Rio (ASX:RIO) shelled out $624 million on exploration and evaluation in 2019, a 28 per cent bump on the previous year. A big chunk of this spend went into copper.

“We are heavily investing in our copper business, which is a short-term drag on profitability and cash flow,” CFO Jakob Stausholm said during today’s earnings call.

Rio’s massive Winu copper-gold project – aka the worst kept secret in exploration – was discovered in 2018 in the Paterson Province of WA.

READ: Rio Grande — The Winu copper find is real, possibly ‘colossal’ – and these juniors are right next door

In 2019, a massive ~124km of drilling was completed, Rio says. Geotechnical, hydrology, mining, processing and basic engineering studies are also well advanced.

The ~$35 billion market cap miner is now targeting first ‘staged’ production in 2023.

“[We are] working to stage gate the project, starting small, but allowing optionality for growth over time,” Rio chief exec Jean-Sebastien Jacques says.

“We are progressing discussion with the traditional owners with a target with an aim to deliver first production as early as 2023.”

Success at Winu and the neighbouring Havieron discovery continues to attract explorers — and millions of dollars in investor capital — like moths to the proverbial flame.

Exploration success story St George Mining (ASX:SGQ) is now hunting for a big prize of its own in the Paterson.

St George is well known for making some major discoveries in the “freakish” and “bizarre”  Cathedrals Belt of WA, which sparked a small ‘nearology’ rush of its own.

St George has now kicked off early stage exploration at its Paterson project,  secured in December last year.

It’s very close to all the action:

The project covers more than 35km strike of stratigraphy (rock layers) similar to that hosting the mineralisation at Winu, Nifty (2 million tonnes copper) and Telfer (27 million ounces gold), the explorer says.

Another Paterson tenement is in the application phase and expected to be granted during the year.

St George executive chairman John Prineas says the company initially pegged the ground without knowing exactly what Rio had found at Winu.

We heard on the grapevine that Rio was mobilising a large camp at the Paterson province,” he told Stockhead.

“Without knowing why, we pegged what we thought was the best ground still available in the area.

“We were smart – and lucky. We got the jump on major mining companies that have since approached us to sell or JV the ground.

“We can’t disclose names and it is too early for us to entertain those ideas.”

Prineas says the St George geologists are confident there’s less ‘cover’ to drill through as well. That means cheaper, more efficient exploration.

“Mag features are more prominent on our ground compared to other areas in the Paterson (e.g. Winu) and this is a textbook indication of relatively less cover,” he says.

“We will know more once we complete the close-spaced airborne mag survey at our ground. Overall, our geologists rate our ground as ‘red hot’ in terms of prospectivity.”