Only one month after its first gold pour at the company’s Warrawoona gold operation, Calidus Resources is looking at its Blue Spec East prospect as an open pit operation following strong drilling results. The move could boost throughput at its nearby plant in Western Australia’s Pilbara region.
The company produced the first gold from its wholly-owned Warrawoona gold project 70km to the north-west of the prospect last month, pouring 33kg and aims to ramp up to an annual 90,000 ounces in stage one.
Historic drilling at Blue Spec East, 20km south-east of Nullagine revealed some significant albeit deep intercepts below 120m with unclear geometry around the controlling structures.
However, a recent round of RC drilling has revealed a different, shallow picture. Five holes returned strong results, headlined by 4m grading 2.42 g/t gold from 12m, 52m going 1.4 g/t gold from 22m and 20m assaying 1.41 g/t gold from 44m.
Further drilling will be needed to sharpen the numbers but Calidus argues the new results more accurately define the shape of the previously identified intersections and verify that mineralisation at depth continues close to the surface where it may be suitable for open-pit operations to drive more ore into its Warrawoona infrastructure.
At Blue Spec, south of the main fault zone hosting the Blue Spec and Gold Spec deposits, drilling has confirmed that a newly identified zone is highly anomalous in gold and pathfinder elements.
The Blue Spec area contains operations that were mined historically from 1906 to about 320m and still has existing decline and shaft infrastructure. Facilities include offices and workshops, extensive roads and historical processing facility and tailings dam. The mine was closed by Anglo American in 1979.
The mineralisation at Blue Spec East, unlike that at Blue Spec and Gold Spec on the main shear, is low in antimony. Almost all samples have less than 120ppm antinomy.
Five widely spaced RC holes between 78m and 100m deep at the Blue Spec South target, about 800m to the west-south-west of Blue Spec East, were less fruitful however they revealed another gold-bearing fluid pathway in the acreage that will need more work with the drill bit.
The results from 670m of RC drilling from Calidus’ Marble Bar prospect have also come back with some healthy, shallow gold hits, including 2m going 8.03 g/t gold from 22m, 2m grading 6.75 g/t gold from 48m and 2m showing 4.53 g/t gold from 85m. A couple of one-metre intercepts went higher than 11 g/t gold.
Management has been working on a feasibility study for Blue Spec and says it is now expected in September after suffering covid-related supply chain delays along with the rest of the industry.
The company has managed to largely complete metallurgy tests and mining studies, including geotechnical work.
The study is looking at a new underground mine targeting existing resources below the historic Blue Spec and Gold Spec underground workings. Calidus says the new results are outside the existing resource figure and could extend the Blue Spec mine life.
The processing route has been settled, however Calidus is still fine-tuning the capex and opex budgets of the sulphide float plant and underground mining operations.
Keeping its options open, Calidus is also running an owner mining study in parallel, for a relatively small underground mining operation.
Calidus Resources Managing Director, David Reeves said: “These results clearly demonstrate there is opportunity for additional mine life at Blue Spec beyond the current resource. In addition, anomalous gold results from a parallel shear are encouraging for the wider area where targeted soil sampling is scheduled to begin shortly.”
Reeves says the initial drilling program at Marble Bar has demonstrated the presence of shallow high-grade gold down dip from the old workings.
The results will be followed up with further drilling as the area may provide additional high-grade ore to Warrawoona, given it is just 25km from the processing plant.
Based on feedback from regulators, the company expects operations will kick off at the end of the wet season, early next year.
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By Matt Birney
