The global mining industry is facing significant challenges through declining ore grades and increased difficulty in securing required water and energy. When combined with increasing societal and shareholder pressure, it is evident that the industry must innovate to minimise the impacts of resource extraction and ensure a sustainable future.
Traditional mineral processing flow sheets, including gravity (spiral separators), magnetic and flotation, utilise significant quantities of energy and water for materials transport and to achieve optimum metallurgical performance. Consequently, these flow sheets are prime candidates to benefit from innovative approaches to lower water consumption.
Recent test work, piloting and infield trials conducted by Mineral Technologies (MT) on their new compact turbo (CT1) separator has demonstrated high recovery of valuable minerals when operating at feed densities of up to 60 per cent solids (w/w). This testing was conducted on various ores and showed comparable metallurgical performance at high feed densities compared to industry standard spiral separators fed at 35 per cent solids (w/w).
A desktop study was conducted on a low-grade, high tonnage African mineral sand wet concentration plant comparing traditional and high density three stage spiral circuits (based on tested performance curves). The simulation showed reductions of >60 per cent in total pumping volume and >70 per cent in water usage, with proportional reductions in energy consumption and equipment sizes. The high density CT1 spiral feed also leads to a high-density tailings product, which reduces tailings pumping volumes by >50 per cent.
The high-density spiral circuit presented in this paper represents a major step forward for gravity beneficiation. The demonstrated reductions in energy and water consumption and tailings volume will greatly reduce the environmental and social impacts of existing and new operations. The reduced capital and operating costs will improve the economics of lower grade marginal deposits and further increase the profitability of high-grade prospects.