Pitwall Stability Analysis-Case Studies*

The importance of pitwall stability in design and economy of open pits has been a subject of considerable research in rock mechanics for some time now. Imperceptible slow mass movement has been a secret agent in inducing major pitwall failure. The problem is location specific and is associated with stress development, shear strength, discontinuity orientations and groundwater regimes. This paper therefore sets out to present pitwwall stability analysis in some selected pits within the Birimian environment in Ghana. Several attitude measurements were taken particularly on the footwall and along the slope face of the oxide, transition and fresh (sulphide) rock materials from some selected pits. The geologic data was subjected to the Romana’s Slope Mass Rating (SMR) analytical procedure and the pitwalls monitored through installed prisms. The oxide/ transition zones gave an SMR quantitative value of 43.1 in the footwall and 44 within the hangingwall, indicating a partial stability at 50o. The fresh rock (sulphide) gave a value of 64 in the footwall showing stability at 55o. As usual, the fresh rock was less problematic as indicated by the SMR assessment compared to the oxide and the transition materials. Creep movement was observed to predominate, being nearly 250 mm/day within the oxidised zone but lesser in the transition and fresh rocks. Induced pitwall failure pattern within the Birimian was more of composite failure (ie.,planar and toppling) capable of destabilising several pits if unchecked

Establishing Ground Vibration Threshold Level for Open Pit Mining Environment - A Case Study

To assess the impact of blasting activities on building structures in open pit mining districts in Ghana a study was carried out in Prestea, a township very close to the perimeter of the Plant North pit of the Bogoso GoldLtd (now Golden Star Resources Bogoso/Prestea Mines), in the Western Region of Ghana. It was observed during the study that the quality of most 'residential building structures within the Prestea township and itsenvirons were generally sub-standard. Most of the houses were in a deplorable state of disrepair with their conditions already triggering failure. Again, it was noted that no records were available to ascertain the structural state of the buildings prior to the commencement of blasting activities at the pit, necessitating the need to carry out a baseline study of buildings in nearby Himan townships for comparative analysis. It was also observed that even though management had selected 12 mm/s as its threshold for its operations in the pits only 6% of the over 542 blasts monitored over a two and half year period had ground vibration values in excess of 1.5 mm/s, with a maximum recorded value of 8 mm/s.It is recommended that management should not adopt ground vibration levels in excess of 2 mm/s for their pit operations because of the poor infrastructure within the surrounding communities. Even though this level can increase drilling and blasting costs considerably, it is considered a better option than expensive lawsuits in the likely event of any further damages that may be caused to building structures in the township

Fluoride in groundwater and its implications in west Gonja District of Ghana

Fluoride levels in groundwater may cause either enamel fluorosis or dental caries depending on their concentrations when consumed. Research has shown that an estimated 60 % of the total intake of fluoride is through drinking water (Selwitz et al, 2007). Boreholes sunk in the West Gonja district had their groundwater analyzed for fluoride. Using World Health Organisation (WHO) standard of (0.5-1. 5 mg/l) as basis, result revealed that concentration deviates from standard set by WHO. Test boreholes drilled in the communities showed three broad categorisations of fluoride levels in the groundwater as

Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution

The study compared the technical efficiency and economic cost of five advanced oxidation processes (Fenton, UV photo-Fenton, solar photo-Fenton, UV/TiO2/H2O2 and FeGAC/H2O2) for degradation of the pesticides chlorpyrifos cypermethrin and chlorothalonil in aqueous solution. The highest degradation in terms of COD and TOC removals and improvement of the biodegradability (BOD5/COD ratio) index (BI) were observed to be (i) Fenton - 69.03% (COD), 55.61% (TOC), and 0.35 (BI); (ii) UV photo-Fenton -78.56% (COD), 63.76% (TOC) and 0.38 (BI);  (iii) solar photo-Fenton - 74.19% (COD), 58.32% (TOC) and 0.36 (BI); (iv) UV/TiO2/H2O2 - 53.62% (COD), 21.54% (TOC), and 0.26 (BI); and  (v) the most technical efficient and cost effective process was FeGAC/H2O2. At an optimum condition (FeGAC 5 g/L, H2O2 100 mg/L, and reaction time of 60 min at pH 3), the COD and TOC removal efficiency were 96.19 and 85.60%, respectively, and the biodegradation index was 0.40. The degradation rate constant and cost were 0.0246 min-1 and $0.74/kg TOC, respectively. The FeGAC/H2O2 process is the most technically efficient and cost effective for pretreatment of the pesticide wastewater before biological treatment.

Perfecting Rural Land Title for Wealth Creation and Sustainable Development

AbstractPerfecting land title refers to the process of securing tenure on land. It refers to the assurance that the land one holds for an agreed period of time and purpose is certain. It requires a level of legitimacy. It is on record that agriculture, forestry and mining sectors constitute about 70% of Ghana’s gross domestic product. However, the lack of several large-scale plantations in Ghana can be partly attributed to the land tenure system. Land rights in rural communities are not secured in that the lands are not themselves well defined and rights are not documented. The study used modern survey methods to clearly map out farms in a systematic manner for farmers under a cooperative for rubber plantation development. The rights of tenant farmers and landholders are clearly and legally documented and registered into the formal land administration system. The spatial and attribute data are incorporated into a Geographic Information System (GIS) that serves as tool for data management on the farmers. The pilot study was successful in improving not only tenure security and data access, but also access to funding by participating farmers. Keywords: Land Tenure Security, Registration, Spatial Data, Attribute Dat

Product Marking and Conformity Assessment of Portland Cements on the Ghanaian Market

Cement bound concrete materials and complementary fittings are requisite ingredients for all civil engineering works. In all these, Portland cement, a basic binding ingredient for the concrete work is the dominant binder. In Ghana, there are various brands of cement on the market. Five major brand products currently in circulation include the Ghana Cement (GHACEM), Western DIAMOND Cement (DIAMOND), CIMAF Cement, DANGOTE Cement and SUPACEM Cement. Increased infrastructural development has placed high demand on cement consumption. Consequently, new products keep emerging in the market. Indeed, a standard measure to provide product marking and evaluations of conformity to standard Class thresholds are required for the desired specification, properties and the performance quality of the cement products. This research therefore sets to ascertain the strength quality of the five cement brands on the Ghanaian market by checking their conformity to C-30 and C-40 standard compressive tests, using their 32.5-R and 42.5-R flagship brands. To achieve this, concrete cubes were moulded with fixed mix ratio of 1:1⅟2:3 and 1:1:2 for C-30 and C-40 respectively. To achieve the desired strength conformity, the slump as well as the coarse and fine aggregate constituents were standardised. The results indicated that the cement brands despite parading same strength thresholds in the market, do not exhibit same strength build-up. There are significant variations in growth of compressive strength over time. It was observed also that conformance threshold within 28 days was not attained for a number of the brands. Indeed, not until 56 days or more some of the brands could not achieve their desired compressive strength thresholds

Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution

The study compared the technical efficiency and economic cost of five advanced oxidation processes (Fenton, UV photo-Fenton, solar photo-Fenton, UV/TiO2/H2O2 and FeGAC/H2O2) for degradation of the pesticides chlorpyrifos cypermethrin and chlorothalonil in aqueous solution. The highest degradation in terms of COD and TOC removals and improvement of the biodegradability (BOD5/COD ratio) index (BI) were observed to be (i) Fenton - 69.03% (COD), 55.61% (TOC), and 0.35 (BI); (ii) UV photo-Fenton -78.56% (COD), 63.76% (TOC) and 0.38 (BI);  (iii) solar photo-Fenton - 74.19% (COD), 58.32% (TOC) and 0.36 (BI); (iv) UV/TiO2/H2O2 - 53.62% (COD), 21.54% (TOC), and 0.26 (BI); and  (v) the most technical efficient and cost effective process was FeGAC/H2O2. At an optimum condition (FeGAC 5 g/L, H2O2 100 mg/L, and reaction time of 60 min at pH 3), the COD and TOC removal efficiency were 96.19 and 85.60%, respectively, and the biodegradation index was 0.40. The degradation rate constant and cost were 0.0246 min-1 and $0.74/kg TOC, respectively. The FeGAC/H2O2 process is the most technically efficient and cost effective for pretreatment of the pesticide wastewater before biological treatment. Copyright © 2018 BCREC Group. All rights reserved Received: 26th July 2017; Revised: 26nd September 2017; Accepted: 27th September 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Affam, A.C., Chaudhuri, M., Kutty, S.R.M. (2018). Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 179-186 (doi:10.9767/bcrec.13.1.1394.179-186

Improving Land Tenure Security through Customary Boundary Demarcation- A Case Study

In sub-Saharan Africa, one of the barriers to development and wealth creation in the peri urban and rural areas is land tenure insecurity. This is mainly due to a number of factors including the absence of clear unambiguous boundaries between allodial owners and the absence of credible documentation of land rights. This research sought to establish and document over 190 km of the boundary of Juaben paramouncy in a manner that ensured peace, harmony and tenure security. Disputes were resolved through less costly Alternative Dispute Resolution (ADR) mechanisms and Customary Land Secretariat (CLS) that catalogued and maintained up to date register on the land. This resulted in conflicts that have raged on for decades, sometimes leading to injury, property destruction and loss of lives come to an end. The benefits of this improved land tenure security are enhanced agricultural productivity, wealth creation for rural dwellers, peace and stability. Boundary demarcations and documentations established were important steps in the process of reformation and improving land tenure security in the rural communities. Information retrieval was simplified and transaction cost made cheaper. Keywords: Land Tenure Security, Customary Boundary Demarcation (CBD), Alternative Dispute Resolution (ADR

Multivariate Statistical Evaluation of Geochemical Data from Quartz Vein-Associated Gold Mineralisation at the Badukrom Prospect within the Tarkwaian Base

The Kawere conglomerate at the base of the Tarkwaian Group in the Iduapriem Mine appears to show good prospect for hydrothermal gold mineralisation evidenced by major structures mapped from magnetic and Airborne Electromagnetic (AEM) geophysical data. Detailed geological mapping and sampling at Badukrom target which lies within the Kawere rocks confirm the presence of multiple structures as well as quartz veins indicative of potential hydrothermal gold mineralisation. Follow up soil sampling conducted within the area revealed a strong anomalous trend from the southern portion. Two diamond drilled (DD) holes pushed to delineate the extent of the anomalous zones returned narrow veins of significant gold intersections. Twenty-five (25) samples of the Badukrom hydrothermal Au mineralisation intersects were sent for analysis to ascertain the optimum pathfinder element suite for the hydrothermal targets within the Iduapriem concession. A total of fifty-nine elements were analysed via ICP-MS and ICP-OES. Multivariate statistical evaluation was carried out on the results to understand the geochemical associations of Au and the other elements to aid future exploration programmes planned for the hydrothermal targets. Multivariate analysis of the geochemical data using Pearson product-moment of correlation suggests a stronger positive correlation of gold with Iron, Antimony, Sulphur, Chromium, Vanadium respectively. However, the Spearman Rank correlation data indicates that, the optimum pathfinder elements for hydrothermal Au are: As, Sb and Te.   Keywords: Tarkwaian Base, Statistical Evaluation, Hydrothermal Mineralisation, Geochemical Dat