Nigerian Coal Corporation Wikipedia
It reopened in 1972, and became the country''s largest coal mining operation until its closure. Ogboyoga I Coal Field, Kogi State; Ogboyoga II Coal Field, Kogi State; OgwashiAzagba Lignite Field, Delta State; Okaba Coal Field, Kogi State; Okpara Mine, Anambra State; Onyeama Mine, Enugu State; Oyeama Mine, Anambra State; Owupka Mine, Benue State; Ribadu Mine