Presentation Summary
Pre-concentration opportunities are available for most operations to improve the quality of their mill feed through higher grade, eliminating fine/soft contaminants or coarse/hard material. Unfortunately, our current metallurgical testing practices make it very difficult (if not impossible) to demonstrate these opportunities.
So there’s the dilemma: we cannot include pre-concentration stages in flowsheet design without some level of demonstration and yet, we never get the opportunity. As an industry, we are obliged to ensure our plant feed requires the lowest power and water consumption and the smallest footprint tailing-management facility. For a greenfield project, we cannot evaluate pre-concentration due to a lack of standardised testing methods and sample topsize. It’s also exacerbated by our current testing practices where sample preparation involves stage-crushing down to a manageable size.
It is the author’s opinion that metallurgical testing protocols need to change to allow bulk and particle sorting technologies as well as simple screening to isolate the low-grade, ‘poor quality’ component in the ore being sent to our process plants. Geometallurgical domains should be established early, based on deportment of valuable metal(s) at both coarse and fine size fractions (otherwise known as liberation). Domains should be defined based on their unique operating cost vs. recovery response.
Unless changes are made to the sample mass and topsize provided to the lab and the methods used for preliminary characterisation, the mining industry will continue to lag behind in implementing technology that is both currently available and rapidly advancing.
