EL 3347 Cadell Annual report for the period 28 July 2003 to 27 July 2004

Abstract

Exploration activities carried out during the 2003-2004 reporting period were designed to determine the uranium mineralisation potential of the Steven's Anomaly area in the northwestern corner of the tenement. This consisted of a helicopter assisted drilling program of one diamond drill hole, CDD001. The hole was spudded on the sandstone plateau immediately south of the airborne radiometric anomaly that defines Steven's Anomaly. No mineralisation was intersected, but a number of geochemical and gamma ray anomalies were encountered in sandstone and basement near the unconformity. The largest uranium anomaly (18.2 ppm in total digest) is the only one that appears to be associated with significant labile uranium (12900 ppb in U_G950). Unfortunately, the vertical extent and geochemical characteristics of the basal >0.6 m thick radiogenic pegmatite interval was not tested because the hole was terminated. Lead isotope data are interpreted to indicate the derivation of lead in the lower 15 m of sandstone and upper 40 m of basement from a dominantly uranium source. 207Pb/206Pb is as low as 0.2 and 208Pb/206Pb is as low as 0.42. There are a number of lines of evidence supporting the former existence of a hydrothermal system at CDD001 involving transport of uranium through (and rarely introduction into) Mamadawerre Sandstone and Nimbuwah Complex above and below the unconformity, including: 1. narrow low-order labile uranium concentrations; 2. lead isotope data indicating a mainly U source; 3. stratified illite, chlorite and haematite alteration defined by lithology, whole-rock geochemistry and PIMA data; 4. stratified clay alteration and silicification in the Mamadawerre Sandstone, implying the former presence of stacked aquifers and aquicludes; 5. phosphatic lenses near the basal unconformity.