Geology Reference
In-Depth Information
16
Diamond-Bearing Gravels Along the Lower
Kwango River DRC
Michiel C.J. de Wit and Edmond Thorose
16.1
Introduction
16.2 Historical Background
The Kwango/Cuango River rises in the highlands of Alto
Chicapa in the Angolan Province of Lunda Sul, where it is
referred to as the Cuango River. It descends from an eleva-
tion of 1,395 m amsl and flows for some 1,100 km before it
joins the Kasai River in the Democratic Republic of Congo
(DRC) at 292 m amsl. It drains a catchment area of some
Wikipedia.org
)
. It is the largest left bank tributary of the
Kasai River. The Wamba and Kwilu rivers are the Kwango
The first diamond in the DRC was discovered in 1903 in the
Katanga Province by
Tanganyika Concessions Ltd (TCL),
which ultimately led to the discovery of the barren
Kundulungu kimberlite province in 1908. In 1906 geologists
of the newly established company
La Soci ´t ´ Internationale
Foresti
`
re et Mini
`
re du Congo (Formini
`
re)
visited the
Kwango River mainly in the search for gold. This was
followed with prospecting expeditions by Janot and Dunbar
in 1909 and 1910 in the search for diamonds but none were
found (Fieremans
1977
). In 1909 the same company had
already discovered the now famous Tshikapa Alluvial dia-
mond fields, 500 km east of the Kwango basin in which
Janot was involved (Formini`re
1956
).
Geological missions of the Lower Kwango were
conducted from 1912 to 1914 and of the Wamba River in
1914 by Passau and Asselberghs respectively. The latter
person, on behalf of the
Syndicat G ´n ´ral des Recherches
Mini`res du Kasai (SGK),
described some of the local geo-
logy but more importantly recognized five terrace levels
between Kingushi and the Francois-Joseph waterfalls along
the Kwango River (Fig.
16.2
) (Asselberghs
1919
).
Diamonds were recorded for the first time on the Kwango
by Young in 1921 (Fieremans
1977
) who recovered five small
diamonds (weighing 0.195 cts; average size of 0.039 cts/stn)
from two samples just below the confluence of the Kwilu and
Kwango Rivers (Young
1921a
,
b
). This was followed with an
expedition by Young and Faucett in 1921-1922 who
prospected the river from Bandundu to the Lonzo/Kwango
confluence (Fig.
16.2
) where 10 diamonds were recovered
close to this confluence weighing 0.43 cts (average size of
0.043 cts/stn) (Young
1921a
,
b
). Hill and Hoffmann who
travelled from the Lovua River, south-west of Tshikapa, to
the Francois-Joseph Falls in 1921 and then downstream to
Kasongo Lunda reported no diamonds (Fieremans
1977
).
Smith and Faucett were instructed by
Formini`re
and
SGK
to explore the upper Kwango in the third major
s
main right bank tributaries before the confluence with the
Kasai.
In Angola the Cuango River flows in a northerly direction
and covers a distance of 455 km before the Angolan/DRC
border just south of Tembo, from where it is known as the
Kwango River. The river then follows the Angola/DRC
border for some 300 km. It then flows for roughly 345 km
in the DRC before the Kwango River joins the Kasai near the
town of Bandundu.
Diamonds are associated with alluvial sediments within
this river system both in Angola and the DRC and this paper
covers the exploration results from terrace and flood plain
(locally referred to as river flat) deposits associated with the
river section that forms the border between the two countries
(Fig.
16.1
).
'
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