Operations are fully controlled by Tandem Liber. These operations are coordinated from our compound location in Bo. All members of the team have a long history on a personal level. There is a high acceptance of each other skills, personalities and expertise. Next to that is there a exceptional relationship with the locals. These relationships are divers, from the minister to the village chiefs. But always based upon respect and the will to make things work towards a mutual benefit.

Tandem Lieber Holdings - Columbite


Columbite, also called niobite, niobite-tantalite and Columbite [(Fe, Mn)Nb2O6], is a black mineral group that is an ore of niobium. It has a submetallic cluster and a high density and is a niobate of iron and manganese.



Gold is a chemical element with symbol Au (from Latin: aurum) and atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable and ductile metal. Chemically, gold is a transition metal and a group 11 element.
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The mineral group tantalite [(Fe, Mn)Ta2O6] is the primary source of the chemical element tantalum. It is chemically similar to Columbite, and the two are often grouped together as a semi-singular mineral called Coltan
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Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and Columbite.
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Name Chemical Type Status
Gold Au PM IVME / PR
Silver Ag PM IVME
Silica SiO2 MM
Aluminium AL2O3 MM IVME
Cadium CaO MM
Chromium Cr2O3 MM IVME
Iron Fe2O3 MM IVME
Potassium K2O MM
Magnesium MgO MM
Mangnese MnO MM
Sodium Na2O MM
Titanium TiO2 MM IVME
Barium Ba MM IVME
Cerium Ce REE IVME
Dysprosium Dy REE
Eribium Er REE
Europium Eu MM
Gallium Ga MM
Gadolinium Gd MM
Hafnium Hf MM
Holmium Ho REE
Lanthanum La REE IVME
Luterium Lu REE IVME
Niobium Nb MM IVME / PR
Neodymium Nd REE IVME
Praseodymium Pr REE
Rubidium Rb MM
Scandium Sc REE IVME
Samarium Sm REE
Strontium Sr MM
Tantalum Ta MM IVME / PR
Terbium Tb REE
Thorium Th MM
Thulium Tm REE
Uranium U MM IVME
Vanadium V MM IVME
Tungsten W MM IVME
Yttrium Y REE
Ytterbium Yb REE
Zirconium Zr MM IVME