(Bloomberg) -- Aliko Dangote has started work to double capacity at his huge oil refinery in Nigeria, which when finished will rival the world’s largest site and give Africa’s richest person a stronger grip of global fuel supply chains. Dangote Group has begun construction at the Lekki site on a new facility that will be able to process 700,000 barrels a day of crude oil, according to David Bird, chief executive officer of Dangote Petroleum Refinery & Petrochemicals.