Base metal mining oriented group Rio Tinto has, as expected, increased its offer for uranium developer Hathor Exploration.The move comes just days after rival bidder Cameco Corp trumped the global miner with a C$625m ($615m) offer. Rio Tinto is now offering to acquire all of Hathor's common shares at C$4.70 in cash per share, in a bid which values Hathor at around C$654m on a fully-diluted basis.Cameco Corporation made an unsolicited revised offer of C$4.50 per share on 14 November. In a statement, Rio Tinto said: "The Hathor board of directors has reaffirmed its support for Rio Tinto's increased offer and unanimously recommends that Hathor shareholders accept and tender their common shares to Rio Tinto's increased offer." NR