BHP surges again on gold speculation

BHP Billiton Ltd cracked the $150 billion mark in terms of market capitalisation today, as its share price surged briefly above $45 amid speculation that it is set to reveal a massive expansion of gold reserves at Olympic Dam in South Australia.

BHP closed $1.46 higher for the day at $44.60, giving it a market capitalisation of $149.68 billion, while global rival Rio Tinto Ltd gained $1.36 to $108.04.

Today's mining giant rises, which took the market with them, follows yesterday's performance with BHP Billiton lifting $2.14 to $43.41 and Rio Tinto was $3.47 higher at $106.68.

BHP is expected to release its resource upgrade for the copper, gold and uranium mine as part of its annual report tomorrow.

The Olympic Dam contains the world's largest resource for uranium, the fourth-largest deposit for copper, as well as being among top Australian mines in gold and silver.