Old water bore leads to lucky find for Great Boulder

An old water bore hole has lead to a dose of serendipity for Great Boulder Resources, writes Barry FitzGerald in his weekly Garimpeiro column.

Newly listed Great Boulder Resources (ASX:GBR) is off to a flying start in the discovery stakes thanks to a good dose of serendipity at its remote Mt Venn project east of Laverton in Western Australia.

Originally a fifth-ranked gold and base metals exploration project when Great Boulder raised $6.1 million in an initial public offering last year, Mt Venn has shot to prominence as an emerging copper-nickel-cobalt discovery.

And it is all down to a water bore hole drilled in 2015 by Gold Road (ASX:GOR), the $600 million company which has partnered up with South Africa’s Gold Fields to develop the 6.2 million oz Gruyere gold deposit at a cost of $532 million.

Gruyere lies about 30 km west of Great Boulder’s Mt Venn and as part of its water needs Gold Road got out and about drilling the Thatchers Soak palaeo-channel which snakes through the parched region.

It was high-tech stuff too, with Gold Road mapping the palaeo-channel in an airborne electro-magnetic (EM) survey which identified an interesting EM anomaly on the common boundary between one of its tenements, and Great Boulder’s Mt Venn ground.

Gold Road drilled a hole in the EM anomaly and a preliminary assessment found that the 2015 test had returned copper and nickel mineralisation.

Great Boulder more recently acquired the tenement and earlier this year sent off the pulverised samples from the hole for comprehensive testing.

Much to its delight, the results confirmed the EM anomaly relates to primary bedrock sulphide mineralisation, with peak results of 1.7 per cent copper and 0.2 per cent nickel, with cobalt, gold and silver values.

Highly promising

It meant Great Boulder was able to announce what it described as highly promising copper, nickel and cobalt intersections from the first hole drilled at its Mt Venn prospect — even if the hole was drilled two years earlier, and by someone else.

Still, it was exciting stuff for Great Boulder which has since been busy doing all the things that need to be done before it tests the potential of the discovery with targeted drill holes.

Of particular note is the assessment that the water bore hole clipped the edge of the (conductive) anomaly, with the main zone of interest being some 450 metres to the south.

Another “strong’’ EM conductor is located a further 2 km south along the same magnetic trend and also sits in Great Boulder’s ground.

Technically speaking the company, which last traded at 15c for a market cap of $10m (it was holding cash of $4.3m at the end of June), is now conducting its first exploration at Mt Venn, with ground EM and aircore geochemical sampling underway.

Results from the survey and sampling, which will define and prioritise targets for the next phase of drilling, can’t be too far away now.

The hope is that the work confirms Mt Venn’s potential as an emerging copper-nickel-cobalt province.

While Mt Venn might have floated to the top in terms of near-term importance, it’s not as if Great Boulder’s other projects have fallen by the wayside.

That is particularly so with its Tarmoola gold project, 40 km north-west of Leonora in WA (Mt Venn is 130 km east of Laverton).

Great Boulder recently reported what it described as extremely promising results from its first surface sampling program at the project which sits in the part of WA which is home to the 9 million oz Gwalia mine and the 3 million oz Thunderbox mine owned by others.

Rock chip surface sampling from outcropping rock and quartz veins, as well as historical workings, returned results which included a best result of 23.9 grams of gold per tonne.

A maiden drilling program is planned after the completion of soil sampling to define the extent of the mineralisation.