Ghana Mining Journal

Assessment of Water Quality in A Mining Community Using Remote Sensing and GIS Techniques

C. B. Boye — 2023-07-14

Abstract

Mining communities are faced with several environmental challenges associated with exploration, extraction and processing of minerals. The last few decades has witnessed massive activities of illegal small scale gold mining in or close to water bodies in most mining communities leading to pollution of the water resources. The traditional methods of monitoring water quality is a difficult task due to the extent of manual work required and the time involved. An alternative approach for assessing surface water quality is by using remote sensing data which has the advantage of broad coverage area and multi-temporal data availability for effective monitoring. This study used remote sensing techniques and field data to evaluate the water quality for the Prestea-Huni Valley Municipality. The normalized difference water index (NDWI) and normalized difference turbidity index (NDTI) were estimated from remote sensing data obtained from Landsat 9 satellite. The field samples were analysed at the Laboratory to determine some water quality parameters that is Total Suspended Solids (TSS) and Turbidity. These respective quality indicators values were used to produce interpolated maps for the study area using Inverse Distance Weighting approach. The values of the water quality indicators obtained from the reflectance values of the satellite images were found to be highly correlated with the measured water quality parameters acquired from the laboratory analysis. Very high turbidity and TSS values were recorded for most of the rivers in the study area, particularly the Ankobra which exceed the standard for drinking water set by the WHO and the Ghana water Company Limited. The utilization of GIS techniques and water quality indices in the assessment of water quality in this framework proved to be a beneficial contribution statistically to the monitoring and management of water resources.

Removal of Cadmium by Silver Nanoparticles Incorporated in Electrospun Natural Rubber Latex/Polyvinyl Alcohol Matrix

L. B. Osei — 2023-07-14

In this study, the efficiency of silver nanoparticles (AgNP) incorporated into electrospun natural rubber latex/polyvinyl alcohol (NRL/PVA) nanofibre matrix to remove Cd²⁺ from aqueous solution was examined. Electrospun AgNP-NRL/PVA nanofibre composites were produced using silver nitrate (AgNO₃) concentrations of 0.01 M and 0.015 M. Maximum Cd²⁺ was adsorbed at pH 7 for both nanofibre composites but at different reaction times of 20 min for 0.01 M AgNP and 40 min for 0.015 M AgNP. The maximum adsorption for 0.01 M AgNP was 14.9674 mg/g and 30.1129 mg/g for 0.015 M AgNP. Adsorption data were tested with Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms as well as pseudo-first order (PFO), pseudo-second order (PSO), Elovich and intra-particle diffusion kinetic models. Cadmium adsorption by both nanofibre composites fitted best to Freundlich isotherm. Adsorption data for 0.01 M AgNP fitted best to PFO kinetic model, whilst that of 0.015 M AgNP fitted best to Elovich kinetic model, with 0.015 M AgNP having a lower desorption constant and larger boundary layer (β = 0.1793 g/mg; C = 7.5959 mg/g) than 0.01 M AgNP (β = 1.0351 g/mg; C = 4.5942 mg/g). The nanofibre, 0.015 M AgNP, fitting best to Freundlich isotherm and Elovich kinetic model, showed that Cd²⁺ was chemisorbed. In general, 0.015 M AgNP was more efficient in adsorbing Cd²⁺ than 0.01 M AgNP. After the adsorption process, silver (Ag) concentration in the treated water (0.01 M AgNP = 0.0425 mg/L, 0.015 M AgNP = 0.0510 mg/L) was below US EPA and WHO guidelines of 0.10 mg/L for both nanofibre composites, rendering the treated water good enough for human use. Therefore, this work has shown the potential of AgNP incorporated in an electrospun NRL/PVA nanofibre matrix to remove contaminants (Cd²⁺) from contaminated water.

A Simple Statistical Model for Predicting Crude Oil API Values

S. A. Marfo — 2023-07-14

American Petroleum Institute (API) gravity value is the main indicator of crude oil quality and marketing value; hence, it must be simply and accurately determined. Existing crude oil API prediction models are complex and time-consuming because they use lots of parametric properties for predictions. Herein, we propose a simple two-variable (aromatic and naphthene content) statistical model for predicting crude oil API values. The statistical model in this study was developed using multiple linear regression techniques on about 80 crude oil samples from different locations. The study shows that the developed model in this work could accurately predict crude oil API gravity values with a standard error of 3.14 and a correlation matrix of 0.92. Also, the model confirmed that the use of crude oil aromatic and naphthene content could accurately describe its API values. The model could predict crude oil API better than some API models in literature by 38% - 62%. The findings in this work provide a simple and fast method of determining crude oil API for crude marketing and inspection.

Estimation of the Methane Generation Potential of the Tamale Landfill Site Using LandGEM

N. K. Amoatey — 2023-07-14

Though inevitable, waste generation due to man’s activities must be appropriately managed as a security measure to safeguard public health. This is seen in the efforts by many municipal assemblies to address sanitation issues. For a lower middle-income country such as Ghana, most of the waste generated ends up at the landfill. Disposing waste at landfill sites solves immediate public health concerns such as the foul odour; it provides the right conditions for generating methane anaerobically. Methane is a potent greenhouse gas and a very rich energy source. The study was conducted to estimate the methane generation potential of landfills in Ghana. The waste was characterised according to ASTM D5231-92 and the various waste fractions were as follows; food 43.1%, plastics 17.8%, glass bottles 2.3%, paper and cardboards 9.0%, metals 3.3%, textiles7.3%, wood 0.8% and inert 16.6%. It also revealed negligible variation in the waste characteristics across the two major seasons in Temale, Ghana. The LandGEM model was used to estimate the methane generation potential of the landfill site based on the waste characterisation data. The study showed that 77% of the total waste disposed of at the Tamale landfill site could decompose to generate methane at an average rate of 921.95 m³/hr during the 30 years lifespan of the Tamale landfill site and would reach a peak of 2222 m³/h in 2036. This shows enough gas can be generated for any LFG emission project.

The Use of Social Media as a Means of Information Dissemination among Postgraduate Students: A Case of the University of Mines and Technology (UMaT), Tarkwa

G. Pomfowaa — 2023-07-14

The introduction of social engineering technologies and applications has significantly altered the global communication of information. Social media has enabled a tremendous contribution to academic discourse in which faculty and students engage in academic activities with less face-to-face contact. It appears that graduate students make extensive use of these new technologies in their academic work. This study aims to determine the impact of graduate student use of social media tools at the University of Mines and Technology in Tarkwa (UMaT). This study aims to establish if Postgraduate Students at UMaT rely on social media or Web 2.0, as well as the advantages and disadvantages of using social media in their studies and research. Both primary and secondary data are used in the study. While secondary data was gleaned from academic publications, the primary data was gathered through the distribution of a questionnaire. The data collected were analysed using a simple descriptive analysis, and it was found that research and lectures were the most common academic applications of social media. The cost of an internet connection was a barrier to using social media platforms and was expensive and unstable.

Optimal Design of Gasifier Reactor for Crop Residues Gasification Using Integrated MCDM Techniques/QFD Approach

I. Osei — 2023-07-14

Gasification technology has a critical role to play in the quest to provide off and on-grid renewable energy solutions for rural agricultural communities. Optimal gasifier design is essential for sustainable energy generation and operation of gasifier systems. The aim of this study is therefore to design an optimal gasifier reactor for the gasification of crop residues using Integrated Multicriterial Decision Making (MCDM) Techniques and Quality Function Deployment (QFD) methodological approach. The MCDM/QFD framework consists of user requirement, engineering parameters and seven gasifier types. The engineering parameters were categorised under five sections and the best gasifier type under each category was determined using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The design characteristics of the best ranked gasifier type under each category was incorporated into a stratified downdraft gasifier reactor type. The characteristic of five crop residues and consideration of a 10-kW engine system for electricity generation was used to size and designed the gasifier reactor. The study revealed that updraft gasifier is the optimal gasifier that is efficient and can handle wide range of feedstock characteristics. Similarly, stratified downdraft and circulating fluidized bed gasifier are the optimal in terms gasifier operating conditions and good syngas quality respectively. A 45-kW semi-batch stratified Downdraft (SD) Gasifier with internal diameter and height of 0.36 m and 1.7 m respectively were designed based on average fuel consumption of 23 kg/hr and an airflow rate of 26.31 m³/hr. The optimal gasifier consists of a screw auger system, an extended ash collection bunker, and a gas recirculation combustion unit.

Development of Integrated QFD/MCDM Framework for Optimal Selection of Gasifier Reactor for Crop Residue Gasification in Ghana

I. Osei — 2023-07-14

A comprehensive methodological approach taken into account concerns of end users, optimal technical engineering parameters is proposed in this study to select optimal gasifier reactor type for the gasification of crop residues in Ghana. Eleven technical/economic user requirements based on the existing challenges of the gasification system in Ghana were identified. The Analytical Hierarchy Process (AHP) was used to determine the weight of importance of each user requirement. Thirteen gasifiers operating and design engineering parameters were identified. A Quality Function Deployment (QFD)/Multi-Criteria Decision-Making techniques (MCDM) methodological approach for the optimal selection of gasifier reactor using the user requirement, engineering parameters and seven gasifier reactor types was developed. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was used to rank the various gasifier types based on the thirteen technical parameters and corresponding weights as determined from the QFD. Low tar content, use of multiple feedstocks and high syngas quality with relative weights of importance of 0.28, 0.14 and 0.13 respectively were identified to be the three most important user requirement in the selection of optimal gasifier for crop residue gasification in Ghana. Similarly, based on the outcome of the QFD framework, feedstock moisture content, gasifier operating temperature and feedstock particle size were identified to be the three most important gasifier engineering parameters. The results of the study revealed that, stratified downdraft gasifier reactor is the optimal gasifier type with the required engineering characteristics for crop residue gasification in Ghana.