- Miners track commodity prices lower- Yields rise at Spanish debt auction- ECB expected to maintain ratesLondon's blue chip index was trading well over a whole percentage point lower by midday as Eurozone concerns continued to dampen the mood ahead of a policy rate decision by the European Central Bank (ECB). Just four stocks were making gains on the FTSE 100.The ECB is to announce its interest rate decision in the next hour, which is widely expected to be unchanged from the previous month, left at the record-low level of 1%. More importantly, the ECB President Mario Draghi will give the rune readers some exercise in his afternoon press conference. Eurozone retail sales volumes fell by 0.1% month-on-month and 2.1% year-on-year in February, according to Eurostat. The consensus was expecting both monthly and annual readings to be unchanged.Spain has this morning issued €2.59bn euros in short- to medium-term government debt, the bottom part of its €2.5-3.5bn target range. The auction saw bid-to-cover rates broadly fall and yields rise. In the secondary markets before midday, the borrowing cost of Spanish 10-year debt was up 17 basis points at 5.60% while Italian 10-year yields had risen 14 basis points to 5.31%, according to Marketwatch.Meanwhile, US stock futures were pointing to a negative start on Wall Street ahead of ADP payrolls data due out later today. Weighing on sentiment was the minutes of the March 14th Federal Open Market Committee meeting which showed that members had become less inclined to boost the economy through quantitative easing.Investors seemed to shrug off some relatively positive economic data closer to home, which saw both activity and new business in the UK service sector grow at a stronger-than-expected rate in March.FTSE 100: MINERS PROVIDE A DRAGMetals and oil prices took a beating today after the Fed quashed expectations of extra stimulus last night, sending the miners to the bottom of the pile on London's blue-chip index. Fresnillo, Evraz, Polymetal, Rio Tinto and Antofagasta were firmly out of favour.High street retailer Next fell after it was revealed last night that its Chief Executive Officer Simon Wolfson sold off 125,000 shares in the firm. Sector peers Marks & Spencer and Kingfisher were also lower.Pearson was a heavy faller after going ex-dividend. Wolseley, Bodycote, Interserve and Phoenix Group were also among the stocks trading without the rights to their latest dividends. Shares in power producer International Power were slightly lower after the board rejected the indicative 390p-a-share offer from majority shareholder GDF SUEZ, saying that it undervalues the company. FTSE 250: BTG IN DEMAND, WHILE KENTZ FALLS BTG, the specialist healthcare company, has upped its full year revenue guidance after a strong showing at its licensing & biotechnology business. The firm is raising its revenue estimate for the year ended March 31st 2012 from a forecast of £160m-£165m to £190m-£195m. Engineering services group Kentz took a tumble after announcing that two non-executive directors are to substantially reduce their shareholdings. Kerbet, a company which represents the holdings of Tan Sri Mohd Razali Abdul Rahman and Hassan Abas, intends to sell 12m Kentz share via a secondary placing. Tan Sri Mohd Razali Abdul Rahman is Chairman of Kentz.FTSE 100 - RisersShire Plc (SHP) 2,056.00p +1.28%GlaxoSmithKline (GSK) 1,435.50p +0.49%Tate & Lyle (TATE) 714.50p +0.42%SABMiller (SAB) 2,595.00p +0.15%HSBC Holdings (HSBA) 559.20p +0.05%FTSE 100 - FallersFresnillo (FRES) 1,578.00p -5.57%Evraz (EVR) 360.30p -5.08%Weir Group (WEIR) 1,717.00p -4.02%Polymetal International (POLY) 900.00p -3.90%GKN (GKN) 201.10p -3.55%Wolseley (WOS) 2,358.00p -3.28%Antofagasta (ANTO) 1,115.00p -3.21%Hargreaves Lansdown (HL.) 472.60p -3.08%Marks & Spencer Group (MKS) 372.20p -3.02%Barclays (BARC) 223.40p -3.02%FTSE 250 - RisersDaejan Holdings (DJAN) 3,321.00p +2.82%AG Barr (BAG) 1,176.00p +2.71%Anglo Pacific Group (APF) 308.00p +2.63%Stobart Group Ltd. (STOB) 128.30p +1.99%BTG (BGC) 344.60p +1.86%Moneysupermarket.com Group (MONY) 128.20p +1.67%BH Global Ltd. USD Shares (BHGU) 11.88 +1.54%Aquarius Platinum Ltd. (AQP) 143.50p +1.49%PayPoint (PAY) 642.50p +1.26%Cable & Wireless Worldwide (CW.) 34.80p +1.16%FTSE 250 - FallersPetropavlovsk (POG) 509.00p -7.62%Kentz Corporation Ltd. (KENZ) 437.50p -7.51%Exillon Energy (EXI) 145.00p -7.35%Savills (SVS) 340.70p -6.68%Heritage Oil (HOIL) 142.50p -6.43%Logica (LOG) 93.10p -5.77%Afren (AFR) 132.90p -5.41%Amlin (AML) 321.60p -5.30%Melrose (MRO) 411.00p -4.49%Ruspetro (RPO) 220.00p -4.35%BC