OZ Minerals Limited Prominent Hill 2018 Mineral Resource and Ore Reserve Statement and Explanatory Notes As at 30 June 2018 TABLE OF CONTENTS PROMINENT HILL MINERAL RESOURCE STATEMENT AS AT 30 June 2018 ................................................. 4 Summary ............................................................................................................................................. 4 Setting ................................................................................................................................................. 6 Changes in the June 2018 Mineral Resource Estimate ......................................................................... 7 JORC CODE, 2012 EDITION, TABLE 1 .................................................................................................. 10 Section 1 Sampling Techniques and Data ........................................................................................... 10 Section 2 Reporting of Exploration Results......................................................................................... 14 Section 3 Estimation and Reporting of Mineral Resources ................................................................. 15 Competent Person’s Statement ......................................................................................................... 20 Contributors ...................................................................................................................................... 20 PROMINENT HILL ORE RESERVE STATEMENT AS AT 30 June 2018 .......................................................... 21 Summary ........................................................................................................................................... 21 Prominent Hill Ore Reserve Estimate for 2018 ................................................................................... 22 Changes in the June 2018 Ore Reserve Estimate ................................................................................ 24 JORC CODE, 2012 EDITION, TABLE 1 .................................................................................................. 27 Section 4 Estimation and Reporting of Ore Reserves .......................................................................... 27 Competent Person’s Statement – Underground ................................................................................ 32 Contributors ...................................................................................................................................... 32 Prominent Hill 2018 Mineral Resource Statement Issue Date: 12/11/2018 Page 2 of 32 and Explanatory Notes as at 30 June 2018 LIST OF FIGURES Figure 1: Location of Prominent Hill, South Australia ............................................................................... 6 Figure 2: Copper metal changes in 30 June 2018 Prominent Hill Mineral Resource estimate update* ...... 8 Figure 3: Gold metal changes in 30 June 2018 Prominent Hill Mineral Resource estimate update* .......... 8 Figure 4: Long projection of Prominent Hill 2018 Mineral Resource showing future drill target areas ...... 9 Figure 5: Ore Tonne changes in the Underground Ore Reserve Estimate update*.................................. 25 Figure 6: Copper metal changes in the Underground Ore Reserve Estimate update* ............................. 25 Figure 7: Gold metal changes in the Underground Ore Reserve Estimate update* ................................. 26 LIST OF TABLES Table 1: Copper Mineral Resource estimate as at 30 June 2018 ............................................................... 5 Table 2: Gold Mineral Resource estimate as at 30 June 20181.................................................................. 5 Table 3: Metal Pricing and Metallurgical Recoveries .............................................................................. 17 Table 4: Prominent Hill Ore Reserve Estimate as at 30 June 2018 .......................................................... 22 Table 5: Prominent Hill Ore Processed for the period 1 July 2017 – 30th June 2018 ............................... 23 Table 6: Underground Cut-off Grade ..................................................................................................... 27 Table 7: Stope Dilution and Ore Recovery .............................................................................................. 28 Table 8: Stope Dilution Grades .............................................................................................................. 28 Table 9: Metallurgical Recoveries .......................................................................................................... 29 Table 10: Prominent Hill Economic Parameters ..................................................................................... 30 Prominent Hill 2018 Mineral Resource Statement Issue Date: 12/11/2018 Page 3 of 32 and Explanatory Notes as at 30 June 2018 PROMINENT HILL MINERAL RESOURCE STATEMENT AS AT 30 JUNE 2018 Summary The Prominent Hill June 2018 Mineral Resource has been estimated at 130 million tonnes of copper mineralisation grading 1.1 per cent copper and 0.6 grams per tonne gold and 20 million tonnes of gold mineralisation grading 1.2 grams per tonne gold. The Prominent Hill Mineral Resources consist of the Prominent Hill Underground and Surface Stockpiles. Mineral Resources are inclusive of Ore Reserves. This Mineral Resource estimate update supersedes the previously reported Mineral Resource estimate in the ASX release “Prominent Hill underground Reserve growth continues, mine life extended to 2029” released on 21 November 2017. The updated Prominent Hill Mineral Resource estimate includes, where applicable, additional delineation and grade control drilling completed since the cut-off date of the previous Mineral Resource release, reflects geological interpretation adjustments and improved classification confidence, and mining depletion. The June 2018 Copper Mineral Resource estimate is 7 per cent lower in mineralisation tonnes, 9 per cent lower in copper metal tonnes and 4 per cent lower in gold ounces than the previous Mineral Resource estimate. The Gold Mineral Resource estimate is 12 per cent lower in mineralisation tonnes and 18 per cent lower in gold ounces. The key drivers for change are as follows: Full depletion of all Open Pit Mineral Resources. Decreases in Copper and Gold Mineral Resources due to mining depletion from the Prominent Hill Underground. Growth in Surface Stockpiles due to high volume low strip ratio mining from the Open Pit. Upgrade of an estimated 4 million tonnes of new and Inferred Mineral Resources to Measured and Indicated classification through diamond drilling of the Prominent Hill Underground. Reduction of approximately 3 million tonnes of Inferred Mineral Resources following re-evaluation of geological and continuity interpretations based on improved mineralisation knowledge, partially offset by a reduction in cut-off grade. A summary of the current Prominent Hill Mineral Resource estimate is presented in Table 1 for copper Mineral Resources and Table 2 for gold Mineral Resources. Prominent Hill 2018 Mineral Resource Statement Issue Date: 12/11/2018 Page 4 of 32 and Explanatory Notes as at 30 June 2018 Table 1: Copper Mineral Resource estimate as at 30 June 20181 Category Tonnes CuEq Cu Au Ag Cu Au Ag (Mt) (%)2 (%) (g/t) (g/t) (kt) (koz) (Moz) Measured 50 1.6 1.3 0.6 3 650 890 5 Underground Indicated 23 1.4 1.1 0.6 3 240 430 2 $52/t NSR3 cut-off 46 1.4 1.0 0.6 2 480 850 4 envelope4 Inferred Total 120 1.5 1.2 0.6 3 1,400 2,200 11 Surface Stocks Measured 13 1.0 0.8 0.5 2 110 200 1 $16/t NSR3 cut-off5 Measured 63 1.5 1.2 0.5 3 760 1,100 6 Indicated 23 1.4 1.1 0.6 3 240 430 2 Total Inferred 46 1.4 1.0 0.6 2 480 850 4 Total 130 1.4 1.1 0.6 3 1,500 2,400 12 Table 2: Gold Mineral Resource estimate as at 30 June 20181 Category Tonnes CuEq Cu Au Ag Cu Au Ag 2 (Mt) (%) (%) (g/t) (g/t) (kt) (koz) (Moz) Indicated 2 1.3 0.0 2.3 1 0.9 160 0.1 Underground $52/t NSR3 cut-off Inferred 3 1.5 0.0 2.7 0.7 1.3 250 0.1 envelope4 Total 5 1.4 0.0 2.6 0.8 2.2 410 0.1 Surface Stocks Measured 15 0.5 0.1 0.8 2 17 380 1 $16/t NSR3 cut-off5 Measured 15 0.5 0.1 0.8 2 17 380 1 Indicated 2 1.3 0.0 2.3 1 0.9 160 0.1 Total Inferred 3 1.5 0.0 2.7 0.7 1.3 250 0.1 Total 20 0.7 0.1 1.2 2 19 790 1 1 Table subject to rounding errors. 2 Copper equivalent (CuEq %) calculation can be found under “Cut-off parameters” in the attached JORC Table 1 documentation. 3 Net smelter return (NSR) details can be found under Section 4 “Cut-off parameters” in the attached JORC Table 1 documentation. 4 In situ Cut-off = nominal $52/t NSR envelope interpretation guided by stope optimisation run at 5m x 12m x 20m and geological continuity. Copper-gold Resources are defined only within copper domains and gold Resources are defined only within gold domains. 5 Stockpile Cut-off = $16/t NSR covers rehandle and processing costs. Prominent Hill 2018 Mineral Resource Statement Issue Date: 12/11/2018 Page 5 of 32 and Explanatory Notes as at 30 June 2018 Setting The Prominent Hill iron-oxide copper gold (IOCG) deposit is located in the north-eastern portion of the Archaean to Mesoproterozoic Gawler Craton, South Australia (Figure 1). The Gawler Craton covers approximately 600,000 square kilometres of South Australia. Outcrop in the Mount Woods region is sparse and much of the current understanding of the Mount Woods Domain comes from exploration drilling and geophysical datasets. The Gawler Craton