Browsing by Author "Nghoongoloka, Abner"

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    Re-evaluation of Kombat-style mineralisation and implications for exploration in the Otavi mountainland, Namibia
    (University of Namibia, 2020) Nghoongoloka, Abner
    This study re-evaluates the Cu-Pb and Fe-Mn ore mineralization of the Kombat Mine (ML-16, ML-73B) and Gross Otavi Mine (ML-73C), situated between 19 ̊41’ 30” S, 19̊ 39’ 00” S and 17 ̊40’ 00” E, 17 ̊35’ 00” E (WGS84) based on the field geology, fluid inclusions, petrology, mineralogy and geochemistry. This was to determine the genetic relationship between Fe-Mn and Cu-Pb mineralization. The study has established that the Cu-Pb ore at the Kombat Mine can be classified as an MVT-type deposit, whereas, the Fe-Mn ore can be classified as a stratiform-syn-sedimentary deposit. The formation of the MVT-type deposit is associated with a hydrothermal fluid system with a mean temperature of 183°C and mean salinity of 12.85 NaCl wt. % equivalent, as determined by fluid inclusion studies. Upward brine migration enabled leaching of metals from underlying sediments and precipitation of Cu-Pb ore at upper levels in the carbonate host rocks due to structural traps and chemical interaction. The syn-sedimentary Fe-Mn ore, which is largely associated with calc-silicate lithologies, consists mainly of magnetite and hematite with minor pyrite, hausmannite and jacobsite, was deposited by diagenetic and hydrogenetic processes under changing oxic and anoxic conditions within the sedimentary basin. Acceptable geochemical exploration indicators of the existing mineralization include anomalous values of 0.5% Cu, 0.2% S, 0.05% Pb, 0.03% As; 0.01% Zn; V, W, Mo and Ag is 0.002% each based on portable XRF sample analysis. Mineralogical indicators based on field observations, optical and XRD prospecting include major ore minerals such as chalcopyrite, bornite, covellite, and galena with minor chalcocite, sphalerite, and pyrobelonite, for the Cu-Pb MVT-type ores. For the Fe-Mn ores, hausmannite, hematite with minor, manganite may be are considered.