West Australian gold explorer Focus Minerals (ASX: FML) has announced a Mineral Resource update for the Brilliant South gold deposit to support the upcoming pre-feasibility study (PFS) into a resumption of mining at the company’s Coolgardie gold project in the WA goldfields.
The total Indicated and Inferred open pit resource has increased by 12%.
Updated model includes 49 holes for 13,436m drilled in 2017.
New resource will be included in the upcoming Coolgardie PFS update.
The updated Brilliant South open pit mineral resource includes drilling completed in 2017 and is reported on a dry tonnage basis using 0.7 g/t Au cut off to 230mRL.
Below 230mRL, the underground resource is reported with a 1.5g/t cut off.
Brilliant South is a core part of Coolgardie, which covers 175km2 of highly prospective tenements on the outskirts of the Coolgardie township in the Goldfields.
Focus is in the process of finalising the 2020 Coolgardie PFS update, which will include the newly updated Brilliant South Mineral Resource. The PFS update is expected to be delivered in September 2020.
Open Pit Redevelopment to Support the 2020 Coolgardie PFS
Brilliant South is located 1km south-east of the Coolgardie township and on Mining Licences M15/646 and M15/1788, which are wholly owned by Focus. The open pit is less than 5km south-west of Focus’ Three Mile Hill processing plant (on care and maintenance).
The Brilliant South open pit is a significant gold deposit. The deposit was a major open pit gold producer, mined in stages from the 1970s to the early 2000s, with total production consisting of approximately 88,000oz at an average grade of 2.45 g/t.
Focus announced a resource update for Brilliant South in 2017 (see ASX announcement dated 7 April 2017). The resource, combining open pit and underground, was 5.89Mt at 2.5 g/t for 475,000oz. Since then, Focus has completed 49 holes comprising 36 reverse circulation (RC), four diamond and nine RC/DD holes for a total of 13,436m of drilling. Several significant intersections from this drilling campaign were announced to the ASX on 27 July 2017 and included (calculated at 0.5g/t cut off and up to 3m internal dilution).
This drilling was incorporated into an in-house resource update in June 2017. This in-house resource was not announced at the time. The reason for this is that when reported at the original 1 g/t cut off grade to 260 mRL the total open pit indicated and inferred resource changed by less than ~2%.
However, the gold price has now climbed considerably and, it has been possible to push the floor for open pit resources to 230mRL and reduce the cut off to 0.7g/t Au. Furthermore, in alignment with PFS AUD gold price of $2,200/oz the underground resource cut off has been reduced to 1.5 g/t Au.
The June 2020 Brilliant South Resource model has been used to inform the 2020 Coolgardie PFS. As such, the updated model is being reported prior to releasing the PFS update.