Lunnon Metals’ Lady Herial gold pit: production outcomes and design cues for engineers
Reviewed by Tom Sullivan

First reported on Australian Mining
30 Second Briefing
Lunnon Metals’ completed Lady Herial open pit in Western Australia is expected to deliver about $39 million in pre-tax free cash flow after producing slightly more gold than forecast in the January 2026 feasibility study. Mining finished in early August, ahead of schedule, with final ore processing and reconciliation now under way to refine grade, recovery and cost assumptions. The outcome provides fresh performance data for Lunnon’s future open-pit designs and cut-off strategies in the Kambalda district.
Technical Brief
- Lady Herial is a shallow open pit gold operation in Western Australia.
- Ore was trucked to a third-party processing plant under toll treatment arrangements rather than on-site processing.
- Lunnon Metals used the pit as an initial cash-generating asset while advancing its nickel portfolio.
- Mining data from Lady Herial will be used to refine geotechnical and dilution assumptions for future pits.
- Reconciliation outcomes are expected to inform updated pit shell optimisations and economic cut-off grades across nearby prospects.
- Operational performance at Lady Herial provides a benchmark for contractor productivity and unit mining costs in local conditions.
- The project offers a short-cycle case study in sequencing small open pits within a predominantly underground-focused mining district.
Our Take
An expected A$39 million pre-tax free cash flow from Lady Herial puts Lunnon Metals’ gold exposure into the mid-tier of Western Australian project cash generators in our database, giving it optionality to self-fund parts of its 2026 feasibility work rather than relying solely on equity raisings.
With feasibility work flagged for January 2026, Lunnon Metals is timing its study pipeline to coincide with heightened industry attention on digital and automation integration in Australian mines, as highlighted in the August 27, 2026 piece on AI and connected data, which could influence how it scopes future project designs.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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