Randgold Resources Ltd.'s (RRS.LN) half-cash, half-shares offer for Moto Goldmines Ltd. (MGL.T) is "significantly superior" to a rival offer for the gold exploration firm, Randgold's chief executive said Thursday.

"We're very mindful that bidding wars are destructive in Africa. We've put a lot of effort into delivering something that is different and we think significantly superior to what has been proposed to [Moto's] board," Mark Bristow told Dow Jones Newswires.

Randgold teamed up with AngloGold Ashanti Ltd. (AU) on a deal that values Moto at about 546 million Canadian dollars ($488 million).

Moto's board in June endorsed a CAD513 million all-share acquisition by Red Back Mining Inc. (RBI.T), and would have to pay a CAD15.3 million break fee if it walks away.

Bristow said Randgold's mix of shares and cash allow investors a broader range of options, including cashing out of their investment by taking cash and then selling off a liquid stock.

"Clearly the board of Moto has decided to sell. And we're very motivated to convince them we are the right bias," Bristow said.

For Randgold shareholders, the deal offers entree into Congo, a mineral-rich but potentially risky country.

"It's a big asset. It is quite high risk. But bringing in Anglo as a partner shares the risk," Bristow said.

AngloGold, Africa's largest producer of the precious metal, has agreed to part-fund the acquisition in exchange for an indirect 50% stake in Moto, and separately said it will pay $244 million after Randgold closes its deal.

Randgold, incorporated in Jersey, operates a gold mine in Mali, and is developing projects in Ivory Coast and Senegal.

Moto in a statement said it had received the offer.

"The board of directors of Moto is considering the offer to determine whether it is a superior offer to the plan of arrangement that has been agreed with Red Back Mining Inc.," Moto said.

Red Back wasn't immediately available to comment.

Company Web site: www.randgoldresources.com

-By Jeffrey Sparshott, Dow Jones Newswires; +44 (0)207 842 9347; jeffrey.sparshott@dowjones.com

(By Robb M. Stewart in Johannesburg contributed to this article.)