SEAMIC Newsletter Vol. 10

Despite having such a geological environment, which is conducive for hosting diverse types of
mineralization, most of the mining activities in Tanzania (gold and diamonds) are concentrated
in the Archean Craton. However, in recent years, mining activities of these minerals have been
extended to the mobile belts, a situation facilitated by the fact that most of the lithologies in
the mobile belts originate from tectonic reworking of the marginal portions of the Craton as
proved by most of the recent geochronological research findings available at the Geological
Survey of Tanzania.
ATTRACTIVE INVESTMENT ENVIRONMENT
In the past few years, Tanzania reviewed its investment policy and adopted a Fiscal and
Regulatory regime that has succeeded to attract large private sector led capital investments in a
number of production sectors, mining inclusive. These policy reforms coupled with the good
geological environment have led to the opening up of modern mines including six world class
gold mines of North Mara (Africa Mashariki), Buhemba, Geita, Tulawaka, Bulyanhulu
(Kahama), and Nzega (Golden Pride); one tanzanite mine at Merelani and one diamond mine
at Mwadui. Buzwagi gold mine and Kabanga nickel mine are in an advanced stage of mine
development.
MINERAL DEPOSITS
Gold
About 90% of the total gold output has been won from the Archean Tanzania craton greenstone
belts south and east of Lake Victoria in Northern Tanzania. The remainder of the gold output
has been from the Ubendian Proterozoic rocks, principally in the Lupa in the southwest and
Mpanda fields in the west-central Tanzania. Archean greenstones were deposited in weak zones
in the primitive crust and subsequently affected by intense folding and intrusion of granites.
New exploration fronts include the Kitowero Proterozoic rocks in Masasi south eastern
Tanzania, Mbinga in the southwest, Handeni, Kilosa, Morogoro and Muheza in the east. The
exploration trend now focuses on the mobile belts which have proved in part to represent
tectonically reworked Archean crust. Gold is also known in epithermal Prospects like
Wingayongo in the south east. Rich deposits in the matrix of cobbles in zones over bedrock are
being mined in possibly Tertiary to Quaternary laterites and lateritic soils in the Rwamagaza
greenstone belt at Buziba.
Geita greenstone belt: This is an east-west trending belt which hosts the world class Geita
Gold mine with a resource of 20 million ounces grading on average 4.0 g/t. The greenstone belt
is marked by high relief hills, ridges and a plateau underlain by steeply dipping banded iron
formation (BIF). The Nyanzian Supergroup formations comprise pyroclastics, overlying mafic
volcanics. Laterite is well developed at the surface over mafic volcanic units. Gold
mineralization occurs in native form, often in close association with pyrite, and pyrrhotite in
fractures concordant with the bedding of banded iron formation units. Stratiform
mineralization predominates although quartz reefs are mineralized at some deposits.
Other Gold deposits in the belt include: Lone Cone with a resource of 3.5 M oz; Nyamulilima
has a resource of 2 M oz; The Ridge 8 has a resource of over 0.5 M oz; The Saragura or Allways
Deposit has a gold resource of over 271,000 ounces of gold.
Rwamagaza greenstone belt: This belt lies south of the Geita Greenstone belt and probably
represents the same rocks on the other limb of an anticlinorium. Outcrops of massive mafic
volcanics with some thin beds of tuff are notable. The principal gold mine used to be Mawe
Meru, which is a high grade gold quartz vein containing much pyrite and chalcopyrite. The
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