ASX-listed Saturn Metals has increased the measured, indicated and inferred gold resource of the Apollo Hill project, in Western Australia's Eastern Goldfields, by more than 590 000 oz to 2.83-million ounces, delivering a 26% overall growth in the mineral resource estimate (MRE) and reinforcing Apollo Hill as one of the largest undeveloped, single openpit gold resources in Australia.

The updated MRE will underpin the Apollo Hill definitive feasibility study and form the basis for an updated ore reserve, both of which are targeted for release later this year.

Saturn confirms that substantial growth potential remains, with the mineralisation on site remaining open in several directions. The company will continue with drilling targeting near-surface and lateral extensions.

Notably, an addition of 350 000 oz to the combined higher-confidence measured and indicated mineral resource classification lifts this portion of the resource to more than 2.19-million ounces, which now represents 77% of the total mineral resource and further derisks the project.

The updated MRE is based on an additional 367 reverse circulation and diamond drill holes totalling 62 385 m, which started in July last year.

For context, Saturn explains that 9.46 oz of gold is being returned, on average, for every meter drilled.

Saturn MD Ian Bamborough says the latest MRE is another outstanding results for the company and marks the eighth consecutive, and now largest, resource update on the project.

"Growing Apollo Hill to 2.83-million ounces while simultaneously increasing confidence in the resource is a significant achievement and further demonstrates the scale and quality of the Apollo Hill gold system. Importantly, the entire mineral resource continues to be estimated within a single, simple, large 'Whittle' pit shell, which demonstrates the potential to deliver a highly efficient mining operation through significant economies of scale and a low stripping ratio," Bamborough emphasises.