Abstract: To minimize the wear of backfilling drills and pipes in a paste filling system, it is analyzed that the impact force caused by the free fall of the pulp at the interface of loop and full flow area is the main form of greatly contributing to the wear of backfilling drills and pipes.Combining with the actual situation of mine, and according to the relationship between hydraulic gradient of the running piping and the full flow, two schemes of variable diameter for resistance-increasing are proposed, including a reductive modification of horizontal pipeline from diameter 150mm to 85mm partly and a newly bilayer structure drill model by vertical drills.In addition, a trial was carried out to test the feasibility of modification of horizontal pipeline.The results showed that the full piping rates were increased from 3.6% to 39.42%.

Key words: Drill holes for filling, Forms of wear, Full pipeline flow, Variable diameter for resistance-increasing