Browsing by Author "Mutakyahwa, M. K. D."

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    Atlas of Gold Deposits in Tanzania, Dar es Salaam.
    (University of Dar Es Salaam, 2010-01) Ikingura, J. R.; Mutakyahwa, M. K. D.; Marobhe, I. M.; Manya, Shukrani; Kazimoto, E.; Kasanzu, C.; Mshiu, Elisante Elisaimon
    The Atlas of gold deposits in Tanzania reviews the geology of significant gold deposits in Tanzania taking into account the new information collected from the exploration and mining companies and research work done in the gold producing regions. The emphasis is placed on the nature and composition of the ore and the geological setting of each of the deposit that include host-rocks, structure, hydrothermal wall-rock alteration and timing of gold mineralization.
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    Geology and Geochemistry of Bauxite Deposits in Lushoto District, Usambara Mountains, Tanzania
    (Elsevier, 2003) Mutakyahwa, M. K. D.; Ikingura, Justinian R.; Mruma, Abdulkarim H.
    Bauxite deposits in the Usambara Mountains of north eastern Tanzania occur as remnants of residual deposits on two geomorphologically related plateaus of Mabughai-Mlomboza and Kidundai at Magamba in Lushoto, Usambara Mountains. The parent rocks for the deposits are mainly granulites and feldspathic gneisses of Neoproterozoic Mozambique belt. The plateaus represent a preserved Late Cretaceous–Lower Tertiary old land surface (African surface). Other parts of the Usambara Mountains and the neighbouring Pare Mountains are covered mostly by red–brown lateritic soils and impure reddish-brown kaolinitic clays. The bauxite deposits contain mainly Al2O3 (40–69 wt.%), Fe2O3 (3–10 wt.%), SiO2 (0.16–7 wt.%) and other elements occur in quantities not substantial to affect the quality or processing of the bauxite, and are attributed to the presence of relic minerals. Gibbsite makes up to 98 vol.% of the bauxite ore in special cases. Gibbsite is accompanied by goethite in the ore. Boehmite occurs in small amounts and is usually accompanied by hematite. Impurities include goethite, hematite, kaolinite, and minor relic quartz and microcline. Kaolinite is the sole clay mineral encountered in the bauxite ore, suggesting mature soil profiles and a development of the bauxite deposits on a well-drained peneplanation. Ore reserve estimates from the drilling data and surface geological mapping of the deposits yielded bauxite reserves of about 37 million tonnes.
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    Mercury and Mining in Africa with Special Reference to Tanzania
    (1997) Ikingura, Justinian R.; Mutakyahwa, M. K. D.; Kahatano, J .M. J.
    A study of gold (Au) mining areas in Tanzania is being undertaken to assess environmental impacts arising from the use of mercury (Hg) in gold extraction. Initial results already indicated the presence of elevated Hg concentrations in environmental samples from the mining areas. The mean Hg concentration in river sediments in 4.19 µg/l. soils within gold mining and processing centres exhibit high Hg content (mean 3.39 µg/g) that decreases rapidly to background regional values within a distance of a few kilometres. A review of published Hg data for sediments, fish and aquatic plants from African inland and coastal waters revealed, with a few exceptions, low Hg concentrations close to natural background levels.