Newcrest Mining Limited announced that the Newcrest Board has approved the Lihir Phase 14A Feasibility Study (the Study), endorsing the project into full implementation. As part of the Study, site investigation and trial works have been completed and a robust plan has been developed which extends the Phase 14 cutback and safely steepens the walls of the pit utilising civil engineering techniques. Completion of a drilling program has significantly improved the geotechnical knowledge of the cutback area and enabled refinement of the anchor design and placement to better suit the geotechnical conditions.

Through the Early Works program, mining of Phase 14A commenced in the June 2022 quarter and will continue through to fiscal year 2027. Ore mined from Phase 14A will displace lower grade ore feed to the processing plant, with approximately 13Mt of high and medium grade ore from Phase 14A expected to be fed through to FY26 to produce an incremental approximately 400koz of gold. Lower grade material will be stockpiled and fed progressively over the remaining mine life.

Further application of the civil steep slope technology used in Phase 14A is being assessed to potentially unlock additional high grade mineralisation outside the current Ore Reserve in the northern and eastern extents of the Kapit orebody. This work has the potential to improve the production profile beyond FY31, before the high grade ore from Kapit declines. The design optimisation and associated impact on the longer term production profile is expected to be completed in the second half of calendar year 2023.

In addition, following completion of the Seepage Barrier Feasibility Study in October 2021, an alternative seepage barrier design, the Nearshore Soil Barrier (NSB) option, is currently being studied. The NSB would sit between the No Coffer Dam limit and the existing shoreline of the Inner Harbour, approximately 500m west of the proposed Kapit Seepage Barrier (KSB). Initial work indicates that the NSB would be a simpler solution, faster to construct and less costly.

A Pre-Feasibility Study (PFS) level assessment of the NSB option is currently underway and is expected to be completed in calendar year 2023. The Study production profile has been updated, with mill throughput rates revised to incorporate increased ore hardness based on an improved geometallurgical understanding. Mill operating time has been revised to reflect current mill performance with a more progressive ramp up in improvement.

Options to increase throughput rates continue to be assessed going forward. Recovery assumptions have also been adjusted, with several recovery improvement capital projects no longer meeting Newcrest's investment criteria following the inclusion of cost inflation pressures into estimates. These projects have been placed on hold and will continue to be assessed for potential inclusion into the mine plan at a later date.

In October 2021, Newcrest announced the findings of the Phase 14A PFS and the commencement of the Study and Early Works Program. Phase 14A represents an extension of the Phase 14 cutback that involves safely steepening the walls of the pit by utilising civil engineering techniques to access existing Indicated Mineral Resources which would have otherwise been inaccessible through standard mining techniques. Phase 14A provides an additional high grade ore source that will displace low grade stockpile feed that is required as the mine moves through the transitional zone (Phases 16 and 17) between the Lienitz pit and the high grade Kapit pit (Phases 18 and 19) between fiscal year 2023 and fiscal year 2027.

The Early Works Program has involved investment in civil works and mining fleet, and establishment of the initial Phase 14A benches. Mining commenced in the June 2022 quarter and is planned to continue through to fiscal year 2027. This is expected to deliver: Total ex-pit mining of 35Mt, including 13Mt of high and medium grade ore at an average of 3g/t, which will displace lower grade stockpile ore that would otherwise have been processed in the mill during this time An uplift in the total mill feed grade and an incremental approximately 500koz of gold in feed and approximately 400koz gold produced over the fiscal year 2023 to fiscal year 2026 period.

At the completion of Phase 14A mining, the high wall is expected to be buttressed with backfill to provide long term stability. The buttressing results in the sterilisation of around 550koz of contained low grade gold at the bottom of Phase 21 which would have otherwise been mined from 2032. A key objective of the Study was to improve the confidence of the civil design through a drilling program along with trial installations of the ground anchors.

The drilling program has significantly improved the geotechnical knowledge of the cutback and has enabled refinement of the Study design to improve overall stability and reduce project risk. Expit Mining to 55Mtpa: The Lihir gold production schedule forecasts mining rates to increase up to 55Mtpa over the coming years. Ore from Phase 14A is expected to be mined between FY22 and FY27 with high grade ore fed directly to the mill while the lower grade ore will be processed over the LOM.

Mining rates for Lihir are expected to continue to increase over the coming years through a combination of equipment capacity and mining efficiency projects. Additional mining capacity has been delivered following a program of truck re-builds and the replacement of primary dig units completed in fiscal year 2022. In combination with a maintenance excellence program, mechanical availability has increased to 84% from 79% over the last 12 months.

Mine efficiency improvements identified in the Study have also been realised including improved fleet utilisation, and effective dispatch tactics to reduce equipment delays. Open pit productivity continues to advance with Lihir delivering strong improvement in expit movements during Calendar year 2022.