Ground support for large chambers at Didipio mine

Authors: Bermas, JM; Dumangeng, DA; Reola, CG; Lourence, PB Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2325_15

Cite As:
Bermas, JM, Dumangeng, DA, Reola, CG & Lourence, PB 2023, 'Ground support for large chambers at Didipio mine', in J Wesseloo (ed.), Ground Support 2023: Proceedings of the 10th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 225-236, https://doi.org/10.36487/ACG_repo/2325_15



Abstract:
The Didipio porphyry gold–copper mine, Philippines, will be constructing two large underground chambers for the storage of water with a required service life of at least 15 years. The chambers will be located at a depth of 500 m below the surface in a blocky dark diorite rock mass having an in situ uniaxial compressive strength of 200–250 MPa and Q ratings ranging from 4–6. This paper summarises the results of analyses based on mining industry design methodologies to recommend optimal crown support and sidewall reinforcement. The assessment and methodology satisfy industry design approaches which involved analytical and empirical methods. Analytical systems, such as the boundary element method numerical stress modelling, addressed the potential stress-induced failure analysis and calculated the size of overstress zones around the stopes. Wedge analysis examined structurally controlled failure due to mean joint sets. Empirical methods provided estimates of Q-rating and empirical design charts. Cable bolt patterns and specifications were based on a combination of wedge analyses, numerical modelling, and empirical design charts, using parabolic dome theory.

Keywords: ground support, large chambers, water stope, long-term excavations, support capacity, support design, cable bolt, pressure arch

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