Abstract: Taking the fine tailings as aggregated materials，the slump of the filling slurry and its variation regularity of rheological properties with different concentration were investigated，and the plastic viscosity and yield stress of slurry with different concentration were also measured.The results showed that the concentration of slurry is the key factor influencing the slurry's fluidity.With the concentration varied，there is a critical point in fluidity of slurry.When the concentration is higher than the critical concentration，its fluidity can be dropped rapidly.The critical concentration is 63% for such fine tailings slurry.Therefore，the filling concentration must be lower than 63% for a good fluidity.Based on the Bingham fluid theory，the hydraulic gradient and the capacity of the filling slurry in different pipe diameters with different concentration were measured.The results indicated that the slurry's concentration and the pipe diameters are the key factors affecting the filling capacity and the flow velocity in the same filling double line.The suitable pipe diameter must be chosen to ensure the capacity with the different concentration of slurry.

Key words: Filling slurry, Rheological properties, Filling capacity, Pipeline design