Annual Report ELR 41 Ngalia Project Malawiri Deposit period ending 17 July 2015

Abstract

ELR 41, which lies 30km northwest of Tilmouth Well, covers the historical Malawiri uranium deposit and occurs immediately along strike to the west of Paladin Energy's larger Minerva deposit. As elsewhere in the Ngalia Basin, the Malawiri deposit is a tabular, sandstone-hosted, uranium-vanadium style of deposit located within the Carboniferous Mt Eclipse sandstone. Corner boundary pegs for ELR 41 were picked up by DGPS (<2cm accuracy) during the period. The actual boundary markers were found to be located slightly to the south (20-60m) of the boundaries depicted on the NT DME's STRIKE on-line titles database. The new co-ordinates were submitted to the NT DME to enable an update of the records. Historical drill core from Malawiri (17 holes in total) was located EME's core yard at the Bigrlyi camp and was re-logged in detail during the period. The drillcore is interpreted to contain several fluvial channel sequences with a coarse conglomerate (comprising well-rounded quartzite pebbles) deposited at the base, suggesting the depositional environment was a proximal alluvial fan located close to source. The Malawiri mineralisation is interpreted to lie within the extreme basal part of the Mount Eclipse Sandstone. In late 2014, a high resolution airborne (helicopter) magnetic and radiometric survey was flown over ELR 41 and the surrounding tenement EL 24451; final data and imagery products were received in March 2015. All magnetic data has previously been provided to the DME as part of EL 24451 reporting requirements. Because the Malawiri deposit is deeply buried by about 80m of Cenozoic sediments, an important outcome of the program was the generation magnetic imagery able to reveal Ngalia Basin units through the deep, relatively non-magnetic cover. It is apparent from previous studies that the prospective Mt Eclipse Sandstone is complexly folded and faulted with evidence for structural repetition on various scales. The deep-filtered imagery shows distinct magnetic signatures interpreted as the Vaughan Springs Quartzite and other pre-Mount Eclipse Sandstone units, in particular, the Mount Doreen Formation. Large scale isoclinal folding can be mapped through 80-100m of Tertiary cover. An ore deposit model for the Malawiri deposit on ELR 41 was created using the historic core re-logging data and was combined with an interpretation of the high-resolution magnetic data along the Malawiri-Minerva corridor. An orientation biogeochemical sampling program was undertaken in conjunction with consultant Dr Ian Fordyce in November 2014 across several lines over buried uranium mineralisation at the Malawiri deposit. The aim of the program was to test whether buried uranium mineralisation could be detected at surface by sampling leaves of deeply-rooted tree species. It was found that anomalies at Malawiri generally tend to be displaced off the actual mineralised zone and that there are pronounced differences in element enrichments between tree species. Nevertheless, it seems likely that a systematic sampling program could be successful in locating buried uranium mineralisation beneath thick cover in this area. Detailed petrological work was conducted on a number of ore samples from Malawiri drill core. Uranium mineralisation is typically associated with dark grey clay minerals which are surrounded by hematite-stained sandstone suggestive of a later oxidation overprint. Uranium minerals occur at grain-to-grain contacts between K-feldspar and quartz, and as replacements after pyrite commonly located within the cleavage plains of detrital biotite and chlorite. Exposure to oxidising fluids after uranium precipitation appears to have caused K-feldspar dissolution, remobilisation of uranium minerals and precipitation of hematite. Uranium is only preserved in patches where detrital grain contacts were not exposed to the late fluids and where low-permeability micas and clays have protected the uranium minerals.