Bonanza gold grades can turn emerging miners into market darlings, but a few headline-grabbing high-grade intercepts don’t necessarily make a mine.

As gold miners pump more money than ever into drilling, busy assay labs are sending back some eye-watering results.

While some investors love those +1,000 gram-per-tonne (g/t) gold hits, it’s worth taking a deeper dive into what actually makes a mine economic.

Experienced geologist and fund manager Hedley Widdup of Lion Selection Group says grade is good, but it is far from being “king”.

“‘Grade is King’ seems to roll off the tongue of gold promoters where they can point to high-grade results,” Widdup says. “It’s an easy, but unsophisticated conclusion to say – wow, 25g/t is about 25x the average mine grade.”

But Widdup says while “grade is king” seems to be taken as a given by the market, it is only partially true.

“High-grade does mean high contained value per tonne but says nothing for the cost or difficulty to extract that value,” he says.

Widdup says the shape of an orebody is critical because that is a key factor in how much it costs to extract the gold, dictating how much waste also needs to be mined.

“Narrow orebodies are expensive to mine per tonne of ore because they require low volume and intense effort to extract,” he says. “By contrast broad orebodies can generally be extracted with some sort of efficiency of scale benefit.

“Give me 50m at even 1-1.5g/t gold any day, if it is close to the surface and there is lots more of it – that will be the gold mine. But if all you want to do is get a sugar hit to your share price and are less interested in developing a mine one day… 1m at 500g/t all on its own will do.”

What does make a gold mine is consistent thick intercepts – even if the gram-per-tonne readings aren’t as whopping as hits from projects with thin veins of mineralisation.

Nova Minerals (ASX:NVA) for example, has reported multiple thick, high-grade gold from surface from its RPM deposit at the 9.6Moz Estelle Gold Trend project in Alaska.

Nova this week reported it had uncovered 78m at 16g/t from surface – and that was from within a broader 258m at 5.1g/t.

Other high-grade intersections featured a wide 161m at 8.1g/t from surface, including 117m at 11.1g/t, 45m at 25.3g/t and 14m at 51.2g/t.

Another hole returned 113m at 1.4g/t from just 8m, including 82m at 1.7g/t, 55m at 2.1g/t and 11m at 4.5g/t.

These results continue to prove up the broad zones of high-grade gold at RPM North. Earlier this month Nova announced a 260m intersection at 3.6g/t, including 140m at 6.5g/t.

These hits have sent Nova to the top of the Miner Deck gold intercepts charts twice this month.

 


A look at previous results reveals a notable 400m at 3.5g/t, including 132m at 10.1g/t, which was announced last October.

Nova is now working towards a phase two scoping study, alongside a pre-feasibility study as the company heads towards commercial production at its flagship Estelle Gold Trend project in the Tintina gold province – one of the world’s most prolific belts.

Other chart toppers for gold intercepts include Aston Minerals (ASX:ASO), which was No.1 on MinerDeck’s gold intercepts for 2021 with a whopping 2,035g/t from its Edleston Project in Ontario, Canada.

High-profile company chair and stock spruiker Tolga Kumova has described this explorer as a potential “life-changer”.

However, that extremely high grade was present across only a thin 0.5m interval that was relatively deep at 362m.

Musgrave Minerals (ASX:MGV) took out silver on the charts with a more impressive 15m at 111.6g/t from its Cue project in Western Australia.

Unearthed from only 25m, this strike sent Musgrave shares up over 13% in December.

That hit was also one of a string of high-grade results at Cue that helped identify new gold zones with more bonanza grades, including a 5m zone running 313.4g/t.

And as it builds its Abujar gold mine in Cote d’Ivoire, Tietto Minerals (ASX:TIE) has witnessed its share price climb about 60% over the past year with highlights of 12m at 20.96g/t from 298m, including 2m at 120.21g/t.

This article was developed in collaboration with Nova Minerals, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.

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