ISERME - 2022

Permanent URI for this collectionhttp://192.248.9.226/handle/123/19696

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item: Conference-Full-text
International Symposium on Earth Resources Management & Environment 2022 (Pre-Text)
(Department of Earth Resources Engineering, Faculty of Engineering, University of Moratuwa, 2022-12) Jayawardena, CL
item: Conference-Full-text
Development of a blasting simulator considering gas-rock interaction
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Wataru, I; Daisuke, F; Yoshiaki, T; Tei, S; Shiro, K; Jun-ichi, K; Yoshiaki, F; Jayawardena, CL
Optimization of rock blasting in mining engineering is essential for energy efficiency, cost reduction, and safety. In contrast, the dynamic rock fracture process due to blasting involves highly complex and rapid processes. Thus, it is crucial to develop a reasonable numerical simulator for blasting which can model the following processes: (i)detonation-induced shock wave and gas expansion, (ii)complex dynamic fracture process of rocks, (iii)gas-rock interaction including the impact of shock waves on the blasthole surface and the inflow of blast-induced gas into a dynamically evolving fracture network. Besides, massively parallel computation is indispensable to dealing with the computationally expensive coupling processes (i)~(iii). To this end, this study couples the cubic-interpolated pseudo particle (CIP) method, the combined finite-discrete element method (FDEM) and the immersed boundary method to model the processes (i)~(iii), respectively. A massively parallel computing scheme with general-purpose graphics-processing units (GPGPU) is incorporated for the parallel computation. The applicability of the developed simulator is investigated using a single hole blasting problem. Although further improvements must be achieved, the proposed blasting simulation results indicate that all the processes (i)~(iii) can be reasonably traced. In conclusion, the developed simulator is expected to help investigate the optimization of rock blasting.
item: Conference-Full-text
Optimization of blasting geometry and explosive quantity in control blasting for dimension stone extraction
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Kavinda, SWH; Siriwardana, NAHPER; Chathuranga, JPD; Chaminda, SP; Dassanayake, ABN; Jayawardena, CL; Samarakoon, KGAU; Jayawardena, LC
Dimension stone industry is a widespread market in the globe and has shown promising trends for expansion in the recent years. Dimension stones can be defined as, natural stones that have been selected and extracted to produce stones of precise size and shape. Products of dimension stones have been used for construction engineering practices and various other ornamental purposes. The available extraction practices for dimension stones can be categorized mainly into mechanical cutting and splitting techniques. Pre-split blasting is one of the splitting techniques that can be utilized to liberate dimension stone blocks from the rock deposit. The major drawback of utilizing explosive blasting in dimension stone extraction is the possibility of having high amount of wastes as a result of unnecessary fractures from the excessive explosive energy. By studying the relationship between blasting geometry and explosive quantity towards forming fractures in the selected ornamental stone, the aforementioned issue can be addressed to some extent. Software simulations were done to determine the blast design's ideal parameters for achieving an effective explosive energy distribution in the rock mass. Validation of the obtained simulation results through a field blast can be suggested as further development in the study area.
item: Conference-Full-text
Selection of high-quality aggregates for high-end civil engineering projects such as airport runways
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Deelaka, MDN; Ridmika, AMPS; Subodha, GMP; Samaradivakara, GVI; Abeysinghe, AMKB; Jayawardena, LC
In civil engineering, aggregates normally comprise over 70% by volume in both concrete and asphalt mixes, so that the properties of aggregates mostly represent the overall properties of the mixture. Among these properties, mechanical properties such as toughness and abrasion resistance have a greater influence in construction-related projects since such properties directly affects for its durability. Therefore, it is important to assess the suitability of aggregates prior starting the construction, which can be quantitatively measured through laboratory testing. When it comes to the construction industry in Sri Lanka, finding a suitable aggregate source for high-end Civil Engineering projects have been quite difficult, due to the lack of research and interpretation of data. In this study, all the IML/A grade quarries which are located within the Kalutara District has considered. To assess the suitability, Los Angeles Abrasion Value (LAAV) test and Aggregate Impact Value (AIV) were performed on the Aggregate-Base-Course (ABC) obtained from each. With the comparison performed on the results with respect to the specifications obtained from several high-end civil engineering projects, it was concluded that there are a limited number of quarries available in Kalutara District, which can be used for high-end civil engineering projects.
item: Conference-Full-text
Experimental investigation on factors affecting the bulking of aggregate quarry products
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Wijethunga, WMRTB; Aththanayake, AMDR; Weerasinghe, UASB; Illankoon, IMTN; Dassanayake, ABN; Chaminda, SP; Jayawardena, CL
Aggregate quarry products have long been essential to the construction sector. These aggregate products are produced by blasting the in-situ rock at quarries and subjecting it to primary and secondary crushing. There is a volume change when converting in-situ rock volume into the product volume because of a phenomenon called bulking, which happens when the rock is broken down into smaller particle sizes. Air spaces develop between the rock particles during blasting and crushing activities increasing the volume of quarry products. This study aims to investigate the effect of moisture content, particle size and rock type on bulking of aggregate quarry products. Quarry products (Dust, Chip, ¾” metal ,1.5” metal and ABC [Aggregate-Base-Course]) were collected systematically from six quarries and the bulking factor was tested in different moisture conditions. Furthermore, the mineralogy and specific gravity of collected samples were determined by visual observations and pycnometer method respectively. This study identified that quarry dust and the ABC product exhibit significant deviations in bulking factor with changing moisture content, whereas other products (Chip, ¾” metal and 1.5” metal) exhibit no discernible deviations in bulking factor with increasing moisture content and identified that mineralogy almost no effect to the bulking factor since study area contains similar kind of mineralogy.
item: Conference-Full-text
Evaluation of weathering effect on engineering properties of Sri Lankan gneissic rock
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Karunarathne, GKA; Weerasinghe, WMRT; Dukeraisan, AK; Niroshan, S; Gamsavi, K; Dassanayake, ABN; Chaminda, SP; Jayawardena, CL; Wickrama, MADMG; Jayawardena, CL
Weathering is a natural process common for all kinds of rock types that may occur due to either physical, chemical, or biological reasons. The applicability of rock in different engineering applications has a primary concern with their engineering properties that might have a significant influence from weathering effect. Characterizing such properties based on weathering effect on gneissic rocks of Sri Lanka is essential due to the wide existence and utilization of gneissic rocks. This study was conducted to understand the behavior of engineering properties such as uniaxial compressive strength, durability, hardness, pulse wave velocity, and mineralogical properties of gneissic rock with weathering effect. Engineering properties of gneissic rocks were determined using laboratory tests according to ASTM (American Society for Testing and Materials) for rocks in fresh and weathered states. Results showed that chemical weathering may have influenced gneissic rocks in both Kaduwela and Kudayala quarry sites since Mg percentage has decreased by the weathering effect. Formation of clay minerals with weathering is a significant characterictics of hornblend biotite gneiss in Kaduwela area, rather than the Garnet bearing biotite in Kudayala area. Mechanical properties such as strength and durability decrease when the fresh rocks exposed to weathering. Physical properties such as hardness, and Pulse velocity have decreased in weathered gneissic rock in both areas.
item: Conference-Full-text
Geochemical distribution of selected elements in serpentinite deposit in ginigalpelessa, Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Dilshan, RADP; Sageenthan, A; Weerangana, NGN; Premasiri, HMR; Ratnayake, NP; Abeysinghe, AMKB; Dushyantha, NP; Batapola, NM; Dilshara, RMP; Jayawardena, CL
Serpentinite deposits are well known for their natural enrichments of heavy metals (Ni, Cr, Co) and depletions of macro nutrients (Ca, Mg), which have caused different ecological and health impacts in the surrounding areas. In addition, they are considered as potential sources for rare earth elements (REEs). While Ginigalpelessa, the largest serpentinite deposit in Sri Lanka, has been the focus of several toxicological studies, to date, there have been no significant studies related to geochemical distribution of heavy metals, macro nutrients, and REEs in the deposit. Therefore, the present study is focused on the assessment of geochemical distribution of selected elements (Ni, Cr, Co, Ca, Mg, and REEs) in the deposit. Accordingly, concentrations of these elements in 30 rock and soil samples were analyzed and their geochemical distributions were studied using the results of the present study and literature. Ni (6629 ppm) and Cr (35875 ppm) showed the highest enrichments in the deposit, whereas all the studied heavy metals have exceeded the permissible levels of the World Health Organization. In addition, a low Ca/Mg ratio was observed in the deposit, which explains the inhibition of plant growth in the deposit. Moreover, the identified areas with high enrichments of Ni, Cr, and Co using the prepared geochemical distribution maps will be useful in the spot remediation for toxicity in the deposit. Since serpentine soil is recognized as a low-grade source for Ni, low-grade extraction techniques such as phytomining and bioleaching are recommended to extract valuable metals from the Ginigalpelessa deposit.
item: Conference-Abstract
Identification of potential minerals/rocks in Sri Lankan geological terrain as source of potassium (K) fertilizer
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Nivethithan, T; Ariyawansha, KAPM; Dahlan, ACA; Abeysinghe, AMKB; Ratnayake, NP; Premasiri, HMR; Dushyantha, NP; Batapola, NM; Dilshara, RMP; Jayawardena, CL
Due to the agricultural intensification in Sri Lanka, there is a high demand for potassium (K)-fertilizer inputs. However, in the Sri Lankan geological setting, the presence of major potash sources is minimum though the K- bearing minerals and rocks are abundant. Therefore, exploration of K-bearing mineral deposits is essential to cater the demand of K-fertilizer in the country. In this regard, this research is focused on investigating the K-bearing minerals and rocks in Sri Lankan geological terrain which can be used as K-fertilizers directly or as alternatives for currently available K-fertilizers. During sample collection, K-bearing minerals, such as feldspar and mica and K-bearing gneiss rock samples were collected from Matale, Kaikawala and Kadugannawa areas. Processed samples were subjected to analyse major oxide concentrations and K concentrations and surface topography. Analyses revealed that the highest actual potassium concentrations were presented in orthoclase feldspar (10.35 w/w%) and then biotite mica (9.95 w/w%) whereas other rocks showed the lowest. Based on the results, biotite mica (Kaikawala) and biotite gneiss (Matale) displayed the highest potential for K recovery, whilst the least potential for K recovery was shown in orthoclase feldspar (Kaikawala). However, further studies are recommended to develop this K-fertilizer and to assess whether its application is economically viable.
item: Conference-Full-text
GPR mapping as a method for placer mineral exploration: A case study in Akurala, Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Beddage, BCD; Ijas, MUA; Wijayalath, WATN; Vijitha, AVP; Premasiri, HMR; Jayawardena, CL
Placer mineral exploration includes mapping underlying strata extensively. There are numerous exploration techniques, including electric and gamma logging, shallow vertical drill holes, exploratory trenches, and pits. Due to limitations of these conventional methods, geophysical methods such as Ground Penetrating Radar (GPR), are widely being used. The purpose of this study is to map placer deposits using GPR as an exploratory approach. GPR is a modern, rapid, no-contact, high-resolution technique which transmit, reflect and receipt of high frequency electromagnetic (radar) wave. This study was carried out at Akurala, Galle, Southern Sri Lanka using 300MHz antenna. Based on the GPR data, sand layers were identified in clay beds, of an old riverbed, and the sand layer is deposited as a fluvial deposit, which are the sediments deposited by paleo river channel. Average thickness of the sand bed could be interpreted as 0.94m, extending perpendicular to shoreline, and situated at approximately 1.25m depth below surface level. GPR data profile indicate that the sand layer may enrich with valuable minerals and heavy minerals, and it was validated using thin sections prepared from test pit sampling.
item: Conference-Full-text
Determining the characteristics of the calcite intrusions in the southern part of eppawala deposit and its applicability for the industries
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Peter, GKMR; Sivaruban, S; Jayathilaka, GMANGNMB; Lasantha, MML; Rathnayake, NP; Hemalal, PVA; Batapola, BDNM; Jayawardena, CL
Eppawala is the only phosphate deposit that is currently being mined in Sri Lanka and is composed of mainly two parts northern and southern. The ongoing phosphate mining process in the southern part has resulted in the exposure of fresh carbonatite embedded with large apatite crystals and those intrusions need to be removed before continuing further phosphate mining in that area. Therefore, we need to address a suitable method to use those calcite intrusions properly. In this paper, we are discussing the characteristics of calcite matrix such as critical anions (fluoride, chloride), P2O5 content, heavy metals, oxides, and the suitability of applying those removing calcite boulders for further industries including the fertilizer industry. Ion selectivity, titration, colorimetry, and induced coupled plasma spectrophotometry were used for analyzing the characteristics respectively for fifteen samples from three different boulders in the southern part. Results from critical anions and heavy metal percentages proved the absence of toxicity in calcite matrix and oxides percentages showed that it can be applied directly in its natural form only for the fertilizer industry by a quantitative comparison whereas upgrading processes need to be implemented to meet the specifications in other industries.
item: Conference-Abstract
Spatial distribution of heavy metals in sediments of the Negombo Lagoon, Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Nanayakkara, CJ; Partheepan, N; Kumarapperuma, MY; Ratnayake, NP; Premasiri, HMR; Abeysinghe, AMKB; Dushyantha, NP; Batapola, NM; Dilshara, RMP; Jayawardena, CL
Heavy metals accumulate in the sediments of aquatic environments due to poor water solubility. Their toxic effect poses a significant threat to living organisms. Negombo Lagoon, a vital aquatic ecosystem in Sri Lanka, has become vulnerable to heavy metals mainly from urbanization-related anthropogenic activities. Previous research in this respect has sampling points restricted to the boundary area. Since the heavy metal concentration is a static parameter, continuous research needs to keep the data updated. This study aims to investigate the spatial distribution of several heavy metals (Cr, Ni, Co, Cu, As, Cd, and Pb) in the surficial sediment of the Negombo Lagoon. Fifteen grab sediment samples were collected from the lagoon and analyzed for heavy metal concentration and grain size. The range of concentrations of each metal in test samples were between (78.07 - 222.68 mg/kg) Cr, (376.7-1298.05 mg/kg) Ni, (15.875-43.74 mg/kg) Co, (32.45-112.79 mg/kg) Cu, (20.17-55.81 mg/kg) As, (0.30-1.4 mg/kg) Cd, and (16.57-70.97 mg/kg) Pb. Heavy metal concentrations and sediment grain sizes show significant spatial variation over the Negombo lagoon area. Heavy metals were highly concentrated in locations, where finer sediments are accumulated (i.e., towards the eastern and southern part of the lagoon). Heavy metal concentrations were found to be increased with the decreasing grain size. High heavy metal concentrations are also found at places where there is a river discharge. Among the sources which feed heavy metals into Negombo Lagoon anthropogenic activities such as municipal and industrial waste disposal, rapid urbanization, shipping, and naval activities etc. have a significant impact.
item: Conference-Abstract
Experimental investigation and performance optimisation of washing cycles for pre-processing of coal fly ash
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Brinthan, K; Shivadhahini, S; Senadheera, UAG; Fernando, WAM; Jayawardena, CL; Jayasundara, DRT; Wickrama, MADMG; Jayawardena, CL
Coal Fly Ash (CFA), a by-product of thermal power plant combustion, has a profound focus among researchers due to its pozzolanic properties, porosity, wide chemical composition, and thermal stability. While being suitable for many applications (e.g., pozzolanic material, soil stabiliser, and structural fill), CFA is also a potential precursor for synthesising zeolites, broadly used in wastewater treatment. However, pre-processing is crucial due to the heterogeneous nature of CFA. This work focused on pre-processing CFA prior to wastewater treatment through continuous washing cycles at various operating temperatures. To this end, we studied the pH and conductivity of the solution after washing over multiple cycles, Sauter mean diameter, and the mineralogy of the settled CFA. The gathered results were analysed and optimised through response surface methodology. This was done to find the best combination of the number of washing cycles and temperature to remove soluble ions and increase the surface area of CFA particles. The analytical outcome revealed that five washing cycles at 70°C were adequate, with minimal soluble ions and maximum surface area. Evidently, these findings demonstrated significant improvements in the physical and chemical properties of CFA as a precursor for zeolite synthesis. Therefore, we recommend further studies on this front to extend the effective usage of CFA for the synthesis of commercial zeolites to be used for wastewater treatment.
item: Conference-Abstract
Potentials and issues in manufacturing water-based graphite dispersions (-lubricants) in Sri Lanka as value added end product of natural graphite
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Ekanayake, EMKB; Jayawardena, LC
Sri Lanka is the only country in the world known to extract and produce commercially viable quantities of natural crystalline vein graphite. Currently Bogala Graphite mines and Kahatagaha Graphite mines are famous underground mines and largest natural graphite producers which supply natural vein graphite in the form of various product categories to international graphite market. It is said to be raw graphite or Run-of-mine (ROM) taken from underground mine is subjected to certain value adding steps such as separation into carbon grades and milling and grinding to requested particle size before export. But still value addition of graphite is a hot topic in many technical forums as well as among politicians and civil society. As we know, graphite is a miracle material in the industrial world as it involves or becomes an invaluable material in many industrial products as well as applications. So, among many graphite applications or end products, water-based graphite dispersion (lubricant) which is known as hot forging lubricant is one typical value-added graphite end product which can be produced in Sri Lanka using its own raw material. On the other hand, even though hot forging industry is not available in Sri Lanka, we can focus on our neighboring countries in South Asia specially India and Pakistan where world largest forging factories located and manufactured almost all forged parts for global automotive industry. This paper discusses potentials and issues related to manufacturing water-based graphite dispersions (lubricants) in Sri Lanka. This is one value added graphite end product and formulated specially aiming hot forging industry.
item: Conference-Abstract
A Grain Size Threshold for Quantifying Active Sediment Input: A Case Study of Maha Oya River in the Western Coast of Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Jayathilaka, RMRM; Ratnayake, NP; Wijayaratna, TMN; Silva, KBA; Jayawardena, LC
Rivers have a significant role in the coastal sediment budget as the primary sources of natural sediment. Further, it is essential to comprehend the minimum grain size threshold, also known as the littoral cutoff diameter (LCD), in order to determine the actual contribution of river sediment load to the littoral beach. This study aims to present the LCD as a crucial variable worth taking into account at the regional level when budgeting for littoral sediments. Maha Oya River located on a severely eroding coastline between Negombo and Chilaw on the western coast of Sri Lanka was focus in this study. Here, we collected forty-four beach samples from the swash zone and berm crest during two sediment sampling surveys in March and October 2022. Concurrently, a streamer-type sediment trap was placed at 2 km upper streams of Maha Oya River to capture the bottom to 1.5 meters river sediment load. Sediment samples were sieved by mechanical sieving method in the classic Wentworth grain size scale (63-2000 μm). Additionally, the statistical properties of a grain size distribution, including LCD, skewness, kurtosis, and median grain size (D50), were investigated for sediment samples. Average D50 value on the beach was found to be 394 μm of medium sand that was moderately sorted, symmetrical, and mesokurtic, compared to 655 μm of coarse sand that was poorly sorted, fine skewed, and mesokurtic in river sediment. The LCD values was 141 μm on the beach studied herein, that indicated 10% of the river sediment in the lowest 1.5 m layer may not have remained on the beach in any significant quantity. Therefore, by using the concept of LCD, it is possible to quantify the potential overestimation of river sediment loads to the coastal sediment budget.
item: Conference-Abstract
Upgradability of Quarry Dust Use as a Substitute for River Sand in Plastering Works in Construction Industry
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Weerarathne, KH; Krishanth, S; Vithulyan, S; Dissanayake, DMC; Illankoon, IMTN; Samaradivakara, GVI; Mushmika, PAS; Jayawardena, LC
Due to its low supply and high demand, river sand has become one of the priciest building construction materials. Riverbeds are overly mined for river sand to cater to the high demand, and this has been causing irreversible environmental damage. Manufacturing sand (crushed stones/quarry dust), offshore sand, dune sand, fly ash, and granulated waste are some of the potential substitutes for river sand. This study examined the feasibility of quarry dust as a substitute for river sand for plastering indoor walls under multiple testing scenarios. After removing fines through wet sieving, the upgraded quarry dust can be used as a substitute for river sand for indoor wall plastering.
item: Conference-Abstract
Determining the Invasive Plant Dynamics in Bolgoda Lake Using Open-source Data
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Kannangara, KATT; Shoukie, MB; Nayomi, MPA; Dassanayake, SM; Dassanyake, ABN; Jayawardena, CL; Jayawardena, CL
Identifying invasive plants (IP) and monitoring their dynamics is essential to minimize potential adverse effects on natural resources. Remote sensing (RS) could effectively cater to such requirements by acquiring data in many critical domains. Limitations of spatial resolution, spectral information, and large imagery files usually hinder retrieving, managing, and analyzing remotely sensed data. The cloud-based computational capabilities of Google Earth Engine (GEE) provide the amenities for geospatial data analysis, retrieval, and processing with access to a majority of freely available, public, multi-temporal RS data. Integrating machine learning algorithms into GEE generates a promising path toward operationalizing automated RS-based IP monitoring by overcoming traditional challenges. Use of Classification and Regression Trees (CART) classifier to generate water-vegetation classification over six years (2016-2021) with Landsat 8 and Sentinel 2 images enabled mapping the invasive plants and their dominant component of Water Hyacinth (Pontederia crassipes) across a heterogeneous landscape in Bolgoda Lake, Sri Lanka. Also, the study could develop a relatively accurate classification of the water-vegetation dynamics over the time of interest. The classified time series data indicates the annual variation of the water, vegetation, and non-vegetation classes with rapidly fluctuating seasonal cycles for the vegetation cover. These results could benefit regulatory authorities and institutions to optimize environmental resource management and prioritize eco-preservation attempts. Moreover, the findings reflect the capabilities of deep learning models to identify invasive plant behaviors even with modest spatial and spectral resolution imagery.

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