Activity during Licence Year 5 was less than in the year before, mainly owing to BHP-Billiton having decided at the end of the Phase 1 drilling programme to withdraw its joint venture agreement funding from the Mutooroo and Thackaringa tenements,...
Activity during Licence Year 5 was less than in the year before, mainly owing to BHP-Billiton having decided at the end of the Phase 1 drilling programme to withdraw its joint venture agreement funding from the Mutooroo and Thackaringa tenements, leaving Minotaur Resources with 100% of the subject licence interest and commitments. New work comprised the processing of existing 2000 survey airborne EM data plus downhole geophysical data, the acquisition of 455 line km of additional detailed AEM coverage over the western part of EL 2264, and RC drill testing of two selected AEM anomalies (Rocky and Dingo South-West). For the latter 2 inclined holes totalling 402 m were completed, one at each anomaly. Both holes lacked any appreciable degree of mineralisation, although the AEM anomaly at Rocky prospect was explained by encountering a 2 m wide interval of massive pyrrhotite in the centre of a 15 m thick zone of quartz-magnetite-pyrite. Above this zone the rocks comprise typical layered pelitic-psammopelitic metasediments that are most likely equivalents of the Broken Hill Group. A granite gneiss forms the footwall. The EM conductor was interpreted to represent a metasomatic halo fringing a granite body. No economic metals occur with the intersected conductor. At Dingo South-West, traces of visible sphalerite (to 0.155% Zn) were observed near the top of hole RCD01, over the interval 26-33 m, within a pegmatitic psammite. The source of the targeted weak AEM anomaly was not explained, since no obvious conductor was intersected above the hole's TD at 192 m. During the next licence year, work on renewed EL 2913 comprised final processing of the Mutooroo Tempest datasets, ground EM surveying at Emu and Horseshoe prospects, trial micro gravity surveying at Dingo Ridge and Two Mile prospects, and mineralogical studies of 26 samples of the outcropping lode horizons. The latter analyses, done by electron microprobe at the University of Minnesota, indicated that the gahnite compositions at Mutooroo are amongst the most zinc-rich in the Curnamona Province, containing up to 35 weight percent ZnO (vs. Broken Hil gahnite at 22-33 wt%). Garnets in quartzites at Mutooroo are also typically quite manganese- rich, with around 20 wt% MnO. In October 2003 Minotaur acquired semi-detailed gravity coverage over the eastern side of EL 2913 (949 stations read on a 200 m x 400 m grid laid out across a regional gravity high marking the boundary between the Broken Hill and Thackaringa groups). Comparison of image plots of the gravity data with those of the AEM data for the same area identified three coincident residual anomalies in places where the associated, more subdued magnetic response could be interpreted as corresponding to Broken Hill Group strata. No field work took place in Licence Year 8, as Minotaur was unwilling to sole risk further drilling on its Mutooroo tenement to test the above gravity/AEM targets. Instead it undertook an in-house review of all available geophysical data, to generate a target summary to present to potential joint venture partners. This approach proved fruitful, when a new JV agreement was able to be signed with Japan Oil, Gas and Metals National Corp. (JOGMEC) on 23/5/2005, applying to four mineral exploration tenements within SA and NSW (the Border Project). The following year, between October 2005 and March 2006, saw the completion of moving loop ground EM surveys by JOGMEC to check the reliability of AEM targets at MUT002, MUT016 and Dingo North. Only Dingo North produced a satisfactory time domain EM response. Further detailed, 200 m x 400 m spaced gravity readings were acquired across Dingo North (80 stations) and Fallout Dam (141 stations) prospects on EL 2913 late in 2006, along with some additional moving loop ground TEM coverage at both prospects (3.2 and 7.2 line km respectively). Interpretation of the survey results led to the elimination of both prospects as ongoing targets.
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