A 618km2 land package of highly prospective ground in NSW’s famed New England Orogen (NEO) belongs to $4 million market cap Thunderbird Resources (ASX: THB), which is about to launch an aggressive drilling campaign targeting gold, antimony and silver.
The NEO is one of few underexplored regions of the Tasmanides, and is a Palaeozoic structure – a geological period that was responsible for over 250 million ounces of gold currently extracted or within resources. The region is home to $300 million market cap LRV’s Hillgrove gold and antimony mine, $40 million market cap KNB’s gold deposit, and TMG’s 30,000t antimony resource.
THB’s Kookabookra project has strong potential for a large intrusion related gold system (IRGS) that has many high grade offshoots. One of its prospects, Bear Hill, has historical production of 3,100 ounces at 24.4g/t Au, and THB have found high grade rock chips up to 153.5g/t Au at Mt Secret – which is about to be drilled.
Other prospects include Butchers Reef which historically produced at 32.5g/t Au, and Welcome Stranger Reef which has 42.6g/t Au in vein quartz and is where THB have recently recorded additional samples of 8.56g/t Au and 2.09g/t Au. In total, 428 historical mine workings are littered throughout the project across 40 adits, 40 shafts and 348 shallow prospecting pits – across 250km2.
Economic mineralisation does not need to be present across large surface dimensions or even extreme depth to equate to a sizeable deposit – QLD’s Kidston IRGS produced a whopping 5Moz in just 16 years from a 1,100m by 900m (1km2) footprint that extended 300m deep.
THB’s Rockvale project is right in between LRV and TMG, and is also full of historical production sites with mineralisation – some of which likely trend along the Hillgrove and Chandler faults from LRV’s Hillgrove Project. One of these prospects is Achill, which has recorded 4.65% Sb and 265g/t Ag at workings up to 15m deep – but has never been drilled. Another prospect further west is Taits Gully, which has old workings that extend 150m deep and has recorded outstanding grades of 76g/t Au, 4,350g/t Ag and 4.1% Sb.
THB also counts legendary resources investor Tolga Kumova as a significant shareholder. Tolga was a very early backer of Bellevue Gold (ASX: BGL) when it was just an exploration project in 2016 at a $3 million market cap, before it went on to hit a $2 billion market cap – and he also built Syrah Resources (ASX: SYR) into a $1.5 billion graphite miner in just 3 years. He also recently orchestrated the merger of WA gold explorers Torque Metals (ASX: TOR) and Aston Minerals (ASX: ASO) – which subsequently saw the group surge 400% post transaction.
At a $4m market cap, it’s a far cry away from the $8m market cap that THB acquired the projects at and far less than any of the other significant landholders in the region – with no clear reason for the pullback. Between the November acquisition and now, the gold price has gone from US$2,700/oz to US$3,360/oz, the antimony price has gone from US$38,000/t to over US$62,000t, and the silver price has gone from US$30/oz to US$37/oz.
At the helm of THB is George Ventouras, who was joint-founder, non-executive director and General Manager of Apollo Consolidated (ASX: AOP), which Ramelius Resources (ASX: RMS) acquired for its 1.1Moz at 1.2g/t Lake Rebecca Gold project for $181 million ($146 million enterprise value).
As THB gears up for its September/October drilling campaign at Kookabookra, the company will be releasing results from a recently completed Induced Polarisation (IP) survey, in conjunction with geochemical soil sampling results and the detailed rock chip sampling and geological mapping at the Mannix and Mt Secret prospects – which will strongly inform the drilling plan. The Company is also planning an extensive soil geochemical program over the Bear Hill and Butchers Reef area to define drill targets, which may be tested as a part of the same drill program. Recent results from a LiDAR survey confirmed the 428 historical mine workings, as well as identifying an additional 228 trenches, which THB’s on ground team are assessing for the highest priority targets.
THB’s vast landholding in the New England Orogen, much of which straddles LRV’s Hillgrove deposit, can be seen below:
Source: THB
Bulk Tonnage Potential at Kookabookra
The drilling conducted at Kookabookra so far has been extremely limited in both potential strike of the project and depth. Just 7 RC holes for a total of 323m were completed at Mt Secret, which recorded assays including 17m at 0.43g/t Au from 10m and 1m at 2.5g/t Au from 32m, while Mannix saw 417m from one diamond hole and 12 RC holes, producing 12m at 0.53g/t Au from 10m ending in 1m at 1.62g/t Au.
The main reefs were never drilled either, where on top of Welcome Stranger’s 42.6g/t Au, there is British Lion with 19.3g/t Au, Kookabookra Reef with 18.5g/t Au and 0.33% Sb, and Ditton’s Mine with 17.95g/t Au.
While the drilling results at Mt Secret and Mannix were not outstanding, they do show the potential for a bulk-tonnage disseminated gold system in the granite, and the combination of near-surface high-grade shoots and broader low-grade gold halos at depth is exactly what one would expect in a vertically zoned intrusion-related gold system. Additionally, Kidston’s production averaged a head grade of 1.7g/t, over a decade and a half where the gold price averaged under US$400/oz. At the current gold price of US$3,360/oz, THB has a lot more room to move.
IRGS’ tend to form large bulk-tonnage, lower-grade deposits, typically in granitoid bodies or their halos. Extreme examples include the 11Moz Fort Knox mine in Alaska and the 5Moz Kidston mine in Queensland, each multi-million-ounce gold producers. In the NEO, a relevant analog is the Timbarra gold deposit, around 100 km north of Kookabookra, which is a disseminated granite-hosted gold system.
Timbarra’s resource of 16.8Mt at 0.73g/t Au for 397koz, while modest, demonstrates that reduced I-type granites here can indeed host bulk-tonnage gold mineralisation. The Kookabookra project shares numerous geological similarities with Timbarra, and critically, covers granite units of the same age and type as those associated with Timbarra-style gold. Combined with extensive historical production and mine workings that have high grade rock chips, this dual potential for high-grade orogenic Au-Sb veins as well as a larger IRGS in the granite, makes Kookabookra’s geology particularly compelling.
The evidence of multiple phases of I-type granitic intrusions that are moderately reduced at Kookabookra is a strong indicating characteristic of a classic IRGS setting. Geochemical indicators have reinforced this interpretation, with rock and soil samples around the Mt Secret and Mannix prospects carrying anomalous arsenic, bismuth, and tellurium, which again are strong indicators for an IRGS deposit.
Mt Secret and Mannix’s historical assays, as well as a few of the main reef rock chips, can be seen below:
Source: THB
New England Orogen’s Rich History Yearning to be Conquered
For a region that has all of the key lithological ingredients and geological processes for the formation of rich ore deposits, it is truly astounding that the New England Orogen has been subject to such little exploration.
The NEO is a magmatic source for heat, metal and fluids, as well as metamorphism and alteration, and also hydrothermal fluids to scavenge and mobilise metals. It also has deformation, fluid pathways and structural traps.
While THB’s vast land package is targeting granite, the NEO’s diverse host rocks provide contrasting chemical conditions that should favour the precipitation of dissolved metals from hydrothermal solutions, with weathering and erosion allowing for the formation of surficial deposits, which would ultimately expose the deeper crustal level ore bodies.
Interestingly, there is a virtually exhaustive list of geochemical and geochronological data of almost every single granitic pluton in the NEO, which was pioneered by geologist Bruce Chappel. Bruce’s sustained study of granites from South East Australia and their lithic inclusions led him to recognise that many granite magmas move bodily away from their sources, deep in the crust as a mixture of melt and solid residual material – which implies that many granites exposed at the surface reflect the nature of their deeper source materials.
If this is at all the case for what THB is finding on the surface in the granites at Kookabookra and Rockvale – then exciting times lay ahead for the company. With the IP results just days away, and barely a month or two out from a drilling campaign that will test a litany of shallow, high-grade veins and deeper, bulk-tonnage targets in the two hottest commodities right now – THB’s $4 million market cap could be holding a fair bit of value.
Subscribe here to receive all our coverage of ASX-listed stocks
Disclaimer: This article is for informational and marketing purposes only, and does not constitute financial advice or a recommendation to invest. All opinions expressed are our own. We may receive fees or other forms of compensation in connection with the publication of this content, and may own shares in any of the mentioned companies. Please do your own research and seek professional advice before making any investment decisions.