WA exploration circles are buzzing that Independence Group (ASX:IGO) has made a significant gold discovery about 100km north-east of its world-class Nova nickel-cobalt-copper mine in the remote Fraser Range.

Confirmation of the discovery at the Thunderstorm prospect – a joint venture with junior explorer Rumble Resources (ASX:RTR) – is expected this week, possibly as early Monday.

Although the discovery is at an early stage and would normally not have to be disclosed under the “material’’ disclosure requirements of the ASX given Independence is a $2.8 billion company, the buzz around the find is expected to prompt the company to break cover.

Rio Tinto came under similar pressure to go public with its wholly-owned Winu copper-gold discovery in WA’s Paterson early this year.

As it is, Rumble Resources went into a voluntary suspension last week pending the finalisation of an “announcement to the market in respect of exploration results,’’ now known to involve Thunderstorm.

Rumble last traded at 6.5c for a market value of $25m.

It is one of the more active junior explorers on the ASX outside of its free carried joint venture with Independence at Thunderstorm, a prospect that has sparked interest in the past because of the nearby presence of a big gold-in-soil anomaly.

Previous exploration by others failed to find the source of the anomaly, said to be bigger than the anomaly that led to the 2005 discovery of the multi-million oz Tropicana gold deposit, now one of Australia’s biggest gold mines and owned 70 per by AngloGold Ashanti (ASX:AGG) and 30 per cent by Independence.

Talk in WA exploration circles last week was that the Independence/Rumble Thunderstorm joint venture had hit good gold grade in a paleochannel system, as well as in basement rock. But at this stage, it is only speculation.

What is known is that Rumble is well placed to give the market a good feel for how significant – or not – the Thunderstorm discovery is.

That’s because its technical director, the decorated veteran geologist Brett Keillor, was chief geologist at Independence at the time of the Tropicana gold discovery.

Tropicana sits at the northern end of a 420km stretch of prospective rocks in the Fraser Range, with Nova at the southern end.

Independence controls most of the belt and would dearly love to find another Nova, the main focus of its $30m exploration program in the region this year. But potentially at least, Thunderstorm could be a handy second prize.

Cheering it on is its 15 per cent shareholder, legendary “prospector” Mark Creasy.

The stake dates back to his joint venture with Sirius Resources, the company that discovered Nova in July 2012 and which was acquired by Independence in 2015.

Creasy has been finding deposits in his own right too in the Fraser Range.

His privately held Great Southern Nickel last year confirmed it had notched up a nickel-copper-cobalt discovery at its Silver Knight project area, about 30km from Nova.