A letter of intent had been signed in 2018 covering operation of the plant in Lubumbashi by COBC, as well as  trade finance facility to be provided by Traxys to COBC and an offtake agreement in favour of Traxys for cobalt concentrate produced from the plant.

The cobalt hydroxide plant was to have comprised a "core piece" of COBC's metals strategy, said COBC. The company gave no further detail on why the talks had been terminated.

"We are extremely disappointed that the significant time and effort expended by management on negotiations with Traxys did not result in a concluded transaction for this asset," said Peter Copetti, chairman and ceo of COBC.

The original arrangement included a 10-year joint venture agreement with respect to leasing and operating the plant. Traxys was to provide $30mn in financing in return for full hydroxide marketing and sales rights over the contract period. Under the JV/Lease Agreement, COBC would have invested up to US$2 million to commission the plant.

The DRC plant's capacity is 50,000 t/yr, to produce up to 3,150 t/yr of cobalt hydroxide.