Heavy mineral sands in Kirinda area, deposit characteristics and extraction potential

Abstract

Kirinda fishery harbour is dredged out periodically to pump out sand to maintain its depth. Sand samples (n= 38) were collected from the dredged-out sand pile covering all the regions and were analysed for mineralogy, particle size distribution (PSD) and microscopic observation. Mineralogical analysis via X-ray Diffraction (XRD) revealed positive availability of heavy minerals such as Ilmenite, Rutile and Zircon in different forms of compounds. As per the results of PSD test, more than 90% of the particles lay below 250 μm size. The highest percentage of the distribution fall in the range of 180 μm - 212μm. With the comparison of PSD graphs and geometrical parameters (mean, skewness, sorting, kurtosis) obtained from results, it can be concluded that the sand in the study area is well sorted. The X-Ray Fluorescent (XRF) test was carried out to find the enrichment ratio of heavy minerals. There was a considerable increment in the enrichment ratio of samples before and after Wilfley separation. But the percentage of heavy minerals in the samples is not up to upper continental crust limits of economically minable heavy minerals.