Authors: Pells, PJN


Cite As:
Pells, PJN 2016, 'A note on design parameters for in-pit coal waste dumps in weak rock', in PM Dight (ed.), APSSIM 2016: Proceedings of the First Asia Pacific Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 523-530,

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This paper summarises data from two very large slip failures of in-pit coal mine waste dumps in weak, slaking, claystones and siltstones in equatorial high rainfall areas. It explains why it is dangerously inappropriate to use undrained shear strength parameters for design and monitoring calculations, and recommends residual effective stress friction angles for remoulded, sheared basal layers. However, it is shown that understanding the geometric extents of such dump failures does require adopting undrained shear behaviour.

Bishop, AW & Bjerrum, L 1960, ‘The Relevance of the Triaxial Test to the Solution of Stability Problems’, in Research Conference on Shear Strength of Cohesive Soils, American Society of Civil Engineers, Boulder, Colorado.
Seedsman, RW 1993, ‘Characteristics of Clay Shales’ in J Hudson (ed.), Comprehensive Rock Mechanics, Pergamon Press, pp. 151–164.
Simmons, JV & McManus, DA 2004, ‘Shear strength framework for design of dumped spoil slopes for open pit coal mines’, in Advances in Geotechnical Engineering: The Skempton Conference, Thomas Telford Limited, London, vol. 2, pp. 981–991.

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