Final annual group report, GR231

Abstract

Manganese was the target commodity for EL 27305 and 27308, also known as USI's Gulf Project. The style of manganese expected was Cretaceous sedimentary manganese similar to Groote Eylandt. A detailed desktop study was undertaken to identify the prospective Cretaceous lithologies within the tenements. Subsequently a field visit was undertaken to follow-up on the most prospective areas. The results of the field investigation were disappointing and no significant manganese was discovered. Although not all of the Cretaceous outcrop was visited the remaining areas are unlikely to differ from the visited sites. A 50% reduction of the tenements were made in 2011. The relinquished portions were selected based on the presence of outcropping Cretaceous or potentially buried Cretaceous outcrops. Following the field visit it was hypothesised that the areas of relatively thick transported cover may represent palaeo-depressions in the Proterozoic basement. These depressions, if present during the Cretaceous, may act as depocentres for manganese which was contemporaneous with Groote Eylandt mineralisation. In an effort to explore under cover an AEM survey was proposed. Due to the elevated potential on several of USI's other tenements funding and personnel were required to be reallocated to other project in the Northern Territory. As it is unrealistic that USI will be able to fully commit the funding and time to the Gulf project in the near future they consequently relinquish the remaining blocks and will continue to focus on their other project areas. The areas of potentially buried Cretaceous manganese still remain unexplored and should be followed-up. No attention was given to other commodities such as base metals or diamonds.