(ShareCast News) - London's FTSE 250 was in the red on Tuesday. At 1600 BST, the index was down 1.9% at 16,569.59, in line with the broader market, as mining stocks took a hit.IG Group was the standout gainer after the trading firm posted an increase in revenue in the first three months of the year, although it warned market volatility had made it harder to predict an outcome for the full year. In the quarter to the end of August, revenue rose 24% year-on-year to £106m, driven higher by growth in all regions, although an increase in numbers in Europe was partially offset by a decline in average revenue per user.Polymetal International was also on the front foot after the company said it has reached an agreement to settle the Kyzyl gold project put option for a net consideration of $68m. The put option arose from Polymetal's acquisition of Altynalmas Gold, the holding company for the Kyzyl gold project in Kazakhstan. The company will settle the full contractual put option liability to Sumeru and deliver a cash payment of $300m (£193.9m).On the downside, Kaz Minerals tumbled after Credit Suisse downgraded the stock to 'neutral' and cut its price target. "Given high debt levels, funding risk is high and the valuation very sensitive to medium- to long- term copper price assumptions," the bank said. It added that although it continues to believe that long-term copper prices will need to rise materially from current levels, given expected market deficits from 2018/19, the outlook over the next two years is far less certain.Science and technology company Allied Minds slumped after US hedge fund Kerrisdale Capital outlined the reasons for its short position in the stock. It said Allied has "no objective evidence of commercial success" in its portfolio, while its review of the company's subsidiaries "indicates that they are developing products that are, at best, minor variations on existing alternatives, often in the face of significant competition and without plausible business models."Shares in the AA were under the cosh. Although it reported trading in line with expectations, with a 2.1% uptick in revenue from Roadside Assistance, overall revenue took a 1.4% hit to £484.6m. The company attributed the result to a decline in income from insurance services and reduced volume of driving services training courses.Mitchells & Butlers declined after it announced that Phil Urban has been appointed chief executive. The board confirmed in a statement on Tuesday that Alistair Darby will step down as chief executive of the pub and restaurant operator and will retire from the board and leave the company entirely on 26 September. RisersIG Group Holdings (IGG) 753.50p +2.59%Rank Group (RNK) 271.90p +1.72%Zoopla Property Group (WI) (ZPLA) 215.00p +1.37%NMC Health (NMC) 819.00p +1.36%Halfords Group (HFD) 456.70p +1.04%Polymetal International (POLY) 539.50p +0.75%Indivior (INDV) 220.60p +0.55%Betfair Group (BET) 3,227.00p +0.53%TalkTalk Telecom Group (TALK) 315.50p +0.48%NB Global Floating Rate Income Fund Ltd GBP (NBLS) 95.20p +0.47% FallersKaz Minerals (KAZ) 109.00p -21.98%Allied Minds (ALM) 450.00p -12.62%AA (AA.) 297.40p -10.77%Premier Oil (PMO) 64.05p -10.54%Petra Diamonds Ltd.(DI) (PDL) 92.40p -8.61%Vesuvius (VSVS) 339.00p -6.87%Vedanta Resources (VED) 477.80p -6.59%Bodycote (BOY) 548.50p -5.92%Mitchells & Butlers (MAB) 330.70p -5.89%Senior (SNR) 248.70p -5.76%