The capital raising was extended to accommodate further demand and is one of the largest ever first-time raises by a private vehicle.

The funds comprise $4 billion in committed capital available for immediate drawdown and $1.6 billion in conditional capital.

X2’s investors include major sovereign wealth and pension funds.

Davis thanked investors for their support and said he looked forward to rewarding them with superior returns.

“The blue-chip nature of our investors and the scale of their commitments to date are clear endorsements of the X2 Resources team’s strategy and our track record of creating value,” he said.

“We continue to carefully review a number of opportunities in the sector in detail.

“Whilst value creating opportunities are increasingly evident, the long-term nature of our strategy provides us with the flexibility to target those opportunities where we see the greatest potential for value creation.”

X2 has been linked to assets including BHP Billiton’s Nickel West and thermal coal assets –as well as the operations to be demerged into South32 – Vale’s base metals division, and Anglo American’s coal assets.

Private equity funds have been slow to make a move, despite sitting on huge amounts of cash.

“We think there’s a wall of money out there looking for investment in the resources sector,” Morgans analyst James Wilson said last month.

“The funds are locked away in the coffers of private equity which raised around $8 billion in 2014 for mining projects, but only a fraction was actually invested.

“A combination of cheap equity valuations and an increase in M&A chatter suggests these funds will be deployed in 2015 which will send a strong signal for a change in sentiment towards the resources sector as the smart money gets set.”

Despite being established in 2013, X2 is yet to make any acquisitions.

Davis formed the London-based company after leaving the top job at Xstrata when the company merged with Glencore.

Former Xstrata chief financial officer Trevor Reid, who also left once the merger was complete, has joined Davis at X2, as well as other former Xstrata senior executives Andrew Latham, Benny Levene, Thras Moraitis and Ian Pearce.