Grabinsky, M & Simms, P 2006, 'Self-Desiccation of Cemented Paste Backfill and Implications for Mine Design', 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. 323-332.
The hydraulic and mechanical properties of Cemented Paste Backfill (CPB) that are of principle interest in
Geomechanical Mine Design include rheology, suction (the Soil Water Characteristic Curve or Water
Retention Curve), permeability, stiffness, and static and dynamic strength (including resistance to
liquefaction). All of these properties change as the binder in the CPB hydrates. In some, and perhaps most,
mining applications the rate of hydration, and therefore the rate of hydraulic and mechanical property
change, occurs on a time scale comparable to the rate of CPB delivery to and filling of the stope. This means
that the CPB’s properties are evolving even as it is being deposited and overprinted. This fact can have
serious implications for how we interpret total stress cell results, how arching develops both within the stope
and across the fill barricades, how fill barricades are designed and constructed, and how we evaluate the
CPB’s ability to carry its own self-weight during filling (i.e., resistance to static liquefaction during filling)
and subsequent mining (i.e., resistance to dynamic liquefaction during blasting in proximity to recent fills).
This paper begins by considering some initially unexpected results from an in situ investigation that
illustrates the interaction between rate of binder hydration and rate of stope filling. The framework for
conducting tests to evaluate CPB’s evolving hydraulic and mechanical properties is then considered. Some
initial test results involving static monotonic and cyclic loading of CPB are then reviewed, and the mine
design implications of these test results are considered. The conclusions arising from this work are not yet
meant to be used for practical design, but rather point to the extensive research and development that is still
required before we can rationally carry out optimized design of CPB fills and their barricades.
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remblais miniers cimentés en pâte durant le curage. Proceedings of the 57th Canadian Geotechnical Conference, Quebec City.
Grabinsky, M.W., Simms, P., Bawden, W.F. and le Roux, K. (2005) In situ properties of cemented paste backfill and implications for
mine design. Symposium 2005 on Mines and the Environment, Rouyn-Noranda.
Kim, J.-K. and Lee, C.-S. (1999) Moisture diffusion of concrete considering self-desiccation at early ages. Cement and Concrete
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le Roux, K., Grabinsky, M.W. and Bawden, W.F. (2002) Laboratory analysis of consolidation and hydration of cemented paste
backfill. Proceedings of the 55th Canadian Geotechnical Conference, Niagara Falls.
le Roux, K., Bawden, W.F. and Grabinsky, M.W. (2004) Liquefaction analysis of early age cemented paste backfill. Eighth
International Symposia on Mining with Backfill (Minefill 2004), Beijing.
le Roux, K., Grabinsky, M.W. and Bawden, W.F. (2005) Consolidation and fabric development in cemented paste backfill. Trans.
Instn Min. Metall. (Sect. A:Min. Technol.), in publication.