In this week’s edition of Bulls N’ Bears Big Hits, we examine some of the more curious drill intersections revealed on the ASX, including Culpeo Minerals’ biggest-ever run of 298m at 0.98 per cent copper equivalent from 90m downhole. We also take a close look at other notable drill hits last week from Wildcat Resources, Spartan Resources and Terra Metals.
Here at Bulls N’ Bears, we have zero interest in being bland or leaving ourselves open to suggestion that we don’t provide anything but great variation.
And after scouring the ASX for last week’s most intriguing drill hits, we have landed on a cavalcade of different discoveries.
From copper equivalent in Chile to lithium in Western Australia’s rugged Pilbara region and to gold in the State’s Mid West region and some tasty silver bites in the historic coastal town of Onslow, it is all here for the having.
So, let’s dive in.
Lana Corina project – Coquimbo region, Chile
Hit: 298m at 0.98 per cent copper equivalent from 90m
Assaying 0.01 grams per tonne gold, 0.88 parts per million copper, 144ppm molybdenum and 5.38g/t silver – for an overall average grade of 0.98 per cent copper equivalent – Culpeo hails this 298m run as its longest, continuous mineralised intercept achieved at Lana Corina.
Significantly, while the intercept ends in mineralisation, drilling is ongoing and is now past 700m downhole depth, meaning the mineralised intercept could be even longer when all the assays are in.
The hole was designed to test for near-surface, high-grade copper and to expand western and down-dip extensions of previously-reported high-grade copper-moly intercepts.
Culpeo acquired the 5.5-square-kilometre Lana Corina ground from SCM Antares in March 2022. It was drawn to the project by its past production, big copper hits by previous explorers, its perceived low-risk, low-altitude and proximity to good infrastructure and access. The operation encloses a copper-bearing porphyry intrusive with upper-level high-grade, copper-rich breccia pipes and it has a historic production of about 1 million tonnes running from 1.5 to 2.5 per cent copper.
In June 2022, the company reported multiple high-grade intercepts from initial drilling, in addition to a new breccia pipe west of the Lana pipe. It was followed in January last year by more long, high-grade copper-moly runs.
Culpeo undertook its first systematic geochemical survey between February and March last year along 3km of the north-east-striking key structural zone, in a bid to find prospective copper-bearing surface breccias, alteration, geochemical and structural drill targets.
In March this year, the company reported that drilling along the 3km prospective corridor had intersected 257m at 1.1 per cent copper equivalent from 170m, 173m going 1.09 per cent from 313m and 169m at 1.21 per cent from 239m.
A month later, it revealed it had kicked off 2000m of diamond drilling at Lana Corina to test the broad zones of high- grade copper-moly identified in the 3km-wide corridor, with that program yielding the latest intercept.
Tabba Tabba project – Pilbara region, Western Australia
Hit: 105.3m at 1.1 per cent lithium oxide from 213.7m
Wildcat has put 228 holes for more than 90,300m of combined reverse-circulation (RC) and diamond drilling into its Tabba Tabba project since it began work on the project. The locality has been prospected for decades for its range of pegmatite-hosted minerals that include tin, tantalite, niobium, rare earths and lithium.
In mid-May last year, Wildcat flagged it would acquire 100 per cent of Tabba Tabba from Global Advanced Metals, noting at the time from historical data that it hosted a high-grade tantalum deposit with an estimated mineral resource of 318,000 tonnes at 950ppm tantalum pentoxide.
Tabba Tabba lies about 60km from Mineral Resources’ Wodgina lithium project and largely within 40km from Pilbara Minerals’ world-class Pilgangoora lithium project.
Wildcat kicked off field exploration at the end of May last year in preparation for a maiden drilling program and, with the assistance of a drone survey, soon identified new pegmatites and extensions to known pegmatites. The company mobilised a rig and launched its drilling the following July, then sooled a second rig into the fray in early August.
Mid-September saw Wildcat reveal “a major lithium discovery”, citing a best RC drill hit of 85m at 1.1 per cent lithium oxide, including 59m going 1.5 per cent lithium oxide, from a pegmatite cluster. A month later, it announced it had completed its acquisition of the project and also unveiled more drill results.
The Leia pegmatite produced the best results, including 52m at 1.3 per cent lithium oxide from 117m in one hole and 35m at 1.5 per cent lithium oxide from 200m in another. Back then, the strike length of Leia was said to be more than 1.5km.
Then the company began diamond drilling to test it further, targeting down-dip and plunge extensions of the thicker lithium zones.
The Leia pegmatite is a strike-persistent, tabular, spodumene-dominant body that has now been extended to more than 2.2km long. It has thrown up a bevy of thick, high-grade zones, many intercepts exceeding 50m true width and assays exceeding 1.3 per cent lithium oxide.
In just over a year since the initial project acquisition, Wildcat has massively advanced Tabba Tabba to the point where it can legitimately be designated a significant lithium pegmatite “camp”.
Dalgaranga project, Mid West region, WA.
Hit: 19.67m at 19.43g/t gold from 765.33m
Spartan’s recent high-grade hit, that also includes 3.74m at 62.98g/t gold, raises an inspirational story of a change of fortune – and company name – at its Dalgaranga gold project.
In mid-2022, the company then known as Gascoyne Resources, drilled a series of holes northward at Dalgaranga to test the true width, orientation and extent of the newly-named Never Never lode that is part of an extension to the Gilbey’s mineralised system. The program led to the discovery of a new high-grade lode system on the western flank of the Gilbey’s North near-mine target.
Standout intercepts confirmed the consistent width and continuity of the high-grade, west-striking and steeply-plunging discovery, including best results of 59m at 12.5g/t gold from 139m, including 13m at 51.1g/t gold. The change in drilling orientation, resulting in the discovery of a new style of mineralisation at Never Never, proved transformational for the project.
The discovery prompted a corporate and strategic re-think and a review of the long-term operating plan for Dalgaranga. It ultimately involved placing the mine on care and maintenance to enable the company to focus on defining additional high-grade resources and ore reserves before rebooting mining and production.
The current Never Never mineral resource estimate sits at 952,900 ounces of gold at 5.74g/t, with its deepest down-dip limit below surface being about 850m. Never Never’s latest headline hit lies just below the 850m-deep floor of the current mineral resource estimate.
Given the remarkable uniformity of the mineralised structure, the new intercept represents significant down-dip potential and scope for Spartan to re-categorise deeper parts of the resource estimate – and a chance for an even more significant company makeover.
Terra Metals
Onslow project – 40km north-east of Onslow, WA
Hit: 6m at 179g/t silver from 160m.
The high-grade result, which includes 1m at 1060g/t silver, 0.23 per cent copper and 0.99 per cent tungsten, is one of a suite of assays returned from partial analysis of diamond core from Terra’s three-hole, 1283m maiden reconnaissance diamond drilling program at its Onslow project.
The drilling was co-funded by the WA Government’s Exploration Incentive Scheme (EIS) and designed to test three distinct iron oxide-copper-gold (IOCG) anomalies, allowing the company to qualify for a refund of about $200,000. The project is within the north-western extension of the Proterozoic Capricorn Orogen in the north-eastern portion of the Carnarvon Basin.
Nearby exploration by Western Mining in the 1990s identified the potential for Proterozoic banded-iron formation (BIF)- hosted gold, epithermal silver, IOCG deposits and porphyry copper mineralisation styles.
The prominent new silver hit occurs within a broader geological zone that also carries respectable silver grades, with the intercept being considered typical of high-sulphidation epithermal zones and likely to occur close to an intrusive porphyry stock.
The mineralisation lies within an interpreted high-sulphidation epithermal alteration zone that extends for 26m between 158m and 184m and is considered to be linked to a deeper mineralised porphyry source.
Intriguingly, management says the drillhole sits on the edge of an untested electromagnetic (EM) anomaly it identified from its airborne EM surveying of the area in 2022 and also within an aeromagnetic anomaly.
Terra’s data came up with two high-priority EM anomalies about 2km to 3km apart, with an apparent north-west/south-east strike relationship between them. The high-sulphidation epithermal silver mineralisation identified in the core appears to be coincident with the smaller, most north-westerly EM anomaly.
The first EIS hole tested the bigger EM anomaly to the south-east, which is interpreted to be a conductive body about 600m long and 120m thick, extending down-dip for 120m. Not all of the core from the hole was assayed.
Terra says in view of the recently identified mineralisation associated with the smaller EM anomaly, it will now review and selectively sample the core from first hole in the bigger EM anomaly, in addition to other geochemical and geophysical datasets.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
