The FTSE 100 put in a decent performance on Tuesday, jumping around one per cent as investors shrugged off gloomy comments from the International Monetary Fund (IMF) and instead focused on progress in Greece and a strong start to US corporate earnings season.London's benchmark index finished the day 63 points higher at 6,513, a level not seen since the start of June when markets were beginning to price in the impending withdrawal of quantitative easing in the States.Mining stocks were leading the risers on the Footsie on Tuesday, boosted by rising metal prices across the board. Results from US aluminium giant Alcoa after the closing bell on Wall Street last night were also helping sentiment today, as the company unofficially kicked off second-quarter earnings season with forecast-beating numbers.Investors' concerns over the Eurozone also eased slightly today after finance ministers granted Greece its next instalment of funds from the Troika in exchange for meeting prior conditions. "The discussions between Greece and its creditors have been far smoother in the lead up to [the] agreement than we have become accustomed to, which may be why investors have responded so well to it," said Market Analyst Craig Erlam from Alpari.IMF cuts global growth, up UK forecastsA report by the IMF this afternoon failed to take the shine off stocks today, despite the organisation downgrading its forecasts for global economic growth this year to 3.1%, down from its previous 3.3% estimate in April. 2014 growth predictions have also been cut from 4.0% to 3.8%. The Fund said the move is as a result of "appreciably weaker domestic demand and slower growth in several key emerging market economies, such as Brazil, China, Russia and the CIS countries, as well as by a more protracted recession in the euro area".On a brighter note however, the IMF actually raised its gross domestic product (GDP) forecasts for a small number of economies, including the UK which it expects to grow by 0.9% this year, up from its earlier 0.6% prediction. The 2014 GDP growth forecast was unchanged at 1.5%.Economists at Barclays Research appear to be more optimistic about the UK economy after yesterday raising their GDP projections to 1.1% this year (0.9% previously) and 2.1% in 2014 (1.8% previously).FTSE 100: Miners surge, RBS jumpsHeavyweight miners Vedanta Resources, Fresnillo and Anglo American were making impressive gains before the close, as the sector - which fell sharply amidst heightened market volatility in June - recovered after recent losses. Gold prices were up 1.3% at $1,251 an ounce and silver 1.1% higher at $19.25 an ounce, helping to buoy stocks today.Rio Tinto meanwhile was boosted by the news that its part-owned giant copper-gold mine in Mongolia, Oyu Tolgoi, has started shipping copper concentrate to customers.Banking group RBS was on the rise after the government effectively ruled out a broad investigation into whether the lender should be broken up into a 'good' and 'bad' bank. However, Goldman Sachs, which today upgraded the stock from 'neutral' to 'buy', suggested that a split could actually be good for RBS and address its key challenges: "muted core returns and elevated uncertainty".Marks & Spencer was lower after reporting a 0.3% rise in like-for-like sales in the first quarter, as a strong performance in Food continues to be partly offset by weakness in General Merchandise. Investors cheered oil group Shell's announcement that Downstream Director Ben van Beurden has been appointed as CEO, succeeding Peter Voser who steps down after 29 years with the company.FTSE 250: AVEVA and Ferrexpo impress with updatesEngineering software solutions provider Aveva was a high riser today after saying it had seen a good start to the year in both engineering & design systems and enterprise solutions divisions with steady growth in EMEA and Asia Pacific.Miners were also performing well with Ferrexpo the standout performer after a second-quarter production update. The iron ore producer said that group pellet output was up 11.4% year-on-year in the first half, helped by the ramp up of production from the new Ferrexpo Yeristovo Mining open pit. Mining peers Hochschild Mining, Polymetal, African Barrick Gold and Lonmin were also in demand, with the latter benefitting from an upgrade by Westhouse Securities from 'sell' to 'neutral'.Bucking the trend Centamin which slipped into the red despite saying it achieved record gold production at its Sukari Gold Mine in Egypt in the three months to end of June. The company however kept its full-year guidance unchanged, warning of reduced throughput from commissioning activities in the fourth quarter.FTSE 100 - RisersVedanta Resources (VED) 1,094.00p +8.53%Royal Bank of Scotland Group (RBS) 304.40p +5.40%Aberdeen Asset Management (ADN) 399.60p +3.55%Schroders (SDR) 2,408.00p +3.53%Fresnillo (FRES) 951.00p +3.26%GKN (GKN) 332.40p +3.04%Anglo American (AAL) 1,282.00p +2.97%Hammerson (HMSO) 534.50p +2.89%Weir Group (WEIR) 2,162.00p +2.76%Wood Group (John) (WG.) 878.50p +2.75%FTSE 100 - FallersITV (ITV) 150.20p -1.70%Eurasian Natural Resources Corp. (ENRC) 210.40p -1.68%Marks & Spencer Group (MKS) 453.20p -1.41%easyJet (EZJ) 1,335.00p -1.40%Capita (CPI) 1,023.00p -1.35%Lloyds Banking Group (LLOY) 66.35p -1.12%WPP (WPP) 1,171.00p -0.68%Whitbread (WTB) 3,154.00p -0.54%William Hill (WMH) 464.00p -0.51%Reed Elsevier (REL) 788.00p -0.44%FTSE 250 - RisersAveva Group (AVV) 2,578.00p +13.67%Ferrexpo (FXPO) 155.60p +12.18%Kier Group (KIE) 1,351.00p +8.08%Henderson Group (HGG) 173.10p +7.52%Polymetal International (POLY) 506.00p +6.66%Fisher (James) & Sons (FSJ) 1,079.00p +5.78%Menzies(John) (MNZS) 746.00p +5.07%Computacenter (CCC) 528.00p +4.24%Ocado Group (OCDO) 324.20p +4.21%Carillion (CLLN) 273.50p +3.83%FTSE 250 - FallersCentamin (DI) (CEY) 36.76p -4.17%Evraz (EVR) 95.55p -3.58%Telecity Group (TCY) 989.00p -3.42%Dixons Retail (DXNS) 42.25p -2.65%Howden Joinery Group (HWDN) 266.60p -2.59%888 Holdings (888) 158.30p -1.98%Barr (A.G.) (BAG) 522.50p -1.69%Direct Line Insurance Group (DLG) 225.30p -1.66%Taylor Wimpey (TW.) 104.60p -1.60%Spirent Communications (SPT) 124.00p -1.20%