MPANDA MINERAL FIELD
Introduction.
The Mpanda Mineral Field lies in
west-central Tanzania, immediately adjacent to the town of Mpanda. It
consist of three small field, Mpanda, Sikitiko and Kapapa (Fig.34).The
mineral field lies in rolling cultivated uplands, about 100km east of
Lake Tanganyika. Mpanda-town is the terminus of a spur of the narrow
gauge Central Railway and is served by unsurfaced roads. The Sikitiko
area is now part of the Katavi National Part. The Mpanda Mineral Field
is unique in Tanzania for having produced most of its gold as a
by-period of lead and copper mining during the period 1946-1960 at
Mkwamba Mine.
Only 2.17 tonnes of gold production has
been recorded, all of it since 1936. A small amount of placer gold was
produced from the Mpanda River during 1936-1947. Since 1980,
considerable artisanal mining activity has been noted, especially near
Ibindi.
Geology.
Both Mpanda and Lupa gold areas differ
from the Lake Victoria greenstone belts in being hosted by metamorphic
rocks of Palaeoproterozoic age, rather than Archaean greenstones. During
1970-73, the Soviet company TECHNOEXPORT undertook exploration at Mpanda
(Orlov et al ., 1974). This included over 12,000m of diamond drilling
and over 18,000 m3 of trenching, as well as pitting and other
investigations. Nanyaro (1989) undertook a detailed study of the genesis
of the mineralized veins suitable for underground mining.
The Mpanda Mineral Field consists of
Palaeoproterozoic (2100-1800 m.y.) gneisses metamorphic grades of the
Ubendian Supergroup. These have been intruded by several phases of
Proterozoic granitic rocks, particularly in the Sikitiko area (Fig. 34).
Al conjugate set of NW-trending and NE-trending faults and shears cuts
these rocks.
Mineralisation. Lead, copper, gold and
modest amount of silver and tungsten occur
Figure 33. Iramba Sekenke Greenstone
Belt.
In several veins and shears. Important
production was limited to the Old Mukwamba Mine near the town of Mpanda
and to placers and eluvials near Ibindi
A wide variety of metal and minerals
occur in the mineral field. No systematic study of zoning or ore
controls has been made. In general amounts of banded quartz, with
variable amounts of siderite, calcite, barite, sericite and hematite,
and lesser amounts of pyrite, galena, chalcopyrite and gold. Scheelite
and wolframite are locally present. Orlov (1974) reported traces of
gold-silver tellurides, while sphalerite was uncommon. Shear zones, as
at Mukwamba-Mnyakaliza, Sikitiko, D-Reef and Prospect 36, provided most
of the ore mined from lodes. Ore grades at Mukwamba were in the order of
1-3% lead, 0.1-1% copper, 50-200g/t of silver, and 1.5 g/t of gold.
Widths of several metres were common.
It appear that there is a major
difference in structural and mineralisation style between the northern
Mpanda proper and southern (Sikiiko-Kapapa) areas. Little information is
available about Katuma, a gold-bearing region to the west.
Opportunities.
A detailed review of past drilling on the
Mukwamba- Mnyakaliza shear zone could identify sectors with good
potential for gold and base metal mineralisation of commercial grades.
Current activities in the Mpanda Mineral Field include:-
Extensive small scale artisanal prospecting and mining in the areas
with Gold showing especially those of Ibindi, Magamba, Sitalike, Reef
D and Simbo.