Following the acquisition of an additional stake in Africa-focused coal miner Riversdale Mining, Rio Tinto announced on Friday that it has now taken full control of the target, after months of deliberation and deadline extensions.On Thursday, India-based steel manufacturer Tata Steel sold its 26% shareholding in Riversdale to Rio Tinto Jersey Holdings for a total of A$1.06bn (around £0.69bn)."Tata Steel has decided that it would not want to hold its equity investment in Riversdale Mining Limited which is proposed to be delisted, without any joint venture agreement with the majority shareholder in unlisted Riversdale Mining Limited," Tata Steel said in a press release on its website.The transaction means that Rio raised its stake from 73% to 99.74% in Riversdale.Rio's shares were 1% down, trading at 4,041p, as of 10:15am on Friday. The mining sector on the whole was broadly lower, tracking metals prices down."This is a great outcome for Rio Tinto. The Riversdale acquisition reinforces our strategy of investing in and operating, long-life, cost-competitive mines and businesses with significant growth potential," said Rio Tinto Energy's chief executive Doug Ritchie."We have already started to integrate Rio Tinto's world-class operating and technical capability into the operations. We are determined to develop Riversdale's assets in a sustainable, mutually beneficial manner for the people of Mozambique."---BC