Browsing by Author "Tembo, Malugu M."

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    Analysis of ore hand-crushed size distribution for grinding process in the artisanal and small-scale gold mines production: a case study of Nholi mine, Bahi district
    (College of Engineering and Technology, University of Dar es Salaam, 2022) Tembo, Malugu M.; Mdee, Ombeni J.
    In many parts of the world, artisanal and small-scale gold mines (ASGM) employed numbers of people compared to large-scale mines. The ASGM has been played a crucial role in poverty alleviation and rural development, particularly in developing countries. The mined ore is crushed and ground for beneficiation of gold. The grinding process involved the size reduction of blasted materials to acquire minerals of interest. This paper presents the size distribution of hand-crushed for blasted materials using sieve analysis and digital image processing. The sieve test results for hand-crushed blasted material of three muck-piles were ranged between 17 mm and 36 mm that is equivalent to 20% and 80% passings respectively, with an average of 26 mm. The digital image processing results were about 19.8 mm for 20% passing and 58 mm for 80% passing, with an average of 36.06 mm. The hand-crushed provided a wide range of material distribution than the required size in the grinding unit and increased oversize by 18%. The hand-crushed of blasted materials provides different sizes distribution leading to increase the residence time and power consumption of the grinding units.
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    Assessment of ground water potentiality in semi-arid area of central Tanzania. implication from geology and geomorphology of the dodoman supergroup
    (Taylor & Francis, 2022) Godfray, Godson; Tembo, Malugu M.
    Semiarid areas face challenges in the availability of water for domestic, agricultural and industrial use. The freshwater availability in semi-arid is limited due to low periods of rainfall and high evaporation rate. Groundwater resource is the only promisingsource of freshwater in semi-arid regions. The increased demand for freshwaterin the semiarid region has increased the demand for groundwater exploration. Theavailability of groundwater in the subsurface is influenced by the subsurfacegeology, geomorphological properties and climatical condition of the region. This review aimed to analyse and combine pieces of available information on groundwater potential assessments in the central part of Tanzania. Central TANZANIA is within the craton basement rocks, where most aquifers are crystalline and fractured crystalline rocks. The groundwater origin, movement and existence rely upon numerous geomorphological and geological factors. Because of the terrain's geology and the compartmentalization of aquifers, determining the groundwater potential is difficult in basement terrain. Studying the geomor-phology and geology of groundwater recharge zones is the key to exploring groundwater availability. The integration of geomorphological, geological and geophysical information yields a promising groundwater potential zone for placement of a well. The selection of the geophysical methods depends on the nature and geology of the area. Electrical Resistivity Tomography (ERT) can beutilized in combination with other geophysical methods in fractured andweathered crystalline rocks in the semiarid environment, as in the Dodomaregion, because it is the best geophysical tool for groundwater exploration in thefractured aquifer
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    Estimation of storage tank capacities for different roofing areas for rainwater harvesting in Dodoma urban, Tanzania
    (University of Dar es Salaam, 2022) Mdee, Ombeni J.; Tembo, Malugu M.; Mwegoha, William J. S.
    This study uses a mass balance model and economic analysis technique to present an estimation of roofing areas and storage tank capacity for Rainwater Harvesting (RWH) system. The water-saved benefits were estimated using the monthly rainfall of over 39 years from 1981 to 2020 and five roofing areas. The proposed roof-storage-ratio method presents the minimum requirement of roof area and storage tank size when the ratio value is closer to 1. The benefit-cost ratio and percentage of reliability indicated the optimal roofing areas ranging between 200 and 300 m2 for storage tank capacity between 20 and 25 m3, with a minimum discount rate of 5%. The increased capacity of storage tank and roofing area would also be a potential factor to increase the investment cost for installing the RWH system.
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    Geochemical processes influencing groundwater quality for drinking and irrigation uses in Hombolo catchment
    (IWA Publishing, 2022) Tembo, Malugu M.
    This study identifies the major geochemical processes that regulate groundwater quality in the Hombolo catchment to make it suitable for drinking and irrigation purposes. The major cations and anion concentrations were used to develop the major geochemical processes governing the groundwater quality. The major geochemical processes were evaluated using historical data gathered from 1983 to 2018. The developed geochemical processes indicated the mineral dissolution, ion exchange and evaporation were the dominant that influence groundwater quality in the catchment using mole ratio concept and Gibbs diagram.The suitability of groundwater for irrigation was evaluated using the permeability index (PI), sodium adsorption ratio (SAR), and percentage soluble sodium (PSS) while the suitability of groundwater for drinking was evaluated using the water quality index (WQI). The sodicity indicated to have the average SAR of 5.16 as excellent class, average PSS of 50.89 as permissible to good class and average PI of 74.47 as suitable class level. The groundwater for drinking use indicated the WQI of 104 as poor class level. The groundwater is suitable for irrigation activities but the quality for drinking is deteriorating with time.
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    Identification of potential sites for surface runoff harvesting in the semi-arid area for developing cities. A case study of Dodoma urban, Tanzania
    (Springer, 2021) Mdee, Ombeni J.; Tembo, Malugu M.
    The rapid growth of socioeconomic activities brings the overpressure to the water sources in the semi-arid areas. This paper identifies potential sites for surface runoff harvesting from seasonal rainfall. The potential sites were determined using the analytic hierarchy process (AHP) and weighted linear combination (WLC) techniques with four parameters including runoff depth, drainage density, slope, and lineament density under the GIS environment. The runoff depth was estimated using the Soil Conservation Service method with the three factors such as land use, rainfall, and soil parameters. The normalized weights obtained from the AHP technique were multiplied with the individual weights for each parameter using the WLC technique to acquire the weighted classes (WCs) for defining suitable for surface runoff harvesting. The covered area of about 5.5% for a very high suitable site was obtained followed by 76.4% of the highly suitable site with the WC ranged from 433 to 500% and 372 to 433%, respectively. The covered area of about 18.1% for the medium to a very low suitable site for harvesting surface runoff with the WC between 271 and 372%. The developed potential site map would provide access for harvesting the surface runoff to improve the water shortage during long dry periods, minimize flooding, or reduce the land use across the drainage network in the semi-arid areas.