Barton perseverance pays off with new pit-floor gold zone

In this week’s edition of Bulls N’ Bears Big Hits, we examine some of the more notable drill intercepts revealed on the ASX, including Barton Gold’s 7m at 9.63 grams per tonne gold from 67m at its Tarcoola project in South Australia.

We also take a close look at other interesting drill hits from last week as reported from American Rare Earths’ Cowboy State Mine project at Wyoming in the United States and Lunnon Metals’ Kambalda gold and nickel project in Western Australia.

So, let’s dive in.

Barton Gold Holdings

Tarcoola project – South Australia

Hit: 7m at 9.63g/t gold from 67m

Barton jagged its headline hit in one of 10 recent reverse-circulation (RC) holes for a program total of 882m of drilling that was put into a new gold zone in the floor of the Perseverance open-pit mine at its Tarcoola project in South Australia. The hit includes a juicy 2m slice assaying 28g/t gold from 68m.

And that was not the only grade above 20g/t gold. A string of respectable hits from all 10 holes include 5m at 5.94g/t gold from 11m with 1m at 23.8g/t in one hole and another producing 4m going 10.38g/t from 32m featuring 1m at 34.4g/t.

Two more holes produced 6m at 6.17g/t gold from 39m including 2m running 13.4g/t and 5m going 6.07g/t from 99m with 1m at 28.3g/t gold, respectively.

High grades are no surprise at Tarcoola, where the goldfield produced about 77,000 ounces of gold at an average of about 37.5g/t between 1893 and 1955 from shallow workings on Barton’s mining lease. The latest drilling complements the company’s recently-completed 9025m RC regional campaign through 44 days that focused on multiple interpreted structural targets near the Perseverance mine.

Part of that campaign included 26 holes for 1688m of drilling to probe the Perseverance pit floor and confirmed the existence of high-grade extensions of mineralisation with grades of up to about 12g/t gold. It also identified new structures below the open-pit floor.

Barton remodelled the open-pit mineralisation to include the results from that program to deliver its July update to the Perseverance resource. It reveals that about 31,000 tonnes repose within 60m to 80m of the southern and northern pit floor areas, respectively, at a grade of 1.99g/t gold for 19,900 ounces and also indicates further potential for depth, strike and lateral mineralisation extensions or repetitions.

The 2024 Perseverance resource shell is entirely enclosed within the present open-pit outline that measures about 700m long and a maximum of about 210m wide. The outline fully embraces the known extent of the gold resource hosted by the prominent Deliverance granite vein.

The latest 10-hole program was designed by Barton as a follow-up to explore the new structures identified by the immediate pre-resource estimate drilling in the pit floor and to confirm the possibility of another zone of mineralisation east of the 2024 resource envelope in the south-eastern end of the pit.

Barton’s drilling programs in December 2023 and in April this year came after studies identified multiple local structures analogous to the structural regime hosting the Perseverance gold. It was the first work to compile all known historical gold occurrences into a consistent structural framework in the estimated 130-year history of the Tarcoola Goldfield.

There seems little doubt now that the Perseverance vein is an important influence on mineralisation within the pit environment. Management says just one “Perseverance repeat” could be of considerable value to the company’s regional strategy to put together a number of staged, low-cost developments and operations.

It adds that it sees potential to further convert the new shallow mineralisation at Perseverance into an expanded open-pittable resource within the existing pit profile. It sets the stage for exploiting an earlier-than-expected opportunity for early production using its fully-permitted Central Gawler processing plant.

American Rare Earths

Cowboy State Mine – Wyoming, US

Hit: 172.4m at 3716 parts per million total rare earth oxides (TREO)

American Rare Earths’ latest analyses, including the headline result from its recently-completed program of 23 diamond core and RC drillholes for a planned total of 2670m of drilling, confirm that high-grade potential ore sits in the western portion of its Cowboy State Mine (CSM) in Wyoming.

The campaign was directed towards upgrading resources, providing hydrological, geomechanical and metallurgical testwork materials and other data to advance the company’s mine planning work as it moves towards prefeasibility studies. The work represents the first phase of its multi-stage development of the vastly bigger Halleck Creek deposit – also in Wyoming – which hosts an eyebrow-raising 2.34 billion-tonne JORC resource containing 7.48 million tonnes of TREO.

That resource was updated in February and includes combined oxides of the magnet rare earth elements neodymium, praseodymium, samarium, dysprosium and terbium, comprising about 27 per cent of the total resource at an average grade of 774ppm magnet rare earths oxides (MREO) and containing an estimated 1.8 million tonnes of metal.

The latest drill program comprised 11 HQ diamond holes for a total core run of 1585m, with 672 core samples being collected, logged and shipped to ALS Global’s laboratory for splitting and assay. A further 12 RC holes were also hammered into the ground at the project for a total metreage of 1031m, with another 689 samples also shipped to ALS Global.

American Rare Earths says the campaign confirms that higher-grade potential ore exists in the western section of the CSM deposit, especially near Red Mountain. Having outlined the eastern limits of the CSM deposit, future drilling can now focus more on higher-grade zones closer to Red Mountain, which includes one previous drillhole reporting an impressive 299.1m intercept averaging a healthy 4393ppm TREO.

In addition to the headline hit in the latest campaign, other significant finds include a second hole intercepting 51m running 3390ppm TREO and a third hole nailing 30m going 2203ppm.

Due to a welcome budget under-run, an extra four holes are being drilled for about 730m to target higher-grade zones in Red Mountain and are expected to be completed within the next week. The company plans to update its resource model with the latest data once results from the extra holes are to hand and it can then look at developing its mine plans for the CSM.

Management believes the project has the potential to be the next rare earths mine built in the US, outside of Mountain Pass, and that it could be one of the biggest rare earths developments in North America.

American Rare Earths will now focus on the development of the CSM on part of its Halleck Creek tenements. A recent AU$10.7 million energy fund grant from the State of Wyoming will also see it well-positioned to advance the development of the Halleck Creek resource.

And given that less than 75 per cent of the mineralised zones at the project are yet to be drilled – and with the deposit remaining open at depth – the CSM project offers potential for significant upside and looks poised to become a key project for Wyoming.

Lunnon Metals

Kambalda project - WA

Hit: 23m at 16.61g/t gold from surface

Lunnon Metals says the high-grade RC drill hit from its 100 per cent-owned Lady Herial prospect is not only the best result to date from the site, but is one of a plethora good hits – some of which kick off from surface and stretch up to 23m thick.

Along with the headline hit, the company has reported an additional nine intercepts for separate drillholes, with thicknesses ranging from 6m to 23m at primary intercept grades ranging from 1.15g/t gold up to the 16.61g/t.

The headline hole was drilled to a downhole depth of 24m at an inclination of -60o and includes 6m at 62.47g/t gold from 17m. It also contains 1m at an eye-watering 350g/t gold.

Overall, management says the drilling highlights the existence of two thick, parallel shoots spaced between 50m and 60m apart, with gold being intersected on both structures, which have tentatively been named the Upper and Lower structures. Other mineralisation has also been picked up outside the two structures, including between the two parallel zones and in the footwall of the Lower Structure, which hosts the headline hit.

Another hole returned 13m going 4.1g/t gold from 3m between the two structures.

Both of them outcrop at surface – evidenced by plenty of surface quartz float. Better grade intervals are typically associated with quartz veins, while low-to-modest gold grades are associated with alteration zones around quartz veinlets, veins and shears in the dolerite host rock in wider intervals.

The Upper Structure was intercepted, as predicted by the evolving structural model, and jagged one hole carrying 16m going 1.15g/t gold from 1m and 7m going 2.58g/t gold from surface in another hole. It remains open down-plunge and dip.

The Lower Structure has been intersected during previous drilling by other explorers, including WMC Resources, Gold Fields and ACH Nickel and now also by Lunnon. It is defined as being about 15m to 30m thick within an envelope of grades mostly better than 0.5g/t gold.

After the company established that the grade of the Upper Structure improved near favourable host zones of the Defiance Dolerite known at nearby St Ives, it threw in a few RC holes to test the Lower Structure close to and at surface in the same dolerite. The strategy picked up one hole returning 17m at 1.79/t gold from 17m and a second hole returning 15m going 1.15g/t from 3m, proving that better grades over reasonable widths can be obtained from the Lower Structure.

The Kambalda/St Ives camp is one of Australia’s most prolific centres for gold discovery and production, having produced the precious yellow metal from the area since the discovery of the Red Hill mine in 1896 – right next to Lunnon’s historic Silver Lake nickel mine at Kambalda. The Silver Lake nickel mine was developed on the Lunnon Shoot – which is named after diamond driller Jack Lunnon, who drilled the discovery hole, KD1, in 1966.

As for Lady Herial, analytical results are still trickling in and remodelling will keep pace with the picture that is still being painted as sample results are returned. It is looking increasingly attractive as a priority prospect to meet the company’s gold objectives.

Once the remaining assays have been received and entered into the database, management will undertake further geological modelling and open-pit optimisations that it hopes will lead to a maiden mineral resource estimate.

If that maiden resource picture develops, then Lady Herial has the potential to be Lunnon’s second significant discovery, following its high-grade, near-surface Baker nickel find in 2022.

Is your ASX-listed company doing something interesting? Contact: matt.birney@wanews.com.au