Cu–Pb–Zn–Ag–Au · EL9939 · Talagandra: Three Doors the Last Explorers Left Open

Every company that explored this ground walked away. When we went back through fifty years of open-file records, page by page, we found that three of those exits were premature:

• a drill hole that ended in zinc, abandoned when the rig lost air;

• gold that was assayed but never reported;

• a high-grade gossan whose likely source geometry was never drilled.

The core from these holes is still in the state core library.

The setting

Talagandra sits on the same Silurian volcanic belt as Woodlawn and Captains Flat, the two historical base-metal mines of the Canberra region. EL9939 covers about 118 km² and five prospects:

• Bedulluck

• Westmead Park

• Oak Hill

• Murrumbateman Creek

• Glenesk

Between 1970 and 1982, five companies drilled 41 holes inside the licence, and then the ground went quiet for decades. Core from 21 of those holes (486 boxes) is preserved at the GSNSW Londonderry core library.

Figure 1. EL9939 with the five ranked targets, the watch-list and every historical drill collar. Yellow collars have core held at Londonderry, which means the first tests can start in the core shed, before a single landholder agreement is signed.

Door 1 — Westmead Park: the hole ended in zinc

In 1978 Amoco drilled into a textbook target: coincident IP, magnetic, soil and rock-chip anomalies at a porphyry contact, with surface rock chips to 3,100 ppm Zn, 1,380 ppm Pb and 18 g/t Ag. The hole returned 28 m at ~1,460 ppm Zn to the bottom of the hole, including 4 m at 3,800 ppm Zn. The last sample still carried 1,040 ppm Zn. The rig lost air below the water table and the hole was abandoned. The second hole failed the same way, and neither reached the magnetic peak.

Amoco's report called the anomalies "adequately explained" and recommended surrender.

Figure 2. Westmead Park Zone B section: both 1978 percussion holes coloured by zinc assay, stopping at the water table, short of the magnetic peak. The dashed red line is the diamond hole that should have been drilled.

Door 2 — Oak Hill: gold nobody mentioned

Amoco assayed its Oak Hill diamond core for gold, metre by metre. The logs show 11 m at 0.71 g/t Au with copper from 19 m, including 3 m at 1.5 g/t Au, and a second hit of 1 m at 2.5 g/t Au at 106 m. Gold appears nowhere in the report's conclusions. The core is in Londonderry, so confirming it is a four-figure re-assay.

Figure 3. Amoco hole 78-1 at Oak Hill: logged pyrrhotite zones beside the 1 m gold and copper assays, read directly from the 1978 drill logs.

Oak Hill's strongest magnetic response, a closed bullseye with 2,000–4,000 nT swings, sits at the southern end of a 1.1 km conductor. It has never been drilled. Crone Geophysics ranked a "pipe-shaped" conductor there as its number-one target in 1978. It is still undrilled.

Figure 4. Oak Hill long section: the three 1978 holes cluster to the north, while the strongest magnetic response and Crone's first-priority conductor, both at the southern end, remain untested.

Door 3 — Bedulluck: the source was never found

The Bullivant gossan returned 1 % Cu, 9.9 % Pb and 0.38 g/t Au at surface, with primary sulphide textures in polished section. The one hole beneath it cut zinc–lead veins to 5,100 ppm Zn. It was drilled from the east, though, and the geometry shows it could not have reached a steeply dipping source. The source of the highest-grade gossan in the dataset is unexplained, not missed.

Top results (historical, non-JORC)

Metal	Sample type	Top result	Source
Zinc	Percussion	28 m @ ~1,460 ppm Zn to end of hole, incl. 4 m @ 3,800 ppm	R00015991
Gold	Diamond core	11 m @ 0.71 g/t Au from 19 m, incl. 3 m @ 1.5 g/t; 1 m @ 2.5 g/t	R00015991
Lead	Rock chip (gossan)	9.9 % Pb, 1 % Cu, 0.38 g/t Au	R00016954
Silver	Rock chip	18 g/t Ag with 3,100 ppm Zn	R00015991
Zinc	Diamond core	3 m @ 5,100 ppm Zn + 1,100 ppm Pb	R00016955

The counter-argument

Fifty years of drilling on this belt has found plenty of pyrrhotite and pyrite but no economic base-metal body, and no hole inside EL9939 has returned better than about 1 % over more than a metre. Pyrrhotite is conductive and magnetic, so a conductor-plus-magnetic target can be barren. The best results are single 1970s assays with no quality control. Land access on the Canberra fringe stopped the last two licence holders.

Is the juice worth the squeeze?

Yes, because the first answers are cheap and don't need access. A core re-assay at Londonderry tests the Oak Hill gold and the vein grades for a few tens of thousands of dollars. One ground-geophysics line tests the Oak Hill bullseye, and one diamond hole finishes what Amoco's rig couldn't at Westmead Park. Each target has a written kill criterion, so the downside is bounded. The upside is a Woodlawn-belt system that nobody has drilled properly since 1978.

What's available

CAADIA Metals has compiled the full record into a Technical Synthesis: a 13-page investment case plus a complete evidence file. Every headline number is traced to its source report and page, and the key assays were checked against the original page images. It also includes the targets, the costed stage-gated programme, and the Phase 1 core re-assay sheet.

Do your own research: the source reports are open-file on GSNSW DIGS (R00015991, R00016954, R00016955) and MinView.

Or sign an NDA and we'll send you the synthesis. 

No JORC (2012) Mineral Resource, Ore Reserve or Exploration Target is declared for Talagandra, and nothing on this page should be read as one. Historical results are reproduced from Geological Survey of NSW open-file records for context and have not been verified by a Competent Person for public reporting. Woodlawn and Captains Flat are cited as geological analogues only. Interpretations are working hypotheses. The Talagandra Technical Synthesis sets out the alternatives and the tests that separate them; this page summarises it and does not replace it.