Ora Banda Mining Ltd (ASX:OBM) is on track to deliver the first stoping ore next month from the Riverina Underground operations in Western Australia with all capital projects complete and steady-state production expected in the June quarter.
Development is ramping up as additional levels are accessed, with 575 metres in January representing a 97% increase from the July-December average of 292 metres.
First development ore processed
Pointing to a positive future, the first batch sample of Riverina development ore through the processing plant returned 16,727 tonnes at 2.74 g/t and 93.9% recovery resulting in 1,383 ounces produced.
This was 4% above the mine call grade and around 16% higher than the designed block model grade.
The underground project is the centrepiece of the company’s ‘DRIVE to 100 Project’ that is targeting production of more than 100,000 ounces in FY25.
“An outstanding job”
Managing director Luke Creagh said: “The team at Riverina, both Ora Banda and Byrnecut, have been doing an outstanding job to progress the ramp-up of Riverina. We now have all capital projects complete with ore development continuing and first stopes expected to be mined in March.”
The completion of primary ventilation, dewatering and power infrastructure projects combined with the increase in headings available to the jumbos, sets the mine up well for continued increase in development metres towards the steady state target of 650 metres per month.
Primary ventilation fans installed.
When stoping commences, Ora Banda forecasts the grade will be double the development grade due to the stoping width of 2.2 metres compared to 4.5 metres in development.
Drilling success
Underground diamond drilling also continues at Riverina with 7,379 metres of infill and extension drilling completed since the company’s last operational update on November 28, 2023.
This drilling is highlighting the consistency and high-grade nature of the ore lodes with results including:
- 3 metres at 20.1 g/t gold, including 2 metres at 29.8 g/t;
- 2 metres at 14.8 g/t, including 1.2 metres at 23.7 g/t;
- 2.4 metres at 21.7 g/t;
- 1.3 metres at 19.7 g/t, including 0.7 metres at 35.5 g/t;
- 1.2 metres at 36.6 g/t;
- 1 metre at 24.7 g/t; and
- 0.8 metres at 49.5 g/t.
The extensional drilling has been important in relation to defining the limits of the mineralisation on any given level.
Importantly, a significant amount of drilling has specifically targeted the Murchison Lodes, which were under-drilled in the initial resource drill out.
The primary target of the initial resource drilling was Main Lode East and Main Lode West.
Evaluation work on the Murchison Lodes is ongoing and it is expected that additional ore development will follow on the 2295 level.
“Unlocking a big system”
“The diamond drilling from the underground rig continues to define and extend the mineralisation at Riverina and further supports our view that this is very early days in unlocking a big mineralised and high-grade system,” Creagh said.
“We remain on schedule to achieve commercial production in the June quarter, and this will mark a significant inflection point for the company as it pivots away from a low-grade, open pit operation to a high-grade underground operation as the primary mill feed resulting in increased production at lower costs.”
Commercial production at Riverina Underground will have the key monthly metrics of:
- ~650 metres development (including capital and operating);
- ~30,000 tonnes stoping ore; and
- ~50,000 tonnes of total ore at a reserve grade of 4.3g/t (~6,900 ounces mined).
Main image: Aerial view of the primary power station.