- OFS Engineering and Consulting LTD.
- Tantalite, Niobium, Ore.
- Address:Rua Djalma Ulrich 329 Apto. 1001 Rio de Janeiro RJ 22071-020 Brazil
- Marcassa Comercial Ltda
- ore of manganese, copper, tantalite, columbite, coltan, titanium, tantalum, niobium.
- Address:pedro paulo conceicao Qd M Lt 22 814 cs 04, Lauro de freitas, Bahia, Brazil
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