Development of an Advanced Throughput Forecast Model for Minera Los Pelambres
Minera Los Pelambres (MLP) is a copper mine located in north-central Chile. The comminution circuit consists of two primary crushers and three SABC grinding circuits, treating 175,000 tonnes per day (tpd). MLP built an empirical throughput model using their comprehensive drill core database. The main parameters were SAG feed size (80% passing size or F80), ore breakage and comminution parameters (Axb and BWi), and feed blend proportions. The model achieved good accuracy with mean relative errors of 3.5% and 3.2% on a monthly and annual basis, respectively. However, MLP aimed to further enhance the accuracy and eliminate the need for frequent recalibration to deal with changes in ore characteristics and operating conditions. Hatch was engaged to review the current model, ore characterisation, blast fragmentation, and plant operation and develop a new power-based throughput forecast model. This semi-mechanistic model provides better prediction of the SAG mill feed size based on rock characteristics and blast fragmentation modelling and accounts for coarse (F80) and fines (-10 mm material) in the feed. Thus, the new model achieves lower relative errors (3.0% and 1.4% on a monthly and annual basis, respectively). The new model is more reliable for future changes in ore characteristics, eliminating the need for frequent recalibration and improving long-term accuracy.