Rojas, B, González, A & Barindelli, G 2024, 'Empirical estimation of rock mass caveability using Laubscher and Mathews stability graphs applied to', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 267-285.
(https://papers.acg.uwa.edu.au/p/2435_B-07/)
Abstract: In caving operations, a discontinuous process of propagation could trigger several operational issues with consequences that impact directly throughout the downstream mining process. Therefore, having accurate estimations of caveability of the rock mass plays a key role in mine planning and operation management process. In Chuquicamata Underground mine (MCHS), during 2022, one of the macroblocks (MB) showed a hanging condition, this made evident that the tools used for caveability estimation were not sufficient. In this context, a study was conducted to establish a methodology to estimate the caveability of the MCHS macroblocks, using the empirical stability graph of Laubscher (Laubscher, 1994) and the modified Mathews stability graph (Trueman and Mawdesley, 2003). A back-analysis process was carried out seeking to reproduce different cases of caving propagation collected during the operation of MCHS. The input data for the analysis included a detailed geotechnical site characterization, historical extraction records, geotechnical instrumentation data and presence of preconditioning (PA). The results showed that Laubscher stability graph presents estimation errors between 10% and 45% in terms of Hydraulic Radius (HR) and caving propagation timing. On the other hand, the modified Mathews method showed that in macroblocks with PA, the caving propagation is estimated between 0 to 1 months earlier than the ground data, with an error in HR estimation between -5% and 45%, while for the macroblocks without PA it was estimated between 2 to 3 months earlier than evidenced, with an underestimation of the HR of 30%.