In this week’s edition of Bulls N’ Bears Big Hits, we examine some of the notable drill intersections revealed on the ASX, starting with Santana Minerals’ impressive 48m slice at 5.8 grams per tonne gold from 167.3m in New Zealand.
We also take a close look at other interesting drill hits from last week as reported by Predictive Discovery in Guinea, Venture Minerals in Western Australia and DevEx Resources in the Northern Territory.
The Santana hit came from one of two resource validation holes put into its Bendigo-Ophir discovery – regarded as the most significant single gold deposit in NZ in more than four decades.
Far away in the opposite hemisphere, Predictive Discovery slotted in close behind Santana’s hit, with a decent 43m high-grade gold intercept in its ongoing project development in Guinea. The company says it could be among Africa’s biggest gold plays.
Once again, Venture Minerals has shouldered its way back onto our Big Hits board, another record air-core (AC) drill intercept from the north-west corner of the company’s remarkable Jupiter carbonatite-hosted rare earths deposit.
And finally, but no less significantly amid the world’s revived nuclear debate, DevEx Resources’ recent follow-up reverse-circulation (RC) drilling of previously-reported high-grade intercepts along the Nabarlek Fault Corridor in Australia’s Northern Territory intersected a respectable 7m uranium oxide equivalent hit from 133.4m depth.
So, let’s dive in.
Santana Minerals
Bendigo-Ophir project – Central Otago, New Zealand
Hit: 48m at 5.8g/t gold from 167.3m
Santana jagged this hit in one of two diamond drillholes put into its Rise and Shine (RAS) deposit as part of a resource definition program aimed at validating continuity of high-grade results in previous drilling – and to ensure correct projections for an imminent update to its resource model.
As partial confirmation of the program’s aim, a second diamond hole just 90m south of the first hole came up with a similar 39.5m at 5.1g/t gold from 167.5m in an almost identical structural location as the headline hit.
Santana’s tenements cover 251 square kilometres in NZ’s Central Otago goldfields, 90km north-west of Oceana Gold’s world-class Macraes gold mine that has produced more than 5 million ounces of gold since 1990.
In 2020, Santana bought Matakanui Gold, which held the exploration permits at Bendigo-Ophir. Drilling continued in 2021, when the company put in the RAS discovery hole that intercepted 40.3m averaging 2.05g/t gold.
The company’s Bendigo-Ophir resources occur in four known deposits, including the RAS deposit within the RAS shear zone that hosts gold mineralisation in a strike distance of more than 20km. The RAS deposit has been traced about 1.7km down-plunge, with drilling intersecting consistent thicknesses often exceeding 25m and up to 40m of high-grade gold.
The thick, wide, tabular continuity of the RAS deposit makes it a unique gold system amenable to both open pit and underground exploitation.
The company undertook the diamond drill validation program because it had previously constrained the extents to which high-grade zones were extrapolated in its resource modelling. It was done to avoid the possibility of metal content over-estimation, which is often an issue in high-grade gold deposits.
Management says it welcomes the results from the first two holes which, combined with further structural and alteration logging, show that mineralisation in the core zone is more robust and continuous than it had previously believed. The increased confidence in the core zone estimation is important, given that the zone underpins the company’s prefeasibility study (PFS) mine plan and financial projections.
Santana has already completed five more holes in its resource validation program and is now waiting on results.
As of June, the company has identified multiple gold discoveries through 5km of strike along the RAS shear zone. The combined indicated and inferred resource estimate for the RAS deposit alone is 30.6 million tonnes at an average grade of 2.3g/t gold, containing 2.217 million ounces of gold.
The entire indicated and inferred endowment in Santana’s Bendigo-Ophir resource estimate for the shear zone is an impressive 36.8 million tonnes at 2.1g/t gold for a total of 2.463 million ounces.
Santana says its project has the potential to generate between 100,000 and 120,000 ounces of gold each year.
Predictive Discovery
Bankan project – Guinea
Hit: 43 at 5.58g/t gold from 128m
Predictive reported this superb hit among a bevy of gold runs from resource definition drilling at its “BC” area within its 5.38 million-ounce Bankan Gold project in Guinea, north-west Africa.
The results comprise part of a suite of assays from five diamond drill holes totalling 848m of infill drilling at the company’s smaller BC deposit in the south-west corner of its tenure. The headline hit comes from one of those diamond holes, which infills previous drill-spacing in the central part of the deposit, returning multiple significant intercepts below the PFS pit design.
That hole intercepted the 43m at 5.58g/t gold from 128m in a metasediment-tonalite-skarn complex close to the footwall shear and entirely outside the current PFS pit design, but within the overall resource pit shell. It includes a high-grade component of 17.3m running 11.03g/t gold from 152.7m.
Higher up the same hole, but still below the PFS pit floor, other significant intercepts within the inferred mineral resource pit shell envelope include gold runs of 3m at 1.21g/t from 80m, 3.1m going 3.65g/t from 87m, 5.15m running 1.4g/t from 98m, 8.1m at 2.52g/t from 108m, and 4.2m at 0.95g/t from 119.8m.
The BC deposit hosts an estimated mineral resource of 487,000 ounces of gold, including ore reserves of 207,000 ounces, about 3km west of the main project’s NEB deposit that contains an estimated indicated and inferred resource of 4.89 million ounces of gold.
The company’s resource definition drilling programs are ongoing to support its definitive feasibility study (DFS) and is aimed at refining the current mineral resource estimates and establishing additional deposits to extend the project’s planned 12-year mine life, which management says is “already robust”.
Venture Minerals
Brothers project – 65km south-west of Mount Magnet, WA
Hit: 57m at 3430ppm total rare earths oxides (TREO) from 36m
Venture emphatically shouldered its way back onto our Big Hits board with a new record AC drill intercept from the north-west corner of its sensational Jupiter carbonatite-hosted rare earths target. The headline intercept also includes 32m at 4193ppm TREO.
Management says drilling in the area has been particularly successful and has also reached a singular milestone, for not only has it finally received all the assays from across the entire Jupiter target, but it has also found that three of the top 10 intercepts in the project have come from its latest batch.
Venture has now completed 356 drillholes for about 22km of drilling into the Jupiter target. Assays and logging from the comprehensive program have confirmed that broad clay zones, up to 80m thick, occur through the entire near-surface projection above the Jupiter alkaline intrusion that contains broad, high-grade rare earths mineralisation with excellent grade and thickness.
The recent receipt of the final batch of assays marks the completion of the company’s stage-one resource drill-out, with Jupiter now having been drilled to a density of 500m by 250m across its entire 40sq km area. The company now has a detailed, consistent and regularly-spaced dataset and is well-positioned to focus on initial resource estimation work and advance a comprehensive metallurgical program.
On-going assessment of the dataset continues to confirm that the valuable magnetic rare earths component consistently averages 23 per cent and that uranium and thorium levels both remain extremely low throughout the entire Jupiter system.
The company now holds about 1180sq km of granted exploration licences and 178sq km of exploration licence applications comprising its extensive Brothers project. Venture says it is also now well-positioned to complete its maiden resource estimate.
Jupiter is well-situated in regional WA. It lies about a six hours’ drive from Perth via the Great Northern Highway and about 65 km south-west of the regional town of Mount Magnet. It places it away from significant population centres, yet usefully close to important infrastructure, being less than 10km from the main bitumen highway between Mount Magnet and Geraldton.
And this scribe can’t help but wonder how long it will be before we get a look at some fresh core from the alkaline host to the widespread near-surface rare earths signature.
DevEx Resources
Nabarlek North target – 2km north of Nabarlek uranium mine, NT
Hit: 7.5m at 1821ppm uranium oxide equivalent from 133.4m
DevEx’s recent follow-up RC drilling of previously-reported high-grade intercepts along the Nabarlek Fault Corridor has intersected 7.5m at 1821 parts per million uranium oxide equivalent from 133.4m.
The result comes from about 2km north of the company’s 100 per cent-owned historic Nabarlek uranium mine that lies in the heart of the world-class Alligator Rivers Uranium Province (ARUP) in Australia’s Top End. The Nabarlek mine was once considered – and may still be – Australia’s highest-grade uranium mine, with past production of 24 million pounds (Mlbs) at a grade of 1.84 per cent uranium oxide equivalent.
In its search this year for other Nabarlek-style mineralisation beneath the important unconformity contact, DevEx drilled the Nabarlek North Fault on broad 100m-spaced traverses, testing multiple uranium prospects along the U40 Fault and the Nabarlek Fault Corridor. The campaign is testing targets at the nearby U40 prospect where drilling confirms significant uranium mineralisation within an altered fault breccia at depths well below the unconformity.
Results obtained to date include 1.1m going 4452ppm uranium oxide equivalent from 252.3m, with an impressive internal run of 0.4m at 8637ppm. The system is believed to remain open to the south where the company is planning further follow-up drilling.
DevEx says new drill targets are also emerging adjacent to the Nabarlek Fault Corridor, south-west of the mine.
Two big induced-polarisation (IP) chargeability anomalies have been identified at Coopers South below previous uranium intercepts that include a significant hit of 5m at 1600ppm uranium oxide equivalent from 46m, which was reported last year. Planning is underway to test both targets next month with RC and diamond drilling.
The nearby world-class Jabiluka mine and the prestigious Ranger uranium mine, which produced 300Mlbs at 0.23 per cent uranium oxide equivalent over 40 years, remain DevEx’s principal exploration target models for big, fault-hosted, unconformity-style uranium deposits.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
