Two adjacent licences together covering a large area located to the south of the Barrier Highway between Olary and Manna Hill are being explored for possible large tonnage, mainly buried low grade magnetite deposits that could have formed within...
Two adjacent licences together covering a large area located to the south of the Barrier Highway between Olary and Manna Hill are being explored for possible large tonnage, mainly buried low grade magnetite deposits that could have formed within the Neoproterozoic Braemar Iron Formation. During the second year of Helix Resources' magnetite exploration project, 3D inversion modelling of magnetic data was undertaken by consultant Newexco to aid targeting of a second campaign of exploratory drillholes. The Helix 2008 aeromagnetic data in conjunction with magnetic susceptibility measurements and Davis Tube Recovery (DTR) results from earlier RC drilling were used to give potential tonnage isoshell volumes and shapes for an inferred 5%, 7.5% and 10% DTR cut-off. Two large prospective undrilled magnetic domains were recognised on EL 3956 - the northern one lay ~20 km east of the Maldorky Hills, and the southern one lay close to the south-eastern corner of the tenement. Olary Magnetite designed an 11,000 m RC and 1000 m diamond NQ2 core drilling programme to obtain data from the Braemar Iron Formation in these areas that would allow calculation of a maiden magnetite resource. Drilling began in mid-December 2012, and was ongoing at reporting date: by then, 19 RC holes for 3514 m, plus 871.8 m of diamond cored tails cut in 5 of these holes, had been completed. During the third year, following renewal of both subject licences for second 5-year terms, the above drilling campaign was concluded with the completion of a further 46 RC holes for 6155.5 m plus 115 m of diamond cored tails cut in 6 of these holes. The new drilling defined five separate iron ore prospects where magnetite-bearing massive, bedded and diamictite facies are present, with the massive and bedded units tending to have a higher magnetite content than the diamictites. Laboratory analysis of separated mineral concentrates showed that the average iron content is relatively consistent over an entire facies, but the precision of ore grade determination needs improvement, since the XRF assays have shown shown that there are at times considerable differences between not only Satmagan and returned DTR results but also between DTR results and Fe grades.
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