Journal of the Southern African Institute of Mining and Metallurgy
On-line version ISSN 2411-9717
VAN DER WESTHUYZEN, P; BOUWER, W and JAKINS, A. Current trends in the development of new or optimization of existing diamond processing plants, with focus on beneficiation. J. S. Afr. Inst. Min. Metall. [online]. 2014, vol.114, n.7, pp. 537-546. ISSN 2411-9717.
Gone are the days of stock-standard diamond beneficiation and final recovery circuits that could, with minor modifications, be adapted to treat any diamond-bearing ore source. A new era has dawned, offering the opportunity to streamline existing diamond processing operations or develop simpler, more efficient, and economical diamond processing plants, with the focus on more efficient comminution, beneficiation, and final recovery. This change in scene has been brought about by: ► The introduction, rapid development, and maturation of multiple comminution, sorting, and recovery technologies ► The need to adapt to a new standard of project approach post the commodity super-cycle phase, where optimizing existing operations and developing scalable, 'fit for purpose' new mines are fast becoming the norm in diamond processing plants in both primary and alluvial operations ► The quest for energy efficiency and lower labour costs ► More remote and inaccessible reserves (under lakes, tops of mountains etc.). This paper serves to identify some technology advances and demonstrates how these could be considered as replacements for or in combination with conventional technologies to arrive at an optimum techno-economic solution. To name a few applications/technologies: ► Comminution: conventional cone crusher, modified/specialized cone crusher, and the high-pressure grinding roll (HPGR). Although significant advances have been made in recent years, this paper only briefly covers comminution within the beneficiation circuit design ► Waste sorting: NIR (near-infrared) sorting, optical (colour) sorting, XRF (X-ray fluorescence) ► Primary concentration by combining dense media separation (DMS) with either XRT (X-ray transmissive), pulsed X-ray, jigs, or pan plants depending on the application, scale, and economics ► Final recovery of diamonds with either conventional X-ray technology, pulsed X-ray technology, or XRT. From recent studies, it can be concluded that there is no longer a standard solution, but rather the 'right' or appropriate solution. Through combining a sound knowledge of the ore source (ore dressing studies or on-mine data gathering) and leveraging off the advances in technologies, one is able, through trade-off studies, to arrive at the ultimate techno-economic configuration, the 'right' solution. Emphasis is placed on maximizing diamond recoveries through appropriate technology selection and minimizing the associated costs in an effort to de-bottleneck or improve efficiencies of existing diamond processing plants, or to arrive at the ideal new diamond process plant design.
Keywords : diamond recovery; process design; diamond concentration; optimization.