Bellevue Gold Ltd (ASX:BGL) has delivered 17% more gold than contained in the mineral resource estimate (MRE) for its namesake project from the latest grade control drilling in the Upper Armand area in Western Australia.
This program saw 151 underground diamond holes drilled for 27,189 metres completed and has converted the majority of the MRE's inferred resources to the indicated category.
The Upper Armand area is the first to be grade control drilled from underground after the surface grade control drilling at the Tribune lode in October last year.
“This is a highly favourable result because it demonstrates the conservative nature of the Bellevue resource model and the potential for mined gold to exceed the resource estimate,” Bellevue managing director Steve Parsons said.
“This degree of over-reconciliation provides another layer of insulation early in our mine plan, further de-risking our production and financial forecasts,” he added.
Comparison of the May 2022 MRE (left) and the grade control model (right).
Higher indicated gold grade
The grade control drilling on 20 metres by 10 metres centres has identified unmodelled mineralisation, with closer drill density defining high-grade shoots within the existing drill grid.
Compared to the MRE, the grade control model reports an 86% increase in indicated contained metal as well as a 3.3% increase in indicated gold grade.
Drilling covered a small sample of the global 3.1-million-ounce indicated and inferred MRE, and does not materially change the tonnage of the Bellevue Gold Project resource.
The Upper Armand area is above the main Armand orebody and mineralisation here is hosted in parallel shears around the northern edge of the historic Bellevue gold mine.
New high-grade lode
Notably, drilling has defined an additional high-grade lode between Armand and the Hamilton Lode, with standout results including:
- 0.4 metres at 92.9 g/t gold;
- 0.3 metres at 115.6 g/t gold;
- 1.2 metres at 22.4 g/t gold; and
- 1.5 metres at 17.3 g/t gold.
Other high-grade diamond drill results that have been used to inform the grade control model at Upper Armand include:
- 4.6 metres at 59.7 g/t gold;
- 3.7 metres at 46.7 g/t gold;
- 1.9 metres at 67.7 g/t gold;
- 4.6 metres at 24.5 g/t gold;
- 2.8 metres at 34.7 g/t gold;
- 3.1 metres at 31.6 g/t gold;
- 0.8 metres at 118.3 g/t gold;
- 1.7 metres at 41.9 g/t gold; and
- 1.5 metres at 40.8 g/t gold;
Robust resource
The Tribune grade control model results showed a 3.7% increase in grade and a 2.2% reduction in tonnes for a 1.4% increase in contained metal in the area, compared with the original indicated and inferred resource model.
The gold developer said the positive reconciliation of the results from both Upper Armand and Tribune against the Bellevue project model highlighted the robust nature of the underlying MRE.
As well, the increased drilling density has increased the geological knowledge and confidence in the estimate ahead of plant commissioning in the second half of next year, which would significantly de-risk the mine’s ramp-up phase.
The underground grade control drilling is continuing, targeting the remaining work areas ahead of ore production.