Octava sparks long-awaited copper-zinc drilling blitz in Tasmania.

Octava Minerals has kicked off the first drilling program in almost 50 years at its Sweeney’s prospect, part of the company’s broader Federation project in Tasmania, targeting a rich mix of copper, zinc, silver, tin and untested high-grade indium. 

Once completed, each drill hole will be cased ahead of down-hole electromagnetic (DHEM) surveys to peer sideways for up to 200m, looking for conductors suggestive of massive sulphide mineralisation. 

Initially, Octava aims to focus the drill bit on significant historic intersections that were previously left open at depth. Standout hits from that earlier program included 23 metres grading 1.2 per cent copper, 1.7 per cent zinc, 121grams per tonne (g/t) silver and 1.17 per cent tin. 

Another strike returned 24m grading 0.25 per cent copper, 0.52 per cent zinc, 42g/t silver and 0.27 per cent tin.

Adding to the prospect’s credentials, the company recently collected rock chips samples, which returned uber-high grades of 27.5 per cent zinc, 5.97 per cent tin, 0.58 per cent copper, and 434g/t silver. As an added sweetener several samples came in with good sniffs of indium, however, one specimen registered an impressive indium grade of 860 parts per million. 

In the 1970’s, Renison Goldfields Consolidated also sampled a historical adit at Sweeney’s, recording a very wide hit of 47m grading 0.96% zinc, 0.64% tin and 7 g/t silver.

The company says its prospect was previously viewed as a greisen-style tin system, hosted by a rich intrusion called the Heemskirk Granite, which punches through a sequence of Proterozoic aged sedimentary rocks. 

However, re-interpretation of the old drilling data suggests the structure could host a potentially larger re-mobilised massive sulphide body, with the addition of an intrusion related copper-zinc-tin-silver sulphide feeder zone lurking below.

Octava Minerals managing director Bevan Wakelam said: “This is a fantastic outcome for Octava to be drilling the first holes at Sweeney’s in almost 50 years.”

The company believes Sweeney’s may host a potentially underexplored zone of massive and semi massive sulphide sitting in a world class discovery province of Western Tasmania. Over the years, the region has pumped out a string of long-life mining powerhouses — from MMG’s world-class Rosebery base-metal operation to Metals X’s giant Renison Bell tin mine, and the high-grade Henty gold mine now in the hands of ASX-listed Kaiser Reef.

Moving forward Octava says it is also planning to conduct airborne electromagnetics (EM) survey in early 2026 across its Federation grounds. Since the semi massive to massive sulphide mineralisation at Sweeny’s sits within resistive country rock with no conductive overburden, it is ideally suited to today’s modern and highly sensitive EM techniques. 

Given the strong historic drilling at Sweeney’s, the outstanding rock chips and the prospect’s prime address amid a cluster of world-class mines, a fresh metal hit from Octava’s drill bit could be the spark that finally rekindles exploration interest in this overlooked patch for the first time in more than four decades.

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