Shares in Lonmin, up nearly 10%, have rebounded strongly - having fallen as much as 4% earlier on - after reports that the AMCU union in South Africa has agreed to take an offer from partners Impala, Amplats and Lonmin to employees following strikes began earlier this year.Electronic components distributor Premier Farnell rose after it said trading since its last update in May has continued to be in line with expectations as it outlines a new global structure. The group, which makes connectors to batteries and CCTV cameras, said its performance has been helped by higher-than-expected sales in China, India and eastern Europe.Halma was lifted by a reiteration of Investec's 'buy' recommendation, despite it cutting its target price from 700p to 685p.Infrastructure and construction peers Balfour Beatty and Galliford Try were higher after being appointed preferred bidders to work on a £745m project to build new roads in Scotland. Notably, Carillion was in the red, despite also being named on the deal. Argos and Homebase owner Home Retail also fell after it cautioned that it faced a challenge to match a strong second quarter last year.FTSE 250 - RisersLonmin (LMI) 250.40p +5.79%Alent (ALNT) 347.00p +5.15%Provident Financial (PFG) 2,247.00p +3.45%Premier Farnell (PFL) 215.20p +3.26%Halma (HLMA) 608.00p +2.88%PayPoint (PAY) 1,149.00p +2.86%COLT Group SA (COLT) 149.00p +2.76%Tullett Prebon (TLPR) 288.60p +2.60%Galliford Try (GFRD) 1,190.00p +2.59%Fidessa Group (FDSA) 2,403.00p +2.52%FTSE 250 - FallersImagination Technologies Group (IMG) 241.30p -3.48%Bwin.party Digital Entertainment (BPTY) 114.20p -2.81%Evraz (EVR) 97.25p -2.31%Home Retail Group (HOME) 196.10p -2.24%Booker Group (BOK) 137.20p -2.21%Afren (AFR) 141.40p -1.94%Euromoney Institutional Investor (ERM) 1,155.00p -1.70%Serco Group (SRP) 363.50p -1.68%Ophir Energy (OPHR) 237.00p -1.62%Aveva Group (AVV) 2,209.00p -1.60%NR