Elementis' share price has reacted positively to its announcement that it expects to make more money than expected this year as a swell of activity in the oil and gas sector helped the speciality chemicals supplier lift sales by 11% in the third quarter.Mining stocks such as the African pair Kenmare Resources and Aquarius Platinum are going well, as is the oil engineering services group Lamprell, but the oil and gas explorer Melrose Resources falls heavily.FTSE 250 - RisersKenmare Resources (KMR) 20.35p +4.90%Elementis (ELM) 120.00p +4.80%Lamprell (LAM) 351.70p +4.67%Michael Page International (MPI) 490.00p +3.99%Sports Direct International (SPD) 144.50p +3.07%Premier Foods (PFD) 18.13p +3.01%Hays (HAS) 113.80p +2.99%BTG (BGC) 249.00p +2.89%Marston's (MARS) 103.60p +2.88%Aquarius Platinum Ltd. (AQP) 370.00p +2.69%FTSE 250 - FallersMelrose Resources (MRS) 282.00p -13.18%Devro (DVO) 216.70p -3.69%Redrow (RDW) 106.80p -3.35%Paragon Group Of Companies (PAG) 147.90p -3.08%AG Barr (BAG) 1,190.00p -2.78%Kier Group (KIE) 1,288.00p -2.72%ITE Group (ITE) 179.60p -2.71%CPP Group (CPP) 255.00p -2.67%Senior (SNR) 129.20p -2.42%Yell Group (YELL) 13.78p -2.20%