MLN 955 Gove Annual Report 30 May 2018 to 29 May 2019

Abstract

During the anniversary period 30 May 2018 to 29 May 2019, Rio Tinto mined approximately 12.0 million dry product tonnes of bauxite at the Gove mining operation. No exploration or evaluation work was carried out. The 2018 Mineral Resource and Ore Reserve estimates were completed during the reporting period. Mineral resources are reported as at 31 December 2018. The total 2018 Mineral Resource (exclusive of Reserve), including Inferred, Indicated and Measured classifications, is 28.3 Mdpt at 48.25% Al2O3 and 6.78% SiO2. The Mineral Resource was calculated with no block grade cut-off, but within a bauxite thickness envelope of at least 1m inside a plateau edge buffer of 25m. Although no cut-off has been applied to the model blocks, a mineralised bauxite envelope with a threshold of <16.0% SiO2 and >40.0% Al2O3 was applied. The Ore Reserves estimated as at 31 December 2018, are 141.7 Mdpt at 49.3% Al2O3 and 6.78% SiO2.