Effects of the mineralogical composition and particle size distribution on the rheology of gold and copper tailings

Globally there is an upward trend by mining operations to opt for tailings dewatering technologies to reduce water consumption, minimise surface disturbance (footprint), increase the stability of tailings deposits and, overall, to operate sustainably. The properties of the mine tailings are largely dictated by the type of ore and the process necessary to liberate the metal values. In other words, it depends on the beneficiation process and the mineralogy of the gangue. Due to the importance of selecting the correct strategy for the management of mine tailings, designing a disposal strategy based solely on the requirements of ore processing may overlook opportunities to maximise the viability of the mining operation, especially when dewatering technologies are being considered. As an example, accepting a coarser grind may reduce overall metal recovery; however, the loss in revenue may be offset by improved dewatering performance and lower capital and operating cost to manage the tailings. Therefore, the design of the ore beneficiation process should consider the requirements for tailings disposal, specifically tailings dewatering and storage facility design, in order to obtain more efficient and sustainable mining operations. This paper will discuss the effects of mineralogical composition and particle size distribution of gold and copper tailings on rheological properties, which provides an indication of what can be achieved in thickener underflows. The present paper is based on laboratory tests performed by Golder Associates on mine projects around the globe.