Bulls N’ Bears Big Hits examines some recent notable drill intercepts revealed on the ASX, including Riversgold Limited’s 10-metre intercept grading 8.89 grams per tonne (g/t) gold from 46m, including a 1m hit at 77.96g/t gold, in Western Australia’s Eastern Goldfields.
Resouro Strategic Metals, Indiana Resources and Chilwa Minerals also reported interesting drill results that are worth considering.
Let’s dive in.
Riversgold (ASX: RGL)
Project: Kalgoorlie East gold project
Hit: 10m at 8.89g/t gold from 46m, including 1m at 77.96g/t gold from 54m
Riversgold Limited has scored a decent run of gold hits among 32 recently drilled vertical air core holes for 1805 metres put into the company’s Northern zone.
The target zone is an extensive 600m-wide porphyry intrusive-hosted gold system, 25 kilometres east of Kalgoorlie.
The company’s available results include a best intercept from the Eastern extension of the project running 10m at 8.89g/t gold from 46m, including 1m at 77.96g/t gold from 54m.
Its second-best hit was 7m at 3.14g/t gold from 47m, including 1m going 18.35g/t gold from 50m.
A third hole, 50m southeast of the previous hole, probed 5m running 1.26g/t gold from 46m, including 2m at 2.74g/t gold from 49m.
Two other shorter intercepts include 2m at 11.97g/t gold from 34m from the Northwest extension and 1m at 6.98g/t gold in the Eastern extension from 50m depth, respectively.
The Northeast extension is about 250m northeast of the main part of the deposit and extends from below surface cover to about 100m depth.
All the air core holes on the Eastern extension picked up good grades, including the highest gold grades drilled at the project to date.
The company expects to soon receive the results of analyses for a further 414 samples from 11 air core holes.
The high-density air core drilling program intersects the upper parts of the project’s porphyry host, where grades better than 1g/t dominate to at least 100m depth below surface. One deeper mineralised lobe extends to just beyond 200m vertical depth.
Air core drilling at the Northern zone complements previous deeper drilling campaigns, including an inclined 11-hole 1289m reverse circulation program by Riversgold, in which every hole intersected the host porphyry over an increasing footprint within the tenement.
The company’s best reverse circulation hole nailed 11m at 1.38g/t gold from 80m in the Eastern extension. A second reverse circulation hole scored 18m at 1.94g/t gold from 49m, including 3m running 8.2g/t gold from 60m in the Northeast extension.
The third-best hole, also in the Northeast extension, intercepted 14m at 0.72g/t gold from 41m, including 3m at 2.6g/t gold from 52m.
The previous duo of reverse circulation holes drew initial attention to the Northeast extension, about 250m northeast of the main part of the deposit, which extends from below surface cover to about 100m depth.
Riversgold’s air core drill holes have intercepted higher-grade zones in the shallow, near-surface zones of an extensive gold mineralised porphyry across a growing footprint.
Higher-grade zones – based on an above 1g/t gold cutoff grade - extend from near surface to about 200m depth and occur as multiple zones or extensions.
If the cutoff grade was reduced to 0.5g/t gold, the gold envelope within the 600m long trend tested to date would expand massively to embrace continuous mineralisation extending along the entire trend.
At this stage, the entire porphyry envelope below 300m vertical depth remains open.
The project looks like it could reward some peripheral mapping, low-cost geophysics and a handful of deeper holes to determine the full outline of the porphyry.
It would also help to get a handle on the nature of the vertical grade distribution and various influences on near-surface enrichment.
That work could reveal that the extensions might be the shallow apophyses of a single large porphyry, which could change the game completely.
The company plans to continue evaluating the Northern zone and move towards an initial mineral resource estimate as soon as possible.
Resouro Strategic Metals (ASX: RAU)
Project: Tiros North Block titanium and rare earth elements project, Brazil.
Hit: 1m at 22% titanium dioxide and 18,827ppm (1.88%) TREO from 8m
Resouro Strategic Metals reported encouraging titanium and rare earths results from its recent 21-hole auger drilling program for 206m in the North block of its Tiros titanium and rare earth elements project in Minas Gerais state in Brazil.
Its highlight intercept of 1m at 22 per cent titanium dioxide and 18,827 parts per million (ppm) total rare earth oxides (TREO) from 8m in one hole is supported by a second 1m run grading 25.6 per cent titanium dioxide and 12,138ppm (1.21 per cent) TREO from 19m.
Three other better holes also produced significant results, including 7m at 23.4 per cent titanium dioxide and 0.81 per cent from 5m, 4m at 20.8 per cent titanium dioxide and 1.42 per cent TREO from 6m and 4m at 18.9 per cent titanium dioxide and 1.1 per cent TREO from 5m.
All the results relate to the current auger drilling campaign, which was designed to evaluate the areas outside the company’s main Tiros Central block.
Resouro focussed on the North block in this program because previous auger drilling results pointed to a near-surface high-grade zone. The company is awaiting on results for an additional 18 auger holes for 180m of drilling at the same North block.
The company’s Tiros North Block is a plateau, where the prospective Capacete Formation is preserved. Auger holes were positioned along the plateau rim in prospective zones with little or no overburden to enable better access to the drill positions.
Resouro has recently updated its combined measured and indicated resource estimate for its Central Block mineral resource to 1.4 million tonnes containing 165Mt of titanium dioxide and 5.5Mt of TREO, with an impressive 27 per cent magnet rare earths oxide (MREO) content.
The company says it is among one of the largest mineral deposits of this type globally, particularly in light of its additional 500Mt inferred resource containing 60Mt titanium dioxide and 1.85Mt TREO.
In upcoming work, Resouro intends to deliver a resource statement and a mine plan ahead of a scoping study for a trial mining licence application and has also begun an environmental impact study as part of the licensing process.
The scoping study will generate bulk samples of raw, unprocessed material from the North Block, focused on very high-grade, near-surface, friable material for distribution to potential offtake partners. This will allow the company to evaluate market interest in direct shipping and to guide future development decisions.
Resouro will also continue to test other targets outside its Central Block, where it has concentrated its recent drilling. This work will follow up exploratory drilling that confirmed mineralisation in both its São Gotardo and North blocks.
The company will also use an auger rig to map the Campos Altos block to assess its exploration potential.
The Tiros project has 28 mineral concessions totalling 497 square kilometres in Minas Gerais, which has some of Brazil’s best infrastructure development.
Resouro Resources has landed 25.6 per cent titanium dioxide and 12,138 parts per million total rare earth oxides from 19 metres of auger drilling at its Tiros North Block in Minas Gerais state in Brazil. Credit: File.
Indiana Resources
Project: Minos project, Gawler Craton, South Australia
Hit: 23.05m at 2.62g/t gold from 151.95m.
A seven-hole December to February diamond drilling program at Indiana Resources’ Minos area, in the company’s 5713 square kilometre Gawler Craton project, intercepted an emphatic run of 23.05m at 2.62g/t gold from 151.95m.
A second hole gave up a convincing higher-grade result of 2m at 25.85g/t gold from 351m, while a third hole nailed 16.1m at 1.67g/t gold from 137.9m.
Another long run was obtained in a fourth hole, which cored out 19m at 0.99g/t gold from 167m.
The holes were all step-back diamond tails to reverse circulation pre-collars drilled behind fences of previous southwest-inclined reverse circulation drilling. The program was designed to explore further down-dip extensions of the steeply northeast-dipping multiple mineralised zone.
The diamond drilling campaign followed up reverse circulation drilling at Minos, which yielded encouraging high-grade gold intercepts.
Indiana’s results from the combined drilling confirm that Minos extends further down-dip, which increases the potential for a commercial mining operation at the deposit.
The company has already committed to further drilling at Minos based on the recent results and will mobilise a high-capacity reverse circulation drill rig to later this month to extend the next round of holes. The company will follow up this work with a diamond drill rig to extend several holes down to about 500m depth.
The diamond rig is expected to be on site in June to run a 27-hole program for about 7000m to test the northwest and southeast strike extensions and down-dip extensions of an infill drilling program in the Main zone and for extensions of its Southwest zone.
Chilwa Minerals
Project: Mposa heavy mineral sands project, Southern Malawi
Hit: 6.6m at 12.1% total heavy minerals (THM) from surface, including 1.15m at 31.4% THM from 0.65m.
Chilwa Minerals has received results from a further 194 sonic holes for 1711m of drilling within the northeasterly extension area of its Mposa project in southern Malawi, which the company says exhibit some of the best grades and thicknesses to date.
The second and third-best holes delivered runs of 6.6m at 12.1 per cent total heavy minerals (THM) from surface, including 1.15m at 31.4 per cent THM from 0.65m and 6m at 15.2 per cent THM from surface, including 2m at 33.6 per cent THM from surface.
Mposa has an impressive existing inferred mineral resource estimate of 19.4Mt at 4.3 per cent THM, based on historical air core drilling. An additional 1Mt at 1.9 per cent THM resides at Mposa North.
The results from the latest drill samples are from the northern extents of the Mposa deposit and overlap with the Mposa North mineral resource.
With the existing Mposa mineral resource grading 4.3 per cent THM, Mposa North averaging 1.9 per cent THM and these latest results returning welcome multiples of that grade, the company is optimistic for a possible increase in overall average grade when the resource numbers are updated and expected to be delivered in June.
The company has completed sonic drilling at Mposa over 8km of strike, amounting to 821 holes for 7073m. The results relate to about 7.7km of strike.
The final seven-batch samples from Mposa have been sent to the company's new preferred laboratory in Pretoria.
Chilwa expects to soon receive the results, allowing the company to complete its resource update.
The two sonic rigs also drilled 134 holes for 927m at the company’s nearby Bimbi prospect, as part of a 377-hole program.
Mpyupyu also features a 2022 inferred heavy minerals resource estimate of 19.9Mt at 4.2 per cent THM, based on air core drilling.
Chilwa expects its current drilling pace and the switch to a new laboratory will enable it to complete its drilling program, receive assays and finalise an updated mineral resource estimate for each of Mpyupyu, Bimbi Main, and Bimbi Northeast before the end of June.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
