Applications of impact rolling in mine closure

Authors: Power, R; Avalle, D; Dix, S Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_50

Cite As:
Power, R, Avalle, D & Dix, S 2026, 'Applications of impact rolling in mine closure', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-17, https://doi.org/10.36487/ACG_repo/2615_50



Abstract:
Mine closure presents complex geotechnical challenges associated with rehabilitating large, disturbed landforms, including waste rock dumps, tailings storage facilities (TSFs) and backfilled pits. These landforms often comprise heterogeneous, loosely placed or variably compacted materials with uncertain density, stiffness and long-term settlement behaviour. Closure objectives extend beyond stability to include prevention of spontaneous combustion and protection of groundwater from acid and metalliferous drainage. Achieving stable, low-permeability, trafficable surfaces is therefore essential to meet regulatory criteria, ensure public safety and enable sustainable post-mining land use. Impact rolling has emerged as an efficient, cost-effective and quantifiable ground improvement technique well suited to these conditions. Impact rolling or rolling dynamic compaction applies high energy impact compaction (HEIC) using a tractor-drawn, non-circular drum that delivers concentrated impact loads to the ground surface. Unlike conventional cylindrical drum rollers, it induces deep-seated densification, increasing stiffness, reducing void ratio and lowering permeability across a broad range of mining wastes and overburden materials. This highly productive method enables large areas of uncontrolled or end-dumped fill to be treated rapidly and economically, reducing differential settlement risk and improving overall landform performance. In landform reconstruction, impact rolling is used at pit bases to reduce permeability and limit contaminant migration. During backfilling, thicker lifts can be placed and compacted with confidence, maximising densification and increasing the effective volume of material placed within the void. At final levels, the technique assists in compacting capping layers designed to shed water and control infiltration. For existing landforms, applications include densification of waste rock dumps prior to or during capping, improvement of tailings beaches to support cover systems, and stabilisation of coal discard and overburden fills. Integrated intelligent compaction measurement provides traceability of roller passes, ground response and settlement. When combined with verification tools such as plate load testing, geophysics (MASW, SASW, CSW etc.), cone penetration testing or variable energy dynamic probing and dynamic probing super heavy, impact rolling supports a performance-based closure strategy, delivering durable rehabilitation and reduced long-term risk.

Keywords: impact rolling, settlement, permeability, compaction, mine closure, mine reclamation, mine tailings, coal ash ponds

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