In 2005 , production increased to 42,592 kg .
In 2005 , production has continued to rise again and columbite - tantalite production accounted for 5 % of the value of Burundi 's mineral production as of 2005 .
In 2005 , production increased to 42,592 kg and has continued to rise again and columbite - tantalite production accounted for 5 % of the value of Burundi 's mineral production as of 2005 .