Rio Tinto dominated trading as its deal with Chinese giant Chinalco looked all but dead in the water as the mining giant confirmed it is considering its options.A rights issue to raise up to $15bn could be announced as soon as tomorrow according to reports in Australia. Rio shares slumped by nearly 7% on the news and dragged other miners down with it.The Australian newspaper also reported that Rio Tinto will, instead, look to form a joint venture with rival BHP Billiton, which last year abandoned a bid for Rio Tinto, with the two mining titans combining their iron ore interests. Lonmin, Fresnillo and Kazakhmys are the main fallers alongside Rio.Supermarket chain Wm Morrison's first quarter trading update was ahead of market expectations, prompting Charles Stanley to upgrade its rating on the stock. The broker now advises clients to accumulate the shares, having previously rated the shares as a 'hold'. FTSE 100 - RisersLiberty International (LII) 420.00p +12.00%Hammerson (HMSO) 303.00p +9.29%ICAP (IAP) 430.25p +4.56%British Land Co (BLND) 379.00p +3.76%Aviva (AV.) 346.75p +3.66%Royal Bank of Scotland Group (RBS) 37.20p +3.05%Home Retail Group (HOME) 252.00p +2.86%Shire Plc (SHP) 880.00p +2.74%Morrison (Wm) Supermarkets (MRW) 254.00p +2.63%Next (NXT) 1,537.00p +2.54%FTSE 100 - FallersLonmin (LMI) 1,410.00p -6.62%Rio Tinto (RIO) 2,720.00p -6.59%Fresnillo (FRES) 685.50p -5.90%Kazakhmys (KAZ) 662.00p -5.29%Eurasian Natural Resources (ENRC) 636.00p -3.78%Vedanta Resources (VED) 1,526.00p -3.54%Xstrata (XTA) 703.50p -3.37%Antofagasta (ANTO) 619.50p -3.13%Schroders NV (SDRC) 725.00p -2.95%Schroders (SDR) 845.00p -2.93%