In what has been a very volatile day of trading in London, a number of yesterday's big fallers are attracting the attention of bagain hunters.Among them is New World Resources, the central Europe focused coal miner, which is back on the up after its share price came tumbling down on Monday in line with falling base metal prices. In contrast, the share price of Greggs, the bakery chain famous for cheap takeaway snacks, is a bit flaky, after it said like-for-like sales in the 26 weeks to 2 July were up by just 0.4% from the same period a year ago.FTSE 250 - RisersHays (HAS) 77.50p +11.67%Thomas Cook Group (TCG) 50.80p +11.62%Ashtead Group (AHT) 117.40p +9.72%Grainger (GRI) 101.70p +8.19%Spirit Pub Company (SPRT) 40.00p +8.11%Centamin Egypt Ltd. (CEY) 98.30p +8.02%Imagination Technologies Group (IMG) 329.10p +7.90%Charter International (CHTR) 678.00p +7.70%Homeserve (HSV) 460.40p +7.62%New World Resources A Shares (NWR) 584.50p +7.54%FTSE 250 - FallersCable & Wireless Worldwide (CW.) 33.21p -6.69%Greggs (GRG) 451.50p -6.33%Cable & Wireless Communications (CWC) 30.54p -5.30%Daejan Holdings (DJAN) 2,350.00p -5.17%Drax Group (DRX) 462.20p -4.50%Electra Private Equity (ELTA) 1,409.00p -4.28%3i Infrastructure (3IN) 113.50p -4.14%SDL (SDL) 623.50p -4.08%Salamander Energy (SMDR) 238.90p -3.79%Enterprise Inns (ETI) 41.56p -3.57%