Great Lakes Mineral Province

The Great Lakes Mineral Province, within which TransAfrika's exploration permit areas fall, includes the greenstone-hosted gold deposits in Tanzania and north-eastern DRC and the vein-hosted gold deposits in south-western Uganda, the North and South Kivu provinces in DRC, Rwanda and Burundi.

AngloGold Ashanti Limited has one producing mine, Geita, in Tanzania and an exploration project in DRC. Banro Corporation and MOTO Goldmines Limited have projects in DRC in districts with past production from commercial mines. The Great Lakes Mineral Province has produced at least 20 million ounces of gold historically from hard rock and alluvial deposits, mainly from greenstone-hosted deposits.

Rwanda and neighbouring Burundi are eastern extensions of the gold provinces of eastern DRC which host widespread gold occurrences exploited by artisanal miners and at least one deposit, Kamituga, which has seen modern commercial mining. Folded structures which carry vein-hosted gold deposits in DRC are well developed in the Rwandan permit areas.

In addition to gold, the Great Lakes Mineral Province contains numerous granite-related ore deposits rich in minerals such as cassiterite (tin), niobium-tantalite (also known as coltan), wolframite, beryl, spodumene, amblygonite, monazite, etc. These minerals occur as primary mineralisation and as secondary mineralisation in alluvial or eluvial deposits. Nickel deposits associated with mafic-ultramafic intrusions are also present. Gold is widespread in alluvial and eluvial workings.

The vein-hosted gold mineralisation in the South Kivu Province of DRC and neighbouring areas of Rwanda and Burundi does not fit into a generic deposit type. The gold mineralisation is separate from the cassiterite (tin), tungsten and niobium mineralisation in both space and time, with the gold mineralisation occurring later. The cassiterite (tin) mineralisation can be linked to granite sources, while the origins of the gold are unknown.

Based on published work carried out by Banro Corporation on its mining licences and exploration work by the United Nations in Rwanda, gold deposits in the South Kivu Province of DRC occur as two broad deposit types. The first type is associated with the upright isoclinal folding in synclinoriums. An example of this is the north-south trending Itombwe Syncline running from Bukavu to TransAfrika DRC’s permit areas (EP6059 and EP6060) in DRC. The deposits of Banro Corporation’s Twangiza Project and the alluvials at Luemba occur along this feature. Kamituga and Lugushwa host a similar style of mineralisation in north-east to south-west trending synclinoriums.

The second type of deposit is associated with higher metamorphic grades than the Twanqiza type, brittle ductile deformation and tourmalinisation. Gold is distributed in quartz veins and “stockwork” bound with steeply dipping shears. This type of deposit is found at Namoya in DRC and the Miyove area in Rwanda.

In DRC, the geological units are not geographically well differentiated. The Kivu area appears to consist of a patchwork of different geological structures, most of which are Precambrian in age. The relationship between the different geological units of the Kivu region is poorly known. The stratigraphic units themselves are known over very limited areas, as dense vegetation makes fieldwork difficult.

In contrast to similar geological domains in DRC, the geology of Rwanda is relatively well known and the country appears to have been fully mapped on a regional scale. The stratigraphic units themselves have been mapped over wide areas, as they have identifiable markers that can be used to separate the various lithologies. Rwanda lacks the dense vegetation that is found in DRC, making outcrops more common.