Mining stocks were dominating the fallers list on the FTSE 250 on Friday as risk appetite weakened ahead of the weekend. Kazakhmys, Centamin, Polymetal and African Barrick Gold were all suffering heavy losses by the afternoon.UK recruitment company Hays was extending losses made yesterday after it disappointed with a fourth-quarter trading update. Hays acheived 7% total like-for-like growth in net fees in the fourth quarter, but headline numbers were unchanged year-on-year as a result of a negative currency movements.Dairy Crest was lower after Societe Generale cut its stance on the diary food products group to 'sell'.Leading the upside was construction and support services firm Kier after Jefferies lifted its target price for the stock from 2,093p to 2,203p, keeping a 'buy' rating. The broker said that it expects the group to achieve its target for a double-digit compound annual growth rate in profits by 2020.FTSE 250 - RisersKier Group (KIE) 1,789.00p +4.31%Pace (PIC) 350.40p +4.19%Telecom Plus (TEP) 1,225.00p +3.90%Evraz (EVR) 100.10p +3.25%Northgate (NTG) 525.50p +2.84%Enterprise Inns (ETI) 122.70p +2.76%Dunelm Group (DNLM) 784.50p +2.75%NMC Health (NMC) 451.40p +2.36%Xaar (XAR) 522.00p +2.15%Alent (ALNT) 344.30p +2.08%FTSE 250 - FallersHays (HAS) 123.50p -3.59%Kazakhmys (KAZ) 312.50p -3.55%Centamin (DI) (CEY) 67.05p -3.25%Polymetal International (POLY) 563.00p -3.10%African Barrick Gold (ABG) 225.60p -2.97%Dairy Crest Group (DCG) 442.20p -2.90%Ophir Energy (OPHR) 205.70p -2.88%Synthomer (SYNT) 212.50p -2.75%AO World (AO.) 229.90p -2.50%Morgan Advanced Materials (MGAM) 297.40p -2.17%BC