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Browsing Departmental Conferences by Conference "2nd Annual Conference on Minerals for a Better Future - A Multidisciplinary Approach"
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- item: Conference-Full-text2nd Annual Conference on Minerals for a Better Future - A Multidisciplinary Approach [Pre Text](Department of Earth Resources Engineering, 2007-11) Karunaratne, S
- item: Conference-Full-textAlternative for river sand(Department of Earth Resources Engineering, 2007-11) Ekanayaka, EMTM; Jayawardene, MN; Kannangara, KKDM; Puswewala, UGA; Rathnayake, NP; Chaminda, SP; Vijitha, AVP; Karunaratne, SThe need of finding an alternative for river sand arises due to the over exploitation of river sand and its various harmful consequences. The focus of the current study was on offshore sand, which is clearly one of the most viable alternatives for river sand, with respect to availability, ease of extraction, environmental impact and cost. Offshore sand is already used in Sri Lanka mainly for road filling and it is also used for construction in all over the world. A sea survey was conducted in Kaluthara-Benthota sea area and a resource distribution map was plotted. Samples from Muthurajawela offshore sand stick piles were collected and CT content was checked. Offshore sand saturated with sea water has Cl' content around 0.3%, where as if the seawater is gravity drained; it reduced to around the acceptable 0.075%. The action of an average rain fall would be enough to reduce the CT contents to below acceptable levels. However, two other alternatives were also studied in a limited way, namely manufactured sand and quarry dust are quarry products. While quarry dust is merely a by product from the production of course aggregate and tends to be flaky in shape, manufacture sand is actually produced such that a more desirable "rounded cubic" shape is obtained.
- item: Conference-Full-textApplication of simulation methods to understand tsunami processes around the coastal region of Sri Lanka(Department of Earth Resources Engineering, 2007-11) Rathnayake, RMMT; Nilminie, WNRPN; Senanayake, DS; Rathnayake, NP; Karunaratne, STsunami is one of the most devastating natural disasters which cannot be prevented or precisely predicted even with the modern advanced technology. One of the best solutions for prediction as well as for the risk analysis of this natural disaster is Numerical Modelling. Present study focuses on the generation of earthquake induced different Tsunami scenarios from the potentially high amplitude earthquake generation zones in the Indian Ocean using Tsunami numerical modelling. Simulation modelling for different scenarios was carried out for source, propagation and inundation using UNESCO/IOC recommended interfaces of AVI NAMI and ComMIT, which uses TUNAMI N2 model. Etopo 2, JEBCO (combine SRTM, ETOP2 and Sea Map data) were used for bathymetry analysis. Distribution of wave heights, run up heights for given locations and arrival times of the waves were simulated as output data. Different Tsunamis were simulated, taking Java Sumathra and Macrum zones as Tsunami sources. Wave heights and propagation of Tsunami waves around twelve locations of Sri Lanka were analysed and vulnerable areas for different scenarios were identified. Results further indicated that if a Tsunami is triggered at Java-Sumatra, Southern part of Sri- Lanka will be severely affected, and particularly the Yala region, because of the direct hit of the Tsunami waves. ComMIT simulation results showed strong coupling to Tsunami sediment data and actual tidal records for 26th December 2004 Tsunami. Therefore, ComMIT seems to be one of the best models for Tsunami warning and forecasting in Sri Lanka.
- item: Conference-Full-textCoastal erosion in South Western part of Sri Lanka from December 2006 to June 2007(Department of Earth Resources Engineering, 2007-11) Hansi, MKTN; Lokukankanamage, DMG; Ranasinghe, GP; Witharana, GH; Rathnayake, NP; Karunaratne, SCoastal region is a very valuable area for developing countries like Sri Lanka, since a good protected coastal region will facilitate the tourism as well as fishing Industry. But the coastal erosion, especially in South Western parts of Sri Lanka has significantly destroyed the coastal land. Therefore, effective management of the coastal area has become a necessity. Present study is focussed on the variation of coastal profile at ten selected locations from Moratuwa to Balapitya and the monthly changes of beach width, profile and the grain size distribution of sediment at the mean sea level. The study was conducted from December 2006 to June 2007. Results showed that during North East monsoon, the beach face became wider and gentler whereas, during South West monsoon the beach face became narrower and steeper. Further, the mean grain size showed higher values during North East monsoon period than South Western monsoon. This variation of beach width, beach profile and the sediment grain size was strongly correlated with the rainfall changes and it was concluded that the coastal erosion in this area is directly controlled by monsoon changes.
- item: Conference-Full-textCost estimation and development of cash flow on mining operation (IML/A) (category quarry operation)(Department of Earth Resources Engineering, 2007-11) Amirthasothy, V; Arulvadivel, T; Fareez, MRM; Kommala, KD; Madanayake, TA; Walideniya, HS; Weerawarnakula, S; Karunaratne, SMore than 70 quarry operations are conducted under the IML/A Category licence all over the country. The high demand of metal aggregates for the construction industry (road and buildings constructions) has made industrial quarry operations one of the most profitable mining operations in Sri Lanka. However, present economic situation and increase the number of I ML/ A category quarries in Kaluthara District (13 quarries) causing problems in aggregate industry in this area. Manufactured sand produced in quarries has become a better solution for scarce sand resources as well as to increase the quarry operation revenue. During this study three quarry sites in Kaluthara District were studied in detail and cost benefit analysis was made. Among these TAMAC quarry site was the main source for the study. Selection of a quarry site with low operation cost with minimum damage to the environment plays the major role in success. Proper blasting techniques, crusher plant design, selection of machinery and friendly environmental could increase net profits and help to continue operations in a sustainable manner.
- item: Conference-Full-textGround vibration and air blast overpressure assessment using scaled distance(Department of Earth Resources Engineering, 2007-11) Sivarajan, V; Kumara, KLDS; Hearath, HMSD; Nanayakare, NWP; Welideniya, HS; Weerawarnakula, S; Karunaratne, SIn recent years there was a noticeable developmental activity, especially in industrial as well as construction sectors such as roads, harbours, condominiums etc. This has enhanced and developed aggregate industry and the use of modern technology for its effective operation. Blasting is being used extensively to supply rock aggregates for construction and also to drive tunnels and roads through rugged rocky terrains. There is growing concern on blasting effects on the environment such as dust, toxic gases, noise, fly rock and ground vibration. Worldwide the common allegations mainly focused on damages to residences. Present study was carried out to monitor air blast and ground vibration due to rock blasting. Southern Highway expressway was selected to monitor above effects due to high blast frequency available and the availability of the vast data base. Geological condition of the site, including rock type, drilling and explosive parameters, and distance between blasting and monitoring location, ground vibration and air blast over pressure were recorded. The data was used to develop site specific constants useful for blast programming. By using the site factors, the quantity of explosive per delay or the vibration at particular range of distance could be predicted.
- item: Conference-Full-textNutrients, Fe and bacterial removal in sub surface flow constructed wetlands treating polluted mine water(Department of Earth Resources Engineering, 2007-11) Dharmasiri, KLGNC; Yalini, A; Jeewantha, DLC; Karunarathne, S; Karunaratne, SA study was carried out to compare the performance of a pilot scale subsurface flow constructed wetland system to treat polluted water in Ragama prison quarry, an abandoned mine pit Two cement sand tanks with the dimensions of 7.5 m * 0.75 m x 0.75 m were constructed. Both the tanks used a mixture of aggregates as the substrate, where 40-60 mm was used in the treatment zone and both 20-30 mm and 40- 60 mm was mixed in the ratio of 1:1 in the inlet and outlet zones. Typha Latifolia (T.Latifolia) was planted in one tank, while the other was kept unplanted as the control. The initial plant biomass density was 1.7 kg/m2. Each horizontal subsurface flow bed is fed continously with polluted water at 173 litres per day and the retention time was maintained as 8 days. Concentration of nitrate, nitrite, ammonia, total and ortho phosphate, Fe and faecal coliform in the influent and effluent of the wetland system were monitored daily and their removal rates were determined. Nitrites, nitrates, phosphorus and Fe removal.in planted tank varied between 45%-80% whereas it was between 40%-70% in the unplanted tank. Removal efficiency of free ammonia in planted system was 6 % less than that of unplanted tank .However, bacterial removal in both planted and unplanted tanks were similar being 51%.
- item: Conference-Full-textOffshore sand exploration around Kaluthara-Beruwala area(Department of Earth Resources Engineering, 2007-11) Gunasinghe, AWDC; Chandana, NHS; Ranaweera, DHD; Vijitha, AVP; Rathnayake, NP; Karunaratne, SOffshore minerals are used as a raw mineral for various types of industries around the world. The exclusive economic zone belonging to Sri Lanka more than eight times land area of the country, offering huge potential for extraction and exploitation of minerals. Industrial sector, including mining and minerals, should grow to achieve the development of the country. Therefore this study was carried out to investigate the offshore sand mineral potential around Kaluthara — Beruwela area. About 200 samples were collected from sea floor, from a grid of 500m, 1000m Easting and Northing respectively. Investigation was carried out to identify the variation of particle size and mineral content around the Kaluthara area by sieve analysis. For each sample, particle size distribution curves were plotted and mean particle sizes, sorting and skewness were obtained. Heavy mineral content was also determined using gravity separation, magnetic separation; high tension separation and microscopic observation. Resource maps were plotted and mineral resources areas were demarcated.
- item: Conference-Full-textA pilot study on the mineralogical and geochemical characteristics of a recently discovered in-situ beryl occurrence at Kaltota, South Central Sri Lanka(Department of Earth Resources Engineering, 2007-11) De Silva, PJS; Kuhananthan, P; Consalas, MA; Nazlan, MZM; Afal, MCM; Abeysinghe, AMKB; Rathnayake, NP; Weerawarnakula, S; Premasiri, HMR; Siriwardana, CHER; Karunaratne, SRecently discovered in-situ beryl occurrence at Kaltota, southcentral Sri Lanka was studied by a pilot study of soil survey to probe its mineralogical and geochemical characteristics. Overall mineralization of the occurrence comprises of beryl, garnet, tourmaline, quartz, topaz and zircon. Beryl and tourmaline occur mainly as scattered detrital grains and as gravity-enriched elluvial concentrations within the overburden. Geological evidences suggest subsurface extension of the mineralization in host pegmatite and in contact zone. Total of 18 soil samples were collected from a preplanned grid within the site and, mineralogical analysis was performed on the panned heavy mineral concentrates of soils. In chemical analysis, soil samples were treated with both aqua regia digestion and alkali fusion method followed by Atomic Absorption Spectrometry (AAS). With the better results, alkali fusion method was chosen to obtain be concentrations in the soils. The results of the mineralogical analyses shows an existence of beryl and other gem minerals in different proportions in the heavy concentrates, which are in comparison with the anomalous Be concentrations found in the chemical analyses of soils. The results are to be further examined by a detailed study, probably followed by drilling to elucidate subsurface distribution of the mineralization.
- item: Conference-Full-textRecovery enhancement of graphite tub-dust to 99+ carbon using a mill modification(Department of Earth Resources Engineering, 2007-10) Samarakkody, SATI; Rohitha, LPS; Fernando, WLW; Karunaratne, SThere are many mineral processing methods that are being used in mining and mineral processing industries. One such method very widely used in the graphite industry is froth flotation. During the present study, graphite having a 82- 85% C, with a low market, has been up- graded to Carbon 99% + grade by using flotation. It has been observed that the rod weight in the grinding operation has a major role to play. If the rod weight is increased over and above the critical weight, over grinding takes place. Further, it has been found that pH and the type of collector also play major roles in the graphite processing. Laboratory trials indicate that by using the rod weight of 625kg to 725kg in the rod mill and the particle size range of 75 to 150 microns, maximum recovery of 85% could be achieved at 99% + C grade.
- item: Conference-Full-textRemote sensing and GIS approach for Tsunami damage assessment - a case study(Department of Earth Resources Engineering, 2007-11) Premadasa, WN; Jayalath, SDLD; Weerakoon, HMAB; Dissanayake, DMDOK; Karunaratne, STsunami cause widespread damage to the properties as well as human lives in the coastal regions. Sri Lanka is a vulnerable country for tsunami since Java-Sumatra is a very active subduction zone, where there were several very large earthquakes, during the last three years. Current study investigated the potential of remote sensing and GIS in damage detection after a hazardous event. The case study was carried out at Galle, Sri Lanka and the primarily focus was on identification and assessment of damage due to tsunami in 2004. The gravity of damage could not be identified only with the satellite data always, therefore GIS data and field observations had to be employed in such situations. A field survey was carried out to identify the damaged areas and to investigate the existing situation at present. There is an extensive need for a proper evacuation plan for the country. An evacuation plan was also developed for the Gall city using the road map. Schools and religious places such as temples and mosques near to coastal line were used as gathering places. Using the Contour map of the area, high elevation points were identified as evacuation places. The shortest path to evacuation places from the gathering places were calculated using Arc View Network Analyst Extension. Local authorities can use the proposed evacuation plan and maps to minimise the damage in a possible future tsunami event.
- item: Conference-Full-textRheological behaviour of mineral (clay) suspensions(Department of Earth Resources Engineering, 2007-11) Balasooriya, BARD; Kumara, WC; Prasanna, TGS; Sasekaran, M; Fernando, WLW; Karunaratne, SIn this research, a rotating cylinder viscometer was designed and fabricated to study the structure formation of particles in a mineral suspension and its influence on the relative viscosity q/qo. It is known that the value q/qo is affected by the concentration of suspended mineral particles in an aqueous media. The relative viscosity q/qo thus obtained is related to the volumetric concentration of suspended particles by the equation q = qo + k(f>, where the value k depends on particle behaviour in aqueous medium and is related to the shape, zeta potential and the volume % of particles. By this method it is possible to classify the suitability of surface active minerals in mineral deposits on the basis of the k factor. The rotating cylinder viscometer consists of a cylinder, of known dimensions, immersed fully in a mineral suspension so that it can be rotated by applying a mechanical couple (Force X distance) acting on the cylinder by two identical falling weights which are tied to each other by an inextensible string. Initially the cylinder is made to rotate in water of known viscosity by fully immersing it, thereafter in the known suspension. From the rates of rotation, the viscosities can be compared and hence the k values.
- item: Conference-Full-textStability of mica, k-feldspar and apatite in water, organic matters and citric acid(Department of Earth Resources Engineering, 2007-11) Amaraweera, THNG; Pitawala, HMTGA; Fernando, GWAR; Karunaratne, SThe short term stability of mica, feldspar and apatite in different geochemical conditions were tested in the laboratory. Different proportions of powdered minerals (<125 pm) were mixed with organic matter with water, water and 2% citric acid. The mixtures were kept under room conditions, using controlled moisture content. The water soluble ionic concentrations of each mixture were measured and their variations with the time were studied. The study revealed that the dissolution of minerals is controlled by mineralogical characteristics of them and the chemical nature of solutions. Both mica and feldspar release higher amounts of potassium compared to other ions when they are in water or in moist organic matter. Feldspar is stable whereas mica and apatite are significantly unstable in the citric acid. However, mica released considerably higher amount of iron in the acidic media (pH-2-3). The dissolution of apatite and K-feldspar is low when mineral mixtures contain biotite. Biotite mica and apatite have high potential to use as fertilizers for crops growing in acidic soils.
- item: Conference-Full-textThe use of prototype pelletizer for iron ore preparation(Department of Earth Resources Engineering, 2007-11) Arachchi, GARMG; Jayarathna, STCK; Jeyarupan, G; Thusyanth, M; Fernando, WLW; Karunaratne, SIn this research, a pelletizer was designed and fabricated as a prototype machine to make iron ore pellets to be used as a blast furnace burden. During the iron manufacturing process, iron ore powder of specified particle size distribution is mixed with a binder, coke powder and calcium carbonate. The raw materials are intimately mixed and thereafter treated with a critical amount of water while the pelletizing is taking place. During the pelletizing process the ore particles are subjected to horizontal and vertical forces applied mechanically coupled with the adhesive forces created by water molecules. The forces acting on iron ore particles would facilitate by bringing the particles together and thereby giving uniformity to the pellet. The addition of water has to be carried out carefully as it is a critical parameter. After careful drying, firstly in air and thereafter in an oven at HOC for 2 hours, the green pellets thus obtained were sintered to produce the final pellet to be used in the blast furnace.