Grade and product quality control by microCT scanning of the world class Namakwa Sands Ti-Zr placer deposit West Coast, South Africa: An orientation study

The Namakwa Sands operation is a world class producer of zircon, rutile and ilmenite from mainly semi-consolidated marine and dune sands. This orientation study shows that the high density contrast between the economic minerals as well as the diverse gangue mineralogy allows the use of microCT scanning as a qualitative and quantitative analytical tool. The method has demonstrated the ability to quantify final product quality, grain size distribution, grain shape definition and the identification of external and internal mineral textures. Grain size distribution data generated by microCT scans compares well with data produced by other analytical methods. As a result, the method has the potential to be applied to in situ resource calculations (total heavy minerals - THM, valuable heavy minerals - VHM), run-of-mine (ROM) grade control and the various stages of the mineral beneficiation process. MicroCT scanning applied to heavy mineral producing operations appears promising and should be further assessed against traditional analytical methods. The method also has the ability to assist sedimentological studies with respect to in situ quantitative grain size and sphericity determinations.