BHP, Rio Tinto weigh on London stocks By: MarketWatch October 18, 2010 at 05:25 AM EDT A failed joint venture for iron-ore producers BHP Billiton and Rio Tinto weighs on the FTSE 100 index, while shares of BlueBay Asset Management soar on buyout news. Read More >> Related Stocks: Bhp Billiton Ltd ADR Rio Tinto Plc ADR Royal Bank of Canada