College of Engineering

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Assessment of the Rill Cut and Fill Mining system at Prestea Goldfields Limited
(1990) Adu-Poku, Sampson
The decline in gold production and increasing cost of mining at the Prestea Goldfield Limited (PGL) has called for the need to find ways and means of increasing productivity. This thesis analyses the current rill cut and fill mining system employed at PGL with the view to either modify this system or replace it with more efficient mining system. Three other alternative applicable mining systems intended to replace the current one namely Horizontal Cut and Fill, Sublevel stopping and Shrinkage mining systems have been selected from geotechnical considerations. Technological and economic appraisal of these alternative systems and the current one has been carried out so as to select the most efficient one. It has been established that where the orebody is and above 1.83m and the orebody and the host rock are competent, the sublevel stopping system (alternative C) is most efficient for PGL. The Preparetional Opening Efficiency of this system is 102.17m3/1000t, development cost per ton is ¢3017.52/t, the efficiency is 47.99t/manshift and the stopping cost per ton is ¢572.32/t. this will reduce the stopping cost per ton by 74.24% and increase the efficiency by 96.8%. Where the orebody width is below 1.83m and the host rocks are not very strong, the Horizontal Cut and Fill mining system will be more applicable
The effect of bitumen emulsion on selected engineering properties of lateritic gravel and the potential for reducing erosion of unpaved roads
(2001) Ahiamadi, Samuel Kofi
In Ghana the road network accounts for the overwhelming proportion of both passenger and freight traffic. The network is about 40,000km long and is divided into three functional classes of feeder roads, trunk roads and urban roads. Over 82% of the network is unpaved and unpaved roads can be found in all functional classes of roads and distributed in all the regions of the country. One of the characteristics of unpaved roads is that they tend to deteriorate faster than paved roads. Like in many developing countries, the funds available for maintenance in Ghana is far below that required to keep the roads at the minimum level of service. The unpaved roads are also mostly low volume roads with average daily traffic levels not exceeding 100 even on trunk roads. Given the rather high rainfall in the southern parts of the country, it appears that the major cause of deterioration of unpaved roads in these parts of the country is rainfall-induced erosion. Any financially affordable effort that leads to a delay in the deterioration of these unpaved roads will therefore contribute towards an improvement of the road network. Stabilization is known to be a simple and often affordable method of improving the resistance of unpaved roads to erosion. This project therefore seeks to investigate first how stabilization of lateritic gravel using bitumen emulsion can affect certain engineering properties of lateritic gravel and then secondly to investigate the potential for using this material to reduce rainfall induced erosion on unpaved roads. The study first reviews the factors that affect the deterioration of unpaved roads, the effect of rainfall characteristics on erosion, the rainfall patterns and zones in the country and their effect on the formation of the different types of lateritic gravel. It also reviews the experience of the effects of cement, lime and bitumen emulsion on different lateritic gravel. An anionic bitumen emulsion produced locally was used in the laboratory investigation. The laboratory work consisted of an investigation of the effect of different percentages of the bitumen on the index properties, compaction characteristics, CBR and permeability of samples of lateritic gravel obtained from five borrow pits in two agro-ecological zones of the country The results established an optimal nominal bitumen content of about 2% for improved compaction and strength characteristics. A model pavement prepared with this optimum bitumen content was constructed and the rate of erosion of material from the pavement was compared with a non-stabilized model pavement in the H313 hydrological (rainfall simulation chamber) apparatus. The results showed a four-fold reduction in the amount of material eroded from the model pavement compared with the unsterilized material.
Assessment of the Collaboration and Commitments among Mining Communities, Mining Companies and the Governmental Institutions towards the realisation of Reclamation Goal (A Case Study of the Reclaimed Kubi Mined Site)
(2006) Yeboah, Joseph
Mining is an age old activity in Ghana and dates back to several decades. Starting as a simple alluvial activity it has transformed to the present day industrial level characterized by massive underground drills and heavy surface excavations which come with numerous environmental problems such as land degradation, thus, necessitating the reclamation of affected lands to ensure that society retains multiple use opportunities of such sites. This study which is a case study of Anglogold Ashanti’s reclamation of the their Kubi concession, was to determine the level of involvement of the Kubi communities in reclamation planning and decision making and their overall understanding of the reclamation process, the commitment of the company to reclamation activity in terms of management and hence the general performance of the established trees, species diversity and site conditions of the reclaimed site. Questionnaires were administered to community members while tree height and diameter measurements, species numbers and types and soil samples were taken from repeated sample plots that were laid on the reclaimed site. The study revealed that communities were not involved in the reclamation decision making contrary to provisions under the Environmental Assessment Regulation. Secondly, the communities could not foresee how the reclaimed site could be useful to them in the future as their expectations were clearly different from that of the company. While the exotic species such as Senna seamia and Acacia mangium performed well on the site, almost all the indigenous species such as Ceiba pentandra, Entandophragma angolense and Terminalia ivorensis were stunted because of poor management and accounted for only 3.6% of the reclamation species on the site instead of the 40% indigenous species recommended by the EPA The soil chemical condition with a mean pH of 5.5 was good with most of the soil nutrients tested within the average range for most standard soil classifications. It is recommended that further studies be conducted to find out the heavy metal levels on the reclaimed site because of their potential to contaminate underground water and streams since the communities depend solely on such streams.
Promoting Sustainable Relationship between Mining Communities and Mining Companies; the role of Environmental Impact Assessment (Case study at Prestea and Ahafo Kenyase
(2007) Nsiah, Paul Kofi
Environmental Impact Assessment (EIA) is the official appraisal of the likely effects of a proposed project on the environment and measures to be adopted to protect the environment. One of the primary objectives of EIA is to provide an opportunity for the participation of the various interest groups, particularly the affected communities, in the assessment and review of proposed developments so that their concerns and suggestions are taken into consideration at the final decision-making stage (see Appendices 2 and 3). It is generally hoped that the inclusion of these communities in the various decisions leading to the approval of the project will lead to social acceptability, or otherwise of the project and promote sustainable relationship between the affected communities and the proponent. Nonetheless, recent developments and reports from the Ghanaian media disclose that some conflicts continue to emerge between some mining communities and mining companies. The Prestea community was chosen as a study area following a Daily Graphic Report on October 7th, 2005 (Appendix 1) that there was serious conflict between the community and Bogoso Gold Limited (BGL). The Ahafo-Kenyase community, which was experiencing actual mining operations in less than a year as at the time of the study, was also chosen to assess how the concerns of the local communities were taken into consideration during the EIA process and also to determine whether or not there is the existence of a conflict between the community and the mining company operating in the area, and the immediate causes, if any. The study was undertaken with the purpose of identifying EIA’s role in promoting that sustainable and cordial relationship between the two parties. The principal aim was to examine the conflicts, where they exist, in terms of the extent to which EIA influenced the final decisions prior to the onset of the two projects. The main objectives were: 1. To investigate if any conflicts have occurred between any of the affected communities and the mining company operating in that community, and the immediate causes. 2. To evaluate the extent to which EIA influenced the implementation of the two projects and explore the level of public participation in the EIA process. 3. To assess the nature and firmness of ETA compliance monitoring programmes together with the transparency of the process through public access to information; and 4. To identify the extent to which the EIA procedures provide a means by which an affected community can appeal against non-compliance with EIA decisions. The study was conducted by reviewing the existing ETA Procedures and ETA Regulations in Ghana as well as reviewing the Environmental Impact Statements (EIS) of the two companies: Newmont Ghana Gold Limited (NGGL) and BGL; operating in Kenyase and Prestea respectively. Questionnaires were administered to the Environmental Protection Agency (EPA) and the Prestea community. Direct interviews in the form of community meetings were conducted at the Kenyase communities. The results revealed that there were high levels of Consultation and Public Participation (CPP) at the initial and subsequent stages in the EIA processes of both projects. However, the EIA was not able to prevent conflict in Prestea because the community’s disagreement of opening the surface mining due to its perceived negative impacts was ignored at the final decision-making stage of the ETA process. Other reasons given by the respondents as the immediate causes of the conflict at Prestea included: • The refusal of BGL to employ people from the local community, • The negative impacts that the community experience from the mining activity; and • The demand by the people for the resettlement of the entire Prestea community. EIA was, however, able to prevent conflict in the Kenyase community following several consultative meetings between NGGL and the community who welcomed the commencement of the mining project. The study revealed that though the EIA system in Ghana provides comprehensive ETA procedures and guidelines that support public participation in projects necessitating ETA study, ETA in Ghana has not been able to achieve much in the area. of conflict avoidance owing to certain omissions in the ETA procedures which include the following: • The lack of public participation at the final decision-making stage prior to project approval, • The lack of clear provision for ETA compliance or supervisory monitoring by the EPA in the ETA system in Ghana, • There is also, no provision of a formal channel for the public to appeal against noncompliance with ETA decisions against proponents, and • There is no involvement of the judicial agencies in resolving issues concerning challenging ETA decisions or actions of the EPA. It is hoped that the above omissions will be introduced into the ETA system in Ghana through adequate ETA regulations to help prevent the occurrence of these conflicts in the future
Borehole/Well Water Quality Analysis of the Peripheral Mining Communities of Gold Fields Ghana Limited, Tarkwa Gold Mine
(2007) Sandaare, Robert
Some parts of the minerals industry and the community have viewed water as an inexpensive commodity rather than an asset with significant value. It is important to recognize the role water plays in the environment and in the economic development of communities. This research assessed the quality of community borehole and well water provided by Gold Fields Ghana Limited, as part of its industry approach to water management. The research also assessed the impact of Gold Fields operations and other activities on the quality of the borehole and well water in its peripheral communities. Data was collected and analyzed on sixty four boreholes and wells over a period of three years. The study revealed that pH values ranged between 4.7 and 11.3. Out of the 359 samples analyzed, 3.6 percent was found to be basic while 8.1 percent was acidic. It was also found out that, samples with high pH values were taken immediately after concrete works were undertaken and the impact of the cement used is a contributory factor since cement increases the pH of water. Samples with low pH values were found to be from wells with unhygienic and unsanitary conditions. All the Communities recorded levels of faecal coliforms exceeding the WHO standards for drinking water except the wells located in the Huniso Community. High values of Manganese were recorded mainly in the Huniso wells. These trends could be due to the geology and rock formations of the area. The values at Huniso exceeding the WHO guideline of 0.33 mg/1 ranged from 0.37 mg/1 to 5.0 mg/1. Out of the 12 wells at huniso, three had consistent elevated values of manganese. Well HNS013 increased from 2.54 mg/1 in 2003 to 5.0 mg/1 in 2005, while HNS016 increased from 1.0mg/l in 2003 to 1.48 mg/1 in 2005. Conductivity Values were very low, confirming the low metal dissolution of the Tarkwaian rock. The community wells should be sited properly and must be kept in good hygienic condition to prevent contamination. It was observed that water from some of the boreholes is not potable and hence not good for drinking even though it could be treated. This was due to contaminants such as high and low pH values, high TDS values, high faecal coliforms which do not meet the EPA and WHO guidelines for drinking water. Cyanide values were at the detection limit or absent in all the samples taken. Mercury, lead, iron and arsenic concentrations in samples analyzed from wells around the TSF were very low. It is therefore evident that the operations of Gold Fields Ghana Limited, Tarkwa Gold Mine have not polluted the borehole and well water in its peripheral communities. All the possible contaminants from the company have been observed to be absent from the samples or in negligible amounts. Some of the contaminants observed in the boreholes/wells might be coming from other sources and must be critically investigated if these facilities will continue to serve as sources of drinking water for these communities. The study clearly underscores the need to deepen wells, relocate those which are near access roads and cottage industries, raise the basements of low lying ones and to keep a sanitary and hygienic environment around the wells.
The preparation of low-temperature fusion enamel coatings for corrosion control using local raw materials
(2007-06-19) Danquah, Andrews
An attempt has been made in this study to formulate materials for low-temperature fusion enamel coating from local raw materials and borax that can be applied directly onto steel substrate for corrosion control. Mfensi and Afari clays, and the Mouri feldspar were mixed in various proportions with borax to form various batches. The batches were mixed with water to form slips which were used to coat already prepared steel surfaces and were allowed to dry in the open. The coated steel plates were again dried in the oven and fired at temperatures of 800oC, 850oC and 900oC to mature. The coatings were observed and also physico-chemical tests were conducted to evaluate some properties of the coatings. The coatings matured and adhered very well to the substrate at 850oC and 900oC and showed good hardness and thermal shock resistance as well as good corrosion resistance in brine and 10% nitric acid. The coatings hardness at the above temperatures were between 7 and 8 on the Mohs scale and 70-90 on the BHN(1/60). The coatings thickness at these temperatures was between 0.42mm and 0.5mm. They were able to resist fifteen cycles of heating and quenching from 400oC. The coatings prepared with the Afari clay with its higher content of iron oxide showed better results in terms of hardness and thermal shock resistance than those prepared with the Mfensi clay. However the coatings fired at 800oC did not fuse properly and hence did not show good adhesion to the substrate. They showed a hardness of 4-6 on the Mohs scale and failed on the Brinnel Hardness Tester.
Development of an urban road maintainance management system for Tamale
(2007-08-23) Adi, Solomon Buenor
An urban road maintenance management system has been developed in this study. The seeks, among others, to address the non motorized transport peculiar need of the road network in Tamale, A road condition survey was undertaken in 2004/2005 on the Tamale road network to collect primary data for the development of the system. Road definition, inventory, defect and NMT lane data were collected. The data was used to develop an MS Access 2003 desktop database and also update a digitized Tamale road network map in GIS environment. Visual basic.net programming language was used for the decision support tool development. Cost of treatment of different road defects were studied from the maintenance unit of the Department of Urban Roads and the Department of Feeder Roads and questionnaires on agency » and road user perception of the destructive nature, cost of repair and effect on riding comfort of various defects were also administered to engineers in these agencies and road users. Coupled with work from literature, a customized pavement rating form was developed to calculate the pavement condition index (PCI) of road links. The system recommends appropriate treatments in relation to the PCI of every link and ascertains its condition assessment. Based on the PCI category, the functional classification, economic factor and the traffic level of the road, the urgency of the treatment of one link over another was generated. Customized thematic ArcGIS maps were developed capable of displaying the different road classes, pavement types and the number of the different functional classes of roads within the Tamale network was established as 64, 149, 430 and 495 respectively for A, B, C and D roads. Maps on location of drains, culverts, traffic lights and other road inventories could be shown. Reports could also be saved, emailed and exported MS excel, PDF, CSV document, text document, graphic document, etc. for further analysis
A Study of Sedimentation Management Systems at Newmont Ghana Gold Limited
(2008) Dotse, Daniel Atsu
Many mining communities in Ghana continue to complain about the muddling and pollution of their water bodies as a result of mining activities. It is therefore in this light that the research is undertaken to investigate the erosion and sedimentation management systems of Newmont Ghana Gold Limited within its Ahafo operations, to asses the effectiveness of the systems put in place and determine whether or not the discharges from the mine do not pollute the receiving Tano River which in many cases serves as source of drinking water for communities living along it. To achieve the set objective, sedimentation control practices of the mine were studied, runoffs in the environmental control dams were monitored for a period of 106 days (between August and November) to determine the quality of runoff that are being discharged into the environment, samples were taken upstream and downstream of streams draining the mine area to assess the quality of runoff entering the mine area as well as the quality of those leaving it. Samples were also collected at the inlet points of the various Environmental Control Dams (ECDs) to asses the effects of mining on the streams by monitoring sediment build up during rainy days. Analyses of the results established the fact that although the mining activities generate a lot of sediment into the runoffs, yet the sedimentation dams are able to reduce the sediment loads by 92% to 95% and therefore making discharges from the sedimentation dams to the Tano River to be within the allowable discharge limit of 50mg/l. In conclusion, the activities of the mine do not appear to have adverse effect on the receiving Tano River in terms of sedimentation and therefore recommend this type of sedimentation management system to other mining companies.
Truck Use of Newly-Installed Roundabouts on the Kumasi-Ejisu Section of the Accra-Kumasi-Gonokrom Road (Route N6)
(2008) Odosu, Eric
Truck use of four newly-installed roundabouts on a rehabilitated section of Route N6 in Ghana was investigated. The study was motivated by public opposition to the roundabouts as a result of the occurrence of a number of accidents, particularly truck accidents, shortly after the rehabilitated section had been opened to traffic. The study involved observation of truck driver manoeuvres at the roundabouts, interview on truck driver knowledge of use of the device, and review of the accident records for as well as the as-built drawings of the roundabouts. Of a total of 16 accidents that have occurred to date since the installation, seven (46.7%) involved trucks with all the truck accidents taking place only at a particular roundabout (the University Police Station Roundabout). Of the seven truck accidents, five involved vehicle rollover (overturning). A comparison of the accident records at the intersections before and after conversion to roundabouts did not point to deterioration in safety following conversion except for the intersection at the University Police Station where the reverse was the case. Of 240 truck drivers interviewed who use the route, none knew the essence of the truck apron forming part of the roundabouts as they all considered tracking the apron a traffic offence and as many as 185 (77.1%) said they never use the apron. This perception was well corroborated by the results of the truck manoeuvre study at one of the roundabouts in which 150 (80.2%) of the 187 trucks captured on video manoeuvred the roundabouts in such a way as to avoid tracking the apron. All the drivers interviewed admitted that avoiding the truck apron made manoeuvring the roundabouts very difficult as it required extra caution especially when their vehicles carried load because of the possibility of load shifting. No significant differences existed between the roundabouts in terms of geometric details except that the topography at the location of the roundabout with the highest accident record was relatively steeper than that at the other roundabout locations. It is believed that the high incidence of truck overturning accidents at the University Police Station Roundabout could be attributed to a combination of a possible vehicle imbalance caused by load shifting as the truck drivers manoeuvred to avoid tracking the truck apron and the unfavorable gradient at that roundabout. The installation of the roundabouts should have been preceded by elaborate driver education on how to use the device.
Life cyle assessment of margarine production from palm oil in Ghana
(2008) Asiedu, Alexander Nana Yaw
100 % palm oil-based margarine has an outstanding demand by consumers as it is considered one of the spreads with beneficial nutritional value. Life cycle assessment (LCA) is an excellent tool of environmental management and it provides a widespread knowledge on the environmental burdens associated with a product or human activity. International Organisation for Standardisation (ISO) standards, ISO 14040-43, were followed in the execution of this work. Adequate data for inventory phase was obtained from different factories and farms. Through developed questionnaires submitted to the oil palm producer, TOPP (the largest supplier of crude palm oil to Unilever Ghana Limited) and Unilver Ghana Limited ( sole palm oil refiner and margarine producer in Ghana as of the time of data collection), and from Eco-invent database, inventory data was constantly sought for time duration of one year. Five phases of the 100 % palm oil-based margarine were studied namely oil palm production, palm oil production, palm oil refining and margarine production. LCA data associated with these phases were analysed by employing the GABI Software that was sponsored by the United Nations Environmental Program (UNEP) through the Life Cycle Initiative. The impact assessment method used in this study was the CML 2001 that was produced by Centre of Environmental Science of Leiden University. The analysis of these data by LCA has made it possible to quantify potential impact associated with 100 % palm oil-based margarine production. Seven impact categories were considered namely acidification potential, eutrophication potential, global warming potential, fresh water ecotoxicity potential, human toxicity potential, photochemical ozone creation potential and terrestrial ecotoxicity potential. Characterisation of the data revealed that the oil-refining phase posed the highest environmental burden. Since the product life cycle has a global coverage (e.g. resource extraction in diverse geographical regions), global data or normal values were compared with data for this work. Normalising the characterised environmental interventions revealed that acidification potential, eutrophication potential, global warming potential and photochemical ozone creation potential need mitigation measures when compared to global emissions. Two mitigating measures were recommended: anaerobic reactor system to reduce high organic load in wastewater due to oil losses at the oil production, refining and margarine phases; gas scrubbing system inclusion to reduce the emissions of CO2 and SO2 gases at the steam boiler houses at the oil refining and oil production phases. Inclusion of these mitigating systems can lead to 19.1 % reduction of global normalised environmental impact.
Developing a differential GPS (DGPS) Service in Ghana
(2008) Acheampong, Akwasi Afrifa
The prerequisite for successful execution of projects, applications, services or products reliant on surveys or geo-information, must be a uniform and reliable coordinate reference system. Provision of control points defining these reference frames by conventional methods are expensive, tedious, limited to intervisibility between beacons and the area of survey, thus reducing the effectiveness of networks at night and in poor weather conditions. Signals from Global Navigation Satellite Systems have proven to be fast, accurate and cheaper alternative to conventional methods, but performance indices for autonomous positioning are not satisfactory and as such for high precision assignments, relative or differential positioning techniques must be employed. However, differential positioning does place additional operational demands (two GPS receivers are required with one on known point and a data link between them when DGPS is to be implemented in real-time). A base station has been established at KNUST to provide GPS logs, reference coordinates, and to disseminate differential corrections for post-processing computations. This base will serve as the second receiver required for differential operations. Using the base station, several observation sessions were conducted and processed to compute 2D transformation parameters to integrate GPS data into the National Mapping System. The parameters computed can be used within a maximum radial error of 0.58ft around campus. Further investigations were carried-out on observation times and the solutions obtained showed that at least three hours was found to be optimum time to be spent when coordinating newly established base stations.
Comparative study of electricity storage batteries for Solar Photovoltaic home systems
(2008-08-05) Quansah, David Ato
The installed capacity of solar PV systems in Ghana was about 1MWp in the year 2003. This capacity is expected to increase significantly as the Strategic National Energy Plan (SNEP) seeks to enhance the role of stand-alone solar photovoltaic systems for off-grid rural communities that could not be electrified economically through grid extension. For such systems, it is now widely acknowledged that the high replacement cost and environmental impacts of chemical storage batteries constitute the key challenges to deployment and sustainability particularly in poor rural settings. On a life cycle basis, the storage batteries normally contribute about 40-45% of system cost. This thesis undertakes a comparative assessment of the technical, economic and environmental characteristics of the currently available electricity storage batteries that could be utilized in stand-alone solar PV systems. The batteries considered are Lead Acid, Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion. The technical assessment was based on cycle-life, discharge and charging characteristics and charge retention. Life-cycle cost was used as the economic performance indicator, while human safety risks and ecological impacts formed the basis of the environmental assessment. The cost and other data for the batteries were obtained from literature (print and online) and survey of the retail market in Ghana. The life cycle cost of electricity storage based on online retail pricing data and 12% discount rate ranged from an average of US$0.03 cents for lead acid to US$0.15 cents /Wh for Lithium-Ion batteries. Price data obtained from local suppliers yielded storage costs of 0.17- 0.42GHp/Wh for deep-cycle solar batteries and 0.93-1.0GHp/Wh for shallow-cycle automotive batteries on a life cycle cost basis.
Cost – Benefit analysis of water supply: A case study of Ghana water company limited Ashanti-Region
(2008-08-05) Antwi-Oppong, Frederick
The effect of recent water crisis in and around the cities and regional capitals of Ghana is a great concern. It hindered proper economic growth and put much pressure and stress on workers, women and school children. This research meant to look at the costs and benefits associated with improved water supply to the communities by the water company. Ghana Water Company Limited (GWCL)–Ashanti region was used as a case study. Cost –Benefit Analysis (CBA) is performed on monthly costs and benefits (revenue) from January, 2006 to December, 2007 from GWCL- Ashanti. It used Government of Ghana 91-day Treasury bill rate of 11.27 % (Bank of Ghana) as the discount rate for the analysis. The analysis indicated clearly that, the operation of GWCL is economically viable. The Benefit- Cost Ratio (BCR) gives the value of 1.3466 which is greater than one, the Net Present Value (NPV) is GH¢4,304,701.50 and that is greater than zero. The Internal Rate of Return (IRR) also gives the value of 27% which is also greater than the discount rate of 11.27%. All these clearly show that, the benefits the communities derived from having water supply improved are by far more than the costs incurred. These benefits amount to time saving, less illness, increases productivities at the workplaces, increase in school attendance rates.
Design of a grid connected photovoltaic system for KNUST and economic and environmental analysis of the designed system
(2008-08-08) Dadzie, Frank Yeboah
This research was undertaken to investigate the economic and environmental suitability of the implementation of Grid Connected Photovoltaic Systems in comparison to the use of fuel generators/plant as an alternative source of energy to solve the regular grid failure problem in residential and commercial institutions in Ghana with KNUST as the case study. In this work a 300 kVA grid connected photovoltaic system with 100% battery back up is designed for KNUST. System wiring, installation, maintenance and trouble shooting procedures for the system designed were outlined to show that it is theoretically possible to design a PV grid connected system for KNUST. To simplify the work, the design is undertaken for the 300kVA substation (Ridge substation) and the results are replicated for the remaining substations. The results of this work show that the KNUST Ridge substation requires a 360VDC battery bank with a capacity of 2785Ah (C10 rating). The system requires a 300kVA Trace sun-tied 3-phase Inverter and 1575 of the BP 7180 modules. The total yearly output of the system to the grid is calculated to be 0.296GWh. The 300kVA grid connected photovoltaic system is estimated to cost 2.88 Million dollars. The cost of installing a 300kVA fuel generator is 103,477 dollars. Assuming a loan interest rate of 8% and inflation rate of 12% over a 25 year product life, the calculation of the Average Incremental Economic Cost (AIEC) of the two systems shows that the grid connected PV system has a lower AIEC of 0.67 compared to 12.14 of the fuel generator/plant. This results show clearly that the grid-connected system is economically preferable to a fuel generator of the same capacity as an alternative source of electricity for KNUST. Sensitivity analysis carried out futher shows that the grid connected PV system is more economical at high inflations rates and longer project life times. Also, the net savings in CO2 by choosing the grid connected PV system over the Fuel generator is 180g/KWh and that makes the grid connected PV system more environmentally suitable. It is concluded in this work that in the long term the implementation of a grid connected PV system is both economically and environmentally preferable to a fuel generator/plant.
Impact evaluation of community-managed irrigation schemes
(2008-08-09) Ayaala Anyanwonbe, Thomas
This study was prompted by the observation made on how public infrastructure quickly falls into a state of disrepair in Ghana. The premature deterioration of these capital assets results in further drain on the already scarce resources of the country. This infrastructure, particularly irrigation facilities are left to deteriorate long before their useful life span is completed. To understand the complex issues of water and land resources management, the study sought to focus on socio-economic benefits and problems affecting the sustainability of these schemes. In addition, attempts were made determine how the quality of operation and maintenance services influence the sustainability of these projects and also identify options to improve irrigation performance. For the purpose of the study, two community-managed schemes, Nasia and Dorongo were selected from Northern Ghana based on their accessibility, experience and type of scheme. Both primary and secondary data were gathered for the study. Secondary data such as baseline information was obtained from government and development agencies (for example Irrigation Development Authority and Meteorological Service Agency). Literatures related to the theme of study were also gathered from different sources including the Internet. Primary data was gathered using formal/informal interviews and household interview survey. The household survey was conducted using questionnaires which covered socio-economic factors, management of scheme and maintenance of scheme, external supporting services (Credit accessibility, Extension services and Co-operative market promotion) and technical know-how of users. In addition, physical environmental effects of irrigation like impact of flood, siltation, and erosion were directly observed. Data was analysed using SPSS. Further statistical analysis were conducted to support the analysis on certain identified variables, (average farm input cost per ha, average land preparation/labour cost per ha and field water supply cost per ha), which were considered as principal components of sustainability of the schemes by using Multiple Linear Regression method. From the study of the two irrigation schemes, there are indications that farmers and their communities have benefited a lot from the projects. Such benefits include increase in household incomes, employment creation, food security and performance of some social responsibilities (for example payment of school fees). The major findings associated with the sustainability of the two schemes are related to operation and maintenance, water allocation, water distribution, decision-making and conflict management, land rights, inadequate supporting services, problems in produce market and local institutions. The study indicated that eventhough an irrigation scheme may be well designed, other issues such as operation and maintenance, water allocation, water distribution, decision-making, conflict management, land allocation, access to credit, input supply, high cost of maintenance and repairs, market situation, health situation and the problem of location and accessibility of the scheme to traders can affect the sustainability of such community managed irrigation schemes. Based on the Multiple Linear Regression analyses, it was concluded that the Nasia scheme is sustainable while Dorongo scheme is unsustainable. In conclusion therefore, for farmers to realise the potential socio-economic benefits and enhance the sustainability of these schemes, beneficiaries should not be taken as passive recipients of external intervention, as to simply follow pre-planned and laid-down rules, and that irrigation technologies socially constructed, have social requirements for use and social implications.
Aflatoxin contamination of maize from different storage locations in Ghana
(2008-08-09) Akrobortu, Dick Emmanuel
The contamination of maize by aflatoxins in Ghana is of major concern because of the health hazards associated with it. This study focused on the role played by variations in climatic factors such as relative humidity and rainfall on aflatoxin contamination of maize in different maize storage locations. The study was carried out on samples collected over a period of 10 years (1990 to 1999) in three Districts (Ejura-Sekyedumase, Afram Plains/North-Kwahu and Nkoranza) well – known for maize production in Ghana. The aim was to study the influence of storage locations on levels of aflatoxin contamination and distribution in maize. The findings indicated that significant difference exists between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and Nkoranza (p<0.05). Also there was a significant difference between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and North-Kwahu (p<0.05). There was no significant difference between the contamination levels of samples from North- Kwahu and Nkoranza (p>0.05). The total aflatoxin levels in samples from Ejura-Sekyedumase, North-Kwahu and Nkoranza over the period were 120.50 ppb, 153.20 ppb and 134.17 ppb respectively. For the period 1990 to 1999 the aflatoxin distributions in the storage locations showed that Nkoranza had the highest level in 1997 and 1999 while North-Kwahu had the highest in 1990, 1991, 1993 and 1998. Similarly, Nkoranza and North-Kwahu had equal levels of 10.50 ppb in 1995. The three locations had equal levels of 9.50 ppb in 1994. On the whole, Ejura-Sekyedumase had fair distribution levels since it was the only location with its highest level far below the acceptable level of 20 ppb for humans. I hereby recommend that further research must be conducted in other districts in the country in order to create awareness of the health hazards associated with the aflatoxin contamination.
Impact of road contractor classification on road maintenance delivery in Ghana
(2008-08-10) Yeboah, Joseph Kwame
In recent times the issue of inadequate local contracting capacity for the execution of road construction and maintenance projects seems to be assuming a disturbing national concern. Ineffective system of classifying road contractors, lack of road agency supervisory and monitoring capacity, difficulty in obtaining credit and delayed payment for certified work done, have been mentioned as factors affecting road maintenance delivery. This research seeks to assess the impact of the road contractor classification system; road contractor screening, selection and licensing for road works and in particular road maintenance services. The objectives of the study was: (1) to make a critical assessment of the procedures requirements and features of the system, (2) Identify classification factors affecting performing and non performing contractors and (3) draw lessons for an improved classification and tendering ♦ evaluation procedures. The research reviewed classification systems of some countries to understand the frame work of a road contractor classification system and to learn of best practices. Data collection was conducted by administering four different survey questionnaires to contractors, regional road agency staff of the Ghana Highway Authority (GHA), in two regions. Road maintenance managers of GHA and Ministry of Transportation (MoT) road contractor classification committee members also responded to questionnaires. The questionnaire sought to establish the procedures, criteria, method of evaluation of contractors' application information by the classification committee members. Based on 15 performing and 15 non performing previously selected contractors, road managers evaluated contractor classification factors that influenced the success or otherwise of completed or ongoing projects in the period 2002- 2007. The results show that lack of a proper legal status / structure of the road contractor classification system, weak verification and ineffective evaluation of contractor information results in an adhoc contractor registration and management, inadequate regulation and monitoring. Although the registration system in Ghana has achieved some modest gains in eliminating unsuitable and quack contractors, there is the need to create a separate department, council or board with legal status with a well resourced professional secretariat to be in charge of contractor grading, registration, monitoring and enforcement of contractor classification criteria. Verification and inspection of contractor facilities would then be intensified. In addition the adoption of a point system of evaluating contractors' information at classification would ensure that contractors tendering for road agency projects actually have the resources for which they have been classified.
The Hydraulic Performance of 900mm Diameter Pipe Culvert Using Wenchi - Sampa Road as Case Study
(2008-08-11) Baah, Seth Adjemang
Inadequate drainage of surface and subsurface water can have significant impact on road pavement behaviour and long-term maintenance costs. Interception of water before it infiltrates into the pavement foundation is essential unless the soils are truly free draining. Most pipe culverts are not seen by the travelling public and become noticeable only when a problem arises, such as flooding or settlement in the roadway. Occasionally there is an accident because an unexpected hydraulic failure of pipe culvert causes flood to overtop the roadway. In the past, the 450mm, 600mm, 1200mm and 1800mm diameter pipe culverts were used as cross drainage structures. Due to the hydraulic inefficiencies of the 450mm and 600mm diameter pipe culverts, the Ghana Highway Authority and the Department of Urban Roads decided in the 1980s to make the 900mm diameter pipe culvert (or its equivalent box culvdrt) the minimum cross drainage structure for their roads, as a regulatory measure. However, the hydraulic inefficiencies associated with the 450mm and 600mm diameter pipes were still found with the 900mm diameter pipes. This therefore necessitated the study into its hydraulic performance using the reconstructed 30km section of the Wenchi - Sampa Road in the Brong Ahafo Region of Ghana, as case study. Forty- five 900mm diameter concrete pipe culverts were covered in the study. The prevailing conditions at their locations were assessed. Generally, about half the number of the 900mm diameter pipe culverts were silted and few had their inlets and outlets scoured. The Regional Office of the Ghana Highway Authority was surveyed by administering a questionnaire to find from them their inspection and maintenance programmes for the 900mm diameter pipe culverts on the project road. Much of the information presented has been taken from the Field Survey Results. Information from the literature has also been incorporated and adapted where necessary, to fit highway needs. Appropriate recommendations were made based on the findings.
Impact of heavy goods vehicles on safety and traffic management in the Tamale Metropolis
(2008-08-17) Keketsyor, Mawutor Kofi
This report presents the results of a study to determine the Impact of Heavy Goods Vehicles on safety and traffic management in the Tamale Metropolis from 2005 to 2007. From 1991 to 2006, a total of 235,559 vehicles were involved in road traffic crashes nationwide, 11.8% of which were HGVs. Within the same period, 21626 people died as a result of their involvement in road traffic crashes throughout the country. 11.2% of these fatalities were HGV-related. On the northern corridor of the national trunk road network, freight transportation continues to grow, largely as a result of trade liberalization in the West African sub region. This appears, in part, to have impacted on safety as the main urban centres in the North have recorded a significant number of HGV-related accident cases. Tamale, the Northern Regional capital has had its fair share of these problems. The objectives of the study were to establish the characteristics of accidents involving HGVs, to determine whether HGVs are prone to specific types of accidents, and to identify challenges posed to traffic management as a result of the presence of HGVs on some selected roads in the CBD. Accident data for the study was collected from the files of the Motor Traffic and Transport Unit (MTTU) of the police service in Tamale, and the Building and Road Research Institute (BRRI) accident database in Kumasi. Manual Classified Traffic Counts were also conducted on the Bolga, Daboya, Kumbungu, Dagomba and Gukpegu Roads. Travel Time and Delay Studies were conducted on the roads mentioned to determine the duration, location and causes of delays. Discussions were also held with DUR officials in connection with pertinent traffic management issues on the roads studied. The results of the study show that there was a rapid increase in the number of HGV-related accident cases within the period with 21% out of a total of 76 cases occurring in 2005, 33% in 2006 and 46% in 2007. Fatalities also increased from, 26% in 2005, 29% in 2006 to 45% in 2007 out of a total of 93. The year 2006 recorded the highest proportion (18 out of 45) of people that were hospitalised as a result of their involvement in HGV-related accidents. Sixty-two (62) out of 130 casualties also sustained minor injury during 2006. The number of vehicles involved in HGV-related accidents increased in percentage terms from 20% in 2005, 28% in 2006 to 52% in 2007. It has also been revealed that majority of HGV-related accident cases occurred on link sections rather than at intersections, and that HGVs are prone to Rear-end and Ran-off road types of accidents. The Bolga IMPACT OF HEAVY GOODS VEHICLES ON SAFETY AND TRAFFIC MANAGEMENT [N THE TAMALE METROPOLIS - MSc. THESIS and Kumbungu Roads were identified as the most prone to HGV-related accidents. Congestion occurs on the Kumbungu Road between the Bonzali Junction and the Market Circle Road due to a backflow, onto the Kumbungu Road, of vehicles entering the Savelugu Terminal. The situation is compounded by slow-moving light trucks and inadequate NMT facilities which together creates conflicts on this section of the road. It has been recommended that the remaining sections of the second ring road be developed to the required standard to accommodate HGVs so that those HGVs destined for Bolga and beyond would no longer go through the city centre. In addition, the Metropolitan Authorities in collaboration with the Department of Urban Roads, and Goods Supply Companies should set up a bulk-breaking terminal along the Ring Road so that goods destined for Tamale can be delivered to the city centre by smaller vehicles.
The dynamic cone penetrometer as a validation tool for compaction of crushed rock base
(2008-08-17) Bakobie, Felix
The traditional method of verifying the level of compaction achieved on construction sites using sand replacement method is very time consuming and sometimes difficult to perform. Furthermore, on sites open to traffic the safety of the inspectors while conducting sand cone testing on a construction site can be a concern. Therefore, the objective of this study is to ascertain the extent to which the DCP can be used as a tool to verify the level of compaction achieved in-situ on a crushed rock base. Studies were conducted on an on-going road project to ascertain the extent to which the Dynamic Cone Penetrometer (DCP) can be applied in compaction verification on crushed rock. Compaction studies were conducted on three sections of the project site using a 17 ton vibratory roller. DCP test was conducted alongside sand replacement test to determine the level of compaction for one, two, four and eight roller passes. A linear relation was developed between the level of compaction and DPI values from the DCP test which is of form Log (LC) = a - p* log (DPI), where LC is level of compaction by the sand replacement method and DPI is the penetration rate of the DCP. The values of a and p were found to 2.134 and 0.109 respectively. A further study was also conducted in the laboratory to adjust the DPI values at various water content to constant water content. Three levels of compaction were calibrated and the result relation is linear and is of the form DPI= K + tav, K is a constant that depends on the level of compaction and w is the water content of the material at time of testing. LC=93% CR-B10: DPI = 3.874 + 0.855w LC-97% CR-B25: DPI = 1.228 + 0.836w LC=101% CR-B55: DPI = 1.316 + 0.470w

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