Peschken, P & Hoevemeyer, D 2017, 'Backfilling of pastes and long distance transport of high density slurries with double piston pumps', in A Wu & R Jewell (eds), Paste 2017: Proceedings of the 20th International Seminar on Paste and Thickened Tailings, University of Science and Technology Beijing, Beijing, pp. 125-133, https://doi.org/10.36487/ACG_rep/1752_14_Peschken (https://papers.acg.uwa.edu.au/p/1752_14_Peschken/) Abstract: Filling chambers with pastes in underground mines to increase the safety, climate and cut-off grade is state of the art. By adding gravel the strength is increased and the cement content can be reduced. This results in reduced costs for the backfill process. The results will be shown by examples from different mines. High density slurries are pumped over long distances. At the Polish power plant of Belchatow flyashes are pumped over a distance of 8000 m. After more than 2 years of operation a first resume can be given.