Combined Annual and Final Mineral Exploration Report for EL 26555 Borroloola (Hells Gate) Project 11 September 2008 to 10 September 2020

Abstract

This Combined Annual and Final Report covers mineral exploration by Sandfire Resources Limited (Sandfire) on the Borroloola Project Hells Gate Prospect EL 26555, for the period 11th September 2008 to 10th September 2020 (the 'reporting period'). When granted on 11 September, 2008 over 312 graticule blocks, EL 26555 had prospectivity for both iron ore and manganese mineralisation. The Sherwin Formation, formerly the Sherwin Ironstone Member of the McMinn Formation, in the Mesoproterozoic Roper Group contains massive oolitic to pisolitic ironstone within interbedded medium to very coarse ferruginous sandstone, mudstone and shale. Outcrop of the Sherwin Iron Formation is typically 1-8m thick. Cretaceous and Tertiary superficial horizons overlying the Proterozoic basement have potential for manganese accumulations analogous to the Groote Eylandt Manganese Mine mineralisation. From the grant of EL 26555 on 11 September 2008, a review of existing geological and geophysical datasets during 2008, geological mapping and rock chip sampling of the Sherwin Formation haematitic sandstone during 2009, and assessment of the iron ore potential in 2010 were carried out by Sandfire staff. This was followed by assessment of the manganese potential and prospectivity by consultant Barrie Bolton during 2011. Subsequently, a voluntary partial surrender of 209 graticule blocks was submitted on 8 September 2011, with 103 graticule blocks retained from 11 September 2011. Detailed geological mapping and rock chip sampling by consultant Richard Langford in 2012 recommended drilling that was carried out in a 12 hole RC drilling program (13HGRC001-012) between 25th October and 4th November 2013. The drilling program was designed to test the structure, thickness and continuity of the shallow-dipping Sherwin Formation mineralised horizons that had returned encouraging rock chip sample results. However results from the drilling were in line with downhole samples barren of observed iron mineralisation. The most significant intersection was returned from 13HGRC008 73.0 - 76.0: 3.0m at 60.2% Fe. Rehabilitation of the RC drill pads and access tracks during October 2014 was followed by a DME Mining Environmental Compliance Branch Audit inspection carried out September 2015, as reported in the 2017 MMP Authorisation 0234-04 Variation 5 Review and Amendment Report. During the reporting period of the EL 26555 2018 Annual Report, a technical review of the prospectivity for manganese and iron ore mineralisation concluded that the focus be on the known iron ore mineralisation at the Hell's Gate prospect area, and this led to the partial relinquishment of 88 blocks from the tenement area on 22 August 2018, with 15 graticule blocks retained from 11 September 2018. No exploration activities were carried out during the 2019 and 2020 reporting periods. It was concluded that EL 26555 held low prospectivity for economic iron ore mineralisation, and that it be surrendered on its scheduled expiry date of 10 September 2020.