WHILE resource estimations for mineral sands deposits – often approached simplistically – face many of the same challenges involved when estimating gold or iron ore deposits, there are others unique to mineral sands.
Mineral sands projects often have a long history of ownership change due to market cycles, which means estimations need to include historic data sets, past drilling programs, assaying techniques and approaches to mineral assemblage determinations.
Mineral sands deposits typically have wide drill-hole spacing, which can make domain determination a challenge. It is important to understand the underlying geology as much as possible, and capturing this and the distribution of grades through domaining is critical. The continuity of heavy mineral accumulations can often be very strong in the horizontal plane but restricted in the vertical; this can lead to variograms with high anisotropy ratios, which need to be considered thoughtfully when designing search neighbourhoods. Quantitative Group (QG) has seen the benefits of conducting Quantitative Kriging Neighbourhood Analysis to optimise the searches used for estimation.
For mineral sands deposits, it is essential to not only estimate the heavy mineral content but also slimes and oversize, as they have a direct impact on processing efficiencies. Trent Strickland and John Vann of
QG have assisted Sheffield Resources with estimation and classification of resources for four mineral sands projects during the past year, including the 4.4 billion tonne McCalls project.
QG looks forward to continuing its professional relationship with Sheffield, which is working towards establishing itself as a significant producer of mineral sands products.