Faculty of Engineering, Earth Resources Engineering

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Browsing Faculty of Engineering, Earth Resources Engineering by Subject "EARTH RESOURCES ENGINEERING - Thesis"

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    item: Thesis-Abstract
    Optimization of Sri Lankan underground graphite mining methods, from a view point of rock mechanics and cost
    (2015-06-24) Hettiwatte, MC; Dharmaratne, PGR; Hemalal, PVA
    This research includes the study of the mining method adopted at Bogala Graphite Mines and its suitability compared with other mining methods used in the mining industry. The mining method adopted in Bogala mines has been assessed through this study. It mainly focus on the rock mechanics and financial aspects with comparisons to the mining methods adhered by the Sri Lankan mining industry. The major graphite occurrence discovered more than hundred years has produced highly valued the world over. In Sri Lanka, graphite mineralizations occur in the form of rich veins with steep dips in the South-Western sector of the island, the vast stretch of area which has been famous for graphite mining with thousands of pits in operation during the high demand of the first and second world wars. Where an outcrop is encountered, a pit had been sunk and the steeply dipping vein had been followed to the depths. At Bogala mines, the adoption of Overhand Cut-and-Fill mining method is influenced by the steeply dipping vein environment with rock intercalations and high water inflows with less competent country rock. Although cut–and–fill mining has been traditionally successful ensuring high recovery and safety, only limited studies has been carried out with an engineering input to evaluate this method. With the use of literature and site visits to Bogala mines, the mining method used at Bogala mines, the underground environment and the other mining methods used in the mining industry both internationally and locally have been studied. In evaluating the most suitable mining method, workability, safety and ore dilution and recovery factors of different mining methods were considered and the most suitable method for Bogala mine was evaluated.
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    item: Thesis-Abstract
    Site suitability analysis for water harvesting structures in Suriyawewa, Hambantota district using GIS techniques
    Senanayake, IP; Puswewala, UGA; Dissanayake, DMDOK
    Sri Lanka receives an average annual rainfall varying from 900mm to 6000mm. However, the rainfall is not distributed equally over the island. Hence, traditionally, the country is divided into three main climatic zones as wet zone, dry zone and intermediate zone. Two thirds of the island is occupied by the dry zone, which receives less than 1750mm of average annual rainfall. The dry zone periodically has faced water stress conditions from the past, and Hambantota District appears to be a severely affected area, on the basis of surface water availability. With the ongoing development projects, the demand for water in the district will increase in the next few years. Therefore, implementation of a proper water management system as well as preservation of existing surface and groundwater resources is essential to overcome this problem. A methodology is developed to find the most suitable locations for water harvesting structures in Hambantota District by using Geographic Information System (GIS) techniques. Suriyawewa Divisional Secretariat area is selected as the research area considering its average climatic conditions and location within Hambantota District. This methodology can be generalized to the whole District in the first instance. The research area is hydrologically analyzed to discretize the area into catchments and the preferred catchments to harvest the runoff based on surface area, slope and rainfall are found by using GIS techniques. The selected catchments are then analyzed with geological data and drainage characteristics to find the most suitable catchments to construct reservoirs to store rainwater. The analysis yields four such locations, which were subsequently field verified for spatial accuracy. However detailed local investigations are necessary before proceeding to actual construction of the reservoirs. Groundwater recharging also plays an important role in water management, as groundwater represents 30.1% of the world’s fresh water resources. GIS techniques are employed to integrate data on land use, climate, soil, stream pattern and ground slopes, and consequently to find potential areas for groundwater recharging. Here also, detailed local investigation must precede any construction work in the selected areas. Also, potential areas to implement roof water harvesting projects in Suriyawewa are found by analyzing the rainfall and building cover by using GIS techniques. These areas are recommended to be used as project areas when implementing efficient roof water harvesting methods. The methodology adopted here for Hambantota District can be used for water management in other Districts of the Dry Zone of Sri Lanka such as Monaragala, Puttalam, Ampara, Badulla and Kurunegala, as a solution for water stress conditions in those areas. An increment in water harvesting can significantly increase the crop yields in these areas and improve the economy as most of the Districts in the Dry Zone are agriculture-based. Also, a proper water management system is a must for the industrial development of the area under focus, while it gives a solution to the problems regarding drinking water. Proper water supply plays a major role in infrastructure development of these areas and would form the foundation for the overall development of the country.