Rio Tinto Plc received a $340m. offer from French industrial minerals group Imerys SA for its world-leading talc assets this week, bringing this long-running divestment story close to a logical conclusion.The Anglo Australian mining giant began the search for a buyer for its Luzenac talc assets in late 2007, initially as part of a package with its borates business.Rio Tinto temporarily delayed the sales process in 2009 amid poor market conditions, which management felt had undervalued the assets.However, the market for talc improved during 2010, with the group’s talc-producing subsidiary Rio Tinto Minerals (RTM) reporting 12% higher sales and a 13% rise in production for the filler mineral to 1m. tonnes. Rio Tinto said it was open to offers throughout 2010 and has now entered exclusive negotiations with Imerys, which look set to see Luzenac changing hands in mid-2011.The deal remains subject to the completion of preliminary processes such as...