(ShareCast News) - The FTSE 100 was down 0.47% to 6,520 points as depressed metals and oil prices continued to hammer mining stocks.BHP Billiton shares were down 1.39%, while Glencore stock was 1% lower after the Daily Telegraph reported that activist investor Harris Associates has built a £250m position in the world's largest commodities trader.The move was likely to pile further pressure on Glencore chief Ivan Glasenberg who faces a tough week as the company is expected to report a slump in first-half earnings.Weir Group, which makes valves and pumps for the industry, saw its shares 1.7% lower. Investor sentiment was also dampened by a target price downgrade by Liberum Capital to £13.30 from £14.50.On the positive side Wolseley got a boost after Citigroup upgraded the stock to 'buy' from 'neutral' and lifted its price target to 4,725p from 4,100p as it revisited the valuation in the context of a sector re-rating, balance sheet strength and potential for share gains and margin expansion.Citi said it expects the company to deliver a three-year earnings per share compound annual growth rate of over 16%.TUI shares were up 0.7% after the Times reported that the travel firm was thinking about spinning off some of its assets. Deutsche Bank raised its target price to 1385p from 1235p.FTSE 100 - RisersWolseley (WOS) 4,259.00p +1.24%Admiral Group (ADM) 1,456.00p +1.11%TUI AG Reg Shs (DI) (TUI) 1,170.00p +0.69%Sage Group (SGE) 527.00p +0.67%Associated British Foods (ABF) 3,272.00p +0.55%Antofagasta (ANTO) 572.50p +0.53%Fresnillo (FRES) 670.00p +0.53%Coca-Cola HBC AG (CDI) (CCH) 1,409.00p +0.50%National Grid (NG.) 873.50p +0.46%Carnival (CCL) 3,483.00p +0.37%FTSE 100 - FallersGKN (GKN) 297.00p -1.75%Weir Group (WEIR) 1,437.00p -1.71%Mondi (MNDI) 1,545.00p -1.59%Morrison (Wm) Supermarkets (MRW) 175.20p -1.46%Barratt Developments (BDEV) 643.50p -1.45%St James's Place (STJ) 966.00p -1.43%BHP Billiton (BLT) 1,134.00p -1.39%Whitbread (WTB) 5,120.00p -1.35%Old Mutual (OML) 214.70p -1.29%London Stock Exchange Group (LSE) 2,602.00p -1.21%