METALS-Aluminium jumps to mid-2011 peak, nickel extends rally

(Adds analyst comment, recasts, updates prices) By Manolo Serapio Jr MANILA, April 19 (Reuters) - Aluminium prices surged as much as 5 percent to their highest level in almost seven years on Thursday amid enduring concerns over strained global supply following U.S. sanctions on major Russian producer Rusal, with similar worries also spurring nickel. Three-month aluminium on the London Metal Exchange climbed as far as $2,664.50 a tonne, its loftiest since August 2011, and was trading