In preparation for the AusIMM Geomet ’16 conference in Perth next week we thought a brief introduction to how operational mineralogy can be used to build or enhance geometallurgical models would be of interest. It is a question that we get asked a lot and an area where the application seems to lag behind the capability available to operations now. Mineralogy is often viewed as too complex or too expensive to be a core aspect of a geometallurgical development program but by moving the capability to site a whole range of possibilities is opened up. MinAssist will be presenting a workshop introducing operational mineralogy and how it can be used with production geometallurgy at the Geomet ’16 conference. There are still places available so if you are in Perth be sure to sign up.
Put simply, geometallurgy is the science of relating geochemical assay data to orebody mineralogy and orebody mineralogy to metallurgical testwork results with the ultimate aim of being able to predict metallurgical response using geochemical and mineralogical data. Operational mineralogy uses mineralogy together with geochemical assay data to understand and optimise mineral processing of an orebody. Typically, a geometallurgical model is constructed in the early stages of an operation, perhaps during prefeasibility and feasibility. Operational mineralogy is a component of sampling during active mineral processing and is undertaken once mining and processing has commenced.
There are obvious synergies between geometallurgical modelling and operational mineralogy. One of the first steps of an operational mineralogy program is to undertake a detailed material characterisation study to establish mineralogy and determine key textural information for typical feed material that will be processed in the short to middle term. If a geometallurgical model of the orebody already exists, domains of consistent mineralogy will already have been modelled. The geometallurgical model can be applied as a guide for early operational mineralogy sampling, resulting in a more representative operational mineralogy survey.
Conversely, once an operational mineralogy program is established at a site where a geometallurgical model exists, the mineralogy for feed material can be reconciled with the model. The results of the reconciliation process can be used to update the geometallurgical model. Actual processing performance of feed characterised by operational mineralogy can be used to update the geometallurgical model in order to make it more predictive for processing of future feed material.
For example, a geometallurgical model may have a domain of material where metal recovery is related to a combination of grade and pyrite content. Once updated with operational mineralogy data for feed from this same domain this relationship can be further refined and applied back to predict the behaviour of remaining in-ground material.
Geometallurgical models are based on thousands of assay data points, hundreds of mineralogy analyses and tens of metallurgical testwork results. If a geometallurgical model can be updated with operational mineralogy data and real processing performance data the amount of data in the model will increase exponentially resulting in a far more robust predictive tool.