There are obvious differences between the various interpretations of the term “big hits” – and some of the intersections presented this week show why.
When examining gold, for example, interested students often hope to find a section at least 10 m long with more than 10 grams per ton.
Looking at any other ore, the thickness and quality of a niobium discovery reported by Encounter Resources may not seem spectacular, but in a unique target they are notable. And at Future Battery Minerals, both the intersection and quality in a highlight intersection reported last week are only modest, but they are consistent and extend the footprint of a single target.
Riversgold’s numbers are now dominated by large intercepts of what many would describe as “low” gold grades. However, with gold prices today, economies of scale are breathing life back into the company as it has great potential for large tonnages.
Finally, recent work by Spartan Resources highlights solid intercepts at depths below 20 m with excellent gold grades and strong lateral and vertical continuity of recently discovered mineralization potentially extending to a vertical depth of less than 1,000 m.
Every company almost certainly looks at its own “big hit” numbers from a different perspective.
So let’s get started.
Meeting resources
Aileron Project – West Arunta, Western Australia
Hit: 46 m at 3.1 percent niobium pentoxide from 60 m to the end of the hole at 106 m.
Encounter’s open headline hit reinforces previously reported air core (AC) results from the Crean Carbonatite and strongly underscores this point with a 4-metre run returning 6.4% niobium from 84 metres depth.
And the interception was no one-hit wonder, as a neighboring step-back well also returned 18 meters of 3.2 percent niobium from a depth of 76 meters, including 2 meters of an astonishing 17 percent.
This year’s drilling at Crean has exposed continuous, near-surface, carbonatite-hosted niobium mineralization on four north-south trending lines spaced 200 m apart, with holes spaced between approximately 13 and 50 m apart. The holes reach depths of approximately 90 to 120 m and intersect an apparent east-west trending, steeply north-dipping carbonatite vein that is reported to be uniformly 115 m thick in current intervals.
The main hole is located 200 m east of Encounter’s previously reported 52 m hole grading 3% niobium from 81 m, including 16 m grading 6% niobium in an adjacent section drilled during the Company’s first phase program. Three additional adjacent sections also surround the hole.
Given the distribution of robust values, the common depths and the continuity along strike, there is little doubt that the current mineralized unit is real, so the question now is, how much bigger can it be?
Niobium intercepts appear to be improving to the west – where there are still open holes – and Encounter has already returned the rig to Crean to drill additional holes at 200 metre spacing to extend the discovery in this direction.
Although there is still much detective work to be done as the mineralized unit is traced along strike and at depth, the story promises to make for interesting reading.
Future battery minerals
Kangaroo Hills Project – Goldfields Region, WA
Hit: 27 m with 1.04 percent lithium oxide from 118 m
Future Battery achieved a notable hit in its recent series of six reverse circulation (RC) drill samples from the Big Red pegmatite at its Kangaroo Hills project, which also includes 15 metres of 1.53% lithium oxide from 122 metres depth.
The Company’s Phase 4B program comprised 19 holes totaling 3,109 metres and achieved its objective by advancing northeast from the Big Red mineralization and extending it by a further 250 metres. The six holes trend northeast from the known central axis of the pegmatite and expose a strongly mineralized trend.
Intersections within the trend test approximately 250m of the Big Red pegmatite strike, with the geology looking to remain open to the northeast beyond the current drill limit. This means that when including the southwestern holes at Big Red, the pegmatite has now been defined over a total strike length of approximately 600m and still looks to have more to offer to the northeast.
However, only 250m of Big Red’s strike to the northeast remains to be tested before the Company could be constrained by property boundaries. Importantly, Big Red’s shallower dip to the northeast – approximately 20 degrees at the deepest and northeasternmost hole – results in the deepest section being only 100m vertical depth.
This also means that Big Red could protrude from the property while remaining a flat, thick, well-mineralized structure that is still open to the northeast.
Any strike extension from Big Red to the northeast of the property boundary would need to be approximately 1670 m long before re-entering the Company’s Miriam project, in which it holds an 85% interest.
Including the overlapping Potoroo pegmatite discovery and underlying Rocky trend in Phase 4A drilling, the total surface projected lithium footprint in the Big Red Zone now extends over a strike length of approximately 900 m. The southwestern end of the trend has been thinly drilled and further shallow drilling perpendicular to strike has the potential to find near surface extensions in this direction.
River Gold
Northern Zone Project – 25km east of Kalgoorlie, WA
Hit: 18 m with 4.14 grams per tonne gold from 36 m
Riversgold has returned an 18-metre discovery in its latest RC drilling results at its porphyry-hosted Northern Zone gold project, 25km east of Kalgoorlie in Western Australia, where the company is working to secure an 80 per cent interest following an earn-in deal with Oracle Power last year.
The objective of the program was to further define the shallow, up-dip gold mineralization discovered by the Company in its initial diamond drilling program in August last year and subsequent RC and AC drilling programs this year.
The headline hit was accompanied by a second, longer intercept of 54 m of 0.38 g/t gold from 158 m depth and 14 m of 0.76 g/t from 226 m to the end of the hole, just 185 m to the southeast.
In May last year, Riversgold confirmed that the Northern Zone contains an estimated exploration target of 200 to 250 million tonnes grading between 0.4 g/t and 0.6 g/t gold for 2.5 to 4.8 million ounces. These figures come from London-based Oracle after the company successfully completed drilling in 2021 to validate historical drilling between 1998 and 2012.
During this campaign, Oracle encountered several porphyry intrusive rocks ranging from more than 350 m up to 150 m thick and up to 250 m deep. Some of Oracle’s drill results from its 2021 RC drilling and previous drilling showed spectacularly long gold intercepts ranging from 0.4 g/t to 1 g/t gold.
Riversgold was pleased with the numbers highlighting the potential for a large volume, low grade intrusive gold system (IRGS) with a potential width of over 100m. Following the recent results, the Company is now planning further exploration drilling to the northeast to follow the open direction of the mineralization defined to date.
Management says it is taking inspiration from Saturn Metals’ Apollo Hill project near Leonora, which has an estimated mineral resource of 105 million tonnes grading 0.54 g/t gold for a total of approximately 1.84 million ounces of gold.
Riversgold is currently considering the possibility of emulating Saturn. The Company has a Preliminary Economic Assessment (PEA) that envisages a large open pit bulk mining operation coupled with conventional heap leaching to produce gold doré on site.
Of course, given the current state of development of the Northern Zone, any further consideration in this direction will have to wait until further drilling demonstrates the extent of mineralization and oxidation depths, the limits of free trenching and blast and crush drilling, or… whether the numbers indicate a large underground resource lurking down there.
Spartan Resources
Dalgaranga Project – Murchison Region, WA
Hit: 10.14 m @ 11.26 g/t gold from 996.9 m
Following our previous look at Spartan in this column, the company has returned with another helping of golden goodness from the nearly 1,000-meter-deep Never Never deposit, which lies approximately 275 meters below the lower limit of the estimated mineral resources.
The main section includes 0.77 m of 126.45 g/t gold and penetrates Never Never approximately 100 m above the deepest section of the zone reported to date, confirming robust mineralization at depth.
This confirmation is reinforced by two supporting intercepts from the same program further up the structure: 9.07 m of 17.81 g/t gold from 760.55 m downhole, including 1.52 m of 99.45 g/t, and 10.66 m of 6.55 g/t from 798.02 m, including 0.49 m of 126.00 g/t.
The drilling was conducted in advance of an upcoming resource estimate update and management says the intersections highlight “the incredible potential” that until recently lay undiscovered directly in front of the Company’s processing plant. This discovery is largely due to a change in thinking regarding the dominant structural controls, which has also led to the discovery of the adjacent high-grade Pepper deposit, where recent drilling returned 13.5m of 4.47 g/t gold from 679.50m, including 0.5m of 73.04 g/t.
Drilling at the recently discovered Pepper zone has not yet reached the same density as Never Never, but appears to be catching up quickly. Both Never Never and Pepper remain open at approximately 1,000 m and 700 m below surface, respectively.
Spartan is currently completing permitting and support activities for its underground exploration drilling. The current mineral resource estimate for Never Never contains just under 1 million ounces of gold grading 5.74 g/t.
Development is scheduled to begin in the third quarter of this year and the numbers will be eagerly awaited, as will the next drill holes when they arrive from a depth below the magical 1,000 m.
Is your ASX listed company doing something interesting? Contact: matt.birneyatwanews.com.au