The money, which comes from five investors, consists of $2.5 billion in committed equity capital funding and $1.25 billion of conditional funding.

X2 is one of a number of funds created by former mining bosses, which are being closely watched by the market but have yet to close any significant deals.

X2 said it was in discussions with other investors to raise further funds.

"We believe the timing for this venture remains very opportune and we will now focus increased attention on starting the investment process," Davies said in a statement.

(Reporting by Stephen Eisenhammer)