Ora Banda Mining Ltd (ASX:OBM)’s weekly performance at its crushing circuit at the Davyhurst Gold Project in Western Australia continued to improve in September.
In an update on the operational ramp-up at its project, the company said the notable aspect of the improvement was the trial of the crushing circuit with 100% primary rock as feed for several days.
Further, gold production for August and September averaged over 5,300 ounces per month, or 80% of the average annual budget production requirement per month.
The company continues to implement changes and improvements to increase towards target production levels.
Trial run
During this trial run, the crushing circuit performance lifted to annual nameplate capacity of 1.2 million tonnes.
Since August, crushed oxide product from a mobile crusher has been supplementing the installed crushing circuit to address the issues with a higher percentage of oxide feed in the blend.
Ora Banda will continue to supplement its crushing operations as required whilst focusing on planning mining activities to further improve the feed blend.
Other updates
Other operational items include:
? The site sample preparation laboratory is now operational, which will improve assay turnaround;
? A new drill rig is currently undergoing commissioning to improve drill penetration rates at Missouri;
? The tailings storage facility cell construction is almost complete, with tailings forecast to be deposited into the cell from October;
? Diamond drilling at the Golden Eagle underground mine intersected mineralised contacts where expected according to the revised interpretation. Gold grades and widths were not economic and mining at Golden Eagle is now unlikely to be extended beyond January; and
? Staffing levels, like many mining companies, continues to be problematic for Ora Banda and its contractors.
The company is currently re-forecasting its annual production based on the above and will advise if there is any change to guidance once complete.
Lithium occurrences
Outside of the disposed Mt Ida tenements, the company retains extensive land holdings with known lithium occurrences, which have also been categorised as lepidolite.
Ora Banda is gathering further samples for the purposes of mineralogical testing to confirm the ratio of spodumene to lepidolite.
The test-work results are expected to take several months to be received.
Whilst there is no recorded historical exploration for lithium within Ora Banda’s land holding, several lithium occurrences are known, based on descriptions taken from mapping and drilling activities, which intersected lithium during gold-focused exploration.
Lithium occurrences identified at Riverina occur in narrow more than 2 metres thick pegmatite intrusions, which generally trend east-west and can be up to 500 metres long.
By visual estimate, the percentage of lepidolite can be up to 20% of the rock mass.
A lithium-bearing pegmatite was exposed in the Waihi pit, trending east-west and dipping moderately north.
The pegmatite is about 2 metres thick and has been traced for over 800 metres strike.
Lithium-bearing pegmatite material has also been found on the mullock heap from the Golden Pole historic mine.
A zoned lithium-bearing pegmatite was intersected in drilling at the Gila deposit.
The pegmatites appear zoned with abundant lepidolite within the core of the pegmatite, however, there may be other lithium minerals present including zinnwaldite, petalite and spodumene.
Further analysis of the core is required to determine the full suite of lithium minerals present.
There is a high probability that other lithium-bearing pegmatites exist in the vicinity.
Further sampling work
In addition to the lithium occurrences inadvertently identified through gold exploration, lithium mineralisation has been identified at Mt Ida to the immediate north, and Coolgardie to the immediate south, of Ora Banda’s tenements, both of which have been historically reported to have lepidolite as the dominant lithium mineral.
With Ora Banda’s land tenure considered to be highly prospective for pegmatite-hosted lithium mineralisation, further sampling work will be undertaken to confirm the mineralogy of these identified lithium occurrences.
Engineering review
The company said the final report of the independent engineering review of the Davyhurst processing facility has found no fatal flaws within the processing facility.
Whilst the conclusions and related recommendations are each material to the operation of the processing facility, Ora Banda notes that all key recommendations made were already in the process of being implemented or planned to be implemented.
Additional minor recommendations will also be adopted.
