Markets opened strongly on Thursday morning as strength in the mining sector lifted the FTSE 100 higher ahead of the release of UK growth data.British gross domestic product (GDP) is widely expected to have expanded by 0.1% in the first quarter, according to consensus estimates, rebounding after a 0.3% contraction in the fourth quarter. However, with a number of commentators showing caution about the harshness of austerity measures, there is growing concern that the figures could disappoint, pushing the UK into a triple-dip recession given the recent weakness in Europe.The Footsie has risen strongly over the past two days despite a series of poor economic indicators from the Eurozone, including weaker-than-expected purchasing managers' indices (PMIs) and a gloomy Ifo survey yesterday from Germany."Economists are playing the card which implies that poor data is not always a bad thing for the markets. Many economists are pointing out that a short period of bad data may just encourage policy officials to maintain or even enhance current stimulus measures," said Financial Trader Shavaz Dhalla from Spreadex. "However, investors need to remain on guard to such an argument, as accepting poor data because it can lead to more stimulus measures does not solve the problem in the long-term."FTSE 100: Mining strength offsets disappointing updatesMining stocks were performing strongly early on as metals prices advanced: Randgold, Antofagasta, Vedanta Resources, ENRC, Anglo American and Xstrata were making gains.Polymetal also rose after saying that it has "significantly de-risked" the achievement of its full-year production targets after a stable first quarter. However, the company said that it has initiated a review of all discretionary capital spending including exploration projects due to the recent sharp falls in gold and silver prices. Heading the other way was consumer good group Unilever after it had to rely on robust growth from emerging markets as it grew marginally slower than expectations in the first quarter.Car insurer Admiral was lower after reporting a fall in turnover for the first quarter as tough economic conditions gripped the UK.AstraZeneca was in the red after saying that a loss of exclusivity on several of its brands was to blame for a 12% fall in first-quarter revenue at the pharmaceuticals giant.British American Tobacco impressed after saying it had made a "good start to 2013" as it managed to increase first-quarter revenues despite a slip in volumes.Speciality chemicals firm Croda edged higher after saying that it has ramped up its first-quarter pre-tax profit and expects to report further progress in 2013.FTSE 100 - RisersRandgold Resources Ltd. (RRS) 5,250.00p +4.06%Eurasian Natural Resources Corp. (ENRC) 287.20p +2.32%British American Tobacco (BATS) 3,625.50p +2.18%Antofagasta (ANTO) 931.00p +2.14%IMI (IMI) 1,232.00p +1.99%Polymetal International (POLY) 772.50p +1.58%Vedanta Resources (VED) 1,197.00p +1.44%Xstrata (XTA) 1,006.50p +1.36%Anglo American (AAL) 1,647.50p +1.35%BHP Billiton (BLT) 1,837.00p +1.35%FTSE 100 - FallersUnilever (ULVR) 2,798.00p -1.65%AstraZeneca (AZN) 3,335.00p -1.62%Admiral Group (ADM) 1,330.00p -1.41%International Consolidated Airlines Group SA (CDI) (IAG) 273.30p -1.34%Hammerson (HMSO) 524.00p -0.85%Prudential (PRU) 1,089.00p -0.73%Smith & Nephew (SN.) 743.00p -0.67%Severn Trent (SVT) 1,796.00p -0.66%Diageo (DGE) 1,980.00p -0.65%Associated British Foods (ABF) 1,938.00p -0.62%FTSE 250 - RisersInternational Personal Finance (IPF) 519.50p +8.16%Elementis (ELM) 260.50p +5.30%Kazakhmys (KAZ) 371.30p +3.43%Centamin (DI) (CEY) 41.23p +3.33%Petropavlovsk (POG) 147.10p +3.01%Taylor Wimpey (TW.) 96.45p +2.55%Ocado Group (OCDO) 153.50p +2.47%Lonmin (LMI) 280.10p +2.30%SVG Capital (SVI) 395.70p +2.25%Man Group (EMG) 106.30p +2.21%FTSE 250 - FallersSDL (SDL) 375.80p -2.42%Fenner (FENR) 372.10p -1.82%Telecity Group (TCY) 908.50p -1.78%Carpetright (CPR) 637.00p -1.47%IP Group (IPO) 151.10p -1.24%Unite Group (UTG) 332.00p -1.10%Dixons Retail (DXNS) 37.10p -1.07%Hansteen Holdings (HSTN) 85.10p -1.05%Daejan Holdings (DJAN) 3,814.00p -0.99%Oxford Instruments (OXIG) 1,518.00p -0.91%BC