The competition to take over Ghana's biggest gold miner hotted up on Monday as London-listed Randgold confirmed reports that it is entering the race with an initial bid worth almost $1.5bn.

The new offer jumps well ahead of the main one currently on the table, which sees South Africa's AngloGold - part of Anglo American, the world's third largest mining concern - offering shares worth $1.1bn.

Randgold is offering one share for every two Ashanti shares, while AngloGold's bid offers 26 of its shares for every 100 Ashanti shares.

"Because we are not as large as the other interested party, it retains the independence of [Ashanti through] any possible merger," Randgold chief executive told BBC World Business Report.

Weak gold

Anglo was quick to pour cold water on its rival's offer, saying that Randgold's relatively small size might lead to problems if the cost of the bid left too few resources to invest in improving Ashanti's operations.

"I will not surprise you by saying that I think we are overwhelmingly the right partner for Ashanti," AngloGold chief executive Bobby Godsell told BBC World Business Report.

"Our immediate reaction is that (Randgold) will have to increase their share capital very substantially and wonder what their existing shareholders will have to say about this," said Jonathan Best, AngloGold's Chief Financial Officer.

Anglo's parent, Anglo American, last Friday reported a slight rise in profits thanks to soaring sales at De Beers, the diamond miner in which it has a 45% stake.

But it warned that the rising South African rand and weakness in the gold, platinum and coal mining business made the rest of the year look challenging.

Casting vote?

With the new hat thrown into the ring, Ashanti's current owners have become more cagy.

Lonmin, the London-based miner which owns 28% of the company, originally backed Ashanti.

In a statement last week, Lonmin said it was "pleased to support the merger between AngloGold and Ashanti, which enhances the value of our financial investment".

The company stands by that statement, a spokesman told BBC News Online.

But he said that since another bid had been mooted, it was for the Ashanti board to make its mind up before Lonmin would express a position.

Both bids, he noted, were at an early stage.

The casting vote may lie with the Ghanaian government, which retains 17% and is thought to have been keen that Anglo should face competition in bidding for Ashanti.