Rio Tinto has agreed to sell coal assets it bought through a $4 billion acquisition of Riversdale in 2011 for just $50 million to an Indian joint venture, ending its ill-fated venture in Mozambique's coal sector. The sale of Rio Tinto Coal Mozambique to International Coal Ventures Private Limited (ICVL), includes the Benga coal mine and other projects in Tete province, assets that had a value of $71 million as of March 31 in Rio's books. In 2013, Rio Tinto sacked its chief executive…