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Hard rock gold plant site dedication and feasibility study essentials

Australia's hard rock gold sector remains one of the most active in the world, with producing centres scattered from the Yilgarn craton near Kalgoorlie-Boulder to the porphyry belts of New South Wales around Cadia and the Paleozoic terranes of North Queensland. Each new venture starts the same way: with the long, deliberate exercise of site dedication and a feasibility study that has to satisfy bankers, boards, regulators and community stakeholders all at once. For mid-tier and emerging developers listed on the ASX, the credibility of those documents often determines whether the project ever reaches financial close.

A site dedication plan lays out where the mill, crushers, leach pads, tailings storage facility, workshops, offices and access corridors will sit. It anchors the entire engineering package, from the process flow sheet to the capital cost estimate. A feasibility study then tests whether the chosen configuration can deliver acceptable returns under realistic geological, metallurgical, permitting and operating conditions. Both documents must be tightly aligned, because inconsistencies between them are among the most common reasons financiers delay or reject funding.

The sections that follow outline the core checks that operators across Australia typically run when moving from exploration drilling toward a dedicated process plant footprint, covering geology, metallurgy, site conditions, regulation, economics and field-level verification.

Anchoring the resource estimate before layout work begins

Before any ground is broken for a plant site, the orebody itself has to be understood at a level that withstands external scrutiny. In Australia, that almost always means reporting mineral resources in accordance with the JORC Code, which sets minimum standards for drill spacing, sampling protocols, QA-QC procedures and the classification of Inferred, Indicated and Measured categories. A preliminary economic assessment based largely on Inferred resources is rarely enough to support a process plant dedication decision; Indicated and Measured tonnes are the practical foundation.

Geological continuity also needs to be addressed through oriented core, structural logging and density measurements, since these inputs drive pit slope angles, stope designs and ultimately the throughput assumptions that govern the crushing and grinding circuit. Resource models should be block-modelled and audited by an independent competent person, with the resulting estimate reconciled against production history for any adjacent or nearby pits that share similar lithologies.

Metallurgical test work and flow sheet selection

Hard rock gold ores vary enormously in hardness, grindability, sulphide content and preg-robbing behaviour, so a desktop flow sheet is not enough to lock in equipment selection. A staged test work programme typically starts with comminution tests such as Bond work index, SAG mill comminution testing and abrasion index, then progresses to gravity concentration, flotation, intensive cyanidation and full bottle-roll or column leach trials. The goal is to quantify gold recovery across the expected head grade range and to identify any refractory components that might require fine grinding, biological oxidation, ultrafine grinding or Albion-style leaching.

Once recovery curves are available, the engineering team can size the crushers, mills, gravity circuit, CIL tanks and elution columns with enough confidence to commit to major equipment purchases. Variability composites taken from different ore domains help confirm whether a single flow sheet will handle the life-of-mine feed, or whether blending strategies or staged expansions will be required as mining progresses into deeper or more complex zones.

Site characterisation, climate and infrastructure

Hard rock gold deposits in Australia sit in every climatic zone imaginable, from the monsoonal tropics where humidity drives aggressive corrosion protection requirements, to the arid interior near Kalgoorlie where water is the single most precious utility. Site characterisation has to capture topography, geotechnical conditions, hydrology, flood lines and the availability of raw water from bores, pipelines or desalination. Power supply is another decisive factor: a connection to the South-West Interconnected Network in Western Australia looks very different from a remote site that needs a hybrid solar, battery and diesel solution.

Workforce logistics also shape the layout. The Australian industry's reliance on fly-in fly-out rosters means camp design, airstrip length, road upgrade standards and even bus turnaround geometry need to be planned early, since these civil items often consume 15 to 25 percent of the total capital cost. Proximity to regional centres such as Perth, Brisbane or Townsville can shorten supply chains and reduce mobilisation costs, while truly remote sites require self-contained facilities and disciplined water management.

Regulatory permitting and stakeholder engagement

A plant site dedication cannot proceed in isolation from the permitting path. Each state has its own Mining Act and associated regulations, complemented by Commonwealth oversight under the Environment Protection and Biodiversity Conservation Act when matters of national environmental significance arise. Native Title considerations under the Native Title Act 1993 require notified engagement with traditional owners, often beginning years before ground-disturbing approvals are granted. Heritage surveys, flora and fauna assessments and ground disturbance permitting are usually progressed in parallel with feasibility work rather than left to the back end.

Stakeholder mapping extends well beyond regulators. Pastoralists, shire councils, infrastructure providers and adjacent miners all have a voice, and a feasibility study that has not been sense-checked against these groups tends to suffer cost blowouts during execution. Robust documentation of consultation outcomes, grievance mechanisms and benefit-sharing arrangements is increasingly expected by financiers as well as by the ASX's own ESG disclosures.

Capital cost modelling, economics and risk

The financial case for the plant has to be built on capital and operating estimates that meet the accuracy ranges expected of a Class 3 or Class 4 feasibility study. In the Australian context, this typically means working to plus or minus 15 to 25 percent accuracy on capital, with operating costs benchmarked against comparable operations such as Boddington, St Ives or Mt Magnet. Gold price assumptions need to be tested against a realistic deck rather than spot highs, and the analysis should be run in both Australian dollars and US dollars to capture the impact of exchange rate movements on revenue.

Sensitivity work should isolate the variables that move the net present value most: head grade, recovery, throughput, diesel price, royalty rates and sustaining capital. From there, contingency can be allocated proportionately rather than as a blanket percentage. Many developers formally bring an EPC partner onto the study at this point to validate the capital envelope, and integrated delivery credentials often sit in the lender data room alongside the feasibility itself.

Field verification items before finalising the layout

A short, structured walkover after the desktop layout catches issues that maps alone will not reveal, and the following checks tend to deliver the best return on effort at this stage.

A well-prepared feasibility package, supported by disciplined site dedication work, makes the difference between a project that raises debt on schedule and one that founders in execution. Operators across Australia are tightening their early-stage checklists precisely because the cost of rework has climbed sharply, and integrated engineering groups are increasingly brought in during the study phase rather than after the report is signed. To move from this checklist into a tailored conversation about a specific deposit, the engineering team can be contacted directly to request a scoping review.