Abstract: Goaf filling is the current efficient solution to solve mining subsidence and surface damage during coal mining. The filling material which is prepared with fly ash and coal gangue is pumped into the goaf through the pipe, which not only can provide the material source for filling, but also control the environmental pollution caused by coal gangue and fly ash disordered stacking from headstream. The pipeline transportation is one of the important links. As one of the key points in the design of a pipeline transport, the flow resistance of pipeline is related closely with the pressure loss and flow. There are important parameters in transportation system design, and directly affect the selection of power equipment and the cost of operation. In view of the uncertain status of flow law for the pipeline transportation of high concentration cemented filling slurry, a pipeline transportation test was con- ducted, and the pipeline transportation features with the filling slurry concentrations of 80% and 81% was studied. The results show that the pressure loss shows cyclic change with the change of time during the pipe pumping process, and the pressure loss increases as the concentration, velocity and frequency increase, Meanwhile, the pressure loss shows a linear growth correlation with the velocity of slurry.Morewove, the flow rate also shows a linear correlation with the slurry velocity, which increases with the velocity increases.

Key words: cemented filling slurry, pipe pumping, pressure loss, flow rate