Belem, T, El Aatar, O, Bussiere, B, Benzaazoua, M, Fall, M & Yilmaz, E 2006, 'Characterisation of Self-Weight Consolidated Paste Backfill', in R Jewell, S Lawson & P Newman (eds), Proceedings of the Ninth International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 333-345.
Recent studies showed that for a given mix recipe and curing time the unconfined compressive strength
(UCS) of in situ paste backfill (PB) core samples can be 2 to 4 times higher than samples of the same PB mix
poured into plastic moulds (Belem et al., 2002; le Roux et al., 2002; Cayouette, 2003; Revell, 2004). Also,
the same observations were made for PB samples prepared and cured in laboratory conditions compared to in
situ underground PB samples (Belem et al., 2000 and 2001). These differences in compressive strength could
be attributed at least in part to the PB hardening (e.g. Benzaazoua et al., 2004) conditions in the stope such
as: stope size and geometry, stope walls convergence against the fill mass and its resulting shrinkage (Belem
et al., 2004). Other factors of influence are the amount of bleeding water and the gravity-driven consolidation
settlement of the PB mass which may depend on its physico-geochemical properties and also on the physical
properties of the surrounding rock mass. It was reported that this self-weight consolidation settlement can
reach more than 1 m and is usually considered to positively affect the PB strength development (e.g. Belem
et al., 2002; le Roux, 2002; Cayouette, 2003). A relatively large number of experimental studies are reported
in the literature on the self-weight consolidation of granular slurries, debris, dredge materials or waste rock
and mine tailings (e.g. Been and Sills, 1981; Wickland and Wilson, 2005). The originality of the present
study, however, is that it considers high density slurry (solids mass concentration ranging from 70% to 85%
w/w). To the knowledge of the authors, only very few investigations on the consolidation behaviour of PB
have been completed to date (e.g. Belem et al., 2002; le Roux et al., 2002).
The purpose of this paper is to characterize the physical and mechanical properties of PB prepared at
Louvicourt mine paste backfill plant, poured and cured into 3 m high PVC/Makrolon® polycarbonate sheet
settling columns following three scenarios: fully-drained (FD), half-drained (HD) and undrained (UD)
conditions. The main objective is to better understand the effect of self-weight consolidation settlement of
PB on its physical and mechanical properties.
Been, K. and Sills, G.C. (1981) Self-weight consolidation of soft soils: an experimental and theoretical study, Géotechnique, 31, 4,
Belem, T., Benzaazoua, M., Bussière, B. and Dagenais, A.-M. (2002) Effects of settlement and drainage on strength development
within mine paste backfill, in Proceedings of Tailings and Mine Waste'02, 27-30 January 2002, Fort Collins, Colorado,
Balkema, Rotterdam, pp. 139–48.
Belem, T., Benzaazoua, M. and Bussière, B. (2000) Mechanical behaviour of cemented paste backfill, in Proceedings of 53th
Canadian Geotechnical Conference: "Geotechnical Engineering at the dawn of the third millennium", 15-18 October 2000,
Montréal, Vol. 1, pp. 373-380.
Belem, T., Bussière, B. and Benzaazoua, M. (2001) The effect of microstructural evolution on the physical properties of paste
backfill, in Proceedings of Tailings and Mine Waste'01, January 16-19, Fort Collins, Colorado, A.A. Balkema, Rotterdam, pp.
Belem, T., Harvey, A., Simon, R. and Aubertin, M. (2004) Measurement and prediction of internal stresses in an underground
opening during its filling with cemented fill, in Proceedings of the 5th Int. Symp. on Ground Support in Mining and
Underground Construction. Villaescusa & Potvin (eds.), 28-30 September 2004, Perth, Western Australia, Australia, Tayler &
Francis Group, London, pp. 619 – 630.
Benzaazoua, M., Belem, T. and Jolette, D. (2000) Chemical stability investigation and its impact on the quality of cemented backfill
(in French), IRSST Report No. R-260, 172p.
Benzaazoua, M., Fall, M. and Belem, T. (2004) A contribution to understanding the hardening process of cemented pastefill,
Minerals Engineering. 17, 2, pp. 141–152.
Cayouette, J. (2003) Optimization of the paste backfill plant at Louvicourt mine, CIM Bulletin, 96, 1075, pp. 51-57.
le Roux, K.A., Bawden, W.F. and Grabinsky, M.W.F. (2002) Assessing the interaction between hydration rate and fill rate for a
cemented paste backfill, In Proceedings on the 55th Canadian Geotechnical and 3rd joint IAH-CNC Groundwater specialty
Conferences, Niagara Falls, Ontario, October, 20-23, 2002, pp. 427-432.
Revell M.B. (2004) Paste – How strong is it? In Proceedings of the 8th International Symposium on Mining with Backfill, Septembre
2004, Beijing, The Nonferrous Metals Society of China, pp. 286-294.
Wickland, B.E. and Wilson, G.W. (2005) Self-weight consolidation of mixtures of mine waste rock and tailings, Can. Geotech. J. 42,