(Reuters) – European shares closed sharply lower on Thursday as concerns over the impact of mounting sanctions against Russia weighed on sentiment even as a relentless rally in commodity prices boosted mining stocks. The Europe-wide STOXX 600 index slipped 2.0%, having given up modest gains soon after the open. Travel and retail stocks led a broad-based decline. But the mining index rallied 0.6% and hit its highest since 2008 in the session, as base metal prices hit fresh highs on worries sanctions against Russia over its invasion of Ukraine would hit supplies. [MET/L] Worries about fallouts f…