As on the top tier index, miners made gains as investors sought gains after a volatile week for the sector. Kazakhmys, Bumi, Centamin, Hochschild, and Lonmin all made strong gains by late in the session. African Barrick Gold was performing well one day after its first-quarter results showed an improved picture. Westhouse Securities reduced its target price for the stock today (reflecting revised gold-price forecasts) but said that the results "suggest a bit more room for optimism" following recent disappointments.Meanwhile, electrical engineering company Spectris reported an eight per cent fall in sales for the first quarter, reflecting a deferral of orders and shipment delays. The group experienced weak customer confidence across all its major regions in the first three months of the year.FTSE 250 - RisersKazakhmys (KAZ) 382.00p +23.19%Centamin (DI) (CEY) 38.55p +5.73%Bumi (BUMI) 253.90p +5.57%African Barrick Gold (ABG) 175.10p +5.55%Petropavlovsk (POG) 140.50p +4.85%Hochschild Mining (HOC) 239.80p +4.26%Hikma Pharmaceuticals (HIK) 962.00p +4.00%Lonmin (LMI) 267.50p +3.68%RPC Group (RPC) 393.50p +3.55%William Hill (WMH) 403.60p +3.33%FTSE 250 - FallersSpectris (SXS) 1,906.00p -14.34%Renishaw (RSW) 1,549.00p -5.78%Laird (LRD) 198.00p -5.44%TalkTalk Telecom Group (TALK) 247.30p -3.36%Computacenter (CCC) 528.00p -3.12%Oxford Instruments (OXIG) 1,520.00p -3.06%Interserve (IRV) 461.00p -2.85%Perform Group (PER) 487.00p -2.79%Jupiter Fund Management (JUP) 311.30p -2.29%Morgan Advance Materials (MGAM) 246.10p -2.22%NR