The Panda Hill Carbonatite is an
apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...
and
pyrochlore bearing
sovite
Sovite (or sövite) is the coarse-grained variety (or facies) of carbonatite, an intrusive, igneous rock. The finer-grained variety of carbonatite is known as alvikite. The two varieties are distinguished by minor and trace element compositions ...
carbonatite located in the
Mbeya District of Tanzania. The deposit was found in the mid-1950s by the then Geological Survey of Tanganyika (now Tanzania).
Niobium
Niobium is a chemical element with chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has sim ...
ore occurs largely in pyrochlore bearing sovite (carbonatite composed largely of
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
) and
dolmite-rich carbonatite.
The deposit also contains lesser
phosphate
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phospho ...
mineralisation associated with apatite.
History
Panda Hill was first developed for niobium in the late 1950s and early 1960s by the then N. V. Billiton.
A pilot mill and small open pit mine operated from 1957 to 1960 that produced concentrate that was then shipped to the Netherlands for further processing.
The deposit is currently under development by Cradle Resources to mine niobium by open pit mining methods. The project has reported resources of 96 million tonnes of mineralisation at an average grade of 0.52% Nb
2O
5. If successful the Panda Hill niobium deposit will be the first niobium mine in Africa.
Pandaite
The Panda Hill carbonatite is also notable as being the source location of the mineral pandaite - a hydrated barium-strontium pyrochlore associated with biotite-rich contact metamorphic rocks. Jager et al. recommended the name pandaite after analysing rock samples from Panda Hill in 1958 with the following formula described: (Ba
0.30Sr
0.22Ca
0.05Ce
0.04Na
0.03Fe
0.02K
0.01Th
0.01)(Nb
1.83Ta
0.004Ti
0.17)O
5.61(H
2O)
0.80
Other later recorded occurrences include at Mt Kukisvumchorr in the Khibiny Massif (Kola Peninsula) in Northern Region, Russia; and at the Mrima Hill niobium deposit in Kenya within a residuum
consisting mainly of goethite/limonite and gorceixite.
References
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{{DEFAULTSORT:Carbonatite, Panda Hill
Carbonatite occurrences
Mining in Tanzania