Bloomberg By Mark Burton and Jack Farchy In a stellar year for base metals, aluminum has led the pack. Now, producers say surging raw material costs could drive prices even higher. Alumina, the raw material used to make aluminum, has jumped 56 percent since August after China shut down some production, triggering a wave of buying by traders and aluminum smelters. The rally is putting a strain on metal producers in China, where alumina accounts for 40 percent of the cost of making aluminum. Cost pressures could worsen in the months to come as Chinese environmental reforms weigh most heavily on bauxite and alumina producers. That could provide extra fuel for aluminum’s 27 percent rally this year, the biggest since 2009. "The rise in raw material prices is lifting the global cost curve for aluminum production and that should support higher prices," Svein Richard Brandtzaeg, chief executive officer of Norsk Hydro ASA, said in an interview in London. Prices for other key ...