The Deziwa deposit, around 35 kilometres east of Kolwezi, is estimated to hold 4.6 million tonnes of copper and 420,000 tonnes of cobalt.
Somidez, the joint venture controlling it, is held 51% by CNMC and 49% by Gécamines.
An $880 million project which started construction in May 2018, the Deziwa mine aims to produce 80,000 tonnes of copper and 8,000 tonnes of cobalt per year, according to Somidez.
Sliding cobalt prices have hurt Congo's output of the battery material. Glencore decided in August 2019 to close the Mutanda copper and cobalt mine - the world's largest.
Mutanda shut on November 25, a month before the mine was set to go into maintenance, due to a lack of sulphuric acid.
(Writing by Hereward Holland and Helen Reid; editing by Jason Neely)
By Stanis Bujakera