At work in Limpopo’s Northam 
Platinum Zondereinde mine.

JOHANNESBURG - But a prolonged slump in metals and big losses on earlier solo projects are turning top producers into risk-avoiding wallflowers.

“The mining industry has lost its nerve,” said Randgold chief executive Mark Bristow. “The new fad in town is joint ventures. It’s very strange if you’re a major miner. They should be comfortable in their ability.”

At a time when prices are recovering - helping to make new projects viable again - metals producers including Anglo American, BHP Billiton and Rio Tinto are seeking partners to share the investment risk rather than going it alone as they have in the past.

While the more cautious approach is a consequence of the near-death experience of the 2015 commodity crash, it could limit the pay-off for shareholders during a metals rally.

The shift to more conservative financing comes as the industry confronts a core dilemma: the richest mines in the safest or most-accessible places have mostly been found and built. That means companies are increasingly looking to develop ore bodies that are of lesser quality and may be in higher-risk countries.

“They have to spend more to mine less,” said Rob Crayford, a fund manager at CQS Asset Management’s New City Investment Managers in London. “A lot of the projects out there aren’t that great.”

Still, while prices remain well below their post-recession peaks, they are up enough in the past year or so for companies to consider dusting off expansion plans they shelved during the glut.

The London Metal Exchange index of six base metals, including copper and aluminium, has rallied almost 50percent from a low in January 2016.

Gold is heading for the biggest annual gain since 2010, and iron ore has almost doubled from the all-time lows reached in 2015.

S&P Global Market Intelligence estimates that exploration drilling for metals has risen for five straight quarters, off to its fastest start to a year since 2009, and there are signs the pace is accelerating.

Anglo American says its No1 new project is the giant Quellaveco copper deposit in Peru. But the company wants a partner before development starts, and says it will seek joint ventures for all future new mines, known as greenfield developments.

Melbourne-based BHP, the world’s largest mining company, is set to commit to the $13billion Jansen potash mine in Canada after years of study, but says it wants to bring in a partner to help share the risk.

London-based Rio Tinto also is seeking partners for future developments, while Glencore says it will not build any new mines at all.

“I’m not excited about greenfield,” said chief executive Ivan Glasenberg, noting that over-development in years past created the oversupply and low prices that led to huge losses for the industry. “Unless something changes in the world, I don’t see Glencore doing greenfield for a while.”

Acquisitions are more likely, Glas- enberg said, because it doesn’t make sense to “bring new tons into the market which cannibalises your existing production”.

The industry is still smarting from self-inflicted wounds. Anglo’s giant Minas Rio iron-ore mine in Brazil cost $14billion to buy and build, but it became an expensive mistake as prices plunged by more than half.

Barrick Gold, the largest bullion producer, spent $8.5billion on the Pascua Lama project high in the Andes that has been stalled since 2013.

The company recently signed a deal with China’s Handong Gold Group that may lead to a joint venture on the project.