Desktop study report on the potential of Tantalite occurrence in an area around
Odzi in the vicinity of Tsungwesi River has been compiled at the request of Mr.
Stanley Chituku who required an appraisal of the area as a guide to the Tantalite
mineral potential of his claims.
REGIONAL GEOLOGICAL SET UP
In a regional context, the claims are located within the Mutare-Odzi Greenstone
Belt. The dominant rock types are Ultrabasic in composition namely serpentines,
talc, Tremolite and actinolite-schist. The granite intruded these rocks, resulting in
metamorphism and mineralization. The stress minerals tremolite and actinolite
were abundantly produced in the serpentines and impure limestones. Adjacent to
the greenstone belt, the granite is usually gneissic, the foliation-planes following
the contacts of the belt. Greenstones which form prominent feature of the Mutare
Greenstone belt are rare in the Odzi greenstone belt. In Zimbabwe so far all known
mineable’ tantalite mineralization is known to be genetically related to and located
within pegmatites and pegmatited derived eluvial gravels. Odzi belt is one of the
known five tantalite districts in Zimbabwe. The other districts are Masvingo,
Harare, Hwange and Hurungwe. The pegmatites in the Odzi belt are assumed to
be of the Bulawayan age. The granite- pegmatites in the belt consisting of feldspar
crystals, usually microcline and quartz are said to be widespread. The pegmatites
are said to be dyke like to stock-shaped bodies of 100-300m strike length and
variable thickness (Batholomew 1992).
The location of the claims is shown on the 1: 100 000 geological map extract of the
Odzi Greenstone Belt.
Greizen areas in the vicinity of the claims.
TANTALITE MINERALIZATION POTENTIAL
Lithia greisen containing lepidolite and / or zinnwaldite were discovered in the
Odzi belt, cutting both granite and serpentinite. These greisens are regarded to
have been formed by greisenization of the granite pegmatites, during which the
feldspar was replaced by lithium minerals and also cassiterite, tantalite and
microlite are said to develop. Small amounts of cassiterite and tantalite have also
been found with gravels derived from the greisens. Greizens also occur in the
vicinity of these claims as shown in the regional map indicating high potential of
tantalite mineralization. Tantalite is known in the area to be associated with
pegmatites in granitic terrain and close to contact between granite an Tremolite
TANTALITE MINING HISTORY IN ODZI BELT
The most known occurrences of Tantalite in the Odzi Belt are Bepe and Mwerihari
claims, the Corundum Blue (Shown in 1: 100 000 geological map extract of Odzi)
and Potree Mine.
Geological map extract ofOdzi showing location of Be pe, Mwerihari and Corundum Blue claims.
The Bepe and Mwerahari claims have been the biggest producer of Tantalite in the
Odzi district. In both occurrences, granitic pegmatites, ranging between lOO-300m
strike lengths intruded tremolite schist. The Corundum Blue claims in Sabi North
are three-pegmatite bodies en-echelon cut tremolite schist. The pegmatites strike
north east and dip steeply to south-east. The Portree Mine is situated about 37km
SW of Odzi on the Northern flank of Bepe Hills. The pegmatites over there are
said to consist of thick folded sills containing some mineralized areas of coarse
muscovite greizen with high grade tantalite.
ODZI DISTRICT TANTALITE GRADES
A sample collected from quarry in an area on the east bank of the Tsungwezi River
in 1961 which was under special grant no. 220 gave the following results;
It is most likely that this special grant covers the areas around Neil’s Luck, Dirk
and Portree which are located to the east of Tsungwezi River and have produced
tantalite in the area.
The Odzi area has a well known potential for Tantalite Mineral. Tantalite has also
been produced from areas to the east of Tsungwezi River which is in the vicinity of
the claims being investigated. The location of these claims on a regional geological
map of the Odzi Belt indicates that they are quite prospective for tantalite.
However, geological evaluation of the claims on the ground is recommended. This
may be in the form of mapping, trenching and sampling in the claims to reveal the
full potential of the claims.