This is a CODES–CRC ORE (Cooperative Research Centre for Optimising Resource Extraction) collaborative project and is focussed on understanding the geological controls on grade by size fractionation. In some rocks, mineral phases naturally preferentially fractionate into specific size fractions when the rock is broken. This propensity can be exploited and has the potential to generate an upgraded ore stream through rejection of lower-grade, larger-sized particles. Thus, reducing the amount of energy and water usage in later grinding and processing steps. It can also be used to upgrade very low-grade ore or mineralised waste leading to a reduction in the amount of material sent to waste dumps. The project began in 2016 but had a change of staff and students at CODES in 2019 with the departure of researcher Dr Nathan Fox and two students, and the appointment of researcher Dr Julie Hunt and the arrival of new student Nathaly Guerrero. Karla Morales will join as a Masters student in January 2020.
Research within this project is directed towards identifying predictors for pre-concentration from intact rocks and drill core and is divided into an over-arching research stream and two Masters projects. One Masters project is focussed on grade by size deportment of gold using the Gramalote and Telfer deposits as examples; this is being undertaken by Nathaly Guerrero. The second is directed towards establishing a library of mineralisation styles that show a tendency for pre-concentration in early comminution stages and will begin in 2020. Within the main research stream there are several projects:
- A project on grade by size fractionation of gold at the Carosue Dam project, WA, which was completed in 2019.
- Grade by size fractionation of copper and gold at a Chilean porphyry deposit is ongoing.
- The commencement of a library of grade by size fractionation response for various mineralisation styles at different deposit types (e.g., porphyry, Sedex, VHMS, fault-related) will begin in early 2020 with the ultimate aim of early prediction of amenability for pre-concentration.
As part of the project, researchers and students are testing equipment for its suitability to assist with predicting grade by size response. In 2019 this included measurement of elements and mineralogy (e.g., portable XRF, micro XRF, bench-scale XRF, hyperspectral SWIR & TIR) and rock hardness (e.g., Equotip). In 2020 this will be expanded to include geological structures (e.g., automated systems for RQD), petrophysical parameters, 3D views (e.g., XRT), geochemistry (e.g., photon assay) and additional mineralogy equipment (e.g., LIBS). This work will be done in conjunction with a range of equipment suppliers and labs (e.g., CSIRO, Minalyze, Orexplore, Hylogger, TerraCore, Corescan and TruScan).
