ISERME - 2024

Permanent URI for this collectionhttp://192.248.9.226/handle/123/22912

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item: Conference-Extended-Abstract
An alternative underground hoisting system for Kahatagaha underground graphite mine, Sri Lanka- a case study
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Ekanayake, E.M.K.B.; Dissanayake, K.G.T.D.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
Hoisting systems used in underground mines are essential for the transportation of equipment, personnel, mined ore and thus for the productivity of an underground mine. It consists of various components in which there are shear wheels, winches, wire ropes, lift cages, carriage boxes and electric motors. The safety and reliability of the hoist depends on its design, therefore proper and accurate design of a hoist is essential. A properly designed hoisting system also supports to increase underground productivity as well. Kahatagaha underground graphite mine is the deepest underground graphite mine in Sri Lanka, where the deepest level is 2080 feet below from the surface. The main lift operates up-to 1130 feet level from the surface and there are 5 inclined winzes equipped with pneumatic winches and hanging wooden boxes with the support of wire ropes for hoisting or lowering men and material as hoisting method from 1130 feet level to 2080 feet step by step between main underground levels. This hoisting method is very primitive and it has many bottlenecks when going to increase underground production, productivity and safety. This paper aims to provide a solution for current hoisting system & it`s issues mentioned above and presents the benefits of proposed hoisting system for Kahatagaha underground graphite mine. In fact, a cost-effective and safe hoisting system is a great support for any underground mine so that the proposed design would be a good alternative against the primitive system still in operation.
item: Conference-Full-text
Analysis of subsurface strata of Colombo and Gampaha districts of Sri Lanka, based on geotechnical investigation data
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Karunarathna, K.S.S.; Wasana, N.W.A.P.; Bandara, M.G.K.M.; Ranathunga, R.M.IG.N.K.; Samaradivakara, G.V.I.; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
The subsurface exploration for geotechnical engineering applications in Sri Lanka is mainly based on borehole investigations. Several leading geotechnical engineering companies in the country have already done more than a couple of thousands of subsurface investigations for small- and large-scale civil engineering projects. Even though project-wise subsurface information is available, integration of available subsurface data in proximity, and development of subsurface three-dimensional (3D) models can hardly be seen in the country. This has been a significant disadvantage in the cost and planning of large-scale new investigation projects. Due to lack of information, most of the projects start even without knowing the tentative bedrock level of the area. Hence, in investigation cost estimations, pricing for most of the items is recorded as “rate-only”, hence the total cost could immensely be higher than the available budget with the client. However, if 3D modelling of subsurface strata can be done area-wise, based on already available borehole data, such uncertainties could be minimized. In this research, more than a thousand subsurface investigation reports were reviewed; data were recorded and analysed targeting to interpret the subsurface of the western province of Sri Lanka, and to develop a 3D subsurface model for the same. However, scattered data had to be excluded in data analysis, and eventually, the study was confined to Colombo and Gampaha districts, in which more than sufficient data could be found. By using interpolation methods, surface strata were interpreted in between borehole locations by matching similar geological features. In addition, artificial neural networks were used to forecast borehole data in exceptional cases for a few locations. This helped to improve the spatial coverage and accuracy of the 3D model developed by means of “Surfer” software. The 3D model developed for the study area well demonstrates the subsurface strata and facilitates taking of cross sections in any direction within minutes. Hence, the findings of this research will enhance the outcome of general geotechnical investigation practice in Sri Lanka. This will also be immensely beneficial in planning and budgeting of future large-scale geotechnical investigation projects, more accurately than in the past, saving energy and time.
item: Conference-Full-text
Assessing the applicability of geophysical methods for exploring vein type mica deposits – a case study in Matale district, Sri Lanka
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Wickramasinghe, K.G.K.G.; Arachchige, R.A.N.U.R.; De Zoysa, D.Y..B.; Premasiri, H.M.R.; Abeysinghe, A.M.K.B.; Ratnayake, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A; Jayawardena, C
Mica, a group of silicate minerals characterized by their layered structure, is integral in various industries due to its insulating properties, heat resistance, and aesthetic appeal. Mica is commonly found as pegmatite and vein type deposits. However, vein type mica is extremely difficult to explore because of the complexity of their underlying geology and structural features. Atipola mica mine is one of the well-known mica mining sites in Matale district, Sri Lanka where the exploration of vein type mica deposits is difficult due to their complex geological formation. Therefore, this work attempts to assess the applicability of the Ground Penetrating Radar (GPR) geophysical methods for discovering new mica deposits. The field survey data collecting, and coverage plan were developed to investigate the most appropriate and pertinent area based on preliminary field observations. Since mica mining has emerged as a crucial economic activity in Sri Lanka, this study will also contribute to the investigation and advancement of vein-type mineral deposit exploration in Sri Lanka. Integrating GPR could make it possible to explain the subsurface structure in a non-destructive and appropriate way, which could help with informed mining methods and lead to the right decision regarding the accurate categories of the mineralogy deposit
item: Conference-Full-text
Assessing the influence of microstructural features on deformation of rocks under triaxial loading
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Silva, SAV; Rathnapriya, RHDL; Riyasath, MSM; Dassanayake, ABN; Fujii., Y; Wickrama, MADMG; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Assessing the influence of microstructural features on the deformation of rocks under triaxial loading is vital in rock engineering applications, aiding safe and efficient operations by predicting the deformation of rocks. Triaxial testing offers the simulation of stress conditions within a rock to examine the deformation of rocks with confinements. This research focuses on how microstructural features, such as cementing material and pore geometry, affect the deformation behaviour of rocks subjected to triaxial loading. Two rock types were considered in this study: Kimachi sandstone (medium hard clastic rock) and Bibai sandstone (hard clastic rock). The progressive failure behaviour under Hydro Mechanical (HM) coupling effect was analysed by stress-strain distribution and the fracture geometry was examined using CT images of the specimens which were tested under different confinements. Thin sections were analysed to examine the changes in porosity and the effect on the cementing material with the confinement. The results of the proposed approach reveal a clear influence of the effective confinement on the failure of rocks and how it influences the porosity and cementing material of rocks. It is found that the Bibai sandstone shows a brittle failure and a shearing deformation while Kimachi sandstone shows a brittle to ductile failure and shearing to compaction deformation with the confinement due to the less presence of cementing material within Bibai sandstone compared to Kimachi sandstone. Therefore, with the confinement, the porosity of Bibai sandstone increases while it decreases in Kimachi sandstone. The results highlight the differences in the failure mechanism of a particular rock type for the same effective confinement which is a result of only a partial contribution of the pore pressure on the failure. These findings provide valuable insight into the assessment of microstructural features on the deformation of rocks under triaxial loading, aiding in the development of safer and more efficient rock engineering operations.
item: Conference-Full-text
Assessment of biodiesel production potential and capacity analysis utilizing animal fat waste
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Upamali, W..M.A.; Wijesekara, E.R.J.M.D.D.P.; Amarasinghe, A.M.P.C.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
New Anthony's Farm, a major chicken producer in Sri Lanka, generates significant wastewater during production. This study aims to find a solution for the sludge produced in their treatment plant. Animal fats, a common waste in various industries, require expensive treatment due to environmental regulations. They mainly consist of triglycerides (90-95%), which are further made up of fatty acids like saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated (PUFAs). Animal fat waste offers valuable opportunities for industrial use, but its improper disposal poses significant environmental threats. Sustainable management and utilization of this waste are crucial to protect the environment and extract valuable resources. First, an FFA (Free Fatty Acids) test was done for the top and bottom animal waste fat samples taken from the fat separation Dissolved Air Floating unit in the wastewater treatment plant in 'Anthony's Farm. The NaOH base with the Phenolphthalein indicator titration method was used for this FFA identification. After that, acid treatment was performed to reduce the FFA value of these samples, 60 0C hot water washing was done to purify the animal waste fat sample, and biodiesel was produced by transesterification. Direct transesterification was not obtained for the bottom sample, so the resulting liquid layer was centrifuged at 3000 rpm for 15 minutes and trans-esterified. After that, both samples were used to produce bioethanol. There, the top sample was directly used for bioethanol production without pretreatment, and bioethanol was produced using the glycerol layer of the bottom sample. The acid treatment was done with an H2SO4 Acid-to-fat ratio of 12:1, Temperature around 64°C, and pH - around 7, and it was reduced the FFA value of the top sample from 20.72% to 12.60%, and the initial FFA value of the bottom sample, which was 3.36%, was reduced to 2.80%. Considering this FFA value, the bottom sample seems to have more potential for biodiesel production. Also, the flash point of the biodiesel produced in this way was measured using the Flashpoint analyser, and it was found to be 55.5 0C.
item: Conference-Full-text
Assessment of seasonal and spatial water quality changes in Kelani river, sri lanka
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Rathnayake, A.G.S.N.; Luxman, R.; Udayanga, N.A.P.; Chaminda, S.P.; Ishankha, W.C.A.; Gunawardhana, L.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
The deteriorating water quality of the Kelani River over time has negatively affected environmental health and sustainability. This study aims to determine the relationship between land use types and its impact on the water quality within the Kelani River basin. The analysis utilized a dataset comprising 23 parameters related to water quality, spanning 17 sampling locations along both the primary river and its tributaries from 2003 to 2023. IBM SPSS Statistics (Version 26), was utilized for data analysis, focusing on 7 water quality parameters (pH, dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate, phosphate, and turbidity) that were influenced by land use. From this analysis, 6 sampling locations were selected to represent various segments of the stream, including Aguruwella and Nakkawita for the upstream segment, Pugoda Ela and Wak Oya for the middle stream, and Rakgahawatte Ela and Maha Ela for the downstream segment. This study utilized a combination of GIS and statistical methods over 4 years with a 6-year time interval (2004, 2010, 2016, and 2022). The land use maps were generated by categorizing area into 4 land use types as agricultural area, vegetation area, built-up area, and others, using maximum likelihood supervised classification. Accuracy assessment using the kappa coefficient revealed that overall accuracy was greater than 85 %, for all six sub-catchments across all four years. From the analysis, it shows that the water quality parameters are significantly varied spatially and temporally. From upstream to downstream and over time, water quality has declined. Regression analysis shows the relationship between land use types and 7 water quality parameters. pH, DO, COD, BOD, and nitrate show a correlation with built-up lands, pH, DO, COD, nitrate and turbidity with vegetation areas, and phosphate with agricultural areas. Moreover, this study highlighted, built-up lands and agricultural lands negatively influenced the water quality, while vegetation areas positively influenced. By identifying the correlation between land use types and water quality, this study helps to preserve and enhance the water quality of the Kelani River basin by implementing proper land use management strategies.
item: Conference-Full-text
Characterization of heavy minerals in Nilaveli and Batticaloa beach stretches
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Benjamin, R; Anojithan, M.; Lokugamhewa, S.W.; Ratnayake, N.P.; Abeysinghe, A.M.K.B.; Premasiri, H.M.R.; Dushyantha, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H.; Elakneswaran, Y; Dassanayake, A.; Jayawardena, C.
The northeastern coast of Sri Lanka is notable for its significant heavy mineral deposits, especially the Pulmoddai deposit (containing 70-85 wt% heavy minerals) and the Verugal deposit (containing 45-50 wt% heavy minerals). However, regions like Batticaloa and Nilaveli remain underexplored and show potential. This study conducted a comparative analysis of these two beaches stretches to characterize their heavy mineral content in beach sand. Twenty-four composite samples were collected along the Batticaloa (n=17) and Nilaveli (n=7) stretches. Bromoform separation was used to determine their heavy mineral contents, followed by petrographic microscopic grain counting to ascertain the volumetric percentage of each heavy mineral type. The results revealed a higher mineral content in the Batticaloa beach stretch (1.20-14.50 wt%) compared to Nilaveli (0.36-6.42 wt%), despite Nilaveli's proximity to the Mahaweli River. The Batticaloa beach stretch showed average contents of 53.14% ilmenite, 2.06% rutile, 6.44% garnet, 31.94% zircon, and 4% monazite, indicating a significant potential for economically valuable monazite. The high heavy mineral content identified in the Batticaloa beach stretch suggests that further detailed explorations are warranted to assess the economic viability of the deposit.
item: Conference-Abstract
Comparative analysis of mechanical and mineralogical properties of rocks from maddhapara granite mine, Bangladesh
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Alam, A.M.K.B.; Fujii, Y.; Dipu, N.H.; Ghalib, F.H.; Sajib, A.I.; Ullah, A.S.M.W.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
This study presents a comprehensive analysis of the mechanical and mineralogical properties of rocks collected from Maddhapara Granite Mine (MGM) in the northern region of Bangladesh. The research focuses on the characterization of two main categories of rocks, distinguished by their color and mineral composition, namely the dominant black rock and the flashy colored rock. Microscopic studies were conducted to categorize the rocks, leading to the identification of minerals such as quartz, feldspar, amphibole, and biotite within the rock samples. The black rock was classified as Tonalite, with specific mineral compositions, while the flashy colored rock was identified as granite, exhibiting distinct mineral proportions. The research further delves into the physical properties of the rocks, including density, effective porosity, P-wave velocity, S-wave velocity, and Uniaxial Compressive Strength (UCS). Notably, UCS tests were performed to characterize stress parameters such as crack closure stress, crack initiation stress, crack damage stress, and peak stress for both rock types. The results revealed significant differences in stress levels and mechanical responses between the two rock types, with tonalite exhibiting higher stress levels and distinct mechanical behaviors such as plastic deformation and shear deformation, compared to the granite. These variations are attributed to the dominating minerals present in each rock type, particularly amphibole and quartz for tonalite, and feldspar and quartz for granite. The findings of this study have implications for the stability of drifts and stopes in mining operations, as the mechanical responses of the rocks, influenced by their mineralogical composition, may impact their suitability for various engineering applications. This research contributes to the understanding of rock properties in the context of mining engineering, providing valuable insights for the assessment and utilization of rocks from MGM and similar geological formations.
item: Conference-Full-text
Comparative analysis of vertical metal zonation in Ginigalpelessa and Indikolapelessa serpentinite complex
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Mahendran, M; Maduranga, U.K.D.; Amarasinghe, A.A.Y.D.T.; Abeysinghe, A.M.K.B.; Ratnayake, N.P.; Premasiri, H.M.R.; Dushyantha, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
Serpentinite deposits in Ginigalpelessa and Indikolapelessa Sri Lanka, are known to exhibit a high supergene enrichment of Ni, Cr, and Co in the regolith due to the prolonged weathering of the underlying serpentinite bedrock. However, no detailed studies have been conducted to determine the vertical zonation of these critical metals in these deposits. The vertical metal distribution of a deposit is significant to delineate its vertical metal enrichment patterns and mobilization which may lead to the identification of efficient exploration and extraction methods. Therefore, this study assessed the vertical zonation of Ni, Cr, and Co in both Ginigalpelessa and Indikolapelessa serpentinite deposits. Twenty-four soil (n=12) and weathered rock (n=12) samples from 4 soil horizons (O, A, B, C) in soil profile were collected and analyzed for Ni, Co, Cr, and Cu by ICP-MS. Our findings revealed high metal concentrations in the soil or highly weathered rock samples over the partially weathered rock samples. The Ginigalpelessa deposit demonstrated4 a higher concentration of Ni, Co, Cr, and Cu compared to the Indikolapelessa deposit. It observed that the concentrations of Ni, Co, Cr and Cu in the topsoil were lower compared to deeper horizons (A, B, and C) in some locations. This may have occurred due to the bioavailability of some metals like Ni, which accumulates in the plants and reduce the concentration in the soil. Conversely, the low bioavailability of Cr compared to the other metals have resulted high Cr concentrations in the surface horizon. In addition, previous studies found that Cr is immobile, whereas Ni and Co are scarcely mobile under the moderate acidic conditions in the serpentine soil. During the weathering process, the slightly acidic rainwater leaches these Ni-like metals from the O and A horizons, resulting their enrichment in the B horizon. However, further studies are necessary to identify the suitable leaching or extraction method to recover these metals from serpentine soil. Therefore, this research contributes to a deeper understanding of vertical metal zonation in serpentinite deposits to facilitate more efficient and sustainable exploration of valuable metals like Ni in serpentinite deposits.
item: Conference-Abstract
Comparison of critical metal potential in beach and offshore sediments of Pulmoddai, Sri Lanka
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Nanayakkara, C.J.; Ratnayake, N.P.; Premasiri, H.M.R.; Abeysinghe, A.M.K.B.; Ratnayake, A.S.; Dushyantha, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
The global transition towards renewable energy resources for power generation has increased the demand for critical metals (CMs), including rare earth elements (REEs). This rapid growth of demand coupled with geological scarcity and geo-political concerns has posed great challenges in securing the supply chain of CMs. Therefore, prospecting new CM sources worldwide is of timely importance. In this context, the Pulmoddai coastal stretch in Sri Lanka has been recognized as a dynamic deposit with established potential for REEs and other critical metal resources, currently undergoing beach face mining operations. The focus of this study is to compare the critical metal potential in the beach and offshore sediments in Pulmoddai, Sri Lanka, crucial for determining the origin and delineating the extent of this deposit. Twelve onshore and nineteen offshore samples were collected and analyzed for CMs (V, Cr, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, and Cs) and REEs. Based on the results, light REE content (LREE), heavy REE content (HREE), and total REE content (TREE) were computed for both onshore and offshore locations. For onshore sites, LREE, HREE, and TREE ranged respectively from 43.27 to 244.09 ppm, 19.62 to 92.29 ppm, and 62.92 to 336.39 ppm. Conversely, offshore locations exhibited higher concentrations with the corresponding values ranging from 116.12 to 363.62 ppm, 8.57 to 120.93 ppm, and 167.93 to 484.55 ppm. Sr, Ni, and Cr were determined as the most abundant CMs for both onshore and offshore locations. Sr, Ni, and Cr concentrations ranged from 227.17 to 674.58 ppm, 116.17 to 675.88 ppm, and 43.55 to 112.87 ppm respectively for the onshore locations. The corresponding ranges for offshore sites were determined as 370.86-754.30 ppm, 235.43-721.44 ppm, and 32.51-172.62 ppm. The higher CM content in offshore regions suggests an offshore origin to this dynamic deposit, which is enriched by the offshore sediments transported onshore and deposited on a long-term basis. Therefore, regulatory authorities overseeing the mining operations of Pulmoddai deposit should accurately delineate its extent, integrating both onshore and offshore regions as a unified system, rather than solely focusing on prospecting the longshore areas.
item: Conference-Abstract
Development of a numerical simulation method for complex fracture process of rocks based on 3-D ECZM-FDEM using GPGPU parallel computation
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Takarada, K; Fukuda, D; Di, W; Liu, H; Ogata, S; Maeda, Y; Min, G; Kawasaki, S; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
For the developments of surface and underground mines, numerical simulation has been regarded as a highly crucial approach in terms of mining design and safety. The combined finite-discrete element method (FDEM)[1] has attracted significant attention for reasonably simulating very complex fracture processes of rocks. FDEM is based on the continuum mechanics model considering finite-strain theory, the cohesive zone model (CZM)[2] by utilizing initially zero-thickness cohesive elements (CEs) and potential-based contact mechanics model. The FDEM based on the intrinsic CZM (ICZM), which inserts the CEs at the onset of the simulation, has been the mainstream of previous studies applying FDEM due to its simpler implementation. Although the FDEM is generally known as a computationally expensive numerical method for both two-dimensional (2D) and three-dimensional (3D) problems, the computational acceleration of the ICZM-based FDEM can be achieved with relative ease through parallel computation using general-purpose graphics processing units (GPGPUs). However, the accuracy of continuous deformation when rock is intact is significantly compromised in the ICZM. The FDEM based on the extrinsic CZM (ECZM), which activates CEs only when and where the local stress reaches the given activation criteria, is expected to overcome this issue. However, although the implementation of 2-D ECZM-based FDEM with the GPGPU parallel computation has been reported, its 3-D counterpart has not been achieved. Based on this background, this study proposes a novel master-slave algorithm to achieve the implementation of the GPGPU-parallelized 3-D ECZM-based FDEM. Figure 1 shows the examples results of GPGPU-parallelized 3-D ECZM-based FDEM for uniaxial compression test simulation and spalling test simulation [3]. These results indicate that the developed ECZM-FDEM can reasonably reproduce the fracture and failure patterns of rocks in both static and dynamic tests compared to laboratory tests. The significant advantage of the proposed approach lies in the fact that the precision of continuous deformation can compared to those of the parallelized ICZM-based FDEM. The proposed approach could be an important basis for the further developments of the ECZM-based 3-D FDEM for simulating very complex 3-D rock fracturing processes in the various rock engineering problems.
item: Conference-Abstract
Disaster and attitudinal vulnerability: a systematic conceptual review
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Senavirathna, C; Rajapaksha, S; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Natural hazards represent a destructive force that poses a significant risk to human life, property, and the economy, among other aspects. The impact of natural hazards on the economy and human populations is profound. Various attitudes, beliefs, and behaviors are linked to different demographic groups, some of which may be more susceptible to these hazards than others. In developing nations, catastrophic natural events like tsunamis can deliver a sudden blow to their development trajectory, leading to a costly and challenging recovery process. A key contemporary challenge in disaster preparedness involves the effective application of soft measures, focusing on assessing local awareness, knowledge, perception, and attitudes towards disasters. The primary research inquiry in this investigation pertains to understanding the existing knowledge surrounding attitudinal vulnerability to disasters. The aims of this study include conducting an extensive review of current knowledge on attitudinal vulnerability in disasters and identifying potential avenues for future research.PRISMA framework and guidelines have been followed to conduct this systematic conceptual review. Total of 128 articles were initially identified from the Scopus database using the key words “Disaster”, “Vulnerability” and “attitude”. Review protocol has been developed according to the PRISMA guidelines. Analysis method used in this study was keyword co-occurrence utilizing the VOSviewer software (Version 1.6.20). The principal discoveries of this theoretical manuscript encompass the delineation of forthcoming avenues for research and areas of research deficiency, such as knowledge lacunae, empirical deficiencies, contextual deficiencies, and methodological deficiencies. A comprehensive framework is imperative to grasp the extent of the matter, encompassing both the technical and social repercussions. Subsequent research endeavours should concentrate on the amalgamation of Blockchain and the internet of things to facilitate real-time data utilization in the realm of disaster readiness. Initiatives aimed at enhancing disaster preparedness should specifically target younger demographics for enhancement purposes. In conclusion, the influence of past experiences on current and future preparedness needs to be explored enhancing public attitudes and knowledge of climate change and disaster risk
item: Conference-Full-text
Distillery spent wash as an alternative fuel in boilers and potash recovery from that ash remaining in boilers
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Warnakulasooriya, G.A.P.K.G.G.; Amarasinghe, A.M.P.C.; Lankathilake, L.J.M.U.; Wijesekara, E.R.J.M.D.D.P.; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Waste management stands as a critical global environmental challenge, with a growing emphasis on waste avoidance and the generation of revenue through byproduct recovery. Pollution prevention strategies aim to minimize waste generation, while waste minimization efforts focus on reducing waste volume or toxicity, often through water recycling, process modification, and byproduct recovery. In this context, the utilization of distillery effluent in agriculture presents an opportunity to save on fertilizer costs, enhance agricultural output, and mitigate pollution. However, molasses-based distilleries, along with their primary product, alcohol, generate significant volumes of wastewater known as spent wash. Improper disposal of spent wash into water bodies or land leads to a host of environmental issues. Consequently, recent efforts have shifted towards waste minimization and revenue generation through byproduct recovery. This study focuses an approach to address the challenge of distillery spent wash management by drying the spent wash and utilizing the resulting dried solids as an alternative fuel for boilers. The distillery spent wash contains approximately 14.6% solid content, and the dried solids have a gross calorific value of 13840 J/g. Furthermore, the dried solids possess an ash content of 2.26%, with the ash containing a notable 36.7% potassium oxide content. By transforming distillery spent wash into a valuable resource for boiler fuel, this research not only addresses waste management concerns but also offers a sustainable solution for revenue generation. The utilization of dried solids as an alternative fuel for boilers contributes to reducing environmental pollution associated with improper spent wash disposal while offering a viable source of renewable energy. This study underscores the potential of waste-to-energy initiatives in fostering sustainable waste management practices and enhancing economic viability in the distillery sector.
item: Conference-Full-text
Effect of fracture stiffness in a fault damage zone on seismic source parameters of induced fault-slip
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Gang, M; Sainoki, A; Kodama, J; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
It is well recognized that inherent stress concentration within a fault damage zone may lead to induced fault-slip, resulting in severe damage to underground facilities. Previous research suggests that the intensity of fault-slip is influenced not only by the mechanical properties of the fault core but also by the stiffness of the surrounding rock mass, implying that fracture stiffness could be an important factor that needs to be studied. Therefore, in this study, the effect of the fracture stiffness on seismic source parameters of induced fault-slip is investigated using a mine-wide scale heterogeneous continuum model. The model is constructed based on a discrete fracture network within a fault damage zone, utilizing the crack tensor theory and boundary traction method. The fault core is simulated as a discontinuous plane with interface elements at the center of the model, and fault-slip is induced by gradually reducing the effective normal stress on the fault plane. Seismic source parameters are computed and analyzed under various fracture stiffness conditions. Seismically radiated energy is defined as the work done by the stress perturbation across a closed surface at a distance from the earthquake source, while seismic moment is calculated using the moment tensor of a seismic source in an anisotropic medium. This study investigates increasing fracture stiffness while maintaining a normal-to-shear stiffness ratio of three. Dynamic analysis results reveal a notable impact of fracture stiffness on seismically radiated energy and seismic moment, both of which decrease significantly with increasing fracture stiffness. These findings imply the importance of considering fracture stiffness for more accurate estimation of seismically radiated energy and seismic moment.
item: Conference-Abstract
Enhancing Co2 mineralisation in steel slag with amines for developing a waste to construction material
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Takebe, K; Elakneswaran, Y; Yoda, Y; Kitagaki, R; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Global warming has become an urgent issue due to the increasing atmospheric emission of CO2. In Japan, the steel industry emits a large amount of CO₂ and produces steel slag as an alkaline waste product. Using this steel slag to absorb CO₂ in flue gas is an effective approach for CO₂ emissions and recycling. This study introduces a novel technology utilizing amines to facilitate CO₂ sequestration in blast furnace slag. This innovative approach demonstrates significant potential and flexibility compared to conventional CO₂ capture technologies. In this study, changes in the carbonation efficiency of slag with three types of amines (N-Methyldiethanolamine (MDEA), 2-(Methylamino)ethanol (MAE), 2-Amino-2-methyl-1-propanol (AMP)) were investigated. In addition, this study examined the effect of Portland cement on the carbonation efficiency. In wet carbonation, the CO₂ fixation process entails the introduction of 1 mol/L of amine, water, slag, and cement, followed by a 24-hour leaching process and subsequent 24-hour carbonation. The results showed that adding AMP and cement exhibited the most significant increase in carbonation efficiency, resulting in the formation of 11.07% of the solid weight as CaCO₃, as confirmed by thermogravimetric analysis (TGA). Changes in calcium ion concentration and pH were also investigated in this study. The results showed that a small amount of Ca²⁺ dissolution and an increase in pH occurred in the early stages of the reaction and that the majority of Ca²⁺ dissolution occurred simultaneously with carbonation. In dry carbonation, slag cement paste, made by mixing amine, slag, and cement, was carbonated for 28 days after a 28-day curing period to determine changes in its properties. W/S ratio is 10, slag/cement ratio is 19, amine concentration is 1 mol/L, and CO₂ concentration is 0%, 0.04%, 5%, and 15％. Strength tests showed an increase in strength in the slag cement paste with the addition of MDEA.
item: Conference-Abstract
Enhancing concrete sustainability through carbonated recycled cement powder: a review
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Mylvaganam, N; Yogarajah, E; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Concrete is a vital construction material, but the rapid urbanization has led to a significant accumulation of demolished concrete, especially in developing countries. Despite efforts, only a small fraction of this concrete is recycled, leading to environmental challenges. However, countries like Japan have successfully recycled a large portion of their demolished concrete, primarily for use in road subbase and as Recycled concrete aggregate (RCA) which is typically yields lower quality compared to natural aggregate (NA). Additionally, during RCA production, a significant amount of cement powder is generated, which has the potential to be used as a supplementary cementitious material (SCM). Recent research has explored various valorisation methods for recycled cement powder (RCP), with carbonation emerging as the most sustainable option. Carbonated RCP not only stores CO2 but also improves concrete properties such as compressive strength and durability. Considering the environmental impact of traditional cement manufacturing, the utilization of SCMs, such as carbonated recycled cement powder (cRCP), has emerged as a promising strategy. This approach promotes sustainable recycling practices and contributes to ecological conservation efforts, aligning with the circular economy philosophy. This review highlights recent findings on the accelerated carbonation treatment of RCP, exploring its benefits and applications as a sustainable building material
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Enhancing stockpile inventory management through UAV- based volume estimation: a case study of salt stockpiles in Hambantota mahalewaya
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Perera, M.T.R.D.; Wijesundara, K.K.G.I.; Jayawarna, M.D.; Chaminda, S.P.; Madhurshan, R.; Samarakoon, K.G.A.U.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
Accurate volume estimation of stockpiles is crucial in industries such as Mining, Construction, salt, and Agriculture to optimize resource utilization. This study evaluates the effectiveness of Unmanned Aerial Vehicles (UAVs) compared to Differential Global Positioning System (DGPS) and Total Station (TS) methods for volume estimation of outdoor salt stockpiles in Hambantota Mahalewaya, Southern province of Sri Lanka. The inventory identified two stockpiles, stockpile 1 and stockpile 2, with volumes of 1832.25 m3 and 819 m3, respectively. An optimal elevation of 55m was utilized for UAV surveys, and the results were compared with DGPS and TS measurements. UAV surveying factors affecting errors, including image resolution, Ground Control Points (GCPs), and image processing software, were assessed for both stockpiles. Survey time and cost for each method were also analyzed. Pix4dMapper and Agisoft Metashape software processed UAV images, while Civil3D software processed DGPS and TS data. Results indicated that increasing UAV survey elevation reduced volume error percentages for both stockpiles, with and without GCPs. For Stockpile 1, UAV volume estimation showed a 0.88% difference from the actual volume, compared to 4.81% for DGPS and 3.35% for TS. Conversely, for Stockpile 2, UAV estimation differed by 0.95%, while DGPS and TS showed differences of 0.56% and 0.10%, respectively. UAV surveys proved efficient in terms of survey time and labor intensity. Despite technological advancements, challenges remain, particularly in addressing topographical variations for accurate volume estimation. To improve UAV-based estimation, addressing bottom elevation discrepancies by establishing fixed benchmarks on flat terrains was suggested. Nonetheless, UAV-based approaches offer fast and relatively reliable results, indicating their potential for widespread adoption.
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Evaluation of satellite-derived gravity field models in offshore and coastal regions of Sri Lanka
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Wijesooriya, WMARK; Prasanna, HMI; Gunathilaka, MDEK; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
To understand many geophysical phenomena, including ocean circulation, tectonic plate movement, and the Earth’s interior, it is important to study the Earth’s gravity field. During the past three decades, satellites have measured the Earth’s static gravity. As a result, high-resolution global gravity field models have been available. This paper aims to examine the appropriateness of the satellite derived gravity field models for the offshore and coastal regions of Sri Lanka.While these eight gravity field models with ID 155-EIGEN-6S4 V2, 168-Tongji-Grace 02K, 171-GO-CONS-GCF2-TIM-R6, 174-ITSG-GRACE 2018S, 178-Tongji-GMMG2021S, 148-EIGN-6C4, 152-GECO, 167-SGG-UGM-1, and 177-SGG-UGM2 were used for the study. The mean difference value, standard deviation value, and Root Mean Square values modeled by each of the model between the observed gravity data and the BGI observed gravity data. The results indicated that 171-GO-CONS-GCF2-TIM-R6 and 177-SGG-UGM2 is the more suited model for the coastal and offshore region of Sri Lanka. The study used the SARAL-Altika satellite Altimetry data to investigate the relationship between Mean see surface height and observed gravity. No significant relationship between Mean sea surface height and marine gravity is indicated by. In addition, the influence of gravity model type on each of the LEO satellite orbit predictions was also studied. The findings of the research demonstrate that the optimal type of gravity model applied for LEO satellite orbit prediction depends on a short-term or long-term predictions. The models JGM3, EGM2008, and GL04C are more appropriate for short-term predictions, while the models JGM3, EGM96, and EIGEN2 are the best for long-term predictions. The gravity order and permanent tides also have to be taken into account for the orbital prediction.In conclusion, this research provides valuable insights into the suitability of various satellite-derived gravity field models for Sri Lanka's coastal and offshore regions. The findings also emphasize the need to consider the impact of gravity models on LEO satellite orbit prediction, particularly for new applications such as LEO navigation, which require real-time precise orbits.
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Experimental and numerical analysis of dynamic fracture processes in rock and rock-like materials using NRC vapor pressure agent
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Min, G; Fukuda, D; Di, W.; Liu, H; Kawasaki, S; Cho, S; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
This study investigates the fracture characteristics of rocks and rock-like materials subjected to the Nonex Rock Cracker (NRC), a vapor pressure crushing agent. The NRC generates vapor pressure by instantaneously vaporizing a crystallized water mixture through the thermite reaction. Both experimental methods, using high-speed cameras and dynamic pressure gauges on Polymethyl methacrylate (PMMA) and granite blocks, and numerical simulations with a 3-D combined finite-discrete element method (FDEM) were utilized. Results indicate that gas pressure infiltrating pre-existing cracks primarily drives crack propagation. The study concludes that accurately modeling gas injection into initiated cracks during deflagration is essential for reasonable numerical simulations of rock fracturing processes using NRC.
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Experimental synthesis of zeolites from pre-processed coal fly ash using the microwave irradiation method
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Amirthavarman, V.; Perera, A.W.B.M.; Madhuwantha, G.L.S.; Fernando, W.A.M.; Jayawardena, C.L.; Wickrama, M.A.D.M.G.; Iresha, H.; Elakneswaran, Y.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
Coal power plants contribute by an excess of 40% to the generation of electricity worldwide. Coal fly ash (CFA), being a dominating by-product of coal power generation, is unique due to its physicochemical properties such as thermal stability, chemical inertness, compressive strength, and adsorption. However, reducing the inherent impurities of CFA, which is heterogeneous, has proven to enhance its ability to be valorised into different second-generation products of high value. Pre-processing has been a successful method in eliminating impurities of CFA, and washing cycles method is the preprocessing technique used in this study. Zeolites, a second-generation product from CFA, are well known for their excellent adsorption properties due to their high surface area and porosity, being an optimal solution for wastewater treatment. Also, the microwave irradiation method has proven to be useful and rapid in synthesising zeolites. This study investigates the effect of pre-processed CFA obtained through optimised utilisation of wash cycles, compared to raw CFA, and the feasible conditions of zeolite synthesis from CFA which have undergone the wash cycle preprocessing technique. NaOH concentration and microwave irradiation power were considered as key parameters. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) were utilised to verify the enhanced nature of CFA after pre-processing, and formation of zeolites. The results of XRD infer that Mullite (Al4+2xSi2-2xO10-x) is the major crystal match for CFA obtained from the site. Also, pre-processed CFA yields a better qualitative phase analysis with Mullite than raw CFA, with the former having a peak coverage of Mullite that is approximately three-fold than the latter. Furthermore, according to the experimental results, zeolite L and zeolite Na-Y were produced from the process, having an optimal NaOH concentration of 2.5M and microwave irradiation power of 300W. These findings have been corroborated using XRD and SEM with EDS analyses, and we recommend further extension of the frontier to check the viability of zeolite formation with other critical parameters, paving way to an effective treatment of wastewater.

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