Browsing by Author "Abeysinghe, AMKB"

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An 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, PVA
Gerandi-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.
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Analysis of effect on vibration and air blast in rock quarrying
(Department of Earth Resources Engineering, 2010-09) Senadeera, SMADSI; Erangika, MD; Herath, MHBCW; Wickramasmghe, WIUS; Chaminda, SP; Dharmaratne PGR; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
Blasting induced ground vibration occurring in the quarries has ecome a serious environmental issue in Sri Lanka. To achieve high production targets the number of blasts has increased in the quarries and, therefore, mitigate measures to minimize the detrimental effects of the vibrations have to be identified. This research project on rock blasting was carried out to design a suitable indicating system to predict the ground vibrations and air blasts. In order to assess the variation of intensity of the ground vibration and the air blast over pressure, ground vibrations and air blasts results from two different types of explosives on different types of rocks were monitored. Statistical analysis of the data sets found a high level of confidence on the best fitting empirical relationship between peak particle velocity and scaled distance. By that two site-specific factors were established. A comparison of the analytical work revealed that the level of ground vibration varies significantly with the changing of charge weight per delay, explosive type, rock type and the distance from blasting point to monitoring point.
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Analysis of geological structures for road cut failures: a case study along Balangoda – Haputale main road
(Department of Earth Resources Engineering, 2016-07) Senarathna, CSS; Godaliyadda, DP; Disanayaka, KTD; Premasiri, HMR; Abeysinghe, AMKB; Weerawarnakula, S; Hemalal, PVA
This study is focused on the causes for the road cut failures and suggest a methodology to design road orientation to minimize cut failures considering geology of the rock present in the area. In the past few years, several road cut failures have been recorded in Sri Lanka and there are development plans to construct expressways in hilly areas of the country. Hence, this study is important to minimize and control road cut failures while designing road orientation in a scientific manner. Several of studies were carried out to find the relationship between rock properties of the slope and occurrence of cut failures. This study helps to create a forecasting model for different scenarios. In this study, in order to validate the outcomes, some software were used. “DipAnalyst 2.0” is one of them and is a slope stability analysis software, which is designed to perform kinematic analysis for rock slopes and also calculating factor of safety values for plane and wedge failures based on the limit equilibrium theory. In this study, we identified that rock of the study area mainly dip towards the road (dip direction is parallel to the road direction). It is the main cause for lot of failures.
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Analysis of Geological Structures for Road Cut Failures: A Case Study Along Balangoda – Haputale Main Road
(2016-08-22) Senarathna, CSS; Godaliyadda, DP; Disanayaka, KTD; Premasiri, HMR; Abeysinghe, AMKB; Weerawarnakula, S
This study is focused on the causes for the road cut failures and suggest a methodology to design road orientation to minimize cut failures considering geology of the rock present in the area. In the past few years, several road cut failures have been recorded in Sri Lanka and there are development plans to construct expressways in hilly areas of the country. Hence, this study is important to minimize and control road cut failures while designing road orientation in a scientific manner. Several of studies were carried out to find the relationship between rock properties of the slope and occurrence of cut failures. This study helps to create a forecasting model for different scenarios. In this study, in order to validate the outcomes, some software were used. “DipAnalyst 2.0” is one of them and is a slope stability analysis software, which is designed to perform kinematic analysis for rock slopes and also calculating factor of safety values for plane and wedge failures based on the limit equilibrium theory. In this study, we identified that rock of the study area mainly dip towards the road (dip direction is parallel to the road direction). It is the main cause for lot of failures.
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Analysis of physical and mineralogical properties of aggregate on strength and durability of asphalt concrete
(Department of Earth Resources Engineering, 2018-08) Lakshan, LPS; De Silva, SHSN; Kapilaratne, RDMCLB; Chaminda, SP; Jayawardena, CL; Abeysinghe, AMKB; Samaradivakara, GVI
Asphalt is made by mixing aggregates, filler and binder materials together according to pre-determined ratios. Out of the total asphalt weight, 94% to 95% consists of aggregate. It is not surprising that the performance of asphalt concrete mixtures is influenced by the properties of their aggregate blends, such as gradation, shape (angularity and elongation), texture (roughness) and mineralogy. In asphalt concrete, numerous studies have related gradation, shape, and texture of the aggregate to durability , workability , shear resistance, tensile strength, stiffness, fatigue response, rutting susceptibility, and optimum binder content of the mixtures. However, a few has described about the influence of mineralogy on characteristics of asphalt. This research has been carried on to make an effort to fill that gap between the aggregate mineralogical properties and the characteristics of asphalt concrete. Under the research, a number of representative aggregate samples were collected from different quarry sites which are currently used in the process of manufacturing asphalt all over the country. The samples were subjected to a series of tests in order to determine both physical and mineralogical properties. Marshall stability and flow values of the asphalt mixtures were determined to assess the properties of asphalt made using the collected aggregates. Finally, using test results, an analysis was conducted followed by the conclusions made using the test results, a set of recommendations were proposed.
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Applicability of a neural network model for forecasting ground vibrations in opencast mining
(Department of Earth Resources Engineering, 2018-08) Dassanayake, SM; Dushyantha, NP; Jayawardena, CL; Abeysinghe, AMKB; Samaradivakara, GVI
Ground vibration and air-blast over pressure are two significant undesirables, among many environmental risks, in open-pit mining . Gaining control over the ground vibrations generated by rock blasts had been difficult mainly due to the complexities involved with local geology and properties of the blast. Accordingly, existing empirical equations are only capable of making vague approximations on the vibration frequencies based on site-specific parameters and attenuation factor. Therefore, the available models cannot be generalized to different geo-mining environments to obtain sufficiently reliable forecasts for ground vibration and airblast overpressure. Hence, this study attempts to employ an Artificial Neural Network (ANN) based feed-forward back-propagation algorithm to train a model, using a supervised learning technique to forecast possible ground v i b r a t i on frequencies. The main in-put parameters included in the model are noise level, number of boreholes per single blast, depth and diameter of a borehole, charge per hole, number of delays of the Electric Detonators (ED) in a single blast, burden and spacing. Airblast overpressure and the ground vibration levels will be the output by ANN model. The model was validated using 50 datasets, which were obtained from a quarry site. After adequate training, the model can determine Peak Particle Velocity (PPV) and frequency of Ground Vibrations (GV) for new input parameters with a statistically significant confidence level.
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Applicability of GPR technique for earthen dam failures
(Department of Earth Resources Engineering, 2023-08-28) Arunapriya, GGDPI; Liyanage, AGSI; Kishanth, S; Premasiri, HMR; Ratnayake, NP; Abeysinghe, AMKB
A dam is a structure constructed across a river or stream to store water upstream from the obstruction. Dams are susceptible to damage for various reasons, which can lead to many catastrophic disasters. Therefore, identifying the dam's structural failures prior to a disaster is crucial. Drilling can be used for dam failure identification. But it is costly and destructive. Integrated geophysical methods have always helped in identifying subsurface features. In the current investigation, the applicability of ground penetrating radar (GPR) to detect potential failures in earthen dams was assessed. The Uyanwatta Lake earthen dam was selected as the study area during this investigation, considering the reported water leakage in this dam. A GPR survey was conducted with 100 MHz and 300 MHz antennas along five survey paths. Those are the top of the dam, 1.5 m below the top of the dam, and three distinct paths for the lake's spill. During the interpretation process, clay layers, fractured zones, gravel layers, and water seepage areas were identified. Those water leakage areas indicate that there has been a leak in the dam. Those results were compared with exploratory drill hole data from the Uyanwatta Lake Dam. Drill hole data has only presented information about the rock types present in the dam. But GPR data was able to provide information on loose sediments in the shallow depths of the dam as well. That indicates GPR data has the potential to provide additional information related to earthen dams.
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Applicability of ground penetration radar (GPR) technique to optimize soil Nail Wall designs
Lasan, HLI; Weerasekara, MN; Prashanth, S; Abeysinghe, AMKB; Premasiri, HMR; Samaradivakara, GVI; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Soil nailing is used to stabilize existing natural slopes or excavations using soil reinforcement technique. Due to lack of information on ground profiles and thickness of soil layers, the required soil nail lengths cannot be determined in advance, for most of the steep slopes. Furthermore, the cost of drilling in fresh rock is much higher than the cost of drilling in soft soil and weathered rock. Without proper information on the depth at which the fresh rock is found, a cost-effective soil nail wall design cannot be finalized. This research was focused on studying the methods that can be used for soil nail wall design optimization by applying Ground Penetration Radar (GPR). The study was carried out on an unstable slope near Nursing Training School located in Kandy in the central part of Sri Lanka.The physical properties of soil were determined by direct shear tests, and stability analysis was done by means of “Slope-W” software. GPR techniques were also used in this study. The investigation results showed that the existing slope is unstable, and necessary to be protected. Further, it was identified that the basement rock cannot be encountered at already designed depths of the soil nails, which was subcequently proven as correctbased on data from ongoing drilling for soil nail installations. With the precise knowledge about the underground geological structure using GPR technique, the drilling cost, nail transporting cost, nail off cutting time to complete the total work can be reduced.
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Applicability of pre-heating techniques for recovery of garnet from garnet biotite gneiss
Jayakodi, JDSU; Weliwita, BY; Nishanthan, SS; Samaradivakara, GVI; Abeysinghe, AMKB; Rohitha, LPS; Vijitha, AVP; ; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
In mineral processing industry, the highest energy is consumed by crushing and grinding operations. However, if we can initiate micro cracks in the hard rock pieces in advance, we should be able to reduce the crushing energy and liberate useful minerals economically. Various pre-heating techniques have been tried by the scientists around the world to liberate minerals from rocks. In this investigation, pre-heating techniques were used to liberate Garnet from Garnet Biotite Gneiss. The market price of Garnet varies with the particle size. Hence, the samples were crushed and sized into industry needed three size fractions: (+250-850) μm, (+180-250) μm and (-180) μm. Afterwards, by means of Wilfley Table, Garnet was separated from rocks. Final Garnet recovery percentage was recorded for different temperatures. Furthermore, energy calculation was done for each sample to get an idea about the power consumption. It was observed that the crushing strength decreases with the temperature increment and it has been proven by identifying propagation of micro cracks in thin sections, prepared from rock samples pre-heat treated in Muffle Furnace and Microwave Oven. The analysis reveals that the preheat treated and quenched samples give higher Garnet recovery than Garnet recovered from as-received samples of Garnet rich Biotite Gneiss.
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Applicability of pre-heating techniques for recovery of minerals from rocks
(Department of Earth Resources Engineering, 2018-08) Dasanayake, RB; Jatheesan, N; Nissanka, NACM; Samaradivakara, GVI; Abeysinghe, AMKB; Rohitha, LPS; Abeysinghe, AMKB; Samaradivakara, GVI
In mineral processing industry, liberating of minerals is the most important involvement because it can enhance the purity of the mineral. However, if we can initiate micro-cracks in rock pieces in advance to these operations, it would be more economically viable. Hence, there is a trend i n the world to investigate less energy-consuming methods for propagating micro cracks within rock grains. Previous studies show that preheating techniques such as heating in muffle furnace, microwave preheating can enhance micro-cracks propagation in rocks and samples. Microwaves have several advantages over standard heat application methods namely that they heat only "responsive" phases. Microwaves also heat considerably faster than conventional heating methods as the heating on radiation and conduction heat transfer mechanisms. Therefore, in this scientific investigation, we applied microwave pre-heating technique to liberate Garnet from Garnet Biotite Gneiss for which samples were collected from Boulder Mix Pvt. Ltd quarry in Meepe. To create a weak zone i n between graphite and its gangui rock in graphite bearing rocks which were collected from Bogala Mines in Aruggammana have also tested. Industrial price of garnet vary w i t h the particle size. In general, higher the particle size, higher w i l l be the value. Hence, the recovery of Garnet in this study was considered focused on industry needed particle size which is less than 850 |xm. The analysis revealed that there is a possibility to produce low cost garnet sand which is cheaper than i n the international market with high purity, by means of microwave technology,. Also it is proved that creating a weak zone along the grain boundary of graphite and its gangue rock is possible w i t h microwave pre-heating.
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Application of emulsion explosive and comparative study on water-gel explosives for rock quarrying in Sri Lanka
Dharmaratne, PGR; Hemalal, PVA; Rohitha, LPS; Herath, B; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Dynamite has been the premier and the only high explosive used for mining and construction activities in Sri Lanka for a long period of time. Negative environmental impacts, effect on health and security hazards led to the Government of Sri Lanka (GOSL) to issue directives to find a suitable substitute for Dynamite. Subsequently, Water-Gel explosive was introduced in the year 2011. The poor performance of Water-Gels in wet conditions and it’s low Velocity of Detonation encouraged the use of Emulsion explosives. This research was focused on performing a comparative study of the performance of both Water-Gels and Emulsion explosives by analysis of the ground vibration and the blast air over pressures. The methodology adopted was to conduct ten blasts at one single metal quarry site keeping all other parameters constant. Blasting tests were performed using Emulsion explosives and Water-Gel explosives and the resulting ground vibration and Air-Blast overpressures were measured with Blastmate 111model for each blast. Calculation of mean fragmentation was done and particle size distribution based on photographic evidence of each blast was analyzed. Analysis was carried out demarcating the resultant production pile of aggregates covering a cleared zone. Grid lines inserted on the muck pile facilitated particle counting using photographs and calculating the mean fragmentation.
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Application of GPR to identify carbonate rock cavities related to ground subsidence in Matale, Sri Lanka
(Department of Earth Resources Engineering, 2018-08) De Silva, MSTL; Chiyamvarnan, K; Niroshini, R; Abeysinghe, AMKB; Jayawardena, CL; Abeysinghe, AMKB; Samaradivakara, GVI
Cavity formation within the rocks result in ground subsidence in the regions where carbonate rocks are predominantly present. Identification of ground subsidence potential areas and the probability of such incidents is a challenge without detailed information about the subsurface. Dorakumbura in Matale, Sri Lanka is one such area which faced multiple ground subsidence incidents that demands the investigation of subsurface profile. This study uses Ground Penetrating Radar (GPR) to locate the subsurface cavities in order to create a cavity profile for the Dorakumbura area using 1D and 2D trace analysis of the radargrams. Cavities were identified and analyzed and the results reveal the existence of cavities mostly below the depth of 15 m. Comparison of GPR survey results with the well log data in the region was equivalent. The same methodology is expected to be used in similar regions to identify the presence of cavities which can result in future ground subsidence. It can also assist in suitable site selection without ground subsidence hazards, for the construction and development activities in regions underlying carbonate rocks in Sri Lanka.
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Application of remote sensing and GIS techniques for exploring construction material from inaccessible terrains; case study in Eastern Province of Sri Lanka
(2013-11-11) Premasiri, HMR; Colombage, HCDP; Palamakumbure, D; Kodippili, TKA; Wickramasekara, KT; Abeysinghe, AMKB; Chaminda, SP
Demand for construction materials in the North and Eastern provinces of Sri Lanka has risen significantly due to accelerated construction work in progress to restore the destroyed infrastructures during the civil war. Ground surveying methods to locate quarries within this area are not applicable due to security reasons and the larger area to be covered. Thus a Remote Sensing method is suitable for this task. This study introduces a methodology to locate suitable quarries and sand mines for constructions in the Eastern province. LANDSAT ETM+ images were used for classification. Feasible rocks and sand deposits for quarry operations were located using Multicriteria Analysis (AHP).The highly suitable rock quarries and sand deposits were considered in closest facility analysis. The results showed that the integration of Remote Sensing (RS) and Geographic Information System (GIS) can serve as an effective tool in demarcating suitable sites for construction material and this methodology can also be applied for projects of similar nature.
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Appraisal of electrode configuration characteristics in resistivity surveying
(Department of Earth Resources Engineering, 2019-08) Kankanamge, BU; Chathuranga, SMS; Ruwanika, ILD; Palamure, PK; Abeysinghe, AMKB; Samaradivakara, GVI; Jayawardena, CL; Dissanayake, DMDOK; Samaradivakara, GVI
Non-destructive subsurface exploration methods could reveal subterranean characteristics with minimal consumption of time and resources. However, validity of such interpretations could vary depending on the appropriate use of the controllable parameters in the geophysical method, with respect to the subsurface complexities. Accordingly, this study evaluates the sub subsurface characteristics of several locations revealed by the interpretation of resistivity data to understand the performance of different electrode configurations used in resistivity surveying. The electrode spacings maintained at each configuration was also critically assessed to identify the most appropriate for a particular instance of surveying. Furthermore, subsurface profiles were computed using three different interpretation methods to identify any influences from the interpretation method on the accuracy of the resultant profile. The results reveal a strong dependency of interpretations on the array configuration and maintained electrode spacing. And it was determined a suitable electrode spacing for improved subsurface interpretation. In order to improve accuracy of interpretations, it also suggests the need of developing an upper limit for current electrode spacing (AB) of the Schlumberger Array Configuration, given the general electrode spacing is maintaining a lower limit as AB > 5 (potential electrode spacing).
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Assessing the potential of critical metals and rare earth elements in lateritic soils of the Southwestern region of Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Herath, HMIA; Piyumangi, WAM; Kanishta, KPMK; Abeysinghe, AMKB; Ratnayake, NP; Premasiri, HMR; Batapola, BDNM; Dilshara, RMP
Laterites are currently considered potential targets for critical metals (CMs) exploration considering their near-surface occurrence, large dissemination, and enrichment of CMs in lateritic soil during weathering. Although prominent lateritic formations are found in Sri Lankan geological terrain, the potential for CMs has not been explored yet. Therefore, the present study assesses the potential of CMs in laterites of the southwestern part of the country. 60 samples were collected covering the overall study area and processed for critical metal analysis. The metal concentrations of CMs: Al, Ni, V, Cr, As, Sr, Co, Sc, and REEs were determined from inductively coupled plasma-mass spectrometry (ICP-MS) and Li, Fe, and Al concentrations were determined from atomic absorption spectroscopy (AAS). According to the analysis, critical metals such as Cr, V, Ni, and Th were significantly high in laterite samples ranging from 42-419, 116-583.4, 274 – 1498, and 33 – 472 mg/kg, respectively. REE and other critical metals considered in the study including Co and Cu, showed comparatively low potential. The findings of the study emphasise that laterite soil has significant potential for Ni, V, and Cr, especially in low grades. The conclusion is this analysis will benefit future CMs' exploratory investigations by providing insights into the potential of CMs in Sri Lankan laterite deposits.
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Assessment of environmental impacts resulting from ground vibrations due to piling activities and railway transport
(Department of Earth Resources Engineering, 2018-08) Piyarathna, HDAM; Godagama, GWADC; Maduranga, THT; Hemalal, PVA; Samaradivakara, GVI; Samaradivakara, GVI; Dharmaratne, PGR; Abeysinghe, AMKB; Samaradivakara, GVI
With the development of the country's economy, industrial activities close to urbanized areas have inceased tremendously. These activities are sources of ground vibrations impacting on human life. Resulting annoyance conditions near residential areas and possible human response to ground vibrations have been investigated in this study. Ground vibration have been monitored at precast pile driving sites and at a location close to Panadura-Moratuwa railway line using an A4-channel seismograph. Human perception and disturbance conditions associated with each location is discussed with the criteria given in British Standards. According to the ground vibrations levels measured at the piling site, up to 55 m distance from pile driving locations perceptible level of ground vibrations have been occurred thus caving annoyance to occupants. Zone with adverse comments, extends up to 37 m from the pile and adverse comment possible zone extend up to 50 m from the pile when using pile diver and piles with given specifications. According to ground vibration levels near the railway track, occupants in residential areas will experience annoyance as residential area contains ground vibrations in perceptible amount. Up to 27 m distance from the railway track, ground vibrations levels were measured up to a level of making complaints regarding annoyance made by train.The trench already existed near the railway track (parallel to the rail way track) is capable of reducing ground vibration levels up to 40%.
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Assessment of rare earth element potential in intrusive rocks special reference to massenna zircon granite
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Jayasuriya, JHAATS; Jayathilake, RGMA; Jeyakumar, J; Batapola, NM; Dushyantha, NP; Abeysinghe, AMKB; Premasiri, HMR; Dissanayake, DMDOK; Dassanayake, ABN
Sri Lanka has a geological setting that favors the presence of rare earth elements (REEs), which are currently identified as the most critical and strategic elements in the world. Previous geochemical studies show that intrusive rocks, such as carbonatites, pegmatites and granitoid rocks could be enriched of REEs. Therefore, this research is focused on assessing the REE potential in pegmatites with special reference to the zircon granite in Massenna. The collected samples from the focused areas were subjected for XRD analysis and monazite, apatite, allanite, bastnaesite, and loparite were found as the major RE minerals. Moreover, Massenna zircon granite has the highest REE potential, particularly LREEs and Y, compared to other pegmatites. The presence of REEs in the in-situ soil and sediment samples indicate that, REEs have been transported through weathering and erosion processes of the zircon granite, thus proving the REE potential in the source rock. Furthermore, REEs are mostly associated with felsic minerals rather than mafic minerals. Therefore, this research clearly provides insights of REE potential in the pegmatite bodies in Sri Lanka and more REE explorations need to be carried out in these prospects.
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Assessment of seasonal impacts on groundwater quantity and quality in upstream of Malwathu Oya Basin
Madhushankha, JML; Madhuwan, ARB; Menan, P; Chaminda, SP; Abeysinghe, AMKB; Jayawardena, CL; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Malwathu Oya Basin which covers 2350km2 located in Anuradhapura district is considerably populated and the safety and the available quantity of water is crucial for the people. Water samples were collected from selected locations during South- West monsoon period, Second Inter monsoon period and North-East monsoon period from September 2016 to March 2017. The samples were analysed for pH, turbidity, conductivity, fluoride, chloride, magnesium and calcium as basic drinking water quality parameters. Only the shallow regolith aquifers are considered for the study. The groundwater quality variation of the area shows a considerable variation from dry season to rainy season in general water quality of the area, and is in acceptable limit for most of the basic parameters. With the seasonal changes Fluoride and Chloride content is higher than permissible limits in some areas.
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Assessment of unusual rock weathering in Samanalawewa area in Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Rathnasekara, RMNL; Edirisuriya, EATD; Sajithkanth, T; Premasiri, HMR; Ratnayake, NP; Abeysinghe, AMKB
The research investigates the unusual rock weathering at Samanalawewa dam in Sri Lanka and its significant impact on the dam structure and surrounding area. While previous investigations covered physical, mechanical, chemical, and mineralogical properties, limited attention was given to physical observations. A comprehensive approach was conducted from physical observations, rock sample analysis, and scanning electron microscopy (SEM) to gain a deeper understanding of the weathering mechanisms and potential structural weaknesses. Samples were collected from the quarry site and surrounding locations based on geological maps from 13 locations in both fresh and weathered states. Various rock types were included, such as charnockite (CHA), garnet sillimanite biotite gneiss (GBN), marble (MAR), and khondalite (KHO). Physical observations focused on identifying distinct weathering patterns, colours, and textures on the rock surfaces. These changes happened only in the dam quarry site, not in the surrounding area in the Samanalawewa area. The SEM analysis provided valuable insights into elemental changes. Despite thorough examination, this research did not identify a significant correlation between the observed rapid weathering and the geological characteristics of the Samanalawewa dam and its vicinity. Further investigations are required to unveil the underlying factors responsible for this geological phenomenon and its potential implications for the dam’s stability and long-term viability.
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Bioremediation of lead-contaminated mine waste using microbially Induced carbonate precipitation
Mwandira, W; Nakashima, K; Kawasaki, S; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
The aim of this study was to use microbially induced calcium carbonate precipitation (MICP) technique to bioremediate lead using bacterium Pararhodobacter sp. Laboratory scale experiments conducted, achieved complete removal of lead. This result was further confirmed by SEM and XRD analysis that indicated coprecipitation of calcium carbonate (CaCO3) and cerussite (PbCO3). Furthermore, syringe test demonstrated that MICP based sequestration of heavy metals via coprecipitation with calcium carbonate may be useful for lead bioremediation. Very few low-cost in situ heavy metal treatment processes for lead bioremediation are available; therefore, bioimmobilization of lead by MICP has the potential for application as a low-cost and eco-friendly method for heavy metal remediation.