Open pit mine design and production scheduling deals with the quest for most profitable mining sequence over the life of a mine. The dynamics of mining ore and waste, and spatial grade uncertainty make predictions of the optimal mining sequence a challenging task. Valuation and related decision-making in surface mining require the assessment and management of orebody risk in the generation of a pit design and long term production scheduling. As the most profitable mining sequence over de life of a mine determines both economic outcome of a project and the technical plan to be followed from mine development to mine closure, the adverse effects of orebody risk on performance is critical and are documented in various studies. Ignoring such a consequential source of risk and uncertainty may lead to unrealistic production plans. This paper presented a set of procedures that enable mine planning engineers to carry out a series of analysis, which can be used to evaluate the sensitivity of incremental pit shells and pit designs to grade uncertainty. The results obtained from the analysis have shown to provide valuable information, which can be used to develop mining strategies that are risk resilient in relation to grade uncertainty. A real life application at Sossego copper mine ensure that such procedures are technically implementable, supporting decision-making as (a) in-fill drilling programs; (b) review of mining sequence; (c) identification of areas of upside potential and downside risk and (d) ore blending between mining areas in order to minimize the impact of high risk areas. The goal of this work is to provide an approach for clear risk analysis and management in mine planning cycle to various aspects of pit optimisation and design, resulting in more technically and economically sustainable life-of-mine production plans and mineral reserve depletion.
Digital tools for underground mine planning: Cut-and-fill mining
