Africa Finance Corporation has already expanded its debt or equity funding for resources projects from oil into mines, including bauxite scheme in Guinea.
US Treasury said Gertler has used his close relationship with the country’s president, Joseph Kabila, to amass a fortune through corrupt and opaque deals.
More than half the 2017 combined market cap gains for the world's largest listed miners accrued to just five firms as gold producers drop out of top 10.
A 2014 Preliminary Economic Assessment concluded that the Lofdal project has the potential to produce an average of 1,500 tonnes per annum of separated rare earth oxides.