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.

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Historically cyclone technology has been used for classification and dewatering purposes in mineral processing. It has also been extensively used in the preparation of suitable material for hydraulic backfill. Conversely when it comes to paste backfill plant design, thickening and filtration technology is typically used, and where high backfill strength is required, classified aggregate is often added. These are viable and accepted practices for the preparation of paste backfill; however, in certain applications the use of cyclones within the paste preparation process provides alternatives which can result in lower capital and/or operating cost for the paste backfill system. This paper will present novel applications of cyclone classification and dewatering technologies in the preparation of paste backfill. Specifically, the paper will discuss how cyclones can be used in certain applications to dewater the tailings without the need for thickeners, thereby lowering the capital cost and/or reducing the cement binder requirements and consequently lowering the operating cost. Examples of projects where the use of cyclone classification was considered during the development of the process flow sheet highlights the drivers for its incorporation in the resulting paste backfill systems.

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