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The possibility of increasing the pit slope angles of the Chuquicamata Mine as the pit approaches its planned
closure is being considered. Compared to the conventional mine design, the slope steepening is understood
to raise the net present value (NPV) of the mine, but also, attracts an increase in possible adverse outcomes
related to the increase in the likelihood of slope failures. A quantitative risk evaluation was undertaken to
provide information to assist the mine management in their decision by: defining risks in terms of safety and
economics, quantifying risk level for different slope configurations and comparing results against industry
The approach included three main tasks: (1) evaluation of the total probability of failure (POF)
representative of the stability conditions of slopes. (2) Evaluation of the consequences of slope failure on
safety of personnel. (3) Evaluation of the consequences of slope failure in terms of economic losses
associated with impact on equipment and production, including the Force Majeure event situation (major
economic loss affecting the continuation of the mine business). Options for risk mitigation are also discussed
The main purpose of this paper is to present the process of a risk evaluation of mine slopes; therefore, the
emphasis has been put on the methodology followed rather than on the actual results obtained.
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