KAZ Minerals, Almaty, Kazakhstan

N. Bar, Head of Geotechnical Department, neil.bar@kazminerals.com
G. A. Zlobin, Chief Geotechnical Engineer

Aktogay is a large open pit copper mine in Kazakhstan. The implemented geotechnical research consisted of a few stages, starting from the feasibility study and finishing with the continuous improvement of the mining process. The pitwall design included a few stages of the analyses of the slope stability and mine service life. As mining proceeds, the geotechnical conditions in the pit become increasingly more evident, and the uncertainty of data lowers. The article offers a brief description of approaches to pit slope stability modeling, which are used to get and understand information on geotechnical risk, and which can be integrated with the mining plan and sequence. The combination of 3D ultimate equilibrium method and the finite element analysis was included in the estimate of slope stability at the future stages of open pit mining. The models were developed to act as the digital twins of the actual mining development and to be updated regularly in the course of confirmation of geotechnical features with regard to new effects and additional site studies. The models allow risk prediction by comparing the current condition of pitwall with the qualitative data in case of the ultimate equilibrium method and with the quantitative data in case of the numerical methods. Improved understanding of residual risk helped develop control measures and further research program, and allowed finding the target values of the pore pressure decrease. Furthermore, it enabled comparisons of costs of different options.

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