After taking a triple-digit tumble on Friday following worse-than-expected US jobless data for August, the top-share index is set to take another dive this morning, with City traders predicting the Footsie will open at around 5,200, down from Friday's close of 5,292.Mining giant Rio Tinto is to offload its 57.7% stake in Palabora Mining Company. "Rio Tinto is no longer the natural owner of Palabora due to the limited opportunity to significantly expand copper mining," said Rio Tinto Copper's chief executive, Andrew Harding.Anglo American, which currently holds a 16.8% effective interest in Palabora, will also be divesting its stake in Palabora.Charter International, already opening its books to sector peer Melrose, has confirmed that it is in discussions with US manufacturing group Colfax Corporation regarding a possible cash offer for Charter.Michael Sharp has today been appointed Chief Executive of Debenhams, the department stores group. Sharp was previously deputy to Rob Templeman, who retired as Chief Executive on Sunday, 4 September.