Palatos, E & Yumlu, M 2021, 'Optimisation of backfill operations at Mavres Petres mine', in AB Fourie & D Reid (eds), Paste 2021: Proceedings of the 24th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 327-342, https://doi.org/10.36487/ACG_repo/2115_27 (https://papers.acg.uwa.edu.au/p/2115_27_Palatos/) Abstract: Mavres Petres mine is an underground mine, located in Chalkidiki, northern Greece, that is owned and operated by Hellas Gold; a wholly owned subsidiary of Eldorado Gold Corporation. The mine extracts a highgrade lead and zinc orebody using drift and fill mining method. Backfill is an integral part of mining cycle at Mavres Petres mine. Filtered coarse tailings mixed with cement are used for making cemented hydraulic backfill in a surface batching plant. The paper will discuss and present an overview of the backfill optimisation efforts at Mavres Petres mine, which includes recent changes and upgrades in the backfill plant, improved mix design, backfill quality control, and backfill delivery and placement in order to improve the operational efficiency, product consistency, safety and economic viability of the mine. Keywords: hydraulic backfill, coarse tailings, mix design, arched shotcrete barricades, backfill pre-support, QA/QC, test work, uniaxial compressive strength