Rex Minerals Ltd. has completed an update to both the Mineral Resources and Ore Reserves for the Hillside Copper-Gold Project (Hillside) on the Yorke Peninsula, South Australia. Hillside Mineral Resource Estimate Summary The Mineral Resource Estimate (MRE) for the Hillside Project as of December 2022 is 337Mt @ 0.56% copper (Cu) and 0.14g/t gold (Au), containing 1,897kt of copper and 1,528koz of gold. This MRE supersedes the previously reported MRE for the Hillside deposit which was reported by Rex on 25th May 2015.

The 2022 Hillside MRE is reported at a cut-off grade of 0.2% copper. Hillside Ore Reserves Summary: The Ore Reserves estimate for the Hillside Project as of December 2022 is 186Mt @ 0.53% copper and 0.14g/t gold, containing 989kt of copper and 834kozs of gold. The updated Ore Reserves are based on the July 2021 Stage Two Pre-Feasibility Study transition plan.

The Stage Two transition plan is a series of phased pushbacks that begin during the Stage One Mine Plan. Stage One is approved under the current Program for Environment Protection and Rehabilitation (PEPR). A decision to transition to the Stage Two Mine Plan could occur by year five.

Under this transition plan, the Stage One open pit can transition to Stage Two and continue for more than 20 years of an updated open pit mine schedule. The December 2022 MRE was used as the basis for the December 2022 Ore Reserves estimate. Measured and Indicated Resources have been converted to Proved and Probable Ore Reserves respectively, subject to mine design physicals and an economic evaluation.

Ore Reserves by Rex were calculated from a mine design completed by AMC Consultants and mineral processing work completed by Ausenco. Changes to the Previous 2015 Mineral Resource: Work undertaken as part of the 2022 MRE saw minor changes, due to a modification of the block size in consideration of the natural geometry and distribution of the copper mineralisation at Hillside. The smaller block size provides for a higher level of definition between higher grade and lower grade blocks or waste blocks which match the equipment selection for the proposed Hillside mine.

All other variables including drillhole data, geological interpretation and grade interpolation methods are un-changed since the previous MRE. Comparisons between the 2015 and 2022 Hillside MRE (Table 3) resulted in a reduction of approximately 3% to the copper metal content for the total MRE. Changes to the Previous 2021 Ore Reserve: The Ore Reserves represent an update to the previous Ore Reserves announced to market on 20 July 2021.

A comparison of this Ore Reserves estimate to the 2021 estimate is presented in Table 4. There has been no mining or depletion of the 2021 Ore Reserves since their calculation. Work undertaken as part of the 2022 Hillside Ore Reserves saw no material change to the Ore Reserves from the 2021 Hillside Ore Reserves as a result of the updated Hillside MRE.