Geology Reference
In-Depth Information
17
A Review of the Kimberlites of the Democratic
Republic of Congo
Michiel C.J. de Wit and Hielke A. Jelsma
17.1
Introduction
the early 1950s represented some 75 % of world production
by volume (Fieremans
1953
; Formini`re
1956
).
The presence of kimberlites in the area was however only
realized in 1946 (de Magn
´
e
1946
) and the first detailed
study of the Bakwanga (Mbuji Mayi) cluster kimberlites
was presented by Wasilewski (
1950
). In 1955 the Tshibua
(Tshibwe) cluster kimberlites were found by MIBA. These
were the last kimberlites to be found in the country until De
Beers started exploring, first between 1970 and 1982 and
later between 2004 and 2009. During the first spell the Bas-
Congo kimberlites were found south of Kinshasa close to the
Angolan border in 1974 and in 2005 two further clusters were
discovered near Kabinda, east of Mbuji Mayi. The distri-
bution of the known kimberlite fields is shown in Fig.
17.1
.
Exploration for diamonds in the DRC, then known as Congo
Belge, started in 1900, when King Leopold-II granted the
company
Tanganyika Concessions Limited (TCL)
exclusive
prospecting rights over 155,000 km
2
in the southern part of
the country. Between 1900 and 1909 TCL, a foreign partner
of
Union Mini
`
re du Haut Katanga (UMHK)
and
Compagnie du Chemin de Fer du Bas-Congo au Katanga
(BCK)
, located more than 100 old copper workings in
Katanga (then known as Shaba) Province, discovered tin
near Bukama in 1904, and discovered the country
'
s first
diamond in 1903, in the Mutendele stream in Katanga Prov-
ince, which is a tributary of the Lualaba River in the
headwaters of the Congo River. Further exploration by the
company led to the discovery of a large kimberlite field on
the Kundelungu plateau in 1908.
The first diamond in the Kasai region was found in 1907
by prospector Narcisse Janot, near Tshikapa in the Kiminina
(Tshiminina) River, which is a tributary of the Kasai River
and which became part of the alluvial mines around
Tshikapa that ultimately produced well over 100 Million
carats (Mcts). The discovery encouraged Formini`re to
continue its exploration program that in 1918 led to the
discovery of diamonds near Bakwanga (Mbuji Mayi) Town
where geologist George Young recovered 8,840 diamonds in
one stream sample in the Bushimaie (Mbujimayi) River. By
1920 this was already known as one of the largest deposits of
alluvial diamonds in the world, the production of which in
17.2 Katanga Kundelungu Kimberlite Field
The Kundelungu kimberlites occur as two separate groups
on the Kundelungu Plateau in the south-east of the DRC in
Katanga Province (Figs.
17.1
and
17.2
) and were initially
described by Verhoogen (
1938
). The kimberlites occur to the
east of the exposed section of the Bangweulu block, which is
separated from the Kasai Craton to the northwest by the
Mesoproterozoic Kibaran belt. The Kundelungu Plateau
may be underlain by a basement extension of the Bangweulu
block.
The kimberlite field comprises an eastern and a western
group consisting of 16 and 17 kimberlites, respectively. The
eastern group was discovered by TCL in 1908 (Studt
1910
)
whilst the western group was only found in 1913 by Poulson
(Fieremans
1953
). The majority of the kimberlites are pipes
and were originally evaluated by
Soci ´t ´ Belge Industrielle
et Mini`re du Katanga
(SIMKAT) between 1913 and 1923
and later by De Beers between 1977 and 1982. The pipes
range in size between less than 1 ha to approximately 50 ha
for the Talala pipe. The uppermost rock types comprise both
magmatic and volcaniclastic kimberlites suggesting hypa-
byssal and crater/diatreme facies preserved, respectively.
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