Mining group Vedanta Resources dropped sharply lower as investors reacted to a 17 per cent drop in first-half revenue to 6.2bn dollars on the back of falling commodity prices. Shares in Centrica extended yesterday's declines which came after it warned market conditions remained challenging, particularly in business energy supply in both the UK and the US, in UK gas-fired power generation and in UK gas storage. The company also notably admitted these are "unprecedented times for the energy sector in the UK". IAG was trading in the red but managed to erase some earlier losses after it lifted its profit guidance for 2015, helped by improving margins at British Airways and the ongoing recovery of Spanish airline Iberia. The firm is now targeting a €1.8bn operating profit in 2015, up 12.5% from its previous €1.6bn forecast. BAE and Rolls-Royce were dragged lower by read-across from sector peer Ultra Electronics. The FTSE 250-listed defence group warned that revenue for 2013 would be slightly below the previous year's, hit by 'a number of headwinds', in particular the US government-funded market, and was further hit by a downgrade from Investec. Meanwhile, in contrast to Vedanta, other miners including Fresnillo, Antofagasta and Anglo American were among the best performers this afternoon. Oil stocks were also making gains with Shell and Petrofac heading higher.TUI Travel was putting a good performance - rather curiously given Investec's downgrade of the share price to 'sell' from 'neutral' today. FTSE 100 - RisersFresnillo (FRES) 940.00p +2.73%TUI Travel (TT.) 389.20p +2.13%Mondi (MNDI) 1,017.00p +2.11%Aberdeen Asset Management (ADN) 427.80p +2.05%Anglo American (AAL) 1,439.00p +2.02%Royal Dutch Shell 'A' (RDSA) 2,090.00p +1.85%Royal Dutch Shell 'B' (RDSB) 2,181.00p +1.80%Old Mutual (OML) 200.70p +1.72%RSA Insurance Group (RSA) 104.20p +1.66%BHP Billiton (BLT) 1,939.50p +1.36%FTSE 100 - FallersVedanta Resources (VED) 960.00p -6.25%Centrica (CNA) 338.20p -2.06%CRH (CRH) 1,591.00p -1.61%International Consolidated Airlines Group SA (CDI) (IAG) 367.20p -1.56%BAE Systems (BA.) 447.40p -1.50%Burberry Group (BRBY) 1,469.00p -1.34%Rolls-Royce Holdings (RR.) 1,219.00p -1.30%Melrose Industries (MRO) 306.80p -1.10%Wolseley (WOS) 3,269.00p -1.09%Smiths Group (SMIN) 1,425.00p -1.04%NR