First combined annual report for EL 22872, EL 23892 and EL 25007, period ending 31 October 2006, Australia New Opportunities Programme

Abstract

EL 22872 Plenty River 1, EL 23792 Plenty River 2 and EL 25007 Plenty River 3 were originally generated by AusQuest Limited. The primary target is a cluster of discrete high frequency airborne magnetic anomalies evident on data from a regional airborne survey by the Northern Territory Government. The target concept is that the magnetic anomalies may mark the presence of potential diamond-bearing kimberlite or lamproite pipes beneath thin sand cover. Rio Tinto Exploration Pty Ltd (RTE) has entered a farm-in and joint venture agreement with AusQuest whereby RTE is managing exploration activities within the project area. Detailed interpretation of the airborne magnetic data was carried out and 18 anomalies were selected for ground recovery and follow up. Two of these fell into culturally sensitive areas that were excluded from the tenement area that was granted and did not have any further work. 16 Surface loam samples were collected over the anomalies and processed for diamond indicator minerals and microdiamonds. Encouragingly, a total of 8 minus 0.3mm + 0.2mm microdiamonds were recovered from four of the 16 samples. However, SEM analysis of associated chromite and garnet did not show any grains to be present that could be interpreted to be from a deep mantle source. A programme of reverse circulation drilling was designed to test a selection of the original anomalies plus two other features selected from the airborne data. Of the eight anomalies selected, four were tested by a total of 11 shallow holes with a combined total metreage of 613.5 metres. Analysis of the geochemical samples from the drilling does not show any anomalous concentrations of elements that would be considered diagnostic of possible kimberlite or lamproite. Further work is required to reconcile the previously modelled sources of the magnetic anomalies with this new subsurface information. A suite of surface loam samples and representative 50-60kg samples from the subsurface lithologies intersected in the drillholes have been collected for comparative studies of the provenance and origin of the heavy mineral suite, including the microdiamonds, to the surface loam samples already taken in the project area. These samples will be processed in the next reporting period.