Koba Resources Hits 29m of High-Grade Tin Beside Historic Gilmore Mine
Key Takeaways
- Hole MGRC011 returned 29m at 1.2% Sn, 0.36% Cu and 22 g/t Ag from 111m, including 15m at 2.0% Sn, in the first drilling at Gilmore in over 45 years.
- Koba's MGRC011 averaged 22m at 1.5% Sn against 22m at 0.31% Sn in the 1979 historical hole 11m away, a roughly fivefold grade improvement.
- Only three holes (277m) have been drilled at Gilmore, and with no Mineral Resource reported and true widths unknown, the result is an early signal rather than a defined deposit.
- Stannex showed tin across 2km of strike from 21 holes (2,660m), but grades are lower, with the best being 1m at 1.9% Sn and 10m at 0.25% Sn.
- Follow-up RC drilling at Gilmore is targeted before year end, with a diamond program to confirm true width and supply metallurgical test material, and Stannex follow-up planned for early 2027.
Thick high-grade tin intersected in maiden Mt Garnet drilling
Koba Resources has intersected a thick zone of high-grade tin in its maiden reverse circulation (RC) drilling at the 100%-owned Mt Garnet Tin-Tungsten Project in North Queensland. Hole MGRC011 returned 29m @ 1.2% Sn, 0.36% Cu, 0.017% WO3 & 22 g/t Ag from 111m, including 15m @ 2.0% Sn from 117m.
The program comprised 24 holes for 2,937m, targeting the historical Gilmore Tin Mine and the nearby Stannex Prospect. Gilmore produced 26,169 tonnes @ 7.6% Sn between 1906 and 1922, and the new results suggest significant mineralisation remains beside that old workings footprint.
Ben Vallerine, Managing Director and CEO
“Previous mining at Gilmore averaged 7.6% Sn, and our drilling has demonstrated that significant mineralisation remains unmined…”
Only three holes were drilled at Gilmore so far. For investors, that makes the result an early signal rather than a defined deposit.
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Gilmore Mine delivers standout results
The three Gilmore holes (277m) were the first drilling in over 45 years at the mine, which reached a total depth of 193m during intermittent mining between 1958 and 1980. A strong tin soil geochemistry anomaly extends for approximately 500 metres over and along strike from the mine.
MGRC011 intercept breakdown
Table 1 in the announcement sets out the detail. Tin grades in the body text are rounded, so the parent interval of 1.17% Sn appears as 1.2% in headlines.
| Interval | Length | Sn % | Cu % | Ag g/t |
|---|---|---|---|---|
| 111m to 140m (parent) | **29m** | **1.17** | 0.36 | 22 |
| incl. 117m to 132m | **15m** | **1.99** | 0.58 | 33 |
| incl. 126m to 128m | **2m** | **6.34** | 0.44 | 26 |
| incl. 130m to 132m | **2m** | **3.00** | 1.16 | 53 |
All intersections are downhole lengths, and true widths are not known. That means the drilled thickness may not equal the real thickness of the mineralised structure.
Strike extension and historical context
Hole MGRC013, drilled approximately 230m east of MGRC011, returned 5m @ 0.58% Sn from 9m, including 2m @ 1.2% Sn. The company says this highlights potential to extend mineralisation along strike, beyond the area of historical mining.
Two holes were drilled close to historical diamond holes from 1979 to 1980, allowing direct comparison. MGRC011 sits about 11m from GDD016, which returned 22m @ 0.31% Sn from 117m. Koba’s hole averaged 22m @ 1.5% Sn from 117m over the equivalent interval.
The picture is more modest for MGRC013, collared about 10m from GDD009, which intersected 8.1m @ 0.84% Sn from 18m. MGRC013 confirmed mineralisation in a corresponding position but returned the lower 5m @ 0.58% Sn. The company reported both comparisons, including the one where its hole returned lower grades.
Stannex Prospect shows scale over 2km of strike
At Stannex, approximately 1km northeast of Gilmore, Koba completed 21 broadly spaced holes (2,660m). They tested a 2km x 0.5km tin-in-soil anomaly with coincident induced polarisation (IP) chargeability anomalies, a geophysical technique that can flag sulphide-bearing mineralisation.
The Stannex drill targets were defined by the coincident soil and IP chargeability anomalies, which is why the broadly spaced holes were positioned to test scale across the full 2km of strike.
Tin results were encouraging across 2km of strike, though grades are lower than Gilmore. Key intersections include:
- MGRC020: 1m @ 1.9% Sn from 5m, within a wider 4m @ 0.67% Sn interval (5m to 9m).
- MGRC021: 10m @ 0.25% Sn from 69m.
- MGRC003: 2m @ 0.33% Sn from 42m.
One discrepancy is worth flagging. The announcement highlights describe MGRC020 as 3m @ 0.67% Sn from 5m, while Table 1 shows 4m (5m to 9m). This article uses the Table 1 figure.
Base metals also featured. MGRC024 returned 3m @ 3.4% Zn, 1.5% Pb, 65 g/t Ag and 31 g/t In from 184m, including 1m @ 6.8% Zn from 185m. The company says it will assess whether these metals can aid exploration, since the base metal mineralisation can be, but isn’t always, directly associated with tin.
What tin-tungsten greisen systems mean for investors
Koba describes the mineralisation at Gilmore and Stannex as greisen, vein and fissure-style tin and tungsten mineralisation within both sediments and granites. Greisen is a rock altered by fluids from a granite intrusion, and it can host tin and tungsten.
At Gilmore, the tin comes with copper, silver and tungsten. MGRC011 shows all three alongside the tin, which could add value beyond tin alone, although no metallurgical test work has been undertaken yet.
Reading the numbers correctly matters too. Tin intersections use a 0.1% Sn lower cut-off, meaning samples below that grade are excluded unless they fall within allowed internal dilution. Because widths are downhole, the drilled length is not a confirmed true thickness.
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Next steps and upcoming catalysts
Koba has a busy drilling calendar. The forward work plan includes:
- Earthworks underway at the Stannary Hills Tin-Tungsten Project ahead of maiden drilling at the Kitchener and Jiminy Prospects, scheduled to commence later this month.
- Planned follow-up RC drilling at Gilmore, immediately following the Kitchener and Jiminy drilling, with initial holes targeted for completion before year end.
- Follow-up drilling at Stannex, being planned for early 2027.
- Geological mapping and sampling of tungsten targets across the greater Mt Garnet Project during the remainder of 2026, to advance targets towards drilling in 2027.
- Further drilling at Gilmore, including a diamond drilling program, to better understand structural controls, confirm geometry and true width, and provide material for metallurgical test work.
The results are first-pass and reconnaissance in nature. The announcement states that data spacing is not sufficient to support a Mineral Resource estimate, and no Mineral Resource or Ore Reserve is reported.
Even so, a 29m tin intersection beside a historical mine is the kind of result that gives the next round of drilling real weight.
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