Niobium Inventory

Niobium is estimated to have an abundance of 20 parts per million in the Earth's crust, ranking 33rd among all elements. Some scientists believe that niobium is much more abundant throughout the Earth, but is mainly concentrated in the Earth's core due to its high density. Niobium does not occur in its pure state in nature, but combines with other elements to form minerals. These minerals generally also contain the element tantalum, such as columbite (i.e., columbite, (Fe,Mn)(Nb,Ta)2O6) and coltan ((Fe,Mn)(Ta,Nb)2O6). Minerals containing niobium and tantalum are usually by-products in pegmatites and alkaline intrusive rocks. Other minerals are calcium, uranium and thorium, and niobates of rare earth elements, such as pyrochlore ((Na,Ca)2Nb2O6(OH,F)) and black rare gold ore ((Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6). These large niobium deposits occur in the vicinity of carbonatite (a carbonate, silicate igneous rock), which is also a constituent of pyrochlore.

Brazil and Canada have the largest deposits of pyrochlore. Both countries discovered these deposits in the 1950s and remain the largest producers of niobium concentrates. The world's largest deposits are located in a carbonate intrusive zone in Arasha, Minas Gerais, Brazil, belonging to CBMM (Brazilian Company for Mineral and Metallurgy); another deposit is located in Goiás, belonging to Anglo American Resources, also in carbonate intrusive rocks. These two mines account for 75% of the world's total production. The third largest mine is located near Saguenay, Quebec, Canada, and produces 7% of the world's output.