Partial relinquishment report for EL 25183 Ammaroo Phosphate Project

Abstract

The Ammaroo Phosphate Project is located 240 km southeast of Tennant Creek. The project area contains the 40 km-long, billion-tonne Ammaroo Phosphate Deposit (partly on adjacent EL 24726), which is currently Australia's largest JORC phosphate resource, the satellite Ammaroo South resource (on adjacent EL 25185), the Rockhole prospect, and, as yet untested, greenfields potential in the east. The overall Ammaroo Phosphate Project prefeasibility has been announced. A voluntary partial relinquishment is being made from EL 25183 leaving 41 sub-blocks. This is part of a rationalisation of tenure between the Ammaroo Resource and the railway and is the second voluntary reduction of EL 25183 during 2014. Five RAB holes (APRA039-042 and APRA052) for a total of 249 m and a maximum depth of 72 m plot in the relinquished portion. Four of these holes experienced drilling difficulties. APRA042 was aborted at 20 m in palaeochannel gravel. The others caved at the surface. No prospective stratigraphy was intersected and only two holes were sampled for assay. None of the nine assays from these two holes returned >1% P2O5. This drilling and that and on adjacent ELs in the project has demonstrated that the sub-blocks being relinquished are too far into the basin to be prospective. The basin-edge facies of the Arthur Creek Formation which hosts the phosphate are unlikely to be present and even if there was phosphate present, it would be prohibitively deep for open-pit mining (probably >100 m). The area relinquished also contains a large CLC indigenous cultural exclusion zone which effectively sterilises about one third of the sub-blocks being relinquished and renders the remaining areas too small to justify retention.