The DRC is Africa's largest producer of coltan but believes it is not making the most of this resource. Cargos of unprocessed coltan ore, from which tantalum and niobium are extracted, are taken across the border before being exported to smelters and refineries in Asia, Europe and beyond. The lion's share passes through Rwanda, and much of that is smuggled illegally. Smelters make large profit margins by processing the ore, the final product of which is in high demand in the electronics and telephone