TITANIUM
Introduction.
The
titaniferous magnetite ores at Liganga and elsewhere are discussed in the
Iron Ore section above. None appears to be currently feasibly as a source
of titanium. However, concentrations of resistant titanium minerals exist
along the coast and in some rivers. Of these, the only known occurrences
of potential economic interest are at Bagamoyo, north of Dar es Salaam and
at Msimbati, close to Mtwara, near the border with Mozambique.
Beach Sands.
Sands
with appreciable contents of heavy minerals are reported by Landcastle
(1963) at a number of places on the coast, but the most important deposits
known are between Dar es Salaam and Bagamoyo to the north near the mouth
of the Ruvu River, which drains crystalline terrains inland.
Figure
40: Mineral Occurrence Map, Northwest Quadrant
Figure 40: Mineral
Occurrence Map, Northeast Quadrant
Figure
41: Mineral Occurrence Map, Southwest Quadrant
Figure
41: Mineral Occurrence Map, Southeast Quadrant
Figure
43: Zanzui Ultramafic, airborne magnetics.
The beach
sands were investigated by Cilek between 1970 and 1972 and by the Beach
Sand Company (a joint company between the State Mining Corporation and
Geomin of Romania) between 1974 and 1976. Based on the investigation by
the Beach Sands Mining Company, probable ore reserves of 33.5 Mt were
indicated in the Msimbati deposit, averaging 1.39% ilmentite, 0.22% rutile
and 0.18% zircon. Potential reserves in the Msimbati area could be much
greater. Reserves of 14.0 Mt with very similar grades to the Msimbati
deposits in the Dar es Salaam-Bagamoyo deposit area.
Futher
investigation of the tonnage, mineralogy, mining conditions and
environmental considerations would have to be undertaken on these deposits
before consideration could be given to feasibility. The sands were only
sampled to a metre or so below sea level. Several companies were granted
prospecting licences covering large areas of these deposits.
Rift
Valley Gold Fields undertook investigations in 1999. Reconnaisances work
covering the Tanga and Coast Regions along the coastal area (Bagamoyo,
Mkwaja, Sakura, Pangani and Tanga) comprised a collection of 245 sand
samples and air core drilling, to identify potential areas of Heavy
Mineral (HM) concentrations. The results from the first drilling phase are
gauged as encouraging and represent an excellent start.
OTHER METALS.
Other
metals are known to occur but have not been proved to be economic. Several
occurrences are listed in Harris (1961) and other publications.
Manganese
is known in several places as at Manyoro but not in commercial tonnages or
grades.
Mercury
and silver are unknown as primary ores, but considerable scope exists for
new discoveries of epithermal deposits of gold - silver - mercury -
antimony in the coastal basins as at Wingayongo.
Molybedenum minerals have been noted in gold ores from Archaean
greenstones and Neoproterozoic rocks. Traces of molybdenite have been
recorded from the Razorback Reef of Saza Mine of the Lupa Gold Field;
Kyerwa Syndicate in the Karangwe Tine field; in pink granite in the Nzega
District; in the hornblende granite of Mlimwa Hill (Lion Rock), Dodoma;
Butiama in the Mara Region; and quartz veins near Sango in Rukwa Region
(Harris, 1961).