Current trends in the development of new or optimization of existing diamond processing plants, with focus on beneficiation
P van der Westhuyzen, W Bouwer, A Jakins
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 onmine
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.