Paste fill mix and cost-optimisation efforts at Olympias mine

Authors: Mousli, O; Psychari, E; Yumlu, M

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DOI https://doi.org/10.36487/ACG_repo/2555_30

Cite As:
Mousli, O, Psychari, E & Yumlu, M 2025, 'Paste fill mix and cost-optimisation efforts at Olympias mine', in AB Fourie, A Copeland, V Daigle & C MacRobert (eds), Paste 2025: Proceedings of the 27th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 427-440, https://doi.org/10.36487/ACG_repo/2555_30

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Abstract:
Olympias is an underground mine located in Chalkidiki, Northern Greece, and it is owned and operated by Hellas Gold Single Member S.A., a wholly owned subsidiary of Eldorado Gold Corporation. The mine extracts a high-grade polymetallic deposit using the drift and fill (DAF) mining method. Cemented paste fill has been implemented as the predominant backfilling method at Olympias mine. Cemented paste backfill is an integral part of the mining cycle and constitutes a major component of underground mining costs. During paste system commissioning and initial operations, a high-density paste backfill mix, meeting the high target strengths (1 MPa before vertical exposure and 4 MPa at 28 days curing age) and required flow properties, was developed by incorporating superplasticiser admixtures. Following a revised environmental impact assessment in 2022, the current minimum required backfill strength for DAF mining method is 0.5 MPa for sidewall exposures and working floors, and 1.5 MPa for sill pillars, respectively. The current production schedule and DAF cycle require paste fill achieving strength of 0.5 MPa within three days curing age. This paper presents results of the recent extensive laboratory test work and mix optimisation efforts for developing cost-effective paste fill mix designs that improve the economic viability of the mine while delivering operational efficiency and sustainability. These efforts have contributed to approximately 16% cost reduction per cubic metre of paste fill and there is still room for further improvement as mining and backfill optimisation efforts are ongoing.

Keywords: drift and fill, cemented paste fill, yield stress, mix design optimisation, cement types

References:
Backfill Geotechnical Mining Consultants Pty Ltd 2023, Olympias Pastefill System Operations Review, Internal report, Hellas Gold Single Member S.A., Athens.
Eldorado Gold Corporation 2023, Technical Report Olympias Mine Greece, Vancouver
Henderson, A & Revell, MB 2005, ‘Basic mine fill materials’, in Y Potvin, E Thomas, & A Fourie (eds), Handbook on Mine Fill, Australian Centre for Geomechanics, Perth.
Heracles General Cement Company 2022, Environmental Product Declaration for Pozzolanic Cement, CEM IV/B (P) 32.5N-SR, Lykovrisi.
Heracles General Cement Company 2023a, Environmental Product Declaration for Composite Portland Cement, CEM II/B-M (P-W-L) 42.5N, Lykovrisi.
Heracles General Cement Company 2023b, Environmental Product Declaration for Sulphate Resisting Blast Furnace Cement, CEM III/B 42.5N-SR, Lykovrisi.
Heracles General Cement Company 2023c, Technical data sheet CEM IV/ B (P) 32.5N, Lykovrisi.
Heracles General Cement Company 2023d, Technical data sheet CEM II / B-M (P-W-L) 42.5N, Lykovrisi.
Heracles General Cement Company 2023e, Technical data sheet CEM III / B 42.5N-SR, Lykovrisi.
Kalogeropoulos, SI, Kilias, SP, Bitzios, DC, Nicolaou, M & Both, BA 1989, ‘Genesis of the Olympias Carbonate-Hosted Pb-Zn (Au,Ag) Sulfide Ore Deposit, Eastern Chalkidiki Peninsula, Northern Greece’, Economic Geology, vol. 84, no. 5.
Siron, C, Thompson, J, Baker, T, Darling, R & Dipple, G 2019, ‘Origin of Au-Rich carbonate-hosted replacement deposits of the kassandra mining district, Northern Greece: evidence for late oligocene, structurally controlled, and zoned hydrothermal systems’, Economic Geology, vol. 114, no. 7, pp. 1389–1414.
Siron, C, Rhys, D, Thompson, J, Baker, T, Veligrakis, T, Camacho, A & Dalampiras, L 2018, ‘Structural controls on porphyry Au-Cu and Au-rich polymetallic carbonate-hosted replacement deposits of the Kassandra Mining District, Northern Greece’, Economic Geology, vol. 113, no. 2.
Siron, C, Thompson, J, Baker, T, Friedman, R, Tsitsanis, P, Russell, S, Randall, S & Mortensen, J 2016, ‘Magmatic and metallogenic framework of Au-Cu porphyry and polymetallic carbonate-hosted replacement deposits of the Kassandra Mining District, Northern Greece’, in JP Richards (ed), Tectonics and Metallogeny of the Tethyan Orogenic Belt, Society of Economic Geologists, Littleton, pp. 29–55.




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