Browsing by Author "Prame, W.K.B.N."

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    Determine the Presence of Gold and its Distribution in Upper Nilwala River Basin, Southern Part of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2015) Saranga, B.G.P.T.; Cooray, J. T.; Siriwardhane, S.; Prame, W.K.B.N.
    Gold (Au) is a chemical element, bright yellow dense, soft, malleable and ductile metal. The properties remain when exposed to air or water. It occurs often in free elemental (native) form, as nuggets or grains, in rocks, in veins and in alluvial deposits. Investments made on gold prospecting are only second to oil exploration. This research was carried out to find gold in upper Nilwala River and possible areas that gold can be found. In this study, distributions of indicator elements of gold were studied to identify potential gold enrichments in the upper Nilwala River Basin. Stream sediment samples were collected mainly from the placer deposits see figure 1. Samples were taken at about 1 –2 feet depth on placer deposit or river bed by using a shovel. Also gem pit sediment samples were collected near to the gem bearing layer. Samples were collected using the hand pit method (Fletcher et al., 1997). A total of 1–2 kg of raw samples was taken from each location. Then all samples were transferred to neatly labeled polyethylene bags. About 1 kg of sediment samples were separated by using cone and quarter method. Then heavy sediments of it were separated by panning method . Then it was dried in a hot air oven. Each sample was stored in a labeled sample bags to use for mineralogical analysis carried out using an optical microscope. From remaining dried 1 kg samples were homogenized and near 100 g of samples were again separated using cone and quarter method. Then separated sample fractions were crushed by using vibrating cup mill to less than 63 µm. Optical microscope was used to identify the minerals occur in the heavy sediment sample. Using corn and quarter method substantial amount of heavy sediments were separated for the testing. Using a magnet all the magnetic minerals of the sample was separated. 5X5 equal squares were marked on the glass slid. Then glycerol liquid was applied on the top of that slid. After that heavy sediments were put on to the slid creating a fine layer. Finally both magnetic and nonmagnetic minerals were analyzed. Couples of samples were selected. Magnetic separation was done for those samples. Then for the nonmagnetic section Bromoform test was done. Then the heavy particles were separated. After that the samples were analyzed using an optical microscope. The grinded sediments (<63 µm) were tested using X-ray florescence spectroscopy (XRF) to identify chemical composition and major elements for each sample.
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    Estimating the magnetite content of the Southern part of Eppawala Phosphate Deposit and its parent rock
    (Uva Wellassa University of Sri Lanka, 2015) Erandi, H.P.V.H.; Aththenayake, A.N.B.; Subasinghe, N.D.; Prame, W.K.B.N.
    Phosphorus is one of most important plant nutrients because its function cannot be performed by any other nutrient. Phosphate fertilizer is mainly produced from the natural phosphate rocks worldwide. Phosphate deposit at Eppawala is one of the most economically valuable mineral deposits in Sri Lanka. It contains up to 42% of P2O5 while the citric acid solubility of various components varies from 4% to 6%. Due to strong weathering of apatite-bearing parent carbonatite rock, an economically valuable secondary phosphate deposit has formed (Subasinghe, 2013). Former studies revealed that iron leaching from weathering parent rock played an important role in fixing phosphate and formation of secondary deposit through in-situ diagenesis (Subasinghe, 2012). Source of iron is assumed to be magnetite and other iron bearing minerals. To reap grater benefits from the deposit it is necessary to produce value added products such as triple super phosphates. Due to considerable amount of iron impurities from magnetite and other iron baring minerals, the production of super phosphate may pose some difficulties at industrial level. The objective of this study is to develop a methodology to estimate the magnetite, the main iron- bearing mineral, in the phosphate ore.