Paste Pipeline Transportation of Pumping Backfill Technology with Long Distance and High Stowing Gradient in Cold and High-Altitude Areas

Abstract

A paste pipeline transportation of pumping backfill technology with long distance and high stowing gradient is proposed to solve the problem of filling slurry transportation with low concentration, the filling body poor quality, and the transportation difficulties with long distance and high stowing gradient in Heiniudong copper mine (HCM). The physical and chemical properties of the backfill material, backfill proportion test, circular pipe experiment, and backfill system analysis evaluation were studied in the laboratory and outdoor, and the application in HCM was carried out to evaluate the technology. The research results show the feasibility of considering classified tailings and binder as backfill aggregates, and the optimum proportion of cement-binder-classified tailings applied in the stope and goaf is 1 : 4 : 8 and 1 : 4 : 15, respectively, with paste rheological properties of mass fractions of both being 74%∼76% and the backfill strength of about 1.5 MPa at 28 d. Furthermore, when backfill proportions and rate of flow are 1 : 4 : 8 and 50 m3/h, the pressure loss of the pipeline is around 0.4 MPa/100 m, and the backfill pump meets the backfill requirements. On this condition, the technology is capable of obvious economic benefits with the backfill cost of only 25.56 yuan/t, remnant ore recovery rate of 80%, and new output value of 1.28 billion. It creates a precedent for the paste pumping backfill technology with long distance and high stowing gradient in cold and high-altitude areas. The technology also provides reference mining experience for similar mines.