Ethiopia possesses considerable coal resources, but their low grade, marked by high ash and moisture, restricts industrial utilization. This work examined how run-of-mine coal from the Dedo deposit in Jimma Zone, south-western Ethiopia, responds to froth flotation, with the goal of raising its quality. Duplicate batch tests were run in a laboratory Wedag flotation cell to assess how particle size (−500+250 µm and −125+63 µm) and impeller speed (1500 and 2500 rpm) influence concentrate yield. Kerosene served as the collector and n-octanol as the frother, and the feed mass, conditioning time and reagent dosages were kept fixed. Proximate analysis, sulfur content and calorific value were used to characterize both the raw coal and the floated concentrate. Mean concentrate yield varied from 48.0% for the coarse fraction at 1500 rpm up to 66.5% for the fine fraction at 2500 rpm, which shows that, within the ranges tested, finer particles and a higher impeller speed improved flotation. Compared with the raw coal, the concentrate produced under the best conditions contained less ash (25.66% to 20.28%), moisture (13.63% to 11.06%), volatile matter (33.45% to 25.63%) and sulfur (0.36% to 0.25%), and had a higher calorific value (4806 to 5029.38 cal/g), while fixed carbon increased (27.26% to 43.03%). The findings suggest that froth flotation can give a cleaner, more energy-rich product from Dedo coal; however, the calorific value gain was small (about 4.6%), and only two levels of two variables were investigated. Before process conditions for industrial use can be defined, the effects of collector and frother dosage, solids concentration, pH, air flow rate and conditioning time, as well as the composition of the flotation tailings, still need to be assessed.
This study examines the influence of grinding fineness on concentrate grade, product yield, and copper, molybdenum, and gold recovery during flotation beneficiation of copper-molybdenum ore from the Kalmakyr deposit. Five grinding conditions were compared, corresponding to 57%, 60%, 65%, 70%, and 80% by mass passing 0.074 mm. The evaluation was based on the reported assays, yields, and recoveries of flotation products under the investigated flowsheet. Increasing the proportion of material passing 0.074 mm from 57% to 70% raised copper recovery from 83.79% to 88.73%. At 70% passing 0.074 mm, the combined concentrate yield was 7.76%, with grades of 3.82% Cu, 0.039% Mo, and 5.02 g/t Au; corresponding recoveries were 88.73% Cu, 82.61% Mo, and 77.80% Au. At 80% passing 0.074 mm, copper, molybdenum, and gold recoveries increased further to 89.01%, 83.14%, and 79.67%, respectively, while the combined concentrate yield was 7.72%. Thus, the finer grinding condition delivered the highest reported recoveries, whereas the 70% condition provided a slightly coarser alternative with recoveries close to those obtained at 80%. Without grinding-energy or operating-cost measurements, an economic optimum cannot be demonstrated from these data alone. The manuscript also discusses staged addition of spindle oil, regrinding, and the possible inclusion of centrifugal gravity concentration. These process modifications are distinguished from the grinding-fineness comparison and should not be interpreted as verified improvements without matched experimental controls. The findings provide an experimental basis for comparing practical grinding targets for the investigated ore and identify the additional measurements required before final process optimization.
Geomagnetic exploration techniques largely determine the subsurface geometry and spatial distribution of rock magnetization and have been used to delineate the geometry and potential zones for economic mineralization. This study used outcrops and ground magnetic data collected over parts of Hawal Massif, northeastern Nigeria to determine the subsurface spatial distribution of rock magnetization and potential bearing zones for local mineralization. The geological investigation shows that the Hawal Massif is predominantly underlain by the Precambrian Basement rocks that include granites, gneisses and diorites. These rock units are largely affected by tensile and shear fractures. The latter largely trends in the NE-SW and NW-SE directions. The results also demonstrate that the geometry and potential targets for local mineralization consistently correlate with positive local maxima in total magnetic intensity (TMI) anomalies - those recording residual magnetic values between 180 nT and 350 nT. These zones of local total magnetic intensity (TMI) maxima occurred around Chicago, Jalingo Maiha and Dumo areas and thus represent potential target zones for local mineralization. Consequently, recognizing the effectiveness of ground magnetic data is crucial, as it provides information on the geometry and potential bearing zones for local mineralization, a parameter directly affecting selection of sites for detailed geological mapping, mineral resource assessment and mining activities.
This study investigates the feasibility of pre-concentrating lithium ore from the Udawa deposit using hydrocyclones as a pre-treatment method. The escalating demand for lithium, driven by its pivotal role in energy storage for electric vehicles, mobile devices, and renewable energy systems, makes the efficient extraction of this mineral essential. The Udawa deposit, located in Kaduna State, Nigeria, is rich in lithium-bearing minerals within rare-metal pegmatites. Traditional methods for processing lithium ore, such as flotation and gravity separation, are often energy-intensive and environmentally damaging. Hydrocyclones, gravity-based separators, present a promising solution for pre-concentration by efficiently removing gangue minerals and increasing the grade of lithium ore before further processing. The study focused on optimizing the use of hydrocyclones to separate gangue and improve the lithium concentration in the underflow fraction. Results showed that the hydrocyclone effectively upgraded the ore, increasing lithium oxide (Li2O) content from 3.03% in the feed to 4.2% in the underflow, while minimizing gangue in the overflow. The study also highlighted the potential of integrating hydrocyclone pre-concentration with flotation and magnetic separation to maximize lithium recovery. This approach not only reduces processing costs and energy consumption but also supports Nigeria’s economic diversification goals by promoting local mineral processing. The research recommends further optimization of operational parameters and the exploration of industrial-scale applications to improve the efficiency of lithium extraction and recovery from the Udawa pegmatite deposit.
The gemstone mining sector in Ethiopia's South Omo Zone is predominantly characterized by traditional, artisanal practices with minimal use of modern equipment and negligible integration into organized market structures. Despite the region’s abundance of valuable gemstone resources-including corundum (sapphire, ruby), beryl, and other semi-precious stones-especially in Hammer and Bena Tsemay woredas, the sector remains underdeveloped. Artisanal miners often operate with rudimentary tools, lacking technical training, access to finance, and support infrastructure such as transportation and water supply. The absence of geological surveys, reserve estimations, and standardized gemstone valuation exacerbates inefficiencies and limits market potential. Moreover, the lack of transparent benefit-sharing mechanisms and formal registration systems has led to widespread informal extraction and trade, reducing government and community revenues. The resulting information asymmetry creates tension between miners and exporters. Environmental and safety standards are largely unregulated, and institutional support is minimal. To address these challenges, this study recommends the implementation of structured interventions, including gemstone identification and valuation training, establishment of regional trading centers, promotion of public-private partnerships for value addition, and development of a transparent governance framework. Without strategic reform, the sector’s economic and developmental potential will remain untapped, risking unsustainable exploitation and limited local benefit.
