Integrated Studies for Mapping of Uranium Mineralization in Northern Cape Province of South Africa

Abstract

Globally, there has been an ever increasing demand for uranium. This generates the need to adopt unique methodologies in order to explore the mineral to its full extent. This paper highlights an integrated approach that is adopted to explore uranium occurrences in the Northern Cape Province of South Africa. The study area is located at Springbok of Namaqualand Region. Most of the area is dominated by smooth outcrops formed by "Woolsack" mode of weathering and is characterized by pinkish fine-grained concordia granites of fair size forming the hilly terrains. These granites were intruded by quartz and pegmatite veins which host uranium and associated ores. As part of the integrated approach, remote sensing, geological, geophysical and geochemical studies were carried out in the hilly terrain area of approximately 15 sq km area. Spectral analysis was carried out using ASTER and QuickBird imageries to identify the zones of mineralisation. Band combinations of R (5/8) G (4/6) B (6/7) revealed the occurrence of uranium ore in the study area. Remote sensing and geological studies prioritized area for geophysical and geochemical studies. Ground magnetic analytical signal maps helped in deciphering the sub-surface structural anomalies. Magnetic and radiometric studies revealed that the uranium mineralization was localized along the structural features which were of sub-surficial origin. Geochemical sampling helped to identify the zones with high uranium ore concentration along the structural trend of the area. Further, geochemical data analysis also strongly supported the geophysical data and showed that the host rocks contain mineable quantities of uranium. The above integrated study indicates that uranium mineralisation in this particular area is structurally controlled which is nothing but the manifestations of geological features such as faults, fissures, and joints. The study helped to identify two blocks covering 85 Ha and 174 Ha of area and 7 drilling locations were proposed for exploratory drilling.