The economy of the second largest country in Africa relies heavily on mining. The Congo is the world's largest producer of cobalt ore, and a major producer of copper and industrial diamonds. The Congo has 70% of the world's coltan, and more than 30% of the world's diamond reserves., mostly in the form of small, industrial diamonds. The coltan is a major source of tantalum, which is used in the fabrication of electronic components in computers and mobile phones. In 2002, tin was discovered in the east of the country, but, to date, mining has been done on a small scale. Manono in Central DRC has a significant deposit of lithium and tin with tantalum and niobium and is being developed by an Australian company. Production is expected in 2023.