UK's Keller Group gains after $650 mln US highway contract award
** Shares of engineering contractor Keller Group KLR.L up 5.1% at £34.76
** Co secures a further $650 mln contract variation order on the I-40 highway reconstruction project in the US
** Co says the award increases its order book to about £2.4 bln ($3.18 bln) and supports longer-term revenue visibility
** Stock up 108% YTD
($1 = £0.7544)