Abstract: In view of such problems as the ore and surrounding rock existing in faults and fissures,easy collapse and sliming in a gold mine of Guizhou,the uniaxial compressive strength (UCS) tests and pumping loop-pipe-tests were designed to analyze the strength and fluidity of unclassified tailings-artificial sand cemented backfill slurry.The test results of uniaxial compressive strength (UCS) shows that slurry concentration being 75%~76%,cement dosage being 20% and mass ratio of artificial sand to tailing being 2.9 is the optimal in the bottom of filling,while slurry concentration being 75%~76%,cement dosage 12% and mass ratio of artificial sand to tailing 2.9 is the optimal in the other part.The maximum stowing gradient in this gold mine is 5.7 in 370 m level.Through the pumping loop-pipe-tests,self-flowing transportation for the filling slurry can be achieved at two kinds of optimal ratios.

Key words: Unclassified tailings-artificial sand, Backfill, Structure fluid, Mixture optimization