EL 23931 Batten McArthur River Region NT annual report on exploration activities year 4 of tenure 3 February 2007 to 2 February 2008

Abstract

EL 23931 Batten was granted to Gravity Diamonds Ltd (Gravity) on 03 February 2004. The EL lies within a general area where Gravity is operating a diamond exploration program, much of which is under an exploration agreement with Rio Tinto group companies and Diamond Mines Australia (DMA), which is a 100%-owned subsidiary of Gravity. During 2003 and 2004, DMA had an exclusive arrangement with BHP Billiton to deploy the Falcon airborne gravity gradiometer system in diamond exploration in Australia. The Falcon system has proved effective in diamond exploration since its development by BHP Billiton in the late 1990's.During the first year of tenure Falcon data was acquired over the entire area of EL 23931 which included gravity gradient data, high resolution magnetics and accurate elevation data. Coverage was obtained over the entire tenement, an area of 23 km. Sampling in has included a sampling in drainage that that previously reported chromite that also recovered chromite. These chromites were of ambiguous chemistry, however they matched well with results from sampling in JV ground outside the boundary of EL 23931 that were of possible kimberlitic origin. The probe data spurred an intensive mapping campaign in the south east of the tenement aimed at discerning the provenance of these grains and their possible relationship to a major airborne gravity feature centred only 1.5km south of the tenement and other clustered anomalies possibly extending into the tenement area. The zone has been extensively mapped and is covered by thick sheetwash alluvium and is unsuitable for both drainage and loam sampling. Reassessment and modelling of airborne gravity and magnetic data by staff geophysicists has highlighted three targets in this zone that can only be resolved by auger or percussion drilling.