstract: Mine backfill is an ideal approach to protect land resources, ecological environment, to achieve the mine mode of no-waste-discharged and eliminate the potential hazards. The unclassified tailings from a mine was used as experimental raw material, then the micro-mechanism of consolidating backfill body of super-fineness unclassified tailings and cementitious materials under different conditions by means of XRD and SEM were obtained after analyzing the physical and chemical properties, the chemical components and particle size composition of the unclassified tailings. The cementing agent type #1 and type #2 were taken to replace the regular cement and the uniaxial compressive strength (UCS) of backfill specimens were gained. The experimental results showed that the influence degrees of different cementing agents on the behaviors of UCS were different, when the external experimental conditions were same; and it almost obeyed the law: cementing agent type #1＞cementing agent type #2＞cement. The study also demonstrated that the performance of the cementing agent type #1 were better than the others; and its price was cheaper; therefore, it can reduce the cost of mine backfill. The increasing curves of UCS of backfill samples at different curing times were obtained and it showed that the increasing laws of UCS at different curing conditions were unanimous, in accordance with the exponential function growth curve, although the cementing agents type were different. The cement-sand ratio, slurry concentration and curing time exhibit a positive correlation with the UCS growth curve.

Key words: unclassified tailings, micromechanism, new cementing agent, strength rule