Mining giant Rio Tinto has received clearance for its offer to purchase uranium developer Hathor Exploration for C$4.70 a share, in a bid which values Hathor at around C$654m (£402m) on a fully-diluted basis. The company said that the Canadian Competition Bureau's Commissioner of Competition issued a "no action letter" and Hathor shareholders now have until 17:00 on 30 November to accept and tender their common shares.Hathor's board of directors are said to unanimously recommend the offer.Rio raised its offer price just five days ago after Cameco Corporation trumped its initial offer earlier this month.BC