WA gold producer, Ora Banda Mining has returned a clutch of high-grade drill results from the Golden Eagle underground mine, one of a series of satellite gold deposits lined up to feed the company’s Davyhurst gold processing plant about 120km north-west of Kalgoorlie.
Golden Eagle is located only 3.2km from the 1.2 million-tonnes-per-annum-capacity Davyhurst plant, which is currently treating open-pit ore from the Riverina mine about 30km to the north as the crow flies, plus underground ore from Golden Eagle.
The other gold feed sources including next cab off the rank, the Missouri open-cut mine, sit within 50km of the Davyhurst hub.
Stand-out diamond drill intersections at Golden Eagle from the most recently reported batch were 19m at an average grade of 5.4 grams per tonne gold including 11.1m at 8.9 g/t, and 5.8m at 15 g/t.
Other notable assays included 14.6m at 4.8 g/t, 7.3m at 9.4 g/t and 13.8m at 4.1 g/t, including 4.6m at 9.5 g/t.
The underground diamond drilling was designed to infill and extend the latest mineral resource estimate for Golden Eagle of 393,000 tonnes grading 3.9 g/t gold for 49,000 ounces of contained gold.
Ora Banda says the drilling numbers continue to support its pre-mining expectations for the mine’s north shoot and provide important geological information for the remodelling of the southern mining area.
Importantly, mining of the north shoot has been going to plan and in the southern zone has run into folded ore lodes that require more testing to better understand the gold distribution within the folded sequence.
To that end, additional drilling, mapping and mine development together with geological reinterpretation are under way after the southern mining area was construed as a sub vertical shear, similar to the very consistent north zone.
Ore development activities have identified a “fold nose”, which results in a moderately flat limb to the mineralisation that changes the orientation of the lodes.
The new geometry indicates wider, flatter-dipping ore zones combined with the narrower sub vertical zones previously modelled.
Ora Banda Managing Director, David Quinlivan said: “We are currently developing northwards on the 310 level towards some of these very strong (drill) results and are certainly looking forward to mining this high-grade area in the near term.”
“The southern mining area has also yielded some strong results which our geology team are currently remodelling. The flatter folded ore lode geometry in this area is a new and potentially significant development and we are currently looking at ways to better target this flatter ore zone in future mining programs.”
Gold mineralisation in the folded lodes encountered in the southern mining area has been traced down-plunge for more than 100m so far.
Grade potential of the folded lodes remains strong, according to Ora Banda, with a number of drill holes intersecting what appears to be a high-grade core.
The company suggests the flat lying nature of mineralisation has the potential to increase the ounces per vertical metre in the Golden Eagle underground mine.
The $168 million market-capped Ora Banda started mining at Riverina and Golden Eagle in the March quarter this year.
Combined probable reserves for the half dozen deposits that underpin the initial Davyhurst project stand at 6.1 million tonnes of ore grading an average 2.4 g/t gold for 460,000 ounces of contained gold.
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By Matt Birney
