7th UMaT Biennial International Mining and Minerals Conference – Proceedings
Installed gasifier plants in Ghana are mostly imported with reported technical challenges restricting the optimal use of the technology. A comprehensive methodological approach taken into account concerns of end users, optimal technical parameters and harnessing the advantages in the various gasifier configurations are proposed in this study to design an optimal gasifier for crop residues. Eleven technical/economic user requirements based on the existing challenges of gasification system in Ghana were identified. The Analytical Hierarchy Process (AHP) was used to determine the weight of each user requirement. Thirteen engineering parameters for optimal design of gasifier were identified. A Quality Function Deployment (QFD)/Multi Criteria Decision Making techniques (MCDM) methodological approach for optimal design of the gasifier reactor using the user requirement, engineering parameters and seven gasifier configuration was developed. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was used to rank the various gasifier types based on the thirteen technical parameters and corresponding weights as determined from the QFD. The engineering parameters were further categorised under four sections and the best gasifier configurations under each category were determined using TOPSIS. The base case design was modified based on the best gasifier configurations under each category. The characteristic of five crop residues and consideration of a 10-kW engine system for electricity generation was used to size and designed the gasifier reactor. A 45-kW semi-batch stratified Downdraft (SD) Gasifier with internal diameter and height of 0.36 m and 1.7 m respectively was designed. An average fuel consumption and airflow rate flow rate for optimal gasification of 23 kg/hr, and 26.31 m3/hr were determined respectively. The optimal gasifier designed from modification of the base case designed (SD) consist of a screw auger system, extended ash collection bunker, gas recirculation combustion unit which solves the shortfalls of SD and embed the characteristics of the best gasifier configurations under each category.
Keywords: Gasifiers, Reactor, Crop residues, MCDM, AHP, TOPSIS, QFD Download Full PaperAbstract Single toggle jaw crushers are mainly used as primary crushers in mining and allied industries. Though very productive and energy efficient, this type of crusher is faced with very high jaw liner wear rate. A typical jaw liner has been estimated to have a life span of only three months of continuous usage. The high wear rate has been attributed to the high level of sliding interaction that exists between the jaw liners and the crushed material. Researchers have tried to reduce the wear rate by mainly considering it as material property. The geometric properties of the crusher which equally increase wear of the jaw liners have not been given much attention. This research, therefore, seeks to modify the current design of the single toggle jaw crusher to enhance the wear resistibility of the jaw liners. The paper presents an improved design of Single Toggle Jaw Crusher with the aim of mechanically reducing the liner wear rate. The new design has a passive movable fixed jaw that is allowed to displace vertically to reduce sliding of the material on the surface of the jaw liners during the interaction of the crushed material and the liners. A conceptual design of the new crusher was modelled using Autodesk inventor. Finite element analysis was conducted on the crusher to determine the critical stress locations and displacements in the fixed jaw assembly. The results revealed that a maximum Von Mises stress of 18.398 MPa developed at the top inner corners of the main frame. The stress amount was within safe values as the material used has a yield strength of 207 MPa. A maximum displacement of 0.017 mm occurred at the top middle section of the sliding plate. Fabrication using locally available materials has been completed. A test run of the new crusher has been done successfully. Evaluation of the new design is ongoing.
Keywords: Liner, Jaw Crusher, Wear, Improvement, Modelling, Design Download Full PaperA planning scheme is one of the most used legal documents to manage and outlines how land is demarcated. Land is very significant to socio-economic development since most human activities occur on land. The planning scheme usually indicates sections of land for different purposes such as residential, industrial, recreational, and civic purposes. In most communities, however, development precedes planning which is the main cause of improper land use and planning. The leasing of lands is handled mostly by chiefs and local authorities leading to the indiscriminate sale of land without considering proposed planning schemes. This paper examines improper planning and land use at Akyempim, a community in Tarkwa-Nsuaem Municipality in the Western Region of Ghana. High-resolution images and the proposed planning scheme of Akyempim were used to assess the disparity between the proposed planning scheme vis-a-vis actual development. The orthophoto of the study area and the proposed planning scheme were superimposed to detect areas that do not conform to the planning scheme. It was evident that road networks and lanes had been diverted from their original course. This paper found that all buffer zones as per the planning scheme had been encroached upon and the site proposed for a school has been turned into a residential facility. A proposed Day Nursery School site has also been used by a developer for fish farming. The Akyem road linking the Tarkwa-Takoradi highway compared to the planning scheme has been diverted from its course and also heavily encroached upon. This paper concludes that most developments are not in conformity with the planning scheme. The physical planning department and the Lands Commission should work closely with chiefs and local authorities to curtail the indiscriminate sale of land and to comply with planning schemes since indiscriminate land use can have disastrous outcomes.
Keywords: Akyempim, Planning Scheme, Unmanned Aerial Vehicle, orthophoto Download FullpaperAbstract Due to the increasing use of portable electrical and electronic gadgets as well as hybrid electric vehicles, there is a high demand for materials that can be utilized in producing high energy density and low self-discharge batteries. Thus, lithium is in high demand as it meets these requirements. Spodumene is the core lithium-bearing mineral and it is generally associated with pegmatites, which are currently being explored due to the high lithium content. In Ghana, pegmatites that contain spodoumene occur in several places including Saltpond. Extraction of lithium from minerals and clays can be expensive and energy-intensive. Thus, to meet the rising demand for the metal, it is imperative to develop processes that are cheap and environmentally friendly. This study considered the extraction of lithium from Saltpond pegmatites using seawater as a lixiviant. Lixiviation studies were carried out for 6 hours at a chloride concentration of 10.9 ppm, pulp densities between 20% and 50% and grind size from 80% passing 75 µm to 212 µm. Lithium could be leached from pegmatite using seawater and recoveries increased with decreasing grind size and at higher pulp density. Maximum lithium recovery (75.31%) was achieved after 6 hours of leaching, P80 of 75 µm and pulp density of 50%.
Keywords: Pegmatites, Spodumene, Leaching, Seawater, Pulp density.
Download Full PaperThe Nigerian mining industry is currently being rocked by internal conflicts with criminal elements both within and outside the country penetrating artisanal mining sites with the intent of intercepting their operations and stealing extracted mineral ores. These incessant incursions into mine sites by the invaders mostly result in heavy human casualties and huge economic losses. In this paper, persistent issues of insecurity and artisanal mining across Nigeria have been examined. Primary data collected through field studies, administered questionnaires and oral interview, and secondary data sourced from literature review were used to assess the effect of insecurity on mineral production. The processed, interpreted and analysed data were then subjected to Microsoft Excel for further analysis. Sponsorship of illegal mining has been traced to have the same root with funding of banditry (terrorism) and cattle rustling in North-western Nigerian States. About 80% of artisanal mining activities in this geopolitical zone are illegal, while over 5,000 people have been killed in Zamfara State alone since 2014 when the mining-related violent crimes had been on the increase. The sponsors of these atrocities have been identified to include politicians who have huge mining stakes in their communities and dictate the pace with their wealth. Thus, armed banditry and smuggling of unprocessed minerals have reduced informal mineral production in the country to insignificant figures. Hence, the paper identifies amendment of the current Mining Act to decentralise the ownership and control of mineral resources to the State Level rather than saddling such with the Federal Government alone, exploring robust diplomatic channels with the neighbouring countries to curb the involvement of foreign nationals in illegal mining and other forms of criminality, engaging the mining professionals in critical sectors of the economy and initiating community policing through responsible traditional leadership as panaceas for sustainable mineral production in the country.
Keywords: Insecurity; artisanal mining; banditry; kidnapping; mineral production. Download Full PaperAbstract This research seeks to examine the effect of powder factor variability on granite productivity at Tutu Quarry in Kujama, Kaduna State, North-central Nigeria. Schmidt hammer was used for the in-situ determination of rock hardness. Uniaxial compressive strength (UCS) of in situ rock was estimated from the values obtained from the Schmidt hammer rebound hardness test and its density was determined from laboratory test. After preliminary field studies, ten (10) blasts with varied powder factors were studied and their overall effects on granite productivity examined. Three (3) rock samples were carefully collected from the quarry and subjected to laboratory analysis for UCS and bulk density tests. With spacing and burden kept between 1.7 m and 1.8 m and stemming height also varied between 1.5 m and 2 m, charge columns of between 4.5 m to 6.5 m were maintained, while number of holes drilled per blast was between 64 and 88. Results obtained from the test revealed that the average UCS of the granite samples was 80.67 MN/m2 while the average bulk density was 2465.67 kg/m3. Therefore, considering ten (10) blasts with varied powder factors of between 0.77 kg/m3 and 0.97 kg/m3, total volumes of rock of between 1,109.76 m3 and 2,280.96 m3 was produced. Hence, varied powder factors have been found to have huge effects on rock fragmentation sizes and by extension, granite productivity.
Keywords: Powder factor variability, explosives, granite productivity, blasting. Download Full PaperAbstract Globally, an estimated 1.1 billion printer toner cartridges are sold each year with over 500 million of these ending up in landfills. In this work the potential for recovering iron oxide and carbonaceous materials from waste toner powder is demonstrated through the iron oxide-carbon composite pellet approach. Composite pellets of low-grade nonmagnetic iron ore (sourced from Pudo in the Upper West Region of Ghana) were formed with measured samples of waste toner powder obtained from printing presses on UMaT campus. Reduction studies were then conducted on the cured, sufficiently dry pellets in a domestic microwave oven (Pioneer, Model PM-25 L, 1000 W, 2.45 GHz). Reaction products were characterised by SEM/EDS and XRD analyses and the extent of reduction after 40 min was determined. XRD, XRF and SEM/EDS analyses showed that the waste toner ore consists of spherical samples of magnetite (assaying ~34.2 wt % Fe2O3) and excess carbonaceous materials (assaying ~ 58.75 wt.% to 70.19 wt.% C) for complete reduction of the ore-toner composite pellet. Ashed samples of the waste toner samples revealed iron oxide contents ranging from 80.1 wt% to 84.4 wt% Fe2O3. Further, mass balance on the total removable oxygen from the composite pellet and the reduced metal showed that up to 97.6 wt% of the iron could be recovered from the ore-toner mixture. Waste toner powder is therefore a potential source of iron oxide and carbon for iron and steelmaking technologies. Keywords: Reduction; Pudo Iron Ore; Toner Powder; Extent of Reduction
Download Full PaperGlobally, billions of worn out leather shoes and other leather materials are indiscriminately discarded by the Security forces, Mining companies, etc., at landfill sites or in make-shift dug dumps, with no proven avenues for recycling. Leather materials contain Cr2O3 through the process of tanning; landfilling of worn out leather materials and the other processes mentioned above can easily result in the oxidation of insoluble Cr2O3 (Cr3+) to soluble CrO42-(Cr6+aq), a potential carcinogen. In this investigation, pulverised samples of green ash were produced from crumbed samples of waste leather shoes through an ashing process that lasted for 60 min. Samples of the green ash were then characterised by XRF and XRD; this was followed by high temperature (~1600 °C) reduction studies of composite pellets of ash containing blends of high density polyethylene (HDPE) and charred palm kernel shell (PKS) as reductant in a laboratory horizontal tube furnace. From the results, it was observed that waste leather shoes generated approximately 14.0 wt% ash when ashed completely in air and that the generated ash is a rich source of Cr2O3, with the Cr2O3 concentration ranging from ~47.44 wt% to ~55.44 wt%, depending on the type of leather shoe ashed. Further, the reduction runs revealed that the offgas consists predominantly of CO, with extent of reduction in excess of 99% attained within 40 min. The observed composition range of Cr2O3 in the generated ash makes waste leather shoes potential resource for the Ferrochromium industry.
Keywords: Waste leather shoe; Cr2O3; CrO42-; Green ash; Extent of Reduction Download Full PaperGlobally, as at the end of December 2021, COVID-19 had accounted for over 285 million cases and 5.42 million deaths. In addition to this scary statistics, the pandemic has left in its wake a new category of hazardous waste stream, face masks (FM). This research work investigated the potential for generating Diesel range liquid fuel from discarded FMs using a charred palm kernel shell fired reactor-blower assembly in the temperature range 400 – 450 °C. Samples of discarded FMs (collected from a household in Tarkwa) weighing approximately 2.0 kg were fed from the top of a stainless steel reactor and pyrolysed continuously until gas flow into the condenser ceased. Gases leaving the reactor were condensed in a primary reactor and the condensed fuel was trapped in a plastic container, weighed and characterised by FTIR and GC-MS analyses. The solid by-product (tar) was characterised by FTIR analysis to assess its reuse or safety disposal into the environment. The results indicate that samples of liquid fuel can be produced from discarded FMs with a yield of up to 0.80 litres/kg of pyrolysed material. Results from the characterisation by FTIR and GC-MS analyses showed that the liquid fuel consists primarily of a mixture of aromatic and aliphatic hydrocarbons in the C9-C18 range, along with significant amounts of cycloalkanes. Physical examination and FTIR analyses of the solid by-product revealed a benign product suitable for use as a high temperature gas sealant. It was concluded that liquid fuel production by pyrolysis could offer a sustainable route for the disposal of hazardous end-of-life face masks.
Keywords: Liquid Fuel; Face Mask; Pyrolysis; GC-MS Analysis; FTIR Analysis. Download Full PaperThe Esaase Deposit of the Asanko Gold Mine Ltd (AGM) contains a system of epigenetic gold-related quartz veins hosted by tightly folded and foliated (meta) sedimentary rocks. The gold mineralisation is associated with disseminated sulphide minerals in the quartz-carbonate veins and within the alteration zones of the host (meta) sedimentary rocks. AGM employs a combination of gravity concentration and Carbon-In-Leach (CIL) methods to recover its gold and this has resulted in a recovery rate that ranges from 81.3% to 94.1%. The high recovery rate (>90%) suggests that the gold is free and therefore not locked up in the sulphides that are associated with the mineralisation. However, the recovery rate drops from 94.1 to 81.3% even when the samples contain high amount of sulphides. Since the presence of sulphides in altered rock is one major indicator of gold mineralisation, this research was conducted to determine the ore textural relationship between gold and sulphides and the implication of the ore textures on the current gold recovery methods employed on the deposit. Block (polished) sections were prepared from samples from the ore zones: Transition and Cobra. Petrographic studies were conducted on the samples using the Leica DM2700P petrographic microscope. These studies revealed that the low gold recoveries may be attributed to gold occurrence as inclusions in the sulphides, which is typical for refractory ores, and thus, making it difficult to be extracted by the current method employed at Asanko. Therefore, AGM may have to consider the economics of employing a combination of other methods to liberate the refractory gold and possibly, result in optimum recovery. Keywords: ore textures, gold recovery, refractory ore, Ghana, Asanko.
Download Full PaperHaul truck tyre consumption forms one of the most significant direct cost centres in most surface mining operations. The need to achieve and maintain optimum tyre performance to prolong tyre service life at the mine site is, therefore, very crucial for a sustainable mining operation. To optimise tyre performance and hence reduce tyre usage cost, mine operators need to record, maintain and critically analyze reliable data on tyre failures in order to identify their root-causes, so as to find antidotes to them, especially with regards to premature failures, In this paper, log dispersion plot was used to analyze 425 datasets on prematurely failed tyres over a period of 30 months at the Edikan Gold Mine in Ghana. The failure types were categorized into acute, chronic and acute & chronic. This enabled failure types, key to optimising tyre performance to be identified and prioritized to ensure prolonged tyre service life.
Keywords: Tyre life, tyre failure types, premature tyre failure
Download full PaperBiomass carbonization, particularly (charcoal making), serves as a source of livelihood in rural areas, especially in developing countries. Charcoal is also used as a reducing agent during the pyro-metallurgical extraction of iron from its ores. In the conventional method of biomass carbonization; the release of lots of smoke that contains harmful gases such as carbon monoxide is not environmentally friendly. Globally, Scientists are making efforts to reduce the bad effects of climate change mostly caused by harmful gases emitted during numerous anthropologic activities. This paper presents a design for the smokeless carbonization of biomass. In most conventional methods of carbonization, the reactor stands upwards, leading to the emission of lots of harmful smoke. However, the design being presented provides smokeless biomass carbonization. In this design, the reactor is positioned upside down to allow a downdraught of emissions from the pyrolysis of biomass in the reactor. Thus, smoke and other emissions from the reactor have a longer travel distance within the furnace and are therefore combusted before emerging into the atmosphere. The efficiency of the designed smokeless reactor was compared with that of a conventional method during carbonization of selected biomass such as palm kernel shells, coconut husks, and paper. The results of the investigations showed that in the conventional reactor method, lots of smoke was produced as compared to the smokeless reactor method. The yields of char from each method were compared. The upright method for producing biochar from the palm kernel shells, coconut husks, and paper produced yields of 43.72%, 37.16%, and 9% respectively. Carbonization was possibly incomplete. In the smokeless method, the yields of char from the palm kernel shells, coconut husks, and paper were 31.6%, 22.20%, and 7.8 % respectively and this process, more importantly, was smokeless. Keywords: Pyrolysis, Design, Smokeless, Carbonization, Biomass
Download Full PaperSurface mining blasting techniques may be viewed as the most inexpensive technology used for fragmenting rocks masses compared to underground mining blasting techniques. About 20-30% of the energy used is utilised for rock fragmentation and displacement, while the remainder is lost as ground vibrations, air blast, noise, and fly rocks of which are all dangerous as they pose hazard to the environment. To minimise these effects of blasting, there is the need to use an appropriate stemming height to achieve the purpose of minimising the effects of blasts. This research seeks to introduce the use of a laser distance meter in the measurement of stemming height which can be used as an alternative to the traditional method of measuring the stemming height with tape measures having counterweights tied at its end. The method used involved reviewing relevant literature, data collection from the Gold Fields Ghana Limited, Tarkwa mine with the use of both the proposed device and the tape measure and analysing of the data obtained from the field. Analysis of the data showed a difference which averaged at about 0.05m per the data collected. The use of the proposed device gave readings that were of higher accuracy with their three decimal point values as compared to the tape measure’s readings. The use of the device comes with coupled advantages of simplicity and ease of use as personnel do not need training to use the device. The results obtained showed that the device can be used as an alternative to the use of the tape measure. The frequent need to replace worn-out hand gloves and tape measures and their repercussive accumulative cost would be lower if a laser distance sensor is used instead with a relatively high initial purchase cost.
Keywords: Blasting, Stemming, Stemming Height, Tape Measure, Laser Distance Sensor. Download Full paperThe study purposed to analyse the role human resource (HR) audit plays in Gold Fields Ghana Limited (GFGL) and how it affects the overall performance of the organisation. The study used descriptive research design and employed both qualitative and quantitative research tools to achieve the aim of the study. Primary data was the main source for this research. Questionnaire was used for the data collection from forty-three (43) respondents. The data collected was analysed using STATA statistical software v13. The findings of the study revealed that HR Audit contributes immensely to the performance of the organisation both for employee development and organisational development. The findings of the study also found leadership competencies, training and development, employee engagement and satisfaction as the main factors that contributed to the overall organisational performance of GFGL. The findings of the study further concluded that HR Audit prompted the frequent evaluation and analysis of the various policies and processes that guide the efficient human resource management in the work setting. It is also instructive to note that the HR Audit goes a long way in impacting the performance of GFGL positively and guiding senior management in correcting areas with HR operational inefficiencies. The results of the study recommend HR policies be targeted at maximizing and increasing efficiency to continually achieve optimum performance in the organisation. It further recommended frequent relevant training and development programmes for management and staff to enable them have firm grasp of the HR audit concepts and practices which can potentially influence leadership competencies as well as work satisfaction. Finally, it is recommended that further research in other mining companies be replicated to assess HR audit practices and their impact on performance to increase the scope for generalisation.
Keywords: HR Audit, impact, organisational performance. Download Full PaperIndustrialisation has led to the release of heavy metals such as lead into the environment. Lead can cause miscarriage, low sperm count, kidney, liver and brain damage. Human beings can be intoxicated with lead when they consume water and food such as cocoyam, contaminated with lead. Cocoyam has the potential to sorb Pb into its leaves, stem and root making it dangerous for the millions of lives that depend on cocoyam plant as a source of food. To contribute to the awareness of Pb toxicity, this paper assessed the sorption ability and translocation of lead into the stem, leaves and root of cocoyam plant. Cocoyam plants were grown in soils with solutions having Pb concentrations of 10 ppm and 0 ppm for 14 days. Pb was translocated to the leaves and stem through the root in the control and the 10-ppm Pb-induced soil. The control experiment with an initial soil Pb concentration of 0.757 ppm had 0.088 ppm, 0.07 ppm, 0.053 ppm and 0 ppm of Pb in its leaves, stem, roots and soil respectively in 28 days. The order of increasing lead retention in the plant parts was leaves > root > stem. Absorbance of lead in solution reduced to < 0.001 at day 14. The highest lead sorption occurred at 32.78% in the leaves of the setup containing 10 ppm Pb, while the bioconcentration factor and translocation factor of the plant were 5.87 and 2.11 respectively. The findings from this study indicate that cocoyam plant found in Pb-contaminated soil are prone to contamination, and thus poses health threats. The ability of the edible parts of the cocoyam plant to retain its Pb after boiling, and become bioavailable to human beings should therefore be ascertained.
Keywords: Lead, Cocoyam Plant, Sorption, Bioconcentration Factor, Translocation Factor Download Full PaperThe Wa-Lawra greenstone belt is located in northwest Ghana and is largely dominated by Birimian metavolcanics, volcaniclastics, and metasediments. Previously, regolith materials such as laterites and soils from mixed sources were used to identify pathfinder elements of gold in the belt. However, in-situ laterites will better represent their underlying formations than transported laterites that may contain extraneous sources of element enrichment caused by pollution, which is unrelated to gold mineralization. In this study, petrographic studies of residual laterites and statistical analyses of trace element geochemical data of the residual laterites were performed to identify the pathfinder elements of gold in the Wa-Lawra greenstone belt. Six fresh residual laterite samples were used for the petrographic studies, which revealed the dominance of quartz, amphibole, clinopyroxene, hematite, goethite, magnetite, sphalerite, and pyrite. These minerals contribute Fe, S, Ca, Zn, and other elements to the laterites. The geochemical data of 12 residual laterite samples were used for statistical analysis. P-P plots revealed deviations from the normal distribution and outliers in the dataset. Spearman’s correlation revealed that Cu, Ag As, Pb, Fe, and S have a moderate-strong positive correlation with Au. Hierarchical cluster analysis revealed that there are 3 multi-element associations; a) Fe, Pb, Mn, S, Co, Au, Cr, Cu, Ni, Ag; b) Ti, Zr, Sr, Ca, and c) Rb, Y, Zn, As. Factor analysis shows that the occurrence of Pb, Cu, Ag, and As is directly related to the occurrence of Au. Thus, the best multi-element association of Au for exploration purposes is Pb, Cu, Ag, and As, similar to the previous findings. Single and multi-element anomaly mapping revealed that geochemical anomalies involving these elements are mainly found around the northern and southern parts of the study area. The results of this study confirm what has been reported by the previous studies.
Keywords: laterites, geochemical anomaly, gold, multivariate statistical analysis, petrography Download Full PaperBriquetting is a method of mechanically compacting bulky materials to increase their densities. Imported briquette machines are expensive, need technical expertise, lack spare parts, and require electricity for operation. A hydraulic-operated double mould briquetting machine was successfully developed in this study. The biomass briquetting machine is designed for small-scale biomass briquette manufacturing. A 2-ton-sized hydraulic jack is used to provide two equal but opposite pressures for the production of briquettes from 2 mould boxes. The developed briquette machine was used in the production of sawdust briquettes which were subjected to shatter index and water resistance tests. The physical properties of the briquettes produced were determined at varying biomass-binder ratios of 100:15 and 100:25 by weight using cassava starch as the binding agent. The developed briquette machine consists of two mould boxes positioned vertically opposite to each other at the top and the bottom. Each mould box has 16 set of pistons which aid in the compaction process giving the machine the capacity to produce 32 briquettes at a time. The shatter index and water resistance capacity of the produced briquettes were determined to be 98.6 % and 95.75 % respectively and were attained at an optimum biomass-binder ratio of 100:25. The analysis or tests performed on the briquette from saw dust demonstrate that the machine's performance is good.
Keywords: Briquettes, sawdust, hydraulic jack, piston Download Full PaperPlastics have become the most abundantly generated solid wastes in the last three decades and have become an environmental nuisance. In light of this, industry players have tried to adopt models, techniques and mechanisms to harness their non-biodegradable properties and to reuse them for the benefit of society. This paper focuses on the impact that Low Density Poly-ethylene (LDPE) microfiber has on the geotechnical and hydraulic properties of lateritic soil from Heaven Nkwanta in the Pres-tea-Huni Valley Municipality of Western Region, Ghana. Particle Size Analysis, Specific Gravity Test, Atterberg Limit Test, Proctor Compaction Test, Direct Shear Test and Constant Head Permeability Test were conducted on the lateritic soil samples to assess the behaviour when mixed with varying concentrations of the Microfiber Plastics (˂ 600 µm). Specific Gravity results obtained for the MFP was 0.545, while 2.47 to 1.15 were recorded for MFP at 0% to MFP at 50%. The laterite had a well-graded silty-gravel texture with intermediate plasticity of 17.76 %. Upon adding Microfiber Plastic (MFP), the plasticity of the laterite decreased progressively to 9.88 % at 30 % MFP. Shrinkage reduced from 12.06 % at 0 % MFP consistently to 8.57 % at 30 % MFP, increasing to 9.43 % at 50 % MFP. The Maximum Dry Density (MDD) decreased gradually from 2.19 g/cm3 at 0 % MFP to 1.35 g/cm3 at 40 % MFP. Optimum Moisture Content (OMC) increased from 10.38 % at 0 % MFP to 14.06 % at 30 % MFP. Frictional angles increased from 31.55 ° at 0 % MFP to 48.54 ° at 30 % MFP. The hydraulic conductivity de-creased progressively from 0.078 cm/s at 0 % MFP to 0.004 cm/s at 40 % MFP. The highest cohesion was obtained to be 7.98 kPa at 20 % MFP with the lowest being 4.14 kPa at 10 % MFP. It was observed that the addition of Microfiber Plastic to the lateritic soil improved upon its strength and index properties. The optimal reinforcement benefits were observed at 30 % MFP addition to the laterite.
Keywords: Microfibre Plastic Waste, Lateritic Soils, Geotechnical Properties Download Full PaperRecently, the flotation of major rare earth elements (REE) minerals including bastnasite, monazite, and xenotime has been attracting high level of attention. Anionic collectors such as oleates and hydroxamates have been widely used in the flotation of valuable REE minerals. One of the key gangue minerals in REE deposits is kaolinite. Although there has already been previous research investigating kaolinite flotation from bauxite, there is limited data in the literature focused on flotation of REE minerals from kaolinite rich deposits. Since minerals in different ores may demonstrate differing flotation response, it is imperative to investigate their respective flotation behaviours. This work presents a fundamental study involving zeta potential and microflotation experiments with pure samples of monazite and kaolinite using sodium oleate as a collector. In this study, the floatability of monazite is high at pH 5–9, where kaolinite had comparatively lower flotation response. Complementary zeta potential measurements confirmed that sodium oleate interacts with REE ions on monazite surface resulting in the excellent flotation response, whereas minimal interaction was observed for kaolinite, hence the poor performance.
Keywords: monazite, flotation, kaolinite, sodium oleate, zeta potential Download Full PaperAbstract This paper discusses the combined use of the ‘DRASTIC’ ground vulnerability modelling technique, the analytical hierarchy process (AHP), Geographic Information System (GIS), GPS and Remote Sensing to collect, process, analyse and evaluate the relative and combined influences of the risk factors involved and to map the susceptible areas of land subsidence in the Tarkwa-Nsuaem Municipality of Ghana. The relevant risk factors identified in the study area include high rainfall, drainage density, elevation and slope, soil, land use/land cover (LULC), depth to ground water, proximity to mine sites, geology and hydrogeology. The relative influence of each of the factors were estimated and combined to generate land subsidence vulnerability maps for the study area with five different classes, namely very low, low, moderate, high and very high vulnerability zones. The vulnerability map indicates that a significant proportion (about 17%) of TNMA lies within the high and very high vulnerability zones and these occur mainly at the north-western parts of the area. The results of the current studies may be used as preliminary references or criteria to check the suitability of proposed land uses or development projects in terms of subsidence risk in the study area. It is recommended that land subsidence vulnerability analysis should be integrated in existing land use and resource development planning and approval processes in TNMA and similar mining areas as discussed and demonstrated in the study.
Keywords: Land subsidence, Vulnerability Mapping, Mining Areas, Land use/development Planning, AHP Download Full PaperAbstract
This paper examines improper planning and land use at Akyempim, a community in Tarkwa-Nsuaem Municipality in the Western Region of Ghana. High-resolution images and the proposed planning scheme of Akyempim were used to assess the disparity between the proposed planning scheme vis-a-vis actual development. The orthophoto of the study area and the proposed planning scheme were superimposed to detect areas that do not conform to the planning scheme. It was evident that road networks and lanes had been diverted from their original course. This paper found that all buffer zones as per the planning scheme had been encroached upon and the site proposed for a school has been turned into a residential facility. A proposed Day Nursery School site has also been used by a developer for fish farming. The Akyem road linking the Tarkwa-Takoradi highway compared to the planning scheme has been diverted from its course and also heavily encroached upon. This paper concludes that most developments are not in conformity with the planning scheme. The physical planning department and the Lands Commission should work closely with chiefs and local authorities to curtail the indiscriminate sale of land and to comply with planning schemes since indiscriminate land use can have disastrous outcomes.
Keywords: Akyempim, Planning Scheme, Unmanned Aerial Vehicle, orthophoto Download Full PaperAbstract The on-going drive and demand for green-energy revolution has reflected in attendant increase in the demand for strategic and critical metals and elements such as lithium, tantalum, cobalt, and rare earth elements. Specifically, the projected demands for portable electric devices, plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and electric vehicles (EVs) have highlighted the probable increasing demand for lithium-ion batteries (LIBs). The use of lithium in the production of LIBs has earned it a strategic label in most technologically advanced countries. It has been demonstrated in the literature that lithium extraction from differing resources is based on the generic mineral processing and extractive metallurgical techniques and resource type. Over the years, significant number of flowsheets have been proposed through numerous metallurgical testing programmes, with the overall aim of extracting lithium from both primary and secondary resources. Process mineralogy plays a key role in defining the properties of ores, identifying key opportunities, and ascertaining potential challenges associated with the extraction of lithium. To this end, literature has underscored the importance of mineralogical tools such X-ray diffraction, Quantitative Evaluation of Minerals by Scanning Electron Microscopy, automated scanning electron microscopy, and electron probe microanalysis on the characterisation of ores and separation products, which is crucial in selecting unit operations and subsequent process optimisation campaigns. With Ghana and other developing countries continue to discover lithium deposits, this paper seeks to provide examples of processing opportunities and challenges associated with lithium recovery processes determined through process mineralogical studies, with the overall aim of stimulating ideas and bridging existing knowledge gap in developing countries. Overall, the learnings from this review could serve as a source of inspiration to explore different avenues for sustainable lithium recovery from ores and secondary resources.
Keywords: Critical minerals, green energy, Lithium, Lithium-ion batteries, Process Mineralogy, QEMSCAN Download Full PaperAbstract Due to the increasing use of portable electrical and electronic gadgets as well as hybrid electric vehicles, there is a high demand for materials that can be utilized in producing high energy density and low self-discharge batteries. Thus, lithium is in high demand as it meets these requirements. Spodumene is the core lithium-bearing mineral and it is generally associated with pegmatites, which are currently being explored due to the high lithium content. In Ghana, pegmatites that contain spodoumene occur in several places including Saltpond. Extraction of lithium from minerals and clays can be expensive and energy-intensive. Thus, to meet the rising demand for the metal, it is imperative to develop processes that are cheap and environmentally friendly. This study considered the extraction of lithium from Saltpond pegmatites using seawater as a lixiviant. Lixiviation studies were carried out for 6 hours at a chloride concentration of 10.9 ppm, pulp densities between 20% and 50% and grind size from 80% passing 75 µm to 212 µm. Lithium could be leached from pegmatite using seawater and recoveries increased with decreasing grind size and at higher pulp density. Maximum lithium recovery (75.31%) was achieved after 6 hours of leaching, P80 of 75 µm and pulp density of 50%.
Keywords: Pegmatites, Spodumene, Leaching, Seawater, Pulp density. Download Full PaperIn this work, we investigate the feasibility of using denser bed materials for fluidization and their influence on fluidized bed cell parameters. Quartz in three size ranges (- 1180 + 850 μm, - 850 + 425 μm, - 425 + 250 μm) and aluminum oxide were used as bed materials for fluidization experiments. The existence of some upper size limit for fluidization was confirmed by attempting fluidization in the HydroFloat cell using the stated bed materials at a water rate of 1.08 cm/s, airflow rate of 0.04 cm/s, and a target bed level of 14 cm. The influence of bed material mass and density on bed level was also studied by running the fluidized bed cell with - 425 + 250 μm quartz and aluminum oxide at a water rate of 1.19 cm/s, airflow rate of 0.04 cm/s, and a target bed level of 15 cm. The potential influence of bed material on bubble size was investigated by analyzing images of the cell during experiments. Our results confirm the existence of some upper size limit beyond which fluidization is unfeasible i.e., the bed becomes packed and bubble dissipation is limited. However, using a denser bed material at a finer size remains a feasible strategy for increasing the apparent density of the bed at identical bed characteristics. Frother concentration is the dominant factor influencing bubble size with bed material showing a marginal influence on bubble size.
Keywords: Coarse particle flotation, fluidized bed cell, detachment, bed material Download Full PaperIn this work, we investigate potential limitations to coarse particle flotation due to the finiteness of bubble surface area and the need for a bubble-particle aggregate to have a lower density than the fluid medium for particle collection to be possible. We derived a simple mathematical model which assumes perfect collection efficiency (E = 1) and spherical particles. The model was simulated using a python script and the data obtained is as presented in this paper. Our results indicate that the maximum number of particles attached to a bubble surface depends not only on bubble size but also on fluid density and particle density, especially at extreme coarse sizes. However, this does not necessarily lead to higher particle loads per bubble in terms of mass. Whiles increased fluid density generally increases the maximum bubble load, this increase is not monotonous and may not influence performance within some size ranges.
Keywords: Bubble size, Particle size, Coarse particle flotation, Density Download Full PaperEuler deconvolution is a useful tool for providing initial estimates of the locations and depths of magnetic and gravity sources. In this study, Euler deconvolution was applied to gravity geophysical data from the Tarkwa-Nsuaem Municipality, Ghana to interpret the structures present in the area. The Euler deconvolution method was applied to the residual bouguer map produced using the Kriging method. In addition, other filters including the derivative of the gravity data along the x, y and z directions were employed for the proper delineation of the locations of the various anomalies observed. The surface elevation of the study area varies from -12 .7 m at the sea in the southern part, to 270.6 m at the highest point in the northern part. It is observed that the basin (Volta Basin) to the south also accommodates some ridges, which appear elongated with a high elevation rise of about 134 m, while the upper terrain is associated with several north-south trending ridges with the highest elevation rise of 270.6 m. Euler solutions with different structural indices depicting specific geologic models were obtained from the Euler analysis carried out on the gridded residual data in order to identify the type of structures present in the study area. The best geologic model was derived using the structural indices of 0.5 and 1.0, which are diagnostic of the dyke structures and are significant to mineralisation of the area. The Euler solution revealed a series of dyke-like structures at a depth of 55 to 75 km across the study area. It was discovered in many parts of the study area that lack of appreciable density variation has led to the production of few solutions from the data.
Keywords: Euler deconvolution, kriging, gravity data, structures, bouguer anomaly, Tarkwa-Nsuaem Municipality Download Full PaperIn the analysis and modelling of hydrocarbon reservoirs, understanding initial fluid saturation is critical. The original oil in place (STOIIP) in a field is determined by the initial water saturation (Swi) distribution, which has an impact on dynamic modelling and reserve estimation. The primary reservoir in the Jubilee Field, one of the most productive sites in the Deep Tano contract area, is Turonian sandstone. Early water breakthroughs, among other factors, contributed to a decrease in production predictions in the field. To account for this issue, a detailed estimation of water saturation in a pore facies framework for the Turonian sandstone reservoir was performed. Through detailed petrographic analysis of the studied interval, the reservoir facies and types of pores in the Turonian reservoir system were defined. To assess the pore geometry, the reservoir rocks were classified using various rock typing indices. To determine accurate water saturation, saturation height modeling was performed using capillary pressure data and the Leverett J-Function. In general, diagenetic changes such as quartz overgrowth and calcite cementation reduce the primary reservoir potential of the Turonian reservoir. Capillary pressure data from each pore facies defined by the Flow zone indicator (FZI) method, were averaged to model initial water saturation, and saturation prediction was performed above the free water leg using the J-Function. Attempts to determine accurate water saturation values, particularly in transition zones, have met with limited success; however, this research’s findings can be used to model water saturation using capillary pressure data with a high degree of certainty.
Keywords: Rock typing, Saturation Height, Jubilee Field, Flow zone Indicator Download Full PaperThe toxicity of cadmium (Cd2+) as heavy metal in certain forms and concentrations has drawn attention on various proposed methods to treat cadmium-contaminated solutions. The biological method has been of interest lately due to its environmental friendliness, cost-effectiveness and low energy consumption. This paper, therefore, reports the findings obtained from treating cadmium-contaminated solutions using white-rot fungi Phanerochaete chrysosporium (Pc) and Trametes versicolor (Tv). The influence of biomass concentration (0.5-1 g), contact period (0-24 hrs), and initial Cd2+ solution concentration (50-200 ppm) on the fungi's Cd2+ biosorption ability was assessed. T. versicolor was found to have higher biosorption capacities with 45-80% of the Cd2+ removed, as against P. chrysosporium removing 25-55% Cd2+ from contaminated solution. The ability of both fungi to biosorp Cd2+ increased as the initial Cd2+ concentration increased. The kinetic rates were modelled using the pseudo-first-order and pseudo-second-order. The pseudo-second-order model was found to explain the adsorption kinetics most effectively for both T. versicolor and P. chrysosporium, indicating chemisorption. This study concludes that the white-rot fungi; P. chrysosporium and T. versicolor have the potential to be a low-cost and ecologically-friendly solution for the treatment of cadmium-contaminated water and wastewater.
Keywords: Phanerochaete chrysosporium, Trametes versicolor, Fungal Biomass, Cadmium, Concentration, Kinetic model Download Full PaperAbstract Many industrial processes require oxygen to achieve successful operations. In particular, there are a lot of processes and systems in hydrometallurgy where oxygen and its mass transfer kinetics play an essential role. Conventional gold cyanidation requires a sufficient supply of oxygen in order to improve the leaching kinetics. Ensuring consistent availability of oxygen in the leaching system can increase overall plant recovery and throughput. However, low solubility of oxygen in water presents a major challenge to hydrometallurgists. Moreover, the presence of sulphide minerals, electrolytes, as well as elevated temperatures and high pulp densities significantly reduce oxygen solubility, causing oxygen starvation in gold-leaching systems. Therefore, there is always a constant dosage of large volumes of oxygen through pipes into leaching tanks to meet dissolved oxygen demands. Yet, oxygen availability issues have continually persisted in gold-leaching systems worldwide. This paper will focus on current challenges and developments in gold cyanidation regarding oxygen requirement and availability, as well as oxygen dissolution rate enhancement topics that are generally of interest for gold leaching. It is expected that this review will inspire new research for efficient improvements in oxygen mass transfer for leaching systems.
Keywords: Gold, Cyanidation, Dissolved oxygen, Solubility, Oxygen mass transfer Download Full PaperWaste plastics are often indiscriminately disposed of in the local environment, including the sea, rivers, and stormwater drainage systems. The non-biodegradable waste plastics pollute the environment and disturb aquatic life with deleterious impact on flora and fauna over long-term. Globally, waste plastics have become a major environmental problem, especially for developing countries such as Ghana where there are limited recovery and recycling systems for such wastes. In recent years, however, high-density polyethylene (HDPE) plastic waste, fly ash and wood sawdust have all been used in the construction of bricks. This research sought to investigate the viability of two categories of waste plastics, polyethylene terephthalate (PET) and polystyrene (PS) incorporated into bricks as a building material. The aim is to produce lightweight-fired clay bricks using waste plastics and establish the appropriate clay-to-plastics ratio needed for the production of robust lightweight-fired clay bricks. Shredded plastics passing 250 µm sieve were mixed with fine clay and known amounts of water at different ratios and then moulded. The bricks were then fired at a temperature of about 210 ºC for 11 hours after which their compressive strengths were measured. The test analyses and results showed that lightweight bricks incorporated with plastics have higher compressive strength than conventional bricks, with the Clay: PS ratio of 1:1 displaying the highest compressive strength of 23.26 Mpa. The overall findings, therefore, demonstrate a beneficial waste plastics utilization, leading to environmental clean-up and production of robust lightweight blocks suitable for use as building materials in Ghana’s earthquake-prone areas.
Keywords: Plastics, Polystyrene, Polyethylene terephthalate, Clay and Bricks Download Full PaperBlasting is an important aspect of mining activities in which fragmentation is the key component that determines its efficiency. Blasting efficiency can be evaluated by different design methods. In this study, model was developed for predicting the blast efficiency using artificial neural network (ANN) method. Rock samples were collected from five different blasts of the study area and uniaxial compressive strength test was carried out on the samples in accordance with international standard. The average uniaxial compressive strength (UCS) obtained from the rock samples at ENL quarry is 151.64 MPa and the in-situ block size distribution obtained vary from 1 m2 to 3.08 m2. The determination of the fragment size is achieved using Split-Desktop image analysis. The average percentage value of F50 obtained from the Split-Desktop analyses is approximately 73.16 cm. The results obtained from the UCS, in-situ block size distribution, image analysis of the blasted rocks and the total charge were used to develop a model for prediction of blast efficiency. The prediction of the proposed model using artificial neural network (ANN) is compared with the measured efficiency of five different blasts and the value of R2 obtained is 0.9733. The findings showed that, the model can give a close prediction to the blasting efficiency in the study location. However, most models are usually site specific; hence, there may be differential performance of a model from location to location. It is therefore very imperative to assess the suitability of these models on the various sites.
Keywords: Granite Quarry, Blast Efficiency, ANN, Split-Desktop, AutoCAD. Download Full PaperThe ability to liberate valuable minerals from their host rocks is often achieved by several stages of size reduction. Grinding, the final stage of size reduction in minerals processing, is accomplished in the mining industry by employing steel balls as media. The quality of steel balls utilised in milling circuits have the potential to influence grinding efficiency, mill product quality and comminution circuit expenditure. The iron in the steel balls undergo several reactions and can dissolve via anodic reactions. In addition, the iron ions in solution produced by corrosion of forged steel balls form iron oxy-hydroxide species, thus consuming alkaline pH modifiers such as lime and may also coat precious mineral surfaces. These actions reduce mineral extraction efficiency. This article presents important factors to consider when selecting steel balls for the gold processing industry.
Keywords: Comminution, Hardness, Chemical Composition, Microstructure, Heat treatment. Download Full PaperOffshore technologies that help to separate oil, gas and water cost-effectively and efficiently have been the focus of the petroleum industry. Subsea processing has become a promising alternative for fields located in difficult settings due to flow assurance problems encountered by surface facilities. This paper seeks to model and construct a 3D subsea separation system coupled to a developed simulator software called Separator Processor (Se-Pro) to simulate and monitor the subsea fluid processing system. The developed computer application is used as a human-machine interface (HMI) to optimally control flow valves automatically or manually for the separated distribution of the fluids into various network facilities. The system may also maintain the safe operation of the processing facilities when unacceptable conditions occur by sounding an alarm to the operator. The subsea processing system on the seabed process segregates fluids into various pipelines for effective flow assurance problems minimization and the produced water is re-injected to improve the reservoir pressure decline. The Se-Pro simulator explores the use of process instrumentation and control principles to monitor a horizontal separator that separates oil, gas, water, and sand slurry. The results show a final rendered work of a subsea processing and production simulator that can work in both automatic and manual modes by adjusting flow control valves and level setpoints of the fluids during processing.
Keywords: Subsea Processing Simulator, Subsea Production System, Flow Assurance, Horizontal Separator, Human Machine Interface. Download Full PaperAside from the traditional statistical regression methods, there have been upsurges in using Artificial Intelligence (AI) techniques for predicting and analysing deformations on tunnels, dams, bridges and subways. This upsurge is linked to the self-adaptive nature of the AI to learn and generalize adequately on the dataset yielding good prediction results. However, little AI predictive analytic works on open pit wall deformation based on geodetic measurements have been done in the mining industry where prediction of active pit wall deformation, if not properly evaluated, can be catastrophic, leading to loss of life, property damage and eventual collapse of mining operations. This paper presents a comparative study of three supervised Artificial Neural Network (ANN) techniques - Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Backpropagation Neural Network (BPNN) - to predict mine pit wall deformation. The essence is to carefully choose the best AI technique, which is fault and noise tolerant and has a higher generalization ability. In addition, the selected AI method must correctly handle the non-linearity and high parallelism characteristics exhibited by the rock mass component of the monitored mine pit walls. A total of 709-time series datasets recorded in a daily mark interval were used to develop the ANN prediction models. The overall statistical analyses revealed that the RBFNN demonstrated good prediction power and outperformed the BPNN and GRNN by achieving the least MAPE, MSE, RMSE and the highest R and R2 values of 0.149009%, 0.035698 mm, 0.188939 mm, 0.999984 and 0.999968, respectively.
Keywords: : Mining, Mine Deformation, Artificial Intelligent, Artificial Neural Network, Time series. Download Full PaperGold beneficiation is capital intensive and has several challenges along the recovery route, thus, several methods are sought after to optimise the recovery. Process chemistry needs to be controlled, and pulp density is one of the key parameters that affect leaching and adsorption of gold onto activated carbon. The carbon needs to be distributed uniformly in the pulp to have effective contact with the pregnant solution. In cyanidation systems, pH modifiers such as lime, caustic soda and caustic potash are utilised to raise the pH above 10.5 to ensure the presence of free cyanide in solution for gold complexing. Even though lime is cheap and commonly used, it has the potential to influence rheology, thus affecting carbon movement and recovery relative to the other pH modifiers. In this paper, the rheological properties of slurries conditioned with lime, caustic soda and caustic potash at varying pulp densities of 45%, 50% and 55% were analysed to determine their effects on pulp density, slurry flow and gold recovery. In terms of fluid flow, the pulp conditioned with lime had the highest resistance to flow, and hence the poorest rheology. Recoveries for all the set-ups were observed to increase with decreasing pulp densities, with lime giving a relatively higher average recovery (93.30%) than caustic soda (91.02%) and caustic potash (90.82%). When the pulp densities were matched with specific gravities (S.G), the dispersion of activated carbon within the pulps of various densities indicated S.G. of 1.4 as the optimum for even distribution of carbon in the pulp.
Keywords: : pH Modifiers Pulp Density, Rheology, Cyanidation, Adsorption Download Full Paper Download Full PaperOne of the harmful leaching reagents typically found in metallurgical waste is cyanide (CN-). The damaging effects of cyanide, as well as its potential environmental consequences, make it a major environmental problem, necessitating the management of its toxicity prior to release into the environment. To avoid cyanide poisoning deaths, which occurs when cyanide attaches to critical iron-containing enzymes and prevents them from providing oxygen-rich blood to the tissues, industries that release cyanide-laden effluents are required to keep concentrations below 0.2 ppm. Chemical, physical, and biological approaches are utilised to reduce the amount of cyanide in wastewater. Biotechnological methods that use cyanotrophic bacteria to clean up cyanide-contaminated surroundings have received a lot of attention recently. The aim of this research is to see whether Phanerochaete chrysosporium and Trametes Vesicolor could decompose cyanide under various conditions, such as cyanide concentration, culture mass and time. A control experiment with a 100 ppm cyanide solution and no fungal interaction demonstrated that the cyanide in solution did not degrade naturally or self-degrade. When the effect of biomass (0.2 g, 0.4 g, and 0.6 g) on cyanide degradation was evaluated, the 0.6 g culture mass of P. Chrysosporium and T. Vesicolor resulted in the best myco-detoxification of 90 % and 85 %, respectively, after 48 hours.
Keywords: : : Cyanide wastewater, Cyanotrophic Organism, Detoxification, P. chrysosporium, T. Vesicolor Download Full PaperGeochemical and anthropogenic activities have led to the solubilisation of heavy and toxic metals, which have to be removed to avoid contamination of water bodies. In the mining industry, wastewater is treated prior to discharge into the aquatic environment or recycled back to the processing plant for reuse. Technologies employed in achieving this include the use of Actiflo™ method. The Actiflo™ process is a proven, high performance, compact clarification system that utilises microsand to enhance flocculation and settling. The microsand also enhances system stability, enabling the process to produce a consistently high-quality effluent despite changing raw water conditions such as flow rate or solids content. Since Ghana hosts large volumes of beach sand similar to the sand from Australia (ActisandTM), it was important to assess the possibility of employing the Ghanaian beach sand in the Actiflo™ process. This research was therefore conducted to ascertain the usefulness and compatibility of local beach sands in running the ActifloTM and the possibility of complementing ActisandTM with local sand. Samples from the various beaches (ActisandTM, Saltpond, Cape Coast, Takoradi, Elmina and Sekondi) were subjected to the various stages of oxidation, coagulation and flocculation to determine the percentage of Arsenic precipitated. From an initial concentration of 4.2 ppm, the results revealed that the sands from Saltpond, Sekondi and Takoradi accounted for 85.2%, 84.2% and 84.0% respectively of arsenic removal as against 84.0% for ActisandTM.
Keywords: :ActifloTM, Microsand, Water treatment, Beach sand, Arsenic removal Download Full PaperThickeners are used to recycle larger volumes of water used in Gold Mining Process Plants in order to reduce the consumption of and demand on fresh water. The separation process is stimulated by the addition of flocculants, which aggregate fine particles into flocs for easier settling. Depending on the type of flocculant used, the thickener after flocculation, sometimes produces cloudy overflow which creates problems when recycled. This work therefore sought to study the effect of a new flocculant on the market, superfloc (C 491 HMW), in the flocculation of different types of ores in Ghana so as to ascertain the effective required concentration of flocculant to be used for flocculation. Settling tests were conducted for ore samples from three Mines in the southern half of the Ashanti gold belt, tagged Mine 1, Mine 2 and Mine 3. Each ore had 5 setups; a control, setup conditioned with lime, and setups dosed with lime and 1%, 2% and 3% vol/vol concentration of flocculant (0.05% stock solution). The results showed an upturn in settling velocity with increase in flocculant concentration. All the setups dosed with various concentrations of flocculants also produced clear overflow solution. The best concentration of Superfloc consumed for effective settling of the ores from Mines 1, 2 and 3 were 3%, 2%, and 3% vol/vol respectively. Among the ore types, the ore from Mine 2 responded the best to the Superfloc (C 491 HMW), with settling rate of 1.06 cm/min as against an average of 0.95 cm/min for Mine 1 and 3.
Keywords: :Flocculation, Superfloc Flocculant, Settling Rate, Gold Ores, Thickener Download Full PaperMetal recovery optimisation requires that all metal-bearing components of ores and concentrates be processed until the residue contains minimal values. Gold is recovered by ASGM operations generally after gravity concentration, followed by amalgamation, heating to remove mercury and smelting. After amalgamation, the gold is processed further while the barren black sands may be discarded or stored. However, the low-tech approach offers inefficiencies in recovery, with substantial amounts of gold retained in the barren black sands. In this study, sodium cyanide (NaCN), activated carbon, and zinc shavings were used to recover gold from the barren black sands. X-ray diffraction studies showed that the black sands were predominantly made of hematite. With a head grade of 26.28 g/t, the barren black sands had average gold recovery of 96.42% after 24 hours of conventional cyanidation. The procedure accordingly recovered 25.34 g of gold from every tonne of the discarded barren black sands. Carbon-in-Leach and zinc cementation investigations showed maximum recoveries of 99.95% and 90.34% respectively. The results present important economic pathway for recovering gold from barren black sands, and serve as a platform for further research.
Keywords: : Artisanal Gold Mining, Barren Black Sands, Cyanidation, Activated Carbon Recovery, Zinc Cementation Download Full Paper