Ferrada Venegas, C & Landeros Córdova, P 2024, 'Assessment of the effect of hydraulic fracturing on overbreaking in horizontal developments, Andes Norte project, El Teniente mine', in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 1277-1288, https://doi.org/10.36487/ACG_repo/2465_84
(https://papers.acg.uwa.edu.au/p/2465_84_Ferrada/)
Abstract: The Andes Norte project is the deepest project of the El Teniente mine and will extend its life span by adding 50 more years of exploitation. The development is still under construction and the mine design layout is based on a conventional panel caving exploitation method, with preconditioning by hydrofracturing above the caving level (upward) and below the production level (downward) being one of the main measures for the mitigation of seismic hazards and rockburst risk management strategy during production.
The construction plan for the initial sector of the project considered executing hydrofracturing below the production level at early stages of development. Consequently a large number of horizontal and vertical excavations in the eastern zone of the footprint were carried out in a rock mass previously hydrofractured.
This work will describe the methodology used for geotechnical ground control and the identification of hydraulic fractures at the tunnel scale, focusing on conducting a comparative analysis of the levels of overexcavations that have been generated in horizontal tunnels developed both inside and outside the preconditioned volume under similar geotechnical conditions.

Keywords: overbreaking, geomechanical risks, hydraulic fracturing, tunnelling in high stress