The ore mined from Phase 14A will displace lower grade ore feed to the processing plant, with a plan to feed around 13Mt of high and medium grade ore through to FY26, to produce an incremental about 400koz of gold
Newcrest Mining announced that its Board of Directors has approved the Lihir Phase 14A Feasibility Study (FS), recommending expansion of the Lihir mine, in Papua New Guinea.
The FS, which included site investigation and trial works, outlined a plan to extend the Phase 14 cutback and safely steepen the walls of the pit utilising civil engineering techniques.
Newcrest has started mining of Phase 14A in the June 2022 quarter, through the Early Works programme, with plans to continue until FY27.
The ore mined from Phase 14A will displace lower grade ore feed to the processing plant.
Around 13Mt of high and medium grade ore from Phase 14A is planned to be fed through to FY26 to produce an incremental about 400koz of gold.
The lower-grade material will be stockpiled and fed progressively over the remaining mine-life, said the Australian mining company.
With the completion of a drilling program, the geotechnical knowledge of the cutback area has significantly improved, and enabled refinement of the anchor design, said Newcrest.
Newcrest interim chief executive officer Sherry Duhe said: “The development of Phase 14A is another innovative step forward in realising the full potential of Lihir.
“The findings of the Study are expected to deliver gold production from an additional high grade ore source which would have otherwise been inaccessible through standard mining techniques. The Study outlines an updated life of mine plan, with upside potential.
“The application of steep wall technologies, together with an alternative, lower cost and simpler seepage barrier design have the potential to enable access to additional high-grade zones outside the current Ore Reserve and extend the elevated production profile beyond FY31.”
According to the feasibility study, the project expansion is estimated cost a total capital of around $280m on a real basis, and about $296m on a nominal basis.
The study also suggests a 48% internal rate of return and $202m net present value with a payback of 2.9 years, and an updated Life of Mine (LOM).
Newcrest intends is evaluating the further application of the civil steep slope technology to exploit additional high-grade mineralisation in the north and east of the Kapit orebody.
The works can improve the production profile beyond FY31, before the high-grade ore from Kapit declines.
The design optimisation and its impact on the longer-term production profile is anticipated to be completed in the second half of CY2023, said the company.
Duhe added: “Our team continues to work diligently to maintain a strong focus on capital discipline, placing several recovery improvement capital projects on hold that currently do not meet our investment criteria.
“The Phase 14A ore zone is now well informed by geotechnical drilling that underpins the design and stability of the cutback and we expect Phase 14A to be delivering higher grade ore from FY24.”