When Canada’s Novo Resources Chairman and President Dr Quinton Hennigh moderated a live satellite broadcast from the Pilbara at the Denver Gold Forum at Colorado Springs in 2017, he ignited somewhat of a gold rush. 

Under the midnight sky at the company’s Purdy’s Reward site 45km South of Karratha, Novo Head Geologist Luke Meter and his team used metal detectors, jackhammers and picks to break open patches of rock in a trench to reveal gold nuggets shaped like watermelon seeds. 

Investors caught wind and Novo’s stock value skyrocketed from CAD 3.91 ($4.31) in early September 2017 just before the livestream to a peak of CAD 8.40 ($9.27) on October 6, though the price has since dropped to below the pre-live stream valuation. 

The hype around the so called ‘watermelon seed’ gold nuggets has also slowed down, but companies like Novo are still in the game. 

The company’s main areas of interest include Egina, Beatons Creek, Purdy’s Reward and Comet Well. 

The gold in these regions is found in conglomerates, a sedimentary rock made up of chunks of various materials, leading to similarities drawn with the highly prospective Witwatersrand gold deposit in South Africa, arguably the largest gold deposit in the world. 

“Certainly, from a high-level point of view the conglomerates do share some very distinct similarities,” CSIRO Senior Research Geologist Dr Sam Spinks said. 

The origin of the conglomerates is unknown, but CSIRO recently narrowed it down to two competing theories. 

While some nuggets resemble watermelon seeds, they range in size and shape, leading to suggestions that they may have been caused by a ‘rough and tumble’ life in ancient riverbeds in a sedimentary process. 

The more likely theory, however, is the gold conglomerate may have been transformed and modified through hydrothermal events, according to Dr Spinks. 

This occurs where hot fluids seep through faults and cracks in the rock, causing the metal to deform under high temperature and pressure. 

How the gold formed will have implications for the budding junior miners planning on capitalising on it, Dr Spinks said. 

“The gold that has been moved around hydrothermally is really ne-grained,” he said. 

“That has to be processed very differently to coarse, nuggetty gold, so when it comes to processing, companies will need to be aware of how the gold is actually present in those rocks.” 

This is one discussion happening at Novo. 

“Right now it is about the downstream,” Novo CEO Rob Humphryson said. “How do you get a nugget out of a tonne of rock economically. 

Novo is working with German company Steinert to conduct processing trials using its eddy current separator (ECS). 

Recent extraction from the gravels at Egina of nuggets ranging from one to 10mm demonstrated consistently high gold recovery, according to Novo. 

Novo isn’t the only miner chasing conglomerate-style mineralisation in the Pilbara, with Kairos Minerals uncovering 223 nuggets at its Croydon tenements in July. 

Kairos Executive Chairman Terry Topping said the discovery was promising, as the conglomerate appeared to be analogous with the extensive gold-bearing horizon reported previously by Novo at Purdy’s Reward, demonstrating just how widespread this style of gold mineralisation is in the Pilbara. 

Questions still remain around the significance and economic viability of these gold projects, but Mr Humphryson said time would tell. 

“You cannot force or rush these things, you need to be patient,” he said.