Final Report for Wellington Range & King River Joint Venture 2019 NTGS Geophysics and Drilling Collaboration Funding Alligator River Project

Abstract

Vimy Resources Pty Ltd (Vimy) and Rio Tinto Exploration Pty Ltd (RTX) have formed a JV) to explore for unconformity style uranium mineralisation in the Wellington Range (EL5893), King River (EL25064 and EL25065), and Waidaboonar (EL24017 and EL27059) tenements in Arnhem Land. Exploration activities completed in the Such Wow prospect area over the past three years have identified a highly prospective, north-north-westerly to northerly-striking fault zone within EL5893 that has the potential to host uranium mineralisation. The JV applied to the NTGS for funding from Round 12 of its Geophysics and Drilling Collaborations Program to complete two diamond drill holes within the prospect area. On May 15 Vimy was notified that funding, of up to $ 87,900, had been granted for the completion of two diamond drill holes at the Such Wow and Shiba prospects. The two diamond drill holes, ARDD0001 (258.5 m) and ARDD0002 (275.1 m), were completed between the 26th July and the 31st of July by DDH1 Drilling Pty Limited. The drilling was completed a lot more efficiently than expected, resulting in significant savings. The final CORE contribution to the overall program was $52,718.36 (exclusive of GST). The first RTT drill hole, ARDD0001, was completed approximately 20 m to the west of ARRC0016, an RC hole drilled in 2018 that intersected a 30 m wide zone of weak uranium mineralisation associated with Mg-rich chlorite and phengitic illite alteration. It was noted that the crystalline basement rock was unusually homogeneous, lacking the variable lithologies usually observed in the metasedimentary units. The hole was designed to assist in determining the composition of the basement rocks. The drill hole ARDD0001 collared directly into Mamadawerre Sandstone. Weakly fractured and variably altered, coarse- to very coarse-grained sandstone was intersected down to an unconformable contact at 117.9 m. The crystalline basement rocks intersected below the unconformity are consistent with rock-types of the Palaeoproterozoic Nimbuwah complex; coarse-grained to porphyritic intrusive rocks of granodiorite to granitic composition. Two significant semi-brittle to brittle, poly-deformed, fault zones were intersected between 174 - 216 m and 229 - 237.5 m. Alteration within these fracture zones consisted of intermediate to Mg-rich chlorite and phengitic illite alteration of feldspar and ferromagnesian minerals and quartz-carbonate-chloritepyrite veining. Diamond drill hole ARDD0002 was completed approximately 300 m to the east of ARDD0001. Mapping in the Such Wow area had defined a 300 x 600 m surficial clay alteration zone at the intersection of a north-north-westerly striking fault and a regional significant northerly-striking fault. The hole was designed to test the sandstone directly below the mapped alteration zone and to determine the nature of the basement rocks below the unconformity. Due to the challenging topography in the area, the drill hole was collared directly into the northerly-striking fault zone and did not test the ideal target area for unconformity mineralisation (intersection between northerly-striking, easterly dipping fault & the unconformity). The diamond drill hole was collared directly into intensely fractured and clay altered, Mamadawerre Sandstone. Alteration and fracturing continued to a depth of approximately 40 m. Weakly to moderately altered sandstone extended down the unconformity at 112.19 m. The crystalline basement rocks intersected below the unconformity were similar to those intersected in ARDD0001 and are interpreted to be part of the Nimbuwah Complex. Two significant broad zones of poly-phase, semi-brittle to brittle faulting were observed in the basement between 125 - 132 m and 199 - 275 m. These fault intervals comprise 1 - 5 m wide chlorite annealed, chaotic to mosaic breccia zones often crosscut by narrow discrete clay gouges. Alteration within these zones is similar in terms of mineralogy but more intense than that observed in ARDD0001. Once again, quartz-carbonate-chloritepyrite veining is common within the fractured intervals. The RTT collaborations drill holes completed have provided important information that will assist in generating an improved geological framework for this part of Arnhem Land.