As part of SRK’s assessment of pre-concentration for clients, different mine plans under a range of scenarios are evaluated to determine how rejecting waste ahead of the plant can add value. Is it through reduced dilution, lowering ore transport costs, increasing mineable reserves (by including marginal-grade material) or reprocessing low-grade stockpiles to recover additional value?
A novel output of SRK’s laboratory testing protocol is the full characterization of coarse particle heterogeneity based on a number of selected samples (quite often adjacent mineralized and unmineralized zones and will be mined together). This enables simulations of different circuit configurations. For example: single versus two-stage crushing, screening at various sizes, and bulk sorting followed by particle sorting. Tonnes and grades can be estimated for each flow, providing detailed inputs that engineering firms need when evaluating pre-concentration circuits.
This work opens opportunities also for dynamic simulation. SRK’s Discrete Event Simulation team, based in Sudbury, Canada, has developed a dynamic pre-concentration model using ARENA software. This model is used to assess changes in circuit operating practice as well as logistical factors, like equipment shutdowns (planned or unplanned) and scheduling ore transport when feed rates vary from the pre-concentration circuit. Conventional benefits of Discrete Event Modelling include optimising fleet sizes for truck haulage and concentrate handling, and estimating stockpile capacities upstream and downstream of the pre-concentration circuit.
As companies advance towards implementing pre-concentration, SRK provides ongoing support to engineer these circuits for each orebody and optimise their performance.
