* Names Simon Heale as chairman, Andrew Southam as CFO * Gross costs forecast 8-12 percent higher in 2013 * 2012 core profit excluding ENRC down 30 percent * Shares down more than 5 percent By Clara Ferreira-Marques LONDON, Feb 28 (Reuters) - The prospect of sharply higher costs and spending at copper miner Kazakhmys battered its shares on Thursday, after the company reported a drop in annual profit and warned it would take a hit on its stake in Kazakh rival ENRC.