ERE - 2015
Permanent URI for this collectionhttp://192.248.9.226/handle/123/18295
Browse
Recent Submissions
- item: Conference-Full-textProceedings of ERE 2015 Proceedings of the 9th ERE Conference on Earth Resources Management [Pre Text](Department of Earth Resources Engineering, 2015-07) Hemalal, PVA
- item: Conference-Full-textInfluence of geotechnical conditions on explosive specific charge in Sri Lankan quarrying and tunnelling practices(Department of Earth Resources Engineering, 2015-07) De Silva, PHHM; Anuruddha, HMD; Abeysinghe, AMCL; Priyashantha, KMDC; Hemalal, PVA; Dharmaratne, PGR; Hemalal, PVAQuarrying and underground excavations carried out by drilling-and blasting is the most commen technique usued in sri lankan mining practice Although only a small amount of the explosive energy is efficiently utilized in rock blasting, the economics of subsequent processes such as loading, hauling and crushing are governed by the initial explosive impact on breakage of hard rock. Explosive consumption in the initial stage of rock breakage from the mass is expressed in terms of explosive specific charge or powder factor. Variations in geological and geo-technical parameters such as rock joint characteristics; strength of rock and rock mass rating (RMR) with varying geological characteristics is reflected in the variation of the specific charge of the explosive. Even though there is a large variation in geology over the Sri Lankan land mass only the metamorphic rock terrain has been considered, in studying the influence of geological and geotechnical properties on the determination of the explosive specific charge as an important parameter in blast planning and estimation. The paper emphasises the relationship of rock strength parameters and rock mass rating when estimating optimum explosive specific charge for economical quarrying and tunnelling practices in Sri Lankan conditions.
- item: Conference-Full-textCritical analysis of safety aspects of an underground graphite mine with reference to Bogala mines(Department of Earth Resources Engineering, 2015-07) Karunarathne, KVP; Piyasena, DT; Marino, IJ; Sarvakaran, S; Hemalal, PVA; Dharmaratne, PGR; Hemalal, PVATrend analysis of occurrence of mine accidents was proposed to assess the risks associated with occurrence of underground accidents and human health in order to manage and control measures and support decision making. It provides the right balance between different concerns, such as safety and costs. For this purpose, information collected from Bogala graphite Lanka PLC located at Aruggammana in Kegalle district, Sri Lanka, was used to manage the risks affecting the health and safety of the miners. In order to categorize the data, various hazardous activities were identified and classified under eleven categories: Scaling, Hammering, Supporting, Lifting of weights, Drilling, Graphite transportation, Loading, Mucking, Machine/tool operating, Machine/tool repairing. The ranking process is accomplished by analyzing the past accident records. Further, four critical groups of body parts with different illnesses were obtained. These groups were; eye, limbs, back, head. From these groups, the most common injuries with the highest level of occurrence are sprains, cuts, bruises and contusions. According to the results, the proposed methodology can be a reliable technique for management of mine hazards and coping with uncertainties affecting the health and safety of miners when performance ratings are imprecise. The proposed recommendations can be primarily designed to identify potential hazards and help in taking appropriate measures to minimize or remove the risks before accidents occur in future mining activities in Bogala mines.
- item: Conference-Full-textDetermination of percentage of mineral in beach sand using digital image processing techniques(Department of Earth Resources Engineering, 2015-07) Abeyrathna, PMDGSK; Bandara, IMMS; Ranaweerasinghe, GA; Tharmakulasingham, K; Rohitha, LPS; Hemalal, PVADetermination of percentage ofmineral is extremely important in beach sand mining industry. To select a site for extraction and processing heavy minerals it is important to assess the rough concentrations. The traditional methods are time consuming, costly, high labour intensive and difficult to handle the equipment. A method was developed to determine the percentage of minerals in raw sand by Digital Image Processing. HSV colour space was selected due to its wide range when compared to other colour spaces. Non over lapping samples were analyzed in this research. Most appropriate background was selected using colour analysis of HSV values. Background was differentiated from the minerals by using HSV values. By analyzing the pixels, area occupied by the minerals can be determined and using weight to area relationship, the weight percentage of minerals can be identified. Validation was carried out and using the statics accuracy was estimated. There are some limitations despite the benefits.
- item: Conference-Full-textGeochemical aspects of serpentinite bodies at Ginigalpelessa off Ambilipitiya, Sri Lanka(Department of Earth Resources Engineering, 2015-07) Kumara, HPKSA; De Silva, PS; Dushshantha, MNP; Madhusanka, WDS; Weerawarnakula, S; Premasiri, HMR; Abeysinghe, AMKB; Hemalal, PVAGinigalpelessa Serpentine bodies are located along major tectonic boundary between Highland and the Vijayan Complexes - in the South Eastern part of Sri Lanka. Ultramafic rocks and their soils are rich with specific metals such asFe, Mg, Mn, Ni, Co and Cr. Release of certain metallic elements from weathered rock to soil and their in situ concentration have been identified. "MorindaTInctoria" plants which is wide spread in the area is restricted to area underlain by Serpentinite bodies. Ni concentration in the rocks varies between 2250-3340ppm while over 100% - 175% increase in concentration is found in soil. The plant "MorindaTInctoria" shows high concentration of Ni compared to the same plants collected from elsewhere in the country. The restriction of the plant to the particular area and its growth pattern in the area indicate that the plant could be used as an indicator plant for identifying higher concentration of Nisoil . Increased element concentration from the bed rock to soil has been identified for Fe (260%) Mn (270%), Co (280%) and Cr ( over 6700%) Decreased element concentration has been identified for Mg (580%). Very high Cr values found in soils (over 14000ppm of Cr in soils) leads to investigate the effect of Cr for human health in the area.
- item: Conference-Full-textCharacterization of beach sand deposits with heavy minerals using geo-physical techniques(Department of Earth Resources Engineering, 2015-07) Angammana, UHBIU; Gunasingha, ULDDM; Gunawardana, RA; Srilal, KGC; Ranaweera, KVDNP; Abeysinghe, AMKB; Weerawarnakula, S; Premasiri, HMR; Hemalal, PVAMineralogical analysis through physical concentration and microscopic studies of beach sand is one of the most accurate methods in the determination of percentages of constituent heavy minerals of beach sand. However, in this study a magnetic survey method was tested as a field method to separate magnetic minerals from non-magnetic minerals in beach sand. The main objective of this study is to find out a relationship between magnetic survey data and heavy mineral composition data of beach sand. Beaches at Panadura and Beruwala were selected for the magnetic surveys, owing to their dominance of heavy mineral bearing beach sand. Samples were also taken adequately and systematically from each beach, and were analysed at the mineral laboratory. The iso-dynamic magnetic separator was used to separate the magnetic heavy minerals. ArcGIS software and geo-statistical and normal statistical analyses were used to build the relationship between magnetometer survey data and mineral composition data. analysis was not observed a significant relationship between magnetic survey data and mineral composition data. However, According to the geographically weighted regression (GWR)
- item: Conference-Full-textAn alternative mitigation method for Gerandi-Ella reactivated landslide(Department of Earth Resources Engineering, 2015) Mampitiyaarachchi, CT; Ranathunga, RMIGNK; Rifad, MZM; Thathkalana, UMC; Abeysinghe, AMKB; Indrathilaka, HML; Premasiri, HMR; Weerawamakula, S; Hemalal, PVAGerandi-Ella, a former landslide area is currently under threat of reactivation. National Building Research Organization has implemented a surface and vertical well drainage system to stabilize it. However, vertical drainage system has failed,and an unexpected behavior of groundwater was observed due to presence of clay layers in the colluvium. An effective and economical alternative mitigation method is required to stabilize the area. A particular portion of the site,positioned such that it keeps the rest of the landslide mass intact, was chosen as the study area. Implementing a proper alternative mitigation methodto the study area may help to stabilize the landslide along with existing surface drainage system.Piezometric levels at two boreholes and rainfall data at the study area were analyzed. Stability analysis through the software SLOPE/W gave the current factor of safety as 0.965. A horizontal drain network with suitable design parameters was proposed to achieve a factor of safety of 1.206 by considering the effect of the matrix suction. A series of sand and gravel filled vertical holes capped with 100 cm clay layer are also proposed to expedite the water drawdown through impervious strata to horizontal drains.
- item: Conference-Full-textDelineation of potential sites for gemstone mining in Kura Ganga catchment, Ratnapura: a GIS approach(Department of Earth Resources Engineering, 2015-07) Jaliya, RGC; Thotahewa, AHTTB; Palihakkara, CR; Siriwardena, PRR; Premasiri, HMR; Dharmaratne, PGR; Chaminda, SP; Senanayake, IP; Hemalal, PVASri Lanka has been known as 'Ratnadeepa', which translates to 'Island of gems' because of the precious natural gemstones found in its gravelly soil. Even though the gem industry in Sri Lanka extends back to ancient times, studies on patterns of gemstone occurrences were rare. However, identification of potential gem bearing lands can provide guidelines in mining and land valuation. This study was carried out to identify the potential lands for gemstone mining in Kuru Ganga catchment, Ratnapura, based on patterns of gemstone occurrences and mining cost using integrated geo-spatial technologies. Fieldwork was conducted to collect gravel samples from riverbanks and gem mines. The samples were subjected to microscopic analysis to trace potential gemstones. The results obtained were combined with the data gathered from gem mines and mapped on a GIS platform to identify the occurrence patterns. Mining cost at each sampling location was estimated based on depth to the gem bearing gravel layer, "illamaSubsequently, potential lands for feasible gemstone mining were delineated through a knowledgedriven weighted analysis. The results depict that the South Western region of the Kuru Ganga catchment encompasses the highest feasibility of gem mining while North Eastern region of the catchment has the least feasibility of gemstone mining based on mining cost and values of potential gem varieties in the area.
- item: Conference-Full-textDevelopment of a treatment technique to reduce the water absorption capacity of recycled aggregates(Department of Earth Resources Engineering, 2015-07) Madawa, WKA; Rathnayake, RMSIB; Wijethunga, DB; Gamage, TC; Karunarathne, S; Hemalal, PVAThis study was to find a treatment technique to reduce the water absorption of Recycled Aggregates (RA) which involved preparing a coating to reduce the water penetration. The materials considered for the preparation of coating was Termite Mound Soil (TMS) and ordinary Portland cement. The objective was to find their optimum proportions and the slurry thickness for a coating that gives the lowest absorption. TMS was tested for pozzolanic properties. Chemical composition was tested using Atomic Absorption Spectroscopy and other analytical techniques. Water absorption, particle size distribution, AIV, LAAV of RA was tested to ensure the suitability for construction purposes. Slurries were prepared using cement replacement levels of 0, 20, 40, 60 and 80% of TMS. Three sets of coatings were prepared with water to solid ratios of 1, 1.25 and 1.5. Slurries were prepared in a concrete mixture in which the aggregates were coated for 10 minutes at a speed of 30rpm. After air drying, coated aggregates were tested for the absorption after 14 days. The absorption of treated aggregates was compared with those of natural and untreated recycled aggregates. Aggregates Coated using 50% cement and 50% TMS showed a significant reduction in the water absorption up to 38.44%.
- item: Conference-Full-textPerformance forecasting for the beach nourishment project at Palliyawatta-Uswetakeiyawa Sri Lanka(Department of Earth Resources Engineering, 2015) Azoor, RM; De J Seneviratne, MTMRIC; Saranya, R; Thenugaadevy, P; Gamage, GSM; Premasiri, HMR; Ratnayake, NP; Hemalal, PVABeach nourishment is a soft engineering solution that is increasingly used to combat erosion in a sustainable manner. Sri Lanka's first major Beach nourishment project was carried out over a 1.8 km stretch in the UswetakeiyawaPalliyawatta area, by the Coast Conservation Department of Sri Lanka (CCD). The Project was conducted in January 2012 and 300,000 cubic meters of offshore sand pumped using a dredging vessel was used to nourish the stretch of eroded beach with a total project cost of USD 300 million. This research was carried out to assess the performance and to forecast the future performance of the above nourishment project. Topographic data and grain size data were gathered and analyzed over a period of six months spanning an entire seasonal cycle. Satellite imagery spanning a much larger time period were also analyzed and complemented with the field data. The findings of the research indicate that due to incorrectly oriented sand retention structures and the incorrect grain size of nourished sand, the nourished area is currently undergoing rapid erosion. However, it is forecasted that the beach will come back to its pre-nourished stage after a period of 12 months. This will result in the exposure of a beach rock at the mean sea level and will cause the beach to lose its recreational and aesthetic value, and to prevent this and to retain the nourished sand, the correct orientation of the retention structures and the appropriate grain size for nourishment are proposed.
- item: Conference-Full-textPhytoremediation of heavy metals in mine drainage by tropical aquatic plants(Department of Earth Resources Engineering, 2015-07) Dassanayake, DMSM; Pushpakumara, KBN; Sampath, RPS; Prabhanga, UB; Senanayake, IP; Jayawardena, CL; Hemalal, PVAAcid mine drainage (AMD) is a major environmental problem associated with mining activities. There are several methods to remediate these mine drainage by neutralizing and removing metals from solutions. Those mechanisms can be mainly divided into active or passive systems, which this study describes the utilization of aquatic plants abundant in tropical conditions, in line with the passive remediation technique known as phytoremediation. The plants were selected based on the survivability in the tropical conditions and efficiency of extracting metals. Eichhorniacrassipes(Water Hyacinth) was the most survivable plant, and was deployed to absorb Fe, Cu and Cd from solutions reflecting the generic characteristics of mine drainage. The drainage solutions were created, with increasing concentrations of each ion starting from the permissible threshold values in accordance to the World Health Organization (WHO) guidelines. The results reflect that the efficiency of phytoremediation process with Water Hyacinth was optimum when the solutions were neutral (pH ~ 7) and deteriorating under acidic conditions (i.e. pH<7).
- item: Conference-Full-textNatural gas utilization plan for Sri Lanka(Department of Earth Resources Engineering, 2015-07) Wanniarachchi, KCR; De Mel, WDM; Marasinghe, AGNS; Sinthusan, T; Vijitha, AVP; Hemalal, PVANatural gas is finding its place at the heart of the energy discussion all over the world. It is being a cheap and relatively environmentally friendly alternative energy. The recent emergence of this discussion is due to substantial new discovery of natural gas in Sri Lanka. As a developing country, Sri Lanka spends an excessive amount of money for energy. The new discovery of natural gas deposits may be able to raise the Sri Lankan economy in next decades. To start gas production in the country should have a plan to consume the gas within the country to gain the best use of its research. Under the topic of natural gas utilization system for Sri Lanka the research is carried out to find the best way or the most economical way of utilizing the natural gas in Sri Lanka comparing scale and the economic factors. The research is focused on five special areas :Distribution of NG within the country :Public and private transportation :Power generation: Domestic and industrial use of NG: Fertilizer manufacturing Study area of this research on scientific and economic comparisons of above processes to address this important problem in the presence of uncertainty. This work presents such a method based on decision analysis of gas prices as well. It includes the entire well-to-market supply chain, from extraction, conversion, and transportation, to reconversion at the target market. Finally, it identifies the best gas transporting method according to the current situation, daily production, how these effects to the power generation sector in Sri Lanka, propose the most economical and safe method of using NG for domestic use which suitable for Sri Lankan context with analyzed data with evidence.
- item: Conference-Full-textTsunami modelling and risk assessment of Hambantota, Sri Lanka using integrated remote sensing techniques(Department of Earth Resources Engineering, 2015-07) Fernando, WAM; Aswer, MLM; Premarathna, MWVS; Suthakar, M; Dassanayake, DMDOK; Senanayake, IP; Samansiri, S; Hemalal, PVAThis study was carried out to develop an inundation and risk assessment model in Hambantota coastal area, based on the 2004 tsunami event. This tsunami event was one of the largest tsunamis to cause devastation to human beings, livelihoods, buildings, roads, rails and other infrastructure facilities in the study area. In addition to this study area, other parts of the coastal belt of Sri Lanka also experienced the chaotic outcomes of this tsunami event. By modelling risk, based on the 2004 tsunami event data, inundation and risk assessment for future tsunami event was modelled with a high safety factor. INSPIRE web portal which has been developed based on the TUN AMI mathematical model, was employed in this study to evaluate both inundation and risks to the local communities and their livelihoods with a higher level of accuracy. The main inputs to INSPIRE are topography data/bathymetry data, vulnerability data and fault parameters of the source earthquake, whereas the output maps provide the inundation area, wave velocity along the terrain and the potential risk to the area under consideration. Results of the study represent the variation of the tsunami inundation and the risk assessment of the Hambantota area based on remotely sensed digital elevation data inputs with different spatial resolutions data such as, ASTER, SRTM, LiDAR and GEBCO. Different inundation output maps were analyzed and the risk prone areas were identified. Furthermore, building structures were assigned risk indices based on the vulnerability to damage and fragility curves were developed in the case of a future tsunami event.