Quantification of unplanned ore dilution associated with longitudinal sublevel stoping - Development of new numerical-empirical models

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In a global competitive minerals market, there is continued pressure on mines to reduce costs. One approach to reducing mine costs is by the reduction of ore dilution. Unplanned ore dilution has a direct influence on the cost of a mine stope and ultimately on the profitability of a mining operation. The economic impact of dilution is due to costs associated with the transportation and treatment of waste or low grade rock having little or no mineral value. The additional time required for the backfilling of the larger stope volumes produced by the occurrence of ore dilution due to the extraction of waste rock can also lead to production delays, changes to the mining schedule, and potentially, development rehab costs. The goal of this project is to quantify unplanned ore dilution (or overbreak) associated with longitudinal sublevel stoping method, by establishing new, numerical-empirical dilution models for stope and orezone design, with respect to anticipated stope overbreak and mine scheduling. Identified factors influencing unplanned dilution such as induced stress environment, stope geometry, and the stope setting within the orezone extraction sequence are to be considered. The project case study will be the Lapa Mine of Agnico Eagle Mines Limited located in the Abbitibi region of the province of Quebec. The project findings will be applicable to underground mines employing longitudinal, sublevel stoping to extract steeply dipping, tabular orezones with longhole mining. Such mining systems are commonly found in Canada, USA, Mexico, Australia and South America.