Centers for Ethio Mines Development

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Beneficiation and Characterization Techniques of Coal in the Western region of Tarcha Zuria Wereda, Southern Ethiopia
(Addis Ababa University, 2015-05) Daniel Kassaye; Zekarias Gebreyes (PhD)
Coal stands as the most plentiful and extensively found fossil fuel. Thanks to advanced methods, it can be extracted, moved, and stored efficiently and economically. The global trade of coal is experiencing consistent growth, accompanied by intense competition regarding supply and pricing. Nevertheless, the future commercial viability of coal hinges on its environmental sustainability, particularly on the ability of the power generation sector to minimize sulfur and other harmful emissions. This research examines the extraction methods employed at the Tarcha coal deposit located in Tercha Zuria Wereda, Southern Ethiopia. It utilizes a wet extraction technique to evaluate flotation responses and optimize key factors such as yield percentage and ash content. The primary goal of the study is to enhance the quality of coal by refining flotation processes and minimizing impurities. Laboratory experiments are conducted with varying particle sizes and different ratios of collector to frother in the froth flotation process. The results indicate that the highest coal recovery yields are achieved at a collector-to-frother ratio of 8:4, while also assessing how these variables affect ash content. The data reveal a clear trend of increasing ash content as particle size decreases, highlighting the importance of maintaining specific parameter ranges to optimize yield. Ultimately, this project offers valuable insights that could support local mining operations, particularly the ET-Mining Development Company, which is actively involved in job creation and community development initiatives. The outcomes of this study may also aid Ethiopia in meeting its domestic coal needs, potentially decreasing its dependence on imported coal as the nation advances its coal resource development
A Masters Project on Utilization and Quality Enhancement of Local Kaolin Clay Minerals Through Beneficiation
(Addis Ababa University, 2023-02) Abiyot Ayalew; Anteneh Marlign (PhD); Meseret Aregahegn:-Co-Advisor
Recently, some researchers labeled industrial minerals as ‘Development Minerals ‘because of their crucial role for fast local economic development and their necessity in the industrialization. The commercial term “Kaolin “is one of the most versatile industrial clay minerals composed essentially of kaolinite (Al2O3.2SiO22H2O). Kaolin What we call it as “China clay” have been found in Ethiopia as huge reserve estimated (20 million tons), throughout in the different parts of country. However, manufacturing industries import commercially value-added Kaolin from foreign countries due to the low qualities of local kaolin which have major impurities. The impurities of Kaolin from literatures and from XRF characterization of Raw Kaolin (RK) are quartz, mica, feldspar, iron oxide and titanium oxide minerals. Here my interest was to improve the qualities of this local kaolin through physical, thermal and chemical beneficiation to substitute imported commercial Kaolin. The two principal objectives of kaolin refining were the removal of impurities and the production of the desired particle-size distributions. Possibly to meet some industrial requirements, the coloring impurities (mainly iron oxides and other small amounts of fuxing components) must be removed. Based on the XRF analysis, the raw kaolin ore from AlemTena, Ethiopia containing 64.135 wt% SiO2, 25.747 wt% Al2O3, 4.838 wt% Fe2O3, and 8.22 wt% loss of ignition (LOI). Then it was physically beneficiated, chemically leached, and thermally treated for possible industrial use, especially for ceramic applications. The leaching experiments were carried out using oxalic acid solutions as leaching reagents for the iron extraction and colour enhancement process. A substantial reduction of iron oxide (4.838 to 3.107 wt %) and silica (64.135 to 57.285 wt%) SiO2 on the other hand a substantial increment of alumina (25.747 to 33.662 wt%) Al2O3 from the raw kaolin was observed at operating conditions of 2.0 M oxalic acid, the temperature of 90 °C, and contact time of 120 min. From Chemically leached kaolin we observed a significant whiteness and brightness. In other way the thermally treated kaolin was observed an increment of iron oxide (4.838 to 6.605 wt %) and also it lost its crystalline structure and becomes an amorphous phase but still its alumina and silica contents improved. Generally, from my study I understood that, the physically beneficiated, chemically leached, and thermally treated kaolin raw material can used to fabricate low-cost kaolin-based ceramic products.
Reverse Flotation as a Method for Beneficiation of Sekota Iron Ore
(Addis Ababa University, 2023-06) Temesgen Demissie; Abubeker Yimam (PhD)
Upgrading low grade Sekota iron ore to reduce the unwanted minerals and improve the quality is necessary to address these issues, in order to produce an acceptable feed for a steel production facility. The primary aim was to use reverse flotation as a beneficiation method for Sekota iron ore, in order to get a last flotation that meets the desired specifications. This process was divided into three stages: crushing, grinding, and flotation. For each of these stages, such as grinding, dosage of collectors, flotation duration, and procedures were determined. In the laboratory, where the samples were obtained, the ore was ground in a size of -0.074mm, using 250 grams of ore, with varying amounts of anionic oleic acid as the collector, 5mg/ton of activator and 5mg/ton of depressant, and floated with 2.0 g/ton of ethanol frother. The slurry was maintained at 10.5 using NaOH throughout the process. Before conducting any optimization tests on the iron ore flotation process, a laboratory procedure was developed to carry out the reverse flotation of the iron ore. The results showed that following these parameters, the flotation process achieved a final concentrate with a grade of 39.16% iron and an iron recovery of 41.29%. In this study, with varying duration of flotation, the iron grade ranged from 40-45% with an iron recovery of approximately 42%.
Identification of Reservoir Rocks, Properties and Structural Mapping of the Abay Basin in Viewing of Petroleum Exploration
(Addis Ababa University, 2023-06) Seid Endrie; Ketsela Tadesse (PhD); Bisrat Kebede (PhD) (Co-Advisor)
The basins has unique geological characteristics and holds different types of sedimentary rocks, such as sandstones, shales, carbonates, and volcanic rocks. The Abay (Blue Nile) Basin is located in the northwestern part of the country and covers an area of over 63,000 square kilometers. The Abay Basins covers a sizable area of the country. It includes Were Ilu, Mechale, and Legehida, which have notable oil seep exhibits. The contribution of the Upper Sandstone reservoir rock data is gathered from prior researchers and written materials in order to develop a relevant relationship between the types of reservoir rocks and structural mapping of the study area. In order to undertake the experimental tests for this study, samples are gathered from the field and sent to laboratory centers. In the laboratory, the chemical composition, porosity and permeability values of the reservoir rocks are determined using a representative sample that was collected from the study area. Based on the results of the experiments, the reservoir rock for the Abay (Blue Nile) Basin formation is an Upper Sandstone reservoir rock with relatively good porosity and excellent permeability. The Upper Sandstone rocks in the Abay basin have porosity values that range from 32.31 to 34.35% and permeability values that range from 1766 to 2350 mD, which suggests that the reservoir quality is generally very good (porosity)and excellent (permeability). During field work, it was discovered that the following fault systems were dominate in the study area. These includes; east-west (E-W) trending faults, northeast-southwest (NE-SW) trending faults, and northwest-southeast (NW-SE) trending faults. The oil and natural gas can be gathered and stored in reservoirs, the geological features called hydrocarbon traps. The presence of a petroleum system in the Abay Basin is strongly supported by the oil seepage at Were Ilu. The study area is characterized by rough structures, so airborne geophysical surveys are advised rather than ground geophysical surveys; seismic lines are needed for the study of the Abay Basin in order to delineate structural traps, stratigraphic traps, and indicate active faulting in the areas where it is possible for seismic line surveys; the basin requires further study regarding the main hydrocarbon fluids reservoir rocks, the total organic carbon contents of the source rocks and the carbonate reservoir rocks.
Reverse Flotation Potential of Bikilal Iron Ore Deposit: A Project Work on Wollega Area Western Ethiopia
(Addis Ababa University, 2023-06) Samuel Getaneh; Mulugeta Sisay (PhD); Guta Legesse (PhD) (Co-Advisor)
Iron is one of the most abundant rock forming elements, constituting about 5% of the earth’s crust. It is the fourth most abundant element next to oxygen, silicon and aluminum and after aluminum, the most abundant and widely distributed metal. Iron is extracted primarily from iron ores. The iron ores mainly include oxides and hydroxides such as magnetite (Fe3O4), hematite [Fe2O3], goethite [FeO(OH)], and limonite [FeO(OH)_nH2O].The primary gangue mineral in iron ores is quartz. The main problem regarding to beneficiate the Bikilal iron ore deposit are the presence of some deleterious gangue minerals such as Phosphorous, Alumina and silica and lack of advanced separation equipment. The aim of this project work is to indicate that the Bikilal iron ore deposit has naturally low grade iron content which is 41.2%Fe and it can be improved by anionic reverse flotation. The method used to upgrade this ore is first the qualitative and quantitative mineralogical analysis has been determined by atomic absorption spectroscopy (AAS) to know the initial amount of iron in the ore. Based on this information reverse anionic flotation has conducted in a batch flotation cell in two size classes at 75μm and 63μm. Oleic acid has been used as a collector whereas Ethanol used as a Frother. Modifiers such as activators, depressants and pH regulators have also used to promote the efficiency of flotation process. The concentrate of flotation has been analyzed again by (AAS) to evaluate the performance of the selected method. The amount from the concentrate has significantly increased from 41.2%Fe average grade to 62%Fe grade. The recovery of iron have been calculated as 65% for under 63μm and 74.4% for under 75μm.The amount of the concentrate for 63μm was 215g and that of 75μm was 250g. Therefore the recovery of iron from 215g under 63 μm is 65.5%Fe which is better than the recovery from 250g under 75μm that is 74.4%Fe. This project work mainly conducted based on (AAS) analysis results but it is not suffifeint to judge the general mineralogical composition and beneficiation process that should be applied in the Bikilal iron ore deposit. Therefore additional investigations and laboratory analysis such as (XRD), (SEM) and (XRF) are recommended to come up with a more tangible and realistic data. This paper have also discusses in detail about the factors that can affect the flotation performance of the ore and the alternative chemical reagents that can go through the mineralogy of Bikilal iron ore deposit.
Determining The Liberation Size of Mekaneselam Iron Ore Southern Wollo Zone, Northern Ethiopia: Implication for Beneficiation
(Addis Ababa University, 2023-06) Getahun Meseret; Dejene Hailemariam. (PhD); Belayneh Digafe (Mr.) (Co -Advisor)
Iron is one of the most important types of ferrous metals that extracted from ore minerals of iron, like magnetite, hematite and others. Ethiopia has a lot of iron ore resources which are located in different parts of the country. Among this, Mekane Selam iron mineralization, which is located in south Wollo zone, Northern Ethiopia, is the target area of this project work. The main objective of this project work was to determine the liberation size of the target iron-bearing ore mineral through mineralogical identification, chemical composition analysis, and examination of the particle size distribution. Atomic absorption spectrometry (AAS), X-ray florescence (X-RF), X-ray diffraction (X-RD) analysis, and sieve analysis, were widely used methods for this project work. The chemical composition of Mekaneselam iron ore consists of 16.55–77.59 % Fe2O3, 7.31–59.02% SiO2, and 1.44–17.38% Al2O3. With an average weight percentage of 48.34%,48.96% of Fe2O3, 34.7%,31.8 % of SiO2, 8.2%,10.68% of Al2O3, and 0.018% , 0.19 % of P2O5 and other minor compositions that resulted from X-RF and AAS compositional analysis respectively. The mineralogical results generated from X-ray diffraction showed that Mekaneselam iron ore consists of major iron-bearing ore minerals of 40–60% hematite, 8–59% goethite, with an average value of 49.13% hematite and 27.85% goethite. The dominant associated gangue minerals are 1–21% quartz with an average value of 11.5% and 1–23.5% kaolinite with a mean value of 8.6%. The examination of the particle size distribution of sizing curves shows that 80 percent passing (P80) of the grinded ore sample is 1100μm. The size-wise chemical compositional analysis of AAS revealed that a higher weight percentage of the target ore mineral was recorded under a sieve size range of (-250μm + 180 μm). This implies that the appropriate liberation size of the target iron-bearing ore mineral is found between (-250μm and +180μm) sieve size ranges. This liberation size range shows a cumulative passing of 38% total particles. The chemical and mineralogical results of Mekaneselam iron ore indicate that the ore is very low grade and can be upgraded to commercial values by using gravity concentration followed by a high-intensity magnetic separator. In addition, it can be upgraded by magnetic reduction roasting (MRR), followed by a low-intensity magnetic separator.
Characterization of Ore and Gangue Mineralogy at The Ashashire Gold Deposit, Benishangul- Gumz Region, Western Ethiopia
(Addis Ababa University, 2023-06) Getnet Belachew; Melesse Alemayehu (PhD); Basalifew Zenebe (Mr.) (Co-Advisor)
Gold is a precious metal that is highly prized and has been significant throughout human history. It has been used as money and for ornamental purposes. It is a crucial component in electronics, medical equipment, and other industrial uses. Around the world, mining operations have sprung up in response to the demand for gold, and efficient extraction and processing depend on an understanding of the mineralogy of gold deposits. This study aimed to characterize the mineralogy of the Ashashire gold deposit located in the Benishangul Gumuz Regional State, Western Ethiopia. Six representative mineralized core samples were analyzed using fire assay with atomic absorption spectroscopy (AAS), inductively coupled plasma (ICP), quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and X-ray diffraction (XRD). The study found that the gold in the deposit occurs primarily as native gold and gold-telluride, with a strong association with tellurium and often found as free particles or in association with gangue minerals such as quartz and pyrite. Pyrite is the dominant sulfide mineral detected in all core samples, with only trace amounts of chalcopyrite detected. The gangue minerals present in the deposit are mainly quartz, ankerite-dolomite, muscovite, chlorite, and albite, with lower levels of paragonite, rutile, magnetite, and calcite. The presence of tellurium suggests that specialized processing techniques may be required to liberate the gold from the tellurides. The degree of liberation, liberation sizes, and recovery of gold are all impacted by the texture of the ore. The gangue mineral composition of the ore can also impact gold processing in several ways, including cyanide consumption, clay coating and gold adsorption, ore hardness, mineralogical complexity, and processing costs. The mineralogical data can be used to develop a suitable processing route, taking into account the ore texture, gold mineralogy, and gangue mineral composition. A combination of techniques such as gravity separation, flotation, cyanide leaching, pressure oxidation, and CIL/CIP could be employed to maximize gold recovery and minimize environmental impact. Further metallurgical testing and optimization are necessary to fully understand and optimize gold recovery from this deposit.
Analyzing the Effect of Operational Parameters on the Breakage Mechanisms of Spodumene Mineral to Optimize the Comminution Processes of Lithium Bearing Pegmatite in Kenticha, Ethiopia
(Addis Ababa University, 2023-06) Abdu Ebrahim; Alberto Velazquez Del Rosario (Prof); Ijara Tesfaye (Mr.0
This study is aimed to investigate the optimal operational conditions for breaking down the Kenticha, Ethiopia Li-pegmatite,which contains lithium minerals, particularly spodumene. The goal is to produce high-quality spodumene concentrate by achieving the desired particle size, particle distribution, which are crucial for efficient separation during the physical separation and subsequent froth flotation steps. To achieve this, one sample from Kenticha Li-pegmatite replicated four times were characterized using X-ray diffraction (XRD) and atomic absorption spectroscopy (AAS) techniques for mineralogical and geochemical analysis respectively. XRD analysis confirmed that the ore was predominantly composed of spodumene, with minor amounts of quartz, mica and feldspar. AAS analysis showed that the ore contained a moderately high level of lithium (approximately 2.5%) as well as other trace elements such as iron, and very low amount manganese and phosphorus. The results indicated that the ore had the potential to be a valuable source of lithium for industrial purposes. The sample then were crushed using a Laboratory Jaw Crusher in primary step and the study was conducted for different conditions parameters of grinding as a secondary step using a Laboratory Ball Mill. Optimal breakage mechanism was determined to achieve the desired spodumene concentrate.The results showed that the optimal conditions under the experimental analysis identified as milling power: 41 W, amount of feed: 250 g and the milling speed: 500 rpm, could produce narrow size distribution and the desired particle size for high spodumene concentration. This research has significant implications in the field of lithium mineral processing, providing important insights into the operational parameters that can achieve high-quality spodumene concentrate.
Biostratigraphy, Burial History and Thermal History of Gambella Basin, Ethiopia; Implications for Source-Reservoir Interaction and Hydrocarbon Generative Potential
(2023-06) Changkuoth Dhan; Samuel Getnet (PhD)
The Gambella Basin, located in southwestern Ethiopia, near the Sudan border, covers an area of about 15,350 sq.km. It has a NW-SE elongated outline, and it is presumed to be the southeastern extension of the Melut Basin of South Sudan. Geological data review indicates that sedimentation in the interior Basins of the South Sudan is controlled by intermittent rifting phases that continued up to Mid Miocene. Biostratigraphy, Burial history and Thermal history evaluation of Gambella area, analysis include the Palynological and Paleoenvironment analysis on 104 cuttings samples and 16 sidewall cores from the interval of 60-3500 mKB in Jekow well and carried out on seventy 70 ditch cuttings from the interval 745-3250 in Jacaranda well (PCOB report, 2007 ). The exploration wells, Jekow (in the East) and Jacaranda (in the West) Gambella, Ethiopia which have penetrated the target zone of Sothern Melut Basin extension of the South Sudanese rift Basin. The source rock screening, Thermal Maturity, zonal layer, geologic section, the vitrinite reflectance and the age have target the interest of burial history and the hydrocarbon generative of the Basin. A one-dimensional modeling of Burial history and Thermal history was performed in Jekow and Jacaranda locations using one PetroMod 1-Dimensional modeling of Integrated Exploration Systems of Gesellschaft mit beschränkter Haftung, (GmbH-IES), Germany. However, due to unsuccessful exploration campaign in South Melut Basin where Gambella Basin is extended and in addition to the poor quality seismic data implied that the risk for the petroleum system in the West Gambella Sub-basin is still very high.
Provenance Controls on Porosity Evolution, Adigrat Sandstone, Ogaden Basin, South East Ethiopia
(Addis Ababa University, 2023-06) Mahamed Hassen; Solomon Kassa (PhD)
The Ogaden basin is the largest sedimentary basin in Ethiopia, with 350,000 km2 of areal coverage. Although it is the most studied region, so far 72 wells have been planned to be drilled in the area, i.e., the number of wells per area covered is 4861 km2. This thesis investigates provenance based on petrography, facies analysis of Adigrat Sandstone in Calub-wells and Hilala-wells in the Ogaden Basin, Ethiopia. A Detailed laboratory petrographic analysis was done on 25 sandstone samples (15 sample from the Calub field wells and 10 sample from the Hilala field wells). Changes in the mineral composition and lithofacies of these sediments over time relate to the tectonic development of the region. When the different grain mineralogies are associated with different source rock types, the signals of at least two distinct sediment source regions emerge. The relative amounts of sand-sized material from the study areas indicate a shift in provenance over time; with the advance of the Calub-wells, a mixed provenance of sedimentary and metamorphic source terrains gave way to a depositional record characterized by sedimentary source rocks. Petrographic and modal composition of the sandstone classification displayed mostly quartz arenite with few subarkosic and sublithic arenite. The modal composition of sandstone revealed that the provenances are craton interior, recycled orogeny, and continental block provenance. From the Qt-F-L tectonic setting plot, all samples fall outside of the tectonic setting field as a result of intense weathering. According to the analyzed data, the porosity of the Adigrat sandstone of the two gas fields is medium therefore the reservoir is good.
Upgrading The Iron Grade of Bikilal Iron Ore Using Magnetic Separation Method with Frantz Laboratory Magnetic Separation
(Addis Ababa University, 2023-06) Deagaga Amenu; Dejene Hailemariam (PhD); Wondefrash Mamo (Mr.) (Co -Advisor)
The iron ore deposit of the Western Oromia Region of Ethiopia, at Bikilal, is a huge deposit, but it is low in grade. It assays 19.50 % Fe2O3 and 45.66% SiO2. The present study is an attempt to investigate the potential of this ore for upgrading at laboratory scale. Based on the appreciable differences in magnetic susceptibility between the desired iron minerals and gangue minerals, it was suggested that magnetic separation may be useful to concentrate this type of iron ore. The study used two feed size fractions (-500+75 micrometers; -300+75micrometers) and two currents 0.4 ampere; 0.8 ampere), and performed four experiments by adjusting these operating factors. The iron grade and recovery were measured and recorded for each combination of tests. For run 1and 2, that received -500+75μm and 0.8 and 0.4 ampere respectively, the results of iron grade and recovery, in % were 25.02; 83.73% and 20.84;68.63%. For run 3 and 4, that received -300+75μm and 0.8 and 0.4ampere, the obtained iron grade and recovery were 31.18;90.17 % and 26.64;75.63%. Factorial Design, particularly, Two Level Factorial Design was applied to investigate the effects of feed size (-500+75 and -300+75μm) and current (0.4 and 0.8 ampere) on the process of Frantz laboratory magnetic separator using Design expert v13 software, which shows the significant influence on the values of Fe grade and recovery at roughing stage of the concentrate. The results showed that both feed size and current had a significant effect on the iron grade and recovery, and their interaction had not significant. The optimal condition was found to be using a feed size fraction of -300+75 micrometer and a current of 0.8 ampere, which gave an iron grade of 31.2 % and an iron recovery of 90.2 %. The study demonstrated that the Frantz® Low Field Control Model LFC-2 is a useful accessory for separating ferromagnetic materials according to differences in their magnetic properties. The study also provided some insights into the trends and correlation among the factors and responses, which can help to understand and optimize the magnetic separation process.
Investigating the Potential of the Magnetic Separation Method as an Auxiliary Technique for Upgrading Lithium Ore Mineral from Kenticha Pegmatite Deposit in Guji, Southern Ethiopia
(Addis Ababa University, 2023-06) Berhanu Adugna; Sisay Degu(PhD)
Lithium has become a critical mineral in the energy industry, with significant increases in usage due to the global shift towards green energy alternatives over the past decade. The Kenticha pegmatite deposit in Ethiopia is known to have a feasible content of Li2O, making it a potentially valuable resource for lithium extraction. However, the beneficiation of lithium-bearing minerals is a crucial stage in upgrading the lithium oxide content of the ore and enhancing its economic value. The presence of gangue minerals such as microcline, albite, quartz, muscovite, and iron silicate minerals can complicate the process. Frantz magnetic separators were employed to conduct magnetic separation tests. Samples were collected from four different locations within an upper lithium-rich pegmatite deposit and subjected to analysis, revealing varying percentages of lithium oxide and iron oxide. The effectiveness of a Frantz magnetic separator was examined using feed size fraction and intensity as independent variables, with various combinations of factors tested. The resulting data was analyzed using AAS and XRD techniques to gain valuable information about the separation process and lithium mineral liberation. The separation effectiveness was evaluated based on the results, which indicated that high-intensity magnetic experiments with fine feed size fractions achieved better recovery of lithium oxide and less iron-bearing minerals. The potential for using the magnetic separator as part of a larger processing plant was also discussed, with comparisons magnetic separation method to other conventional lithium processing methods that employed magnetic separation. Finally, potential types of magnetic separators were suggested for the LCT Kenticha pegmatite deposit.
The Flotation Response of Dedo Coal Deposit, Jimma Ethiopia: Implication to Improve the Quality of Coal
(Addis Ababa University, 2023-06) Dejene Amane; Melesse Alemayehu (PhD)
The purpose of this study was to investigate the flotation response of the Dedo coal deposit and to improve its quality. In this project, chemical reagents were used to induce hydrophobicity in hydrophilic coal particles present in coal slurry, and particularly froth flotation techniques were employed. To obtain a general understanding of the floating response of coal from the study area, the yield of floated coal was estimated. The quality of coal before beneficiation (froth flotation) in this project was characterized by a moisture content of 13.63%, volatile matter of 33.45%, ash of 25.66%, sulfur of 0.36%, and calorific value of 4806 cal/gm. After beneficiation, the moisture content was 11.06%, volatile matter was 25.63%, ash was 20.28%, sulfur was 0.25%, and calorific value was 5029.38 cal/gm. These results indicate that impurity contents such as ash, mineral matter, and sulfur resources were reduced, and the calorific value of coal was increased by applying successful froth flotation
Applicability of Gravity Separation Method on The Ashashire Gold Ore Deposit from Benishangul Gumuz Region, Ethiopia
(Addis Ababa University, 2023-06) Misganu Kabeta; Mulugeta Sisay (PhD); Abaynesh Mitiku (Mr.) (Co-Advisor)
The current Project of applicability of gravity separation method for gold ore deposit was conducted in Ashashire locality of Benishangul gumuz region, North western Ethiopia. The purpose of this project is beneficiating the Ashashire gold ore deposit by applying the gravity separation. The Ashashire composites were produced to provide sufficient mass for this study and experiment includes sample preparation, head assay analysis of gold and multi-element, gravity concentration and mineralogical analysis. The study conducted to determine the applicability of gravity separation method by using KC on the Ashashire gold ore deposit. The samples were moderately ground to the standard grind size of P80 - passing 106, 75, 53 μm and this nominal size was selected for the preliminary assessment for Concentration optimization. During the study, a grind optimization was conducted on the composites sample with varying grind size to evaluate the effect of grind size on gold recovery. The gravity testing comprised three-stage concentration by centrifugal knelson concentrator to produce gravity concentrate. High recovery of gold from the gravity concentrates was achieved from the second gravity concentration. Based on the results from laboratory experiments, a grind size of P80 75 μm is selected as optimal size for the ashashire deposit using KC gravity methods. Increasing the grind size from P80 of 75 μm to106 μm decrease recovery rate from 75 % to 54 % or decreasing the grind size from P80 of 75 to 53 μm decrease gold recovery rate to 37%. It was observed that repeat gold head assays varied, indicating the presence of coarse gold particles and uneven gold particle distribution. The native gold grain in the ores is mostly associated with quartz and Fine gold is closely associated with pyrite, forming inclusions and dispersed within pyrite. According to the fire assay, chemical, and mineralogical analyzes data, only gold and telluride is commercially valuable component in the ores. Presence of 2.13 ppm Te was detected in the composite sample during head assay analysis. The differences between assayed head grades and calculated head grades would indicate that the gold is not evenly distributed within the ore and occurs as localised spots. Gold was identified to occur predominantly in the native form and as Au-Te. The sample subjected to gravity separation assayed about 2.6 g/t Au.
Effect of Particle Size on Coal Cleaning by Froth Flotation Method in Didaye Woreda, Wolaita Zone
(2023-06) Tiruye Kassaw; Bogale Tadesse (PhD); Guta Legesse (PhD) (Co-Advisor)
The aim of this study is to investigate the effect of particle size on the efficiency of coal cleaning process by froth flotation. Coal cleaning is an important process, which involves removing ash, and other impurities from coal to improve its quality for energy and industrial use. Froth flotation is a widely used method for coal cleaning, which relies on the difference in surface properties between the coal particles and the mineral matter. However, the efficiency of froth flotation is greatly affected by the size of coal particles. In this study, four different sizes range of coal particles (-500μm+350πm, -350μm+225μm, -225μm+180μm and-180mμ+100μm) were tested for their ability to float in the froth flotation process. Results showed that the efficiency of coal cleaning was highest for particles ranging from at this particle size -350μm+225μm, while particles above +350μm showed the poorest performance. The results suggest that particle size is a critical factor in the success of coal cleaning by froth flotation, and -350μm+225μm coal particles are more amenable to this process. The findings of this study will help in optimizing the coal cleaning process to improve its efficiency index, combustible recovery and ash rejection.
Characterization of Coal Composition of Shela Area, Wolayita Zone, Southern Ethiopia, Implication
(Addis Ababa University, 2023-06) Abinet Markos; Sofiya Abdulkadir (PhD)
The present study focused on the mineral characterization of Kindo-Didaye coal by adiabatic Calorie Metter, Gravimetric, hard groove index and proximate techniques. The result showed that coal quality ranged between (2475.79-10931.96Btu/lb); Sulphur (<0.02 % to 2.93%), moisture (1.21 to 1.99 %), volatile matter (15.45 to 26.37%), ash content (28.19 to 71.26%) and fixed carbon (11.21 to 44.23%). The majority of the Coal samples fall within lignite “B”, subbituminous “B” and sub-bituminous “C” ranks and none agglomerating. The grindablity index of the majority of the coal samples has the range (56.2-66), which HGI values of the Shela area coal samples indicate that most of the samples can be characterized as lignite and are also extremely challenging to grind.
Evaluation of the Nature of Porosity in Carbonate Rock Of Hamanlei Formation, Ogaden Basin, Ethiopia: Implications For Prediction of Reservoir Quality
(Addis Ababa University, 2023-06) Yimam Ali; Solomon Kassa (PhD)
The Ogaden basin is the largest sedimentary basin in Ethiopia having 350,000 km2 areal coverage. It is also the most studied sedimentary basin in Ethiopia. Nonetheless, the amount of data gathered from this baisn is not enough to better comprehend the petroleum system of the basin. The Hamanlei carbonate rock in the basin makes good reservoir rock. The nature of this reservoir rock is complex owing to various factors. Despite detail studies were conducted to understand the reservoir property, particularly core and wireline log study, further studies are needed for better characterization of this reservoir rock. To further characterize the reservoir property, i.e. porosity, of this rock and prediction for reservoir quality, petrographic and image analysis were performed. The outcome of this study provides valuable insights into the mineralogy and texture of the studied rocks. Furthermore, it highlights the importance of understanding the different pore types that enables to better interpret the reservoir quality and potential flow characteristics of the studied rocks. Generally, the porosity value of the reservoir rock is too small which is caused by the dominant proportion of matrix and cement
Value Addition of Ethiopian Gemstones
(2023-06) Mehatebe Gebrewold; Abubeker Yimam (PhD); Aselefech Mitiku (Ms.) (Co-Advisor)
Ethiopia is well recognized for producing gemstones. Numerous high quality gemstone varieties, such as opals, emeralds, sapphires, amazonite, amber, rubies, tourmalines, aquamarines, chrysoprase, peridot, chalcedony, obsidian, agate (scapolite agate), jasper, petrified wood, and various types of quartz, including precious quartz, are the main gemstones mined in the nation. However, the industry continued to generate little appreciable economic advantage because the country mostly exported rough gemstones with no added value. This project study intends to demonstrate the technology needed for adding value to various Ethiopian gemstones and the associated financial advantage. The following measures were taken in order to add value: Sorting the chosen gemstone by specie, selecting clean, color-full, large (excellent size to cut) pieces from the rough collection, cutting, polishing, and ultimately faceting of the chosen gemstone. The value added gemstones are then each given a physical description based on their Color, Clarity, and Cut. Finally, a price estimate has been generated for the gemstones with enhanced value. The project's findings showed that enhancing the value of the rough gemstone might produce earnings of up to 1,610,590 ETB/Kg of Opal, 293,560 ETB/Kg of Crystal Quartz, 213,040 ETB/Kg of Green Obsidian, 48,565 ETB/Kg of Jasper, 43,730 ETB/Kg of Agate and 43,675 ETB/Kg of Black Obsidian. As a result, small-scale gemstone business owners can profit from the high prices of their products and the country can increase the foreign currency revenues from selling the value-added gemstones by adding value to the rough gemstones through the use of relevant technology.
The Beneficiation of Lithium from A Brine Solution of Afdera Lake Using Evaporation and Chemical Treatment Method, Afar, North Eastern Ethiopia
(Addis Ababa University, 2023-06) Elias Mamushet; Bogale Tadesse (PhD); Abayinesh Mitku (Mr.) Co-Advisor
Lithium is a crucial metal with a rapidly growing market demand, mostly due to its use in lithium-ion batteries for electric cars and medical devices. Lithium resources connected to pegmatites and rift-bound brine deposits may exist in Ethiopia. The current project work, the beneficiation of lithium was conducted on Afdera brine lake Afar, North Eastern Ethiopia. This project aims beneficiating lithium using Evaporation and chemical treatment method. Totally 20 litter sample were collected from the lake using Purposive and random sampling method in order to analyzed in the laboratory for Atomic Absorption Spectroscopy (AAS) for the Lithium and major cation as well as for beneficiating lithium metal from the brine solution. The AAS result of the Lithium contents in brine water of Afdera lake is 8.7ppm which is relatively higher than other lakes in the main Ethiopian rift. The concentration of Sodium and potassium is extremely higher in the lake which is 82946 ppm and 661.5 ppm respectively while lithium is much lower. Even if the Lithium concentrations is below the cut of grade 200ppm it was processed using evaporation and chemical treatment method and the content of the lithium reached 53.8% in the concentrate. Despite the lake's lithium concentrations being below what can be commercially extracted, it can still be processed as a byproduct during the manufacturing of potash using sun evaporation pans. The current study strongly suggests that additional research is needed merely to assess the lithium resources as a primary product and as a secondary byproduct during the potash mining process in Afdera Lake and the surrounding area.
Application of Montmorillonite Type Bentonite Clay From Chacha Area as Alternative for Local Construction Material
(Addis Ababa University, 2023-06) Addisu Misgana; Abubeker Yimam (PhD); Enatfanta Melaku (Mr.)
Hollow concrete block are produced from derbanPozolana Portland Cement (PPC), pumice and other aggregates (sand, scoria, gravel and clay). Mixing ratio and composition for HCBs although depend on the availability of materials. It is widely varying among the producers of cottage and industrial scale. However, all producers apply cement as a major constituent for binding. The demand of cement for HCBs and other construction materials is very high while the cement supply is very low. As a result, cost of production and sell price in the market is expensive and becoming not affordable for end users. The objective of this study is to investigate and evaluate the effect in using relatively cheaper bentoniteas cement replacement in HCBs production. Bentonite is available in a bulk when compared to cement. In the process focushas been given for curing and compressive strengthof HCB by varying the amount of cement and bentonite as major constituents in three ways (10kg bentonite replacing 10kg cement, 15 kg bentonite replacing 15 kg cement and 20 kg bentonite replacing 20 kg cement for a single batch /64 HCBs). All HCB samples were produced using 0.84 m3 pumice, 40 liters’ water. In addition silicate analysis (chemical composition) and physical properties (bulk density, moisture content and free swell test) of Chacha clay. Standard Compressive strength tests using (CES24:2013) method for HCBs of six sample replicates with average result on a total of 54 samples tests were made for 14, 21 and 28 age of curing time. For 28days’ age the average compressive strength (N/mm2) of 1.43, 1.27 and 1.23 were achieved by 10%, 15% and 20% bentonite replacement respectively. The compressive strength of HCBs is found to increase with increase of curing age and decreases with increase of the bentonite loading ratio. Generally, replacing of cement with bentonite at 28 days, a 10% bentonite replacement obtained the highest strength value, followed by a 15% bentonite loading ratio and a 20% bentonite loading ratio.

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