Centers for Ethio Mines Development

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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.
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.
Beneficiation and Upgrading of Coal Via Dense Media Separation (DMS) In Ankober Woreda, North Shewa Zone
(2023-06) Gizachew Ayu; Bogale Tadesse (PhD); Henok Tamirat (Mr.)(Co-Advisor)
Coal is a type of fossil fuel and a combustible black or brownish-black sedimentary rock, formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years as rock strata and used as a fuel for energy resource. But, coal is usually formed associated with gang mineral (ash) those can decrease combustibility of coal. Thus, to utilize this resource safely and efficiently, coal separation and concentration is required. Density-based rejection of ash is an effective method to remove gangue before the process of coal combustion for the purpose of improving the quality of coal. By using a uniform crushed particle size of coal sample (-4.75+4.5 mm) in different specific gravities of heavy medium (1.4, 1.6, and 1.6), the specific gravity of 1.4 was found to be the optimum parameters to successfully upgrade the coal and improve its calorific value. Based on the results of the float product of 32.8% of concentrated coal and 24% upgraded coal obtained with reduced ash content of 60.72% and 21.79% increase of fixed carbon at specific gravity 1.4 and also it was found that upgrading, floating, fixed carbon as well as ash reduction subsequently decreases in floats as the specific gravity increases unlike volatile matter. From this work, it can be concluded that beneficiation and upgrading of coal by dense media separation method is good technique to produce improved and safely used coal as an energy source for coal-fired utilization.
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.
Comminution circuit flow sheet Development for Optimum Performance of Iron Ore Processing, in the Case of Sekota, Wagehimra, Northern Ethiopia
(Addis Ababa University, 2023-06) Ephrem Tialhun; Abubeker Yimam (PhD); Megeressa Bedo (Mr.) (Co-Advisor)
Sekota Iron Ore aims to contribute to the economic development of Ethiopia by exploiting and producing high-quality iron ore for both domestic and international markets. The company expects to create employment opportunities and generate revenue for the government, which can be used to invest in other developmental projects. Besides, the establishment of Sekota Iron Ore could also help to reduce the country's reliance on imported iron and steel products, promote local industries and contribute to the growth of the mining sector. Most of the minerals extracted in the nature are founded disseminated with the gangue, this creates a necessity to liberate these particles and reduce the size for principally reach a big concentration of the desired material. As the comminution is by far the largest energy consumer in most mine sites, the study of the mineral processing try to conduct this size reduction with the bigger efficiency possible. comminution flowsheet design is a critical process in the production of iron ore. In this study, the flow rate was fixed at 150t/h with the Crusher specification of a Cedarapids JC24x36 jaw crusher model and a Nordberg Hp 300 S/M cone crusher. Based on the mineralogical information and ore properties provided the AggFlow Version 460.22 software is used to conduct, a comprehensive comminution flowsheet design to achieve the desired particle size distribution and mineral liberation. In the communition of primary crusher stage Iron ore at top size of 42 inches or (1066.8mm) generates 5 different ranges of materials, the first is at a size of 45mm, the second at 10mm, and the third is at 8mm, between 15 and 8mm and between 23.5 and 15mm. The primary crusher, a Cedarapids JC2436 Model Jaw crusher, was required to reduce the feed size with closed side setting of 69.85 mm to a manageable size of end product 21Mtph for further processing. The Nordberg Hp 300 S/M cone crusher was used as a secondary crusher with closed side setting (CSS) of 28mm to further reduce the particle size to 26Mtph. To complete the task several choices analyzed and as final design used 1 jaw crusher Cedarapids Jc 2436, and two cone crushers Nordberg HP 300 S/M. some screening and conveyors placed in the design to increase the reduction ratio of the equipment.
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.
Characterization of Permian to Triassic Formation Within Ogaden Reservoir Ethiopia, Implication of Source Reservoir Interaction
(2023-06) Eshetu Lema; Samuel Getnet (PhD)
The Ogaden region is located on the Somali Plateau, in southeast Ethiopia. Originally a clanbased term, the Ogaden is now commonly used for the entire region below about 1,500 m a.s. l., an area of some 350,000 km2 that encompasses most of the Somali Regional State and includes the southwest portion of Oromia. The Northern Ogaden Basin is underlain by Precambrian basement rocks and Phanerozoic rocks consist of Paleozoic – Mesozoic sedimentary rocks and Cenozoic volcanic and cover rocks. The Phanerozoic of northern Ogaden Basin is formed on an exhumed rift-related, NW-to WNW trending basin that formed as a result of the NE-SW extension that began in Paleozoic. The oldest rocks in the basin are represented by the deposition of Paleozoic-Early Jurassic succession, which is made of continental clastic sediments (Wayu Sandstone and Adigrat Sandstone). They are deposited within grabens bounded by NW-trending and northeast-and southwest-dipping normal faults, which are developed above a top-to-northeast detachment fault. They are un conformably overlain by Middle – Late Jurassic sediments comprised of mainly limestone with minor interbeds of shale and marls (Hamanlei, Urandab and Gabredarre Formation) that pass upward into the Garbeharre Formation, which consists of sandstone, mudstone, shale with minor interbeds of limestone at the base of the succession. The climate is hot, arid to semiarid, corresponding to the Ethiopian bereha and kolla climatic zones. Three basic physiographic provinces are recognized: the Genale and Shebele drainage basins and the Eastern Slope and Plains. The two drainage basins include spectacular upstream canyons that witness the vertical movements that have accompanied the succession of rifting events in the Ethiopian Rift, Afar, and the Gulf of Aden. In strong contrast, the Eastern Slopes and Plains is dipping less than 0.4° on average over hundreds of kilometers to the southeast and is mantled by red sands. Several remarkable Oagden landforms are described and analyzed, including volcanic, fluvial, and gravitational features, some having few equivalents in other areas on Earth.
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.
Identifying the Effects of Diagenesis on Reservoir Quality, Adigrat Sandstone, Ogaden Basin, South East Ethiopia
(Addis Ababa University, 2023-06) Gemeda Ayansa; Solomon Kassa (PhD)
The Ogaden basin is a vast sedimentary basin having 350,000 km2 areal coverage. Although it is the most studied region in Ethiopia, so far 72 wells have been drilled in the area, i.e. the number of wells per area coverage is 4861 km2. Due to large area coverage of Adigrat Sandstone reservoirs there, the Ogaden Basin in SE Ethiopia is of great importance for hydrocarbon exploration and development. However, diagenetic processes, which modify the rock's physical properties, affect its ability to store and flow hydrocarbons, and can have a significant impact on reservoir quality. Despite its significance as a reservoir, it is practically impossible to predict how diagenesis may affect the sandstones' reservoir quality. This study was conducted to find out the types of digenesis and its effect on the quality of Adigrat sandstone reservoir. To this end, 15 (fifteen) thin sections of Adigrat sandstones from YH-4 well were prepared and, ImageJ, JMicroVision, and petrographic analyses were employed to characterize the reservoir's diagenetic effect. The cementation of authigenic clay, silica, growth of authigenic glauconite, mineral dissolution, and load compaction are the key diagenetic processes that have impacted the reservoir quality of Adigrat sandstones. According to the framework grain-cement interactions, Clay cements, particularly illite, that partially line and fill pore spaces, developed alongside or after the early calcite cement's precipitation. Thus, it is inevitable that the reservoir rock’s porosity and permeability will decrease by this clay, which acts as a pore-choking cement.
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
Grindibility and breakage characteristics of Sekota iron ore deposit in Wag-Himra Zone, Northern Ethiopia
(Addis Ababa University, 2023-06) Yohanes Belachew; Bogale Tadesse (PhD); Birtukan Yenealem (Co-Advisor)
In this study, the influence of mill rotation speed and grinding time were investigated on Sekota iron ore grinding process in a batch mill with length 150 mm and inner diameter 150 mm. The particle size distribution of the feed was carried out by an electric sieve and the bulk feed was classified into three samples to perform the grinding test. Three distinct iron ore feed size fractions between -335mm to +0.71mm, -0.71mm to +0.15mm and -3.35 to -0.075mm separated by a series of √2 gaps were prepared. The fractions were milled at different grinding times (5, 15, 25, 35, 45 and 60 min) at 450 rpm and at different mill rotational speeds (250, 300, 350, 450 and 550 rpm) at 25 min. The mill rotation speed and grinding time affect the energy consumption, the desired grind size and the P80 of the feed size fraction. When grinding time increased from 5 to 60 min, the percentage of cumulative mass of target size increased from 8.5 to 31.1%, from 7.1 to 22.8% and from 10.6 to 26% for coarse, fine and mixed iron ore size fractions, respectively. Likewise, a significant amount of the desired grind size is produced as the grinding speed increases until the maximum critical speed is reached. For all feed size fractions, the required grind size amount (-0.075 mm) is not achieved at grinding times from 5 min to 60 min and at maximum mill rotation speed (450 rpm). The product size distribution of the three iron ore feed size fractions were also affected as the grinding time and the mill rotation speed increased from 5 to 60 min and 250 rpm to the maximum speed (450 rpm). The P80 values of all feed size fraction generally decreased both milling time and mill speed are increased from 5 to 60min and 250 to 450 rpm respectively. Unlike the P80, the energy consumption of the ball mill increases significantly as the mill speed and grinding time increase from 250 to 450 rpm and from 5 to 60 minutes respectively.
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
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.
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.
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.
Flotation Response of the Kindo Didaye Coal Deposit, Wolaita Zone
(Addis Ababa University, 2023-06) Temesgen Ayisa; Mulugeta Sisay (PhD)
The main objective of the project was to investigate the optimum flotation behavior of the coal.Flotation 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. The bulk sample from jaw crusher was milled by cross-bitter miller and coal sample was ready for separation in arranged sieve shakers based on their size. Then,fine powder coal samples were prepared by using different size of sieve shaker arranged as and measured the mass of the feeds of each particle size before the starting of flotation processes.In this study, four different sizes range of coal particles (-500 to +250 μm, -250 to +150 μm,-150 to +125 μm,-125μm to +75μm and -75 μm) were tested for their ability to float in the froth flotation process. Because of natural hydrophobicity of coal, there are a range of chemicals used to further enhance the floatability of coal particles.Results showed that the optimum flotation was highest for particle size und.75μm, while particles above +250μm showed the poorest performance and the same result was seen by the increase of kerosene amount at the same particle size. The results suggest that particle size and the over use of reagents are critical factors in the success of flotation response. The findings of this study will help in optimizing the coal cleaning by flotation increasing the heat value of the coal by avoiding the impurities. So in this flotation experiment the calorific value increases.
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.
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%.
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.
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.

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