J. Dankwah, E. Baah, J. Dankwah, J. R. Dankwah, B. Agbenuvor, B. Amankwaa-Kyeremeh, P. Koshy
AbstractPost-consumer thermosets are difficult to recycle because, unlike thermoplastics, they cannot be remoulded to create other items as a result of the extensive cross-linkages in their structure. The increased production of thermoset blends and composites in recent years has greatly increased the amount of waste materials. However, higher levels of carbon and hydrogen present in thermosets make them a potential reductant in the iron extractive industries. In this research work, postconsumer thermoset was transformed into carbon resource through a charring process. The resulting carbonaceous material from the thermoset was used as reductant in the production of metallic iron from the Akpafu-Todzi iron ore and artisanal slag using the microwave technology through the composite pellet approach at varying firing times. Analyses by XRF, XRD and SEM/EDS showed that the Akpafu Todzi iron ore is comprised of the iron oxides hematite (Fe2O3) and wustite (Fe0.942O), while the artisanal slag was predominantly fayalite (Fe2SiO4). Complete reduction of the ore was attained after 120 min reduction but the maximum extent of reduction was 78.84% for the slag, demonstrating the potential of postconsumer thermosets to function effectively as a reductant in the iron extractive industry. Keywords: Reduction; Akpafu-Todzi Iron Ore; Post Consumer Thermosets; Waste Electrical Sockets
{"title":"Production of Iron Nuggets from the Akpafu-Todzi Iron Ore and Artisanal Ferrous Slag using Post Consumer Thermosets (Waste Electrical Sockets) as Reductants","authors":"J. Dankwah, E. Baah, J. Dankwah, J. R. Dankwah, B. Agbenuvor, B. Amankwaa-Kyeremeh, P. Koshy","doi":"10.4314/GM.V19I2.6","DOIUrl":"https://doi.org/10.4314/GM.V19I2.6","url":null,"abstract":"AbstractPost-consumer thermosets are difficult to recycle because, unlike thermoplastics, they cannot be remoulded to create other items as a result of the extensive cross-linkages in their structure. The increased production of thermoset blends and composites in recent years has greatly increased the amount of waste materials. However, higher levels of carbon and hydrogen present in thermosets make them a potential reductant in the iron extractive industries. In this research work, postconsumer thermoset was transformed into carbon resource through a charring process. The resulting carbonaceous material from the thermoset was used as reductant in the production of metallic iron from the Akpafu-Todzi iron ore and artisanal slag using the microwave technology through the composite pellet approach at varying firing times. Analyses by XRF, XRD and SEM/EDS showed that the Akpafu Todzi iron ore is comprised of the iron oxides hematite (Fe2O3) and wustite (Fe0.942O), while the artisanal slag was predominantly fayalite (Fe2SiO4). Complete reduction of the ore was attained after 120 min reduction but the maximum extent of reduction was 78.84% for the slag, demonstrating the potential of postconsumer thermosets to function effectively as a reductant in the iron extractive industry. Keywords: Reduction; Akpafu-Todzi Iron Ore; Post Consumer Thermosets; Waste Electrical Sockets","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"178 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91499758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractArsenic (As) has the potential to negatively affect soils and groundwater quality, and cause several public health challenges. It is usually concentrated and released during metal mining of ores that contains arsenic-bearing minerals. Remediation strategies are in place to avoid pollution. In this study, bauxite from Awaso, Ghana, was characterised, and its ability to sequester As was tested under varying conditions of temperature, Eh and pH. The study showed that the best particle size in the range utilised was 80% passing 2 mm as it allowed easy percolation, and As removal was about 95%. The reaction is a favourable pseudo-second order reaction that is spontaneous and thermodynamically stable and compares well with the Langmuir Sorption Isotherm. About 80% sorption was achieved within 20 minutes of contact with low desorption rate of less than 1.8%. The study thus concludes that bauxite is a good filter for arsenic. Keywords: Arsenic, Bauxite, Filter, Sorption, Isotherm
{"title":"The Use of Bauxite as an Arsenic Filter","authors":"S. Ndur, H. Osei, C. E. Abbey, T. Joe-asare","doi":"10.4314/GM.V19I2.8","DOIUrl":"https://doi.org/10.4314/GM.V19I2.8","url":null,"abstract":"AbstractArsenic (As) has the potential to negatively affect soils and groundwater quality, and cause several public health challenges. It is usually concentrated and released during metal mining of ores that contains arsenic-bearing minerals. Remediation strategies are in place to avoid pollution. In this study, bauxite from Awaso, Ghana, was characterised, and its ability to sequester As was tested under varying conditions of temperature, Eh and pH. The study showed that the best particle size in the range utilised was 80% passing 2 mm as it allowed easy percolation, and As removal was about 95%. The reaction is a favourable pseudo-second order reaction that is spontaneous and thermodynamically stable and compares well with the Langmuir Sorption Isotherm. About 80% sorption was achieved within 20 minutes of contact with low desorption rate of less than 1.8%. The study thus concludes that bauxite is a good filter for arsenic. Keywords: Arsenic, Bauxite, Filter, Sorption, Isotherm","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"508 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80076064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractAttractiveness of fiscal regime has become more important in oil and gas investment decision than the rather geological prospectivity of the province. The terms and conditions contained in the fiscal system influence the investor’s evaluation of project. As Ghana determines to benefit greatly from the exploitation of the oil and gas resources, a robust fiscal system attractive in all economical and technical conditions needs to be designed. Ghana has recently become one of the frontiers in the oil and gas industry following its commercial discoveries of hydrocarbons in Deepwater Tano-Cape Three Point, the Jubilee field. Ghana’s oil industry is very young and some of the basins are under exploration surveillances waiting for commercial discoveries. Ghana’s Jubilee field uses various terms and conditions in her fiscal arrangement to govern the upstream operations. For continuous realisation of economic benefits to the State as well as the contractor, it is important the applicability of Ghana’s fiscal regime at varying boundary conditions of oil price and field reserves are evaluated. Discounted cash flow economic model which considers the major uncertainties was developed to evaluate the economic implications of the Jubilee field fiscal regime. Different price scenarios and varying field sizes were taken through rigorous sensitivity analysis. It was determined that for all field sizes considered at oil prices above $ 40/bbl, contractor’s NPVs are positive. The project take statistics are averagely around 64% for Government and 36% for contractor under the various scenarios except for oil prices less than $40/bbl where the State’s take statistic is above 80% and contractor’s take below 20%. The State receives Additional Oil Entitlement(AOE) only when the oil price is above $40/bbl and the AOE increases steadily with the oil price for all the various field sizes. In general, the Jubilee field fiscal regime is fairly attractive and flexible and ensures stable shares of economic rents between the State and the contractor as the profitability of the field increases. Keywords: Reserves, Fiscal Regime, Cash Flow, Take Statistics, Net Present Value
摘要在油气投资决策中，财政制度的吸引力已经超过了该省的地质前景。财政制度所包含的条款和条件影响投资者对项目的评价。由于加纳决心从石油和天然气资源的开采中获得巨大利益，因此需要设计一个在所有经济和技术条件下都具有吸引力的强有力的财政制度。加纳最近在Jubilee油田深水Tano-Cape Three Point发现了商业碳氢化合物，成为石油和天然气行业的前沿之一。加纳的石油工业非常年轻，一些盆地正处于勘探监视之下，等待商业发现。加纳的Jubilee油田在其财政安排中使用各种条款和条件来管理上游业务。为了持续实现国家和承包商的经济利益，重要的是要评估加纳财政制度在不同油价和油田储量边界条件下的适用性。贴现现金流经济模型考虑了主要的不确定性，以评估朱比利油田财政制度的经济影响。通过严格的敏感性分析，选取了不同的价格情景和不同的场地规模。结果表明，在油价高于40美元/桶的情况下，所有规模的油田，承包商的净现值均为正。除了油价低于40美元/桶的情况下，政府的项目收益统计数据平均约为64%，承包商的项目收益统计数据平均约为36%，而政府的项目收益统计数据高于80%，承包商的项目收益统计数据低于20%。只有当油价高于40美元/桶时，国家才能获得额外的石油权益(AOE)，并且AOE随着油价的稳定增长而稳步增长。总的来说，Jubilee油田的财政制度相当有吸引力和灵活，并确保随着油田利润的增加，国家和承包商之间经济租金的稳定份额。关键词:储备，财政制度，现金流量，统计，净现值
{"title":"Boundary Applicability of the Ghana’s Oil Block Fiscal Regimes","authors":"D. Ocran, E. Broni-Bediako, G. Ofori-Sarpong","doi":"10.4314/GM.V19I2.10","DOIUrl":"https://doi.org/10.4314/GM.V19I2.10","url":null,"abstract":"AbstractAttractiveness of fiscal regime has become more important in oil and gas investment decision than the rather geological prospectivity of the province. The terms and conditions contained in the fiscal system influence the investor’s evaluation of project. As Ghana determines to benefit greatly from the exploitation of the oil and gas resources, a robust fiscal system attractive in all economical and technical conditions needs to be designed. Ghana has recently become one of the frontiers in the oil and gas industry following its commercial discoveries of hydrocarbons in Deepwater Tano-Cape Three Point, the Jubilee field. Ghana’s oil industry is very young and some of the basins are under exploration surveillances waiting for commercial discoveries. Ghana’s Jubilee field uses various terms and conditions in her fiscal arrangement to govern the upstream operations. For continuous realisation of economic benefits to the State as well as the contractor, it is important the applicability of Ghana’s fiscal regime at varying boundary conditions of oil price and field reserves are evaluated. Discounted cash flow economic model which considers the major uncertainties was developed to evaluate the economic implications of the Jubilee field fiscal regime. Different price scenarios and varying field sizes were taken through rigorous sensitivity analysis. It was determined that for all field sizes considered at oil prices above $ 40/bbl, contractor’s NPVs are positive. The project take statistics are averagely around 64% for Government and 36% for contractor under the various scenarios except for oil prices less than $40/bbl where the State’s take statistic is above 80% and contractor’s take below 20%. The State receives Additional Oil Entitlement(AOE) only when the oil price is above $40/bbl and the AOE increases steadily with the oil price for all the various field sizes. In general, the Jubilee field fiscal regime is fairly attractive and flexible and ensures stable shares of economic rents between the State and the contractor as the profitability of the field increases. Keywords: Reserves, Fiscal Regime, Cash Flow, Take Statistics, Net Present Value","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"48 1","pages":"70-76"},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80382161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractHigh cost of metric photogrammetric cameras has given rise to the utilisation of non-metric digital cameras to generate photogrammetric products in traditional close range or terrestrial photogrammetric applications. For precision photogrammetric applications, the internal metric characteristics of the camera, customarily known as the Interior Orientation Parameters, need to be determined and analysed. The derivation of these parameters is usually achieved by implementing a bundle adjustment with self-calibration procedure. The stability of the Interior Orientation Parameters is an issue in terms of accuracy in digital cameras since they are not built with photogrammetric applications in mind. This study utilised two photogrammetric software (i.e. Photo Modeler and Australis) to calibrate a non-metric digital camera to determine its Interior Orientation Parameters. The camera parameters were obtained using the two software and the Root Mean Square Errors (RMSE) calculated. It was observed that Australis gave a RMSE of 0.2435 and Photo Modeler gave 0.2335, implying that, the calibrated non-metric digital camera is suitable for high precision terrestrial photogrammetric projects. Keywords: Camera Calibration, Interior Orientation Parameters, Non-Metric Digital Camera
{"title":"Determination of the Interior Orientation Parameters of a Non-metric Digital Camera for Terrestrial Photogrammetric Applications","authors":"N. Tagoe, S. Mantey","doi":"10.4314/GM.V19I2.1","DOIUrl":"https://doi.org/10.4314/GM.V19I2.1","url":null,"abstract":"AbstractHigh cost of metric photogrammetric cameras has given rise to the utilisation of non-metric digital cameras to generate photogrammetric products in traditional close range or terrestrial photogrammetric applications. For precision photogrammetric applications, the internal metric characteristics of the camera, customarily known as the Interior Orientation Parameters, need to be determined and analysed. The derivation of these parameters is usually achieved by implementing a bundle adjustment with self-calibration procedure. The stability of the Interior Orientation Parameters is an issue in terms of accuracy in digital cameras since they are not built with photogrammetric applications in mind. This study utilised two photogrammetric software (i.e. Photo Modeler and Australis) to calibrate a non-metric digital camera to determine its Interior Orientation Parameters. The camera parameters were obtained using the two software and the Root Mean Square Errors (RMSE) calculated. It was observed that Australis gave a RMSE of 0.2435 and Photo Modeler gave 0.2335, implying that, the calibrated non-metric digital camera is suitable for high precision terrestrial photogrammetric projects. Keywords: Camera Calibration, Interior Orientation Parameters, Non-Metric Digital Camera","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"62 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85125309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Slurry density monitoring is of paramount importance in the industrial world. Most industries, especially cement and mineral processing industries, employ this method to obtain good quality products. However, most Carbon-In-Leach (CIL) tanks of gold processing industries do not use slurry density monitoring systems. As a result, many a time, agitation difficulties occur when the slurry begins to harden. This paper, therefore, seeks to design an integrated anti-hardening system for CIL tanks, with the aid of a microcontroller, to monitor the density of the slurry in order to prevent it from hardening. Slurry density measurement was achieved with the help of a strain gauge pressure sensor and a couple of level sensors. Atmega 328p microcontroller board was programmed to continuously compute the density of the slurry from values of pressure and level of slurry in the tank indicated by the pressure and level sensors, respectively. The microcontroller responds to slurry hardening by activating a light emitting diode and triggering the piezo buzzer when a set point is reached. The designed circuit was successfully simulated using Proteus 8.2 design suite software to ascertain its functionality. Based on the results obtained, the light emitting diode and piezo buzzer activated when the set point was reached. It was concluded that the anti-hardening system is effective for constantly monitoring the density of the slurry to prevent it from hardening. It was also recommended that the mining industries could employ the designed system to monitor the density in order to prevent hardening of slurry in CIL tanks. Keywords: Carbon-In-Leach Tanks, Slurry Densisty, Strain Guage Pressure Sensor, Microcontroller
{"title":"Design of an Integrated Anti-Hardening System for Carbon-In-Leach Tanks","authors":"R. A. Ofosu, E. Normanyo, B. Essilfie-Nyame","doi":"10.4314/GM.V19I2.9","DOIUrl":"https://doi.org/10.4314/GM.V19I2.9","url":null,"abstract":"Slurry density monitoring is of paramount importance in the industrial world. Most industries, especially cement and mineral processing industries, employ this method to obtain good quality products. However, most Carbon-In-Leach (CIL) tanks of gold processing industries do not use slurry density monitoring systems. As a result, many a time, agitation difficulties occur when the slurry begins to harden. This paper, therefore, seeks to design an integrated anti-hardening system for CIL tanks, with the aid of a microcontroller, to monitor the density of the slurry in order to prevent it from hardening. Slurry density measurement was achieved with the help of a strain gauge pressure sensor and a couple of level sensors. Atmega 328p microcontroller board was programmed to continuously compute the density of the slurry from values of pressure and level of slurry in the tank indicated by the pressure and level sensors, respectively. The microcontroller responds to slurry hardening by activating a light emitting diode and triggering the piezo buzzer when a set point is reached. The designed circuit was successfully simulated using Proteus 8.2 design suite software to ascertain its functionality. Based on the results obtained, the light emitting diode and piezo buzzer activated when the set point was reached. It was concluded that the anti-hardening system is effective for constantly monitoring the density of the slurry to prevent it from hardening. It was also recommended that the mining industries could employ the designed system to monitor the density in order to prevent hardening of slurry in CIL tanks. Keywords: Carbon-In-Leach Tanks, Slurry Densisty, Strain Guage Pressure Sensor, Microcontroller","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"40 1","pages":"64-69"},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76901678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractSub-grade is the ultimate load bearer of vehicular traffic load in a pavement structure. A weak sub-grade or problematic soils require some improvements like soil stabilisation, soil reinforcement and/or capping of the sub-grade layer. These sub-grade improvement methods increase the total project cost because non-local materials such as cement, geosynthetics and hydrated lime are commonly used. The use of graded oil palm kernel shells (OPKS) which are local, cheaper and readily available as a soil improvement material was assessed in this research. This assessment was done by mixing sub-grade material with 2.8 mm, 5 mm and 10 mm graded OPKS. 10 %, 20 % and 30 % of each graded OPKS was added separately to the soil to form nine composite materials. These composite materials including the natural soil were tested for their California Bearing Ratio (CBR) values. The investigation proved that the composite made of 20 % 2.8 mm graded OPKS yielded a soaked CBR of 23.5 % which is a 197.47 % increase in soaked CBR compared to that of the natural soil. The soaked CBR samples of the graded OPKS composite materials absorbed lesser amounts of water in comparison to that of the natural soil. This behaviour implies that some capillary force created at un-soaked condition in the composite materials was preserved; therefore, the composite materials generally have higher CBR values than the natural soil. Keywords: Oil Palm Kernel Shells (OPKS), Problematic Soils, Lightweight Aggregate (LWA)
{"title":"Effect of Graded Oil Palm Kernel Shells on Compaction of Weak o Problematic Sub-Grade Soils","authors":"M. Affam, R. Wilson, D. Asenso-Gjambibi","doi":"10.4314/GM.V19I2.3","DOIUrl":"https://doi.org/10.4314/GM.V19I2.3","url":null,"abstract":"AbstractSub-grade is the ultimate load bearer of vehicular traffic load in a pavement structure. A weak sub-grade or problematic soils require some improvements like soil stabilisation, soil reinforcement and/or capping of the sub-grade layer. These sub-grade improvement methods increase the total project cost because non-local materials such as cement, geosynthetics and hydrated lime are commonly used. The use of graded oil palm kernel shells (OPKS) which are local, cheaper and readily available as a soil improvement material was assessed in this research. This assessment was done by mixing sub-grade material with 2.8 mm, 5 mm and 10 mm graded OPKS. 10 %, 20 % and 30 % of each graded OPKS was added separately to the soil to form nine composite materials. These composite materials including the natural soil were tested for their California Bearing Ratio (CBR) values. The investigation proved that the composite made of 20 % 2.8 mm graded OPKS yielded a soaked CBR of 23.5 % which is a 197.47 % increase in soaked CBR compared to that of the natural soil. The soaked CBR samples of the graded OPKS composite materials absorbed lesser amounts of water in comparison to that of the natural soil. This behaviour implies that some capillary force created at un-soaked condition in the composite materials was preserved; therefore, the composite materials generally have higher CBR values than the natural soil. Keywords: Oil Palm Kernel Shells (OPKS), Problematic Soils, Lightweight Aggregate (LWA)","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"88 1","pages":"17-25"},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77151359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractThe suitability of a centerline or upstream design as a sustainable option for construction of future raises for the existing Life of Mine (LoM) downstream Tailings Storage Facility (TSF) at Adamus Resources Limited (ARL) was investigated using Slope/W in GeoStudio Software. Review of technical information, evaluation of the performance of the existing Stage 6 dam, and geotechnical investigations of available construction materials were undertaken in this research. Insights were gained about the TSF’s life cycle and current bearing capacity for intended future raises. Viable geotechnical parameters were established to define construction material specifications as well as input data for modelling the new designs. The British Standards Institute (BSI) standards were adopted for all the material testing protocols carried out at the Council for Scientific and Industrial Research-Building and Road Research Institute (CSIR-BRRI) laboratory in Kumasi. The scope of modelling covered the original downstream as well as the centerline and upstream options. The geometric design and stability analysis focused only on the southern and northern embankments of the TSF. The modelling outputs yielded reliable Stability Factors of Safety (FoS) for all designs investigated, above the regulatory criteria. Subsequently, a semi-quantitative multi-criteria evaluation was used to select the preferred option between the centreline and upstream alternatives. The results showed that technically, economically and by regulatory compliance, the centreline design is a better alternative and therefore recommended for adoption by ARL. Keywords: Tailings Storage Facility, Geotechnical Parameters, Stability Analysis, Modelling, Multi-Criteria
{"title":"Re-Design of Mine Tailings Storage Facility for Adamus Resources Limited","authors":"B. Owusu-Yeboah, D. M. Gyimah, C. Akayuli","doi":"10.4314/GM.V19I2.4","DOIUrl":"https://doi.org/10.4314/GM.V19I2.4","url":null,"abstract":"AbstractThe suitability of a centerline or upstream design as a sustainable option for construction of future raises for the existing Life of Mine (LoM) downstream Tailings Storage Facility (TSF) at Adamus Resources Limited (ARL) was investigated using Slope/W in GeoStudio Software. Review of technical information, evaluation of the performance of the existing Stage 6 dam, and geotechnical investigations of available construction materials were undertaken in this research. Insights were gained about the TSF’s life cycle and current bearing capacity for intended future raises. Viable geotechnical parameters were established to define construction material specifications as well as input data for modelling the new designs. The British Standards Institute (BSI) standards were adopted for all the material testing protocols carried out at the Council for Scientific and Industrial Research-Building and Road Research Institute (CSIR-BRRI) laboratory in Kumasi. The scope of modelling covered the original downstream as well as the centerline and upstream options. The geometric design and stability analysis focused only on the southern and northern embankments of the TSF. The modelling outputs yielded reliable Stability Factors of Safety (FoS) for all designs investigated, above the regulatory criteria. Subsequently, a semi-quantitative multi-criteria evaluation was used to select the preferred option between the centreline and upstream alternatives. The results showed that technically, economically and by regulatory compliance, the centreline design is a better alternative and therefore recommended for adoption by ARL. Keywords: Tailings Storage Facility, Geotechnical Parameters, Stability Analysis, Modelling, Multi-Criteria","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87722051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractCoconut shells are used as precursors for preparation of activated carbons. The shells could vary in terms of their maturity. The influence of the maturity of the shells on gold adsorption efficiencies of derived activated carbons (ACs) from gold di-cyanide solution was investigated. The shells were pyrolysed at 900 ºC and the resulting chars were activated in steam at the same temperature for different durations. Assessment of the properties of the derived ACs revealed that; the hardness, gold adsorption capacities and rates of gold adsorption of the ACs depended on the maturity of the shells. The more matured the shells the harder the AC. The relative hardness and gold adsorption rates of the mature coconut shells activated carbons, HMand RM, respectively and those of the less mature shells, HLand RL, respectively were in the order of HM >HL and RM >RL. The relative hardness of the ACs derived from the more mature and less mature shells after 3 hrs activation were 99.3% and 94.0%, respectively and the gold adsorption rates were 5.78 mg Au/hr/gand 4.95 mg Au/hr/g, respectively. The adsorption rates and relative hardness depended on the duration of activation, where longer activation times resulted in increase in the adsorption rates and a decrease in relative hardness of the derived ACs. Keywords: Adsorption, Activated Carbon, Coconut Shells, Maturity, Relative Hardness
{"title":"Effects of Maturity of Coconut Shells on Gold Adsorption Efficiencies of Derived Activated Carbons","authors":"W. Buah, J. Darmey, F. Osei","doi":"10.4314/GM.V19I2.7","DOIUrl":"https://doi.org/10.4314/GM.V19I2.7","url":null,"abstract":"AbstractCoconut shells are used as precursors for preparation of activated carbons. The shells could vary in terms of their maturity. The influence of the maturity of the shells on gold adsorption efficiencies of derived activated carbons (ACs) from gold di-cyanide solution was investigated. The shells were pyrolysed at 900 ºC and the resulting chars were activated in steam at the same temperature for different durations. Assessment of the properties of the derived ACs revealed that; the hardness, gold adsorption capacities and rates of gold adsorption of the ACs depended on the maturity of the shells. The more matured the shells the harder the AC. The relative hardness and gold adsorption rates of the mature coconut shells activated carbons, HMand RM, respectively and those of the less mature shells, HLand RL, respectively were in the order of HM >HL and RM >RL. The relative hardness of the ACs derived from the more mature and less mature shells after 3 hrs activation were 99.3% and 94.0%, respectively and the gold adsorption rates were 5.78 mg Au/hr/gand 4.95 mg Au/hr/g, respectively. The adsorption rates and relative hardness depended on the duration of activation, where longer activation times resulted in increase in the adsorption rates and a decrease in relative hardness of the derived ACs. Keywords: Adsorption, Activated Carbon, Coconut Shells, Maturity, Relative Hardness","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87751177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cadastral surveys in Ghana often employ well known surveying equipment such as Total Station andGNSSreceivers or a combination of both. These survey techniques are well-established and widely accepted. However, there are limitations in certain areas. In situations where difficult terrain and inaccessible areas and dense vegetation are encountered or when surveyor’s life may be at risk, Unmanned Aerial Vehicles (UAVs) could be used to overcome the limitations of these well-established survey instruments. This research used high resolution images from UAV (DJI Phantom 4) to survey plots within the University of Mines and Technology land area. Coordinates of the boundary points were extracted using Agisoft Photoscan.GNSSreceivers were also used to survey the land and the same boundary point coordinates obtained and compared. This enabled the establishment of accurate ground control points for georeferencing. The coordinates obtained from both UAV andGNSSSurveys were used to prepare cadastral plans and compared. The difference in Northings and Eastings from UAV andGNSSsurveys were +0.380 cmand +0.351 cmrespectively. These differences are well within tolerance of +/-0.9114 m(+/-3 ft) set by the Survey and Mapping Division (SMD) of the Lands Commission for cadastral plans production. This research therefore concludes that high resolution images from UAVs are suitable for cadastral surveying. Keywords: Unmanned Aerial Vehicles, Drones, Global Navigation Satellite Systems, Cadastral Surveys
{"title":"Suitability of Unmanned Aerial Vehicles for Cadastral Surveys","authors":"S. Mantey","doi":"10.4314/GM.V19I1.1","DOIUrl":"https://doi.org/10.4314/GM.V19I1.1","url":null,"abstract":"Cadastral surveys in Ghana often employ well known surveying equipment such as Total Station andGNSSreceivers or a combination of both. These survey techniques are well-established and widely accepted. However, there are limitations in certain areas. In situations where difficult terrain and inaccessible areas and dense vegetation are encountered or when surveyor’s life may be at risk, Unmanned Aerial Vehicles (UAVs) could be used to overcome the limitations of these well-established survey instruments. This research used high resolution images from UAV (DJI Phantom 4) to survey plots within the University of Mines and Technology land area. Coordinates of the boundary points were extracted using Agisoft Photoscan.GNSSreceivers were also used to survey the land and the same boundary point coordinates obtained and compared. This enabled the establishment of accurate ground control points for georeferencing. The coordinates obtained from both UAV andGNSSSurveys were used to prepare cadastral plans and compared. The difference in Northings and Eastings from UAV andGNSSsurveys were +0.380 cmand +0.351 cmrespectively. These differences are well within tolerance of +/-0.9114 m(+/-3 ft) set by the Survey and Mapping Division (SMD) of the Lands Commission for cadastral plans production. This research therefore concludes that high resolution images from UAVs are suitable for cadastral surveying. Keywords: Unmanned Aerial Vehicles, Drones, Global Navigation Satellite Systems, Cadastral Surveys","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80588274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Tarkwa district is an important gold mining area in the Southwestern part of Ghana. The main source of potable water supply to the Tarkwa Nsuaem Municipality is from the Bonsa River treatment plant managed by the Ghana Water Company Limited (GWCL). The River is under threat from serious contamination by illegal mining ("galamsey") activities within its catchment area. Consequently, the amount of water supplied to the Municipality has not kept pace with its growing population due to increasing treatment cost and supply difficulties. The need to find alternative and sustainable sources of potable water supply to augment that from GWCL to the Municipality has become imperative. A large void volume created as a result of the abandoned underground mine operated by Gold Fields Ghana Limited (GFGL), after its closure in 1999 has flooded. This potential water resource is being pumped out daily, and wasted, sometimes spilling-over to low lying areas around the mine when allowed to reach its decant level. This study estimated the quantity of water in the Abontiakoon Vertical Shaft (AVS) which is part of the large underground void using survey production figures and post-closure void filling parameters resulting in 2.8 x 106 m3 and 2.9 x 106 m3 respectively. The rate of recharge to the underground water was also estimated to ascertain the sustainability of the void water should it be considered for use by employing the model of predicting rebound on “void filling” basis and average dewatering rate before closure at 2 535 m3/day and 2 618 m3/day respectively; indicating that recharge to the AVS reservoir is about 6 x 106 gal/day or 30% of current daily water supply deficit in the TNM. The estimated potential volume of mine water in storage in the entire Tarkwa underground void is 32 x106 m3. Two samples of the mine water were taken in November 2011 and February 2015 for quality analysis, in order to have a fair knowledge of the water quality parameters. The quality of the underground water was found to be potentially good, and not likely to cause any health threats, or water quality problems. Depth sampling is recommended to determine the chemical profile of the reservoir. Keywords: Reservoir, Municipality, Bonsa River, Contamination, Tarkwa
Tarkwa地区是加纳西南部一个重要的黄金矿区。Tarkwa Nsuaem市饮用水供应的主要来源是由加纳水务有限公司(GWCL)管理的Bonsa河处理厂。这条河正受到其集水区非法采矿活动的严重污染威胁。因此，由于处理费用增加和供应困难，供应给该市的水量跟不上其不断增长的人口。寻找可替代和可持续的饮用水供应来源，以增加从GWCL到市政当局的需求已成为当务之急。加纳金矿有限公司(Gold Fields Ghana Limited, GFGL)于1999年关闭了一座废弃的地下矿山，造成了一个巨大的空隙，现在已经被水淹没。这种潜在的水资源每天都在被抽走，但却被浪费了，有时当水位达到正常水平时，水会溢出到矿井周围的低洼地区。本研究使用调查生产数据和关闭后的空洞填充参数估算了Abontiakoon竖井(AVS)的水量，该竖井是大型地下空洞的一部分，分别为2.8 x 106立方米和2.9 x 106立方米。采用“充填”回弹预测模型和关闭前平均脱水速率分别为2 535 m3/d和2 618 m3/d，对地下水回灌速率进行了估算，以确定是否考虑利用空洞水的可持续性;表明AVS水库的回灌量约为6 × 106加仑/天，占目前TNM每日供水量不足的30%。估计整个塔尔夸地下空隙中矿井水的潜在储存量为32 × 106 m3。分别于2011年11月和2015年2月对该矿水样进行了水质分析，以了解该矿水样的水质参数。调查发现，地下水的质量可能是良好的，不太可能造成任何健康威胁或水质问题。建议采用深度取样来确定储层的化学剖面。关键词:水库，直辖市，邦萨河，污染，塔克瓦
{"title":"Estimation of the Quantity of Water in the Abandoned Underground Mine of Gold Fields Ghana Limited Tarkwa: A Potential Source to Augment Water Supply to Tarkwa Municipality","authors":"J. K. Obosu, J. Kuma, W. Buah","doi":"10.4314/GM.V19I1.2","DOIUrl":"https://doi.org/10.4314/GM.V19I1.2","url":null,"abstract":"The Tarkwa district is an important gold mining area in the Southwestern part of Ghana. The main source of potable water supply to the Tarkwa Nsuaem Municipality is from the Bonsa River treatment plant managed by the Ghana Water Company Limited (GWCL). The River is under threat from serious contamination by illegal mining (\"galamsey\") activities within its catchment area. Consequently, the amount of water supplied to the Municipality has not kept pace with its growing population due to increasing treatment cost and supply difficulties. The need to find alternative and sustainable sources of potable water supply to augment that from GWCL to the Municipality has become imperative. A large void volume created as a result of the abandoned underground mine operated by Gold Fields Ghana Limited (GFGL), after its closure in 1999 has flooded. This potential water resource is being pumped out daily, and wasted, sometimes spilling-over to low lying areas around the mine when allowed to reach its decant level. This study estimated the quantity of water in the Abontiakoon Vertical Shaft (AVS) which is part of the large underground void using survey production figures and post-closure void filling parameters resulting in 2.8 x 106 m3 and 2.9 x 106 m3 respectively. The rate of recharge to the underground water was also estimated to ascertain the sustainability of the void water should it be considered for use by employing the model of predicting rebound on “void filling” basis and average dewatering rate before closure at 2 535 m3/day and 2 618 m3/day respectively; indicating that recharge to the AVS reservoir is about 6 x 106 gal/day or 30% of current daily water supply deficit in the TNM. The estimated potential volume of mine water in storage in the entire Tarkwa underground void is 32 x106 m3. Two samples of the mine water were taken in November 2011 and February 2015 for quality analysis, in order to have a fair knowledge of the water quality parameters. The quality of the underground water was found to be potentially good, and not likely to cause any health threats, or water quality problems. Depth sampling is recommended to determine the chemical profile of the reservoir. Keywords: Reservoir, Municipality, Bonsa River, Contamination, Tarkwa","PeriodicalId":12530,"journal":{"name":"Ghana Mining Journal","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79250124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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