Design and field implementation of steel straps reinforcement for pillar stability in high-deformation underground mining: engineering basis and lessons learned

Authors: Castro, D; Barindelli, G; Fumeron, J; Ottesen, M Download Paper

DOI https://doi.org/10.36487/ACG_repo/2625_11

Cite As:
Castro, D, Barindelli, G, Fumeron, J & Ottesen, M 2026, 'Design and field implementation of steel straps reinforcement for pillar stability in high-deformation underground mining: engineering basis and lessons learned', in D Cumming-Potvin & J Wesseloo (eds), Ground Support 2026: Proceedings of the 11th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 1-12, https://doi.org/10.36487/ACG_repo/2625_11



Abstract:
The stability of pillars in large-scale underground operations represents a significant geomechanical challenge, particularly in environments characterised by high-stress and pronounced rock mass deformation. This paper presents the engineering, design, and field implementation of a steel straps (hereafter referred to as straps) reinforcement system as a supplementary support element for pillar repair and rehabilitation at the Chuquicamata underground mine. The proposed system integrates high-strength steel straps with conventional support elements, including welded wire mesh, shotcrete, and tensioned cable bolts, with the objective of enhancing confinement and improving load redistribution within the support system. A design framework was developed based on static structural analysis using SAP2000, where the support system was modelled to evaluate its response under representative loading conditions. The results indicate that the inclusion of straps contributes to a reduction in bending demands within the shotcrete lining through improved load transfer mechanisms. The paper describes the design methodology, including the conceptual basis of the reinforcement system, modelling assumptions, and criteria adopted for dimensioning. Emphasis is placed on understanding the role of straps within the overall support system, particularly in terms of structural continuity and interaction between reinforcement elements. Field implementation is discussed in terms of constructability, installation sequence, and integration with operational constraints. While no direct measurements of support loads were available, the study incorporates 3D scanner measurements and qualitative field observations of the early-stage response. Key lessons learned are presented, highlighting both the benefits and limitations of the system, and identifying opportunities for design optimisation in future applications. The findings contribute to the development of more robust and adaptable support strategies for underground mining environments subjected to large deformation demands.

Keywords: anchorage systems, rock mechanics, pilar reinforcement, underground mining, steel straps

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