main precious metal, gold, is currently mined and processed at the
Navachab Mine situated, a few kilometers outside the town of Karibib,
in central western Namibia. The Navachab Gold Mine is wholly owned
by Anglo Ashanti Gold (Pty) Ltd. Minor amounts of gold are also
recovered as by-product from copper-smelting of the Otjihase and
Matchless concentrates at Tsumeb. The main styles of gold mineralization
in Namibia are associated with replacement skarn, stockwork quartz
veins (Navachab) and turbidite-hosted gold veins (Ondundu). Several
exploration companies exploring for precious metals in Namibia report
gold mineralization associated with iron oxide-copper-gold deposits,
auriferous pegmatites, tourmaline-hosted breccias and epithermal
shear-zones (Gold Map (91.9
KB)). Further potential exist for the discovery of new gold
deposits; the Otjikoto, Onguati and Otjimbojo occurrences have been
found during recent years. The Otjikoto gold deposit, which is situated
some 300 km north of the Navachab gold mine, is reported to have
a similar style of gold mineralization like that found at Navachab.
The Otjikoto deposit is held under an exclusive prospecting license
issued to African Rainbow Minerals and Exploration Ltd.
The Navachab Gold Mine is situated within the southern central zone
of the Damaran Orogenic belt. The distal skarn and stockwork quartz
vein-type mineralization of Navachab is associated with northwest-southeast
trending strike-slip fault systems and subsidiary structures. The
main ore body at Navachab is some 35 m thick, with gold mineralization
present in replacement skarn and in sheeted quartz veins.
than 85% of the gold occurs as native gold and the remainder
as maldonite (Au2Bi). Navachab Gold Mine has the capacity to treat
1.32 million metric tonnes of ore per year. In 2004, gold production
was 647 kg, compared with 2,331 kg in (2003) and 2,653 kg in (2002).
The drastic decrease during 2004 was attributed to a suspension
of open-pit mining, due to the installation of new mining equipment.
The Navachab Mine has recently delineated additional ore reserves,
and was granted an additional 15-year mining license from the Ministry
of Mines and Energy.
The Ondundu hydrothermal gold deposit is situated approximately
100 km northwest of the town Omaruru. Auriferous quartz veins
are hosted by clastic sedimentary sequence sandstones, mudstones,
siltstones and shale of the Kuiseb Formation. The most important
type of veining is the stratabound, greasy grey translucent quartz
veins that host the gold. The mineralized veins are predominantly
situated on the common fold limb of the syncline and anticline
(shear zone). Alteration products and large arsenopyrite crystals
are typically associated with sediments surrounding the quartz
veins. Tensional joints within quartz veins may have acted as
channel ways for the remobilization of gold, anomalous quantities
of visible gold are directly related to highly fractured quartz
veins. Gold Fields investigated the Ondundu gold deposit in the
1980’s, and determined an in situ ore reserves of 4.2 Mt
at 3.21 g/t gold in the country rock and a further 800 000 t in
quartz veins at a grade of 17.0 g/t Au. Currently, Westport Resources
is re-evaluating the Ondundu gold deposit.
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