Kilimapesa Gold - Kenya
The Lolgorian SL91B is predominantly in the Precambrian Migori Greenstone Belt of south western Kenya, which is dominated by rhyolites, andesites, basalts and minor banded ironstones, tuffs and agglomerates. The Migori Greenstone Belt is an extension of the granite-greenstone terrain of the Tanzanian Craton to the south and extends from Lake Victoria in the west and is terminated in the east by the Late Proterozoic Mozambique Mobile Belt and the Tertiary Rift Volcanics (phonolites). It is separated from the southern Mara Greenstone Belt (Tanzania), which hosts the 4.0Moz North Mara Mine by the extensive undifferentiated Migori Granite and from the northern Kakamega Greenstone Belt by the north east trending Winam or Nyanza Trough (a failed arm of the East African Rift situated at Kisumu town).
The 90 km long Migori Greenstone Belt is responsible for most of Kenya's gold production. The Migori Gold Belt is represented by a WNW trending shear complex of anatomising shear zones with orientations that roughly parallel the strike of the belt. Most of the gold from the Migori Greenstone Belt (and associated silver and copper) comes from the massive sulphides of the Macalder Mine. This mine represents the only significant gold massive sulphide deposit on the Tanzanian Craton and currently stands at a resource of 1.24Moz gold using a 0.25g/t cut-off (Kansai Mining Corporation).
The Lolgorian SL91B is located on the eastern end of the Migori Gold Belt. The southern portion of the licence is underlain by the extensive undifferentiated leucocratic Migori Granite and syenite. The greenstone volcano-sedimentary package to the north of the contact consists of calc alkaline volcanics, basalts, tuffs, shale, graywacke and Banded Iron Formation ('BIF'). This sequence, younging to the north, has a regional strike of 100 ° and dips to the SW at ~65 °. The BIF forms two parallel ridges in the south west of the licence area.
Structurally, the licence consists of a duplex of shear zones that form part of the regional shear zone complex, bound by WNW trending shear zones. The contact with the Migori Granite is sheared and foliated, confirming that at least some of the granite was intruded prior to or during the deformation. The Lolgorian SL91B contains several colonial gold workings, in which mineralisation is generally controlled by the WNW trending shears. At Blue Ray Mine, the largest of the known mineralised locations, the ore body occurs as oblique veinlets and silicified zones in the low strained central portions of the WNW shear package. At the adjacent Caldwell Mine, mineralisation formed in the same regional structure but as oblique en echelon fractures. At Teng-Teng Mine, which was recently mined by SEBIMU, gold values are contained in quartz veins, striking 090-100 ° and dipping 70 ° south, with gold contents of 15-20 g/t. Masarura Mine in the west of the licence differs slightly in that the mineralisation appears to be plunging high grade shoots at the intersections of the regional low grade 110 ° shearing and localised 020 ° fractures. The mineralisation at Embitir Workings stands out from the others as mineralisation occurs in a NS trending shear and associated with abundant disseminated sulphides (pyrite and arsenopyrite) and quartz veinlets. The mineralisation on Kilimapesa Hill was not exploited during the colonial mining times. The entire known mineralised target package in this area extends the length of the licence (15 km) and has an estimated width of approximately 1 km.