Mining giant Rio Tinto has received a request from the US Federal Trade Commission (FTC) for more information regarding its pending sale of the Jacobs Ranch coal mine in Wyoming.Rio Tinto agreed in March to sell the mine to Arch Coal for a total cash consideration of $671m.Rio Tinto said is will respond positively to this request for information and will continue to co-operate with the FTC.Completion of the transaction remains subject to the expiration of the waiting period under the Hart Scott Rodino Act.