DUBAI - Emirates Aluminium Co., the joint venture building the world’s biggest smelter, may start producing the lightweight metal earlier than next April as originally scheduled, investor Mubadala Development Co. said. “There is opportunity to start production earlier,” Jeremy Nottingham, a senior adviser at Mubadala, said in an interview in London today. “It’s going extremely well and we definitely want it to start as soon as possible.” Mubadala, the Abu Dhabi state-owned investment company, and Dubai Aluminium Co., the largest aluminum smelter in the Middle East, are partners in Emirates Aluminium, also known as Emal. The venture’s smelter in Abu Dhabi will have an initial capacity of 700,000 metric tonnes a year and will double in size with the completion of a second phase. Gulf nations such as the United Arab Emirates, Qatar and Saudi Arabia are seeking to expand into metals, petrochemicals and plastics production to diversify their economies and capitalise on natural-gas reserves, which provide cheaper electricity than in North America and Europe. Production costs will be among the lowest in the world, Nottingham said. Emal is in talks with Abu Dhabi about a 20-year contract for gas supplies, he said.