ISERME - 2019

Permanent URI for this collectionhttp://192.248.9.226/handle/123/14735

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International Symposium on Earth Resources Management & Environment 2019 [Pre Text]
(Department of Earth Resources Engineering, 2019)
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Study on royalty for Sri Lankan quarry mining of industrial minerals using photogrammetric 3D modelling
(Department of Earth Resources Engineering, 2019-08) Jayawardana, KPSR; Athukorala, DRM; Chathuranga, HMD; Chrishoban, M; Sampath, JAB; Hemalal, PVA; Dharmaratne, PGR; Premasiri, HMR; Chaminda, SP; Wickrama, MADMG; Dissanayake, DMDOK; Samaradivakara, GVI
Royalty is a payment made to the owner of mineral rights for the privilege of extracting minerals from the ground on a lease agreement. Globally, there are three main methods used for the royalty calculation; namely unit based, value based and profit based methods. A combination of unit and value based systems is practised in Sri Lanka. However, an explosive based equation without any scientific base is adopted for the determination of excavated quantities of some minerals. The main objective of this study was to find an accurate method to calculate excavated quantity of a rock for calculation of royalty for industrial minerals in Sri Lanka. Initially, a multiple-borehole blast was carried out in a selected 'A Grade' quarry. A total station survey and an Unmanned Aerial Vehicle (UAV) survey were conducted to determine the excavated rock volume. The collected aerial photographs for photogrammetric 3D modelling were processed using Agisoft PhotoScan, Bentley ContextCapture and Drone Deploy softwares. The accuracy of each method was determined by comparing each estimated depleted volume with the value obtained from weighing the blasted tonnage. Photogrammetric 3D modelling gave the least deviation from the actual volume.
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Prediction of air over pressure due to blasting in tropically weathered granite quarries in Malaysia with multi-variable regression analysis
(Department of Earth Resources Engineering, 2019-08) Bhatawdekar, RM; Mohamad, ET; Armaghani, DJ; Mahmud, N; Dissanayake, DMDOK; Samaradivakara, GVI
World class infrastructure is developed ai Johor Bahru city of Malaysia. Granite is the most commonly available rock for production of aggregates. Blasting is essential for breaking of rocks. Environmental effects due to blasting are associated with flyrock, ground vibration, air over pressure and dust. Some of the aggregate quarries are proximate to human habitation. Many complaints are received by quarry management from different quarries by nearby habitants for (noise) air over pressure due to the blasting. This study was undertaken to investigate different parameters which contribute to air over pressure. At the end of study, multi variable regression analysis used for correlating with air over pressure (AOp) developed. Tropically weathered granite can be classified as fresh, slightly weathered, moderately weathered, highly weathered and completely weathered. Data were collected for 110 blasts from three quarries consisting of hole diameter (mm), burden(m), stemming length(m), charge per meter(kg/m), powder factor(kg/m3), joint aperture (mm), maximum charger per delay (kg), distance of blast from monitoring point (m) and measured AOp. Sensitivity analysis varies from 0.82 to 0.98. The data is analysed with multi variable regression analysis (MVRA) and equation was developed for predicting AOp with 8 input parameters. R2 with predictor equation and measured value shows 0.66.
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Issues and remedial measures in river sand mining - a case study related to artisanal river sand mining in Mahaweli River in Mahiyangana area, Sri Lanka
(Department of Earth Resources Engineering, 2019-08) Ekanayake, EMKB; Rupawansha, WKAS; Dissanayake, DMDOK; Samaradivakara, GVI
The demand for river sand for construction purposes has increased significantly in Sri Lanka in recent years, particularly due to the tsunami disaster that occurred in Dece: eer 2004 and post war period . 'U r 2009. This high demand led to a major incre«i:.c in sand mining in many areas. The current demand for sand for building construction within the country is approximately 7- 7.5 million cubic metres per year. Mahaweli river, the longest river in Sri Lanka is acting as major source of river sand supply for construction industry in the country. Certain areas along the river have become dominant sand mining sites in Mahaweli river. Among that river sand mining sites, Mahiayangana area has been very famous for river sand for a long period. In Mahiayangana area, river sand mining is extensively engaged industry and created major income earning source for thousands of rural folks living nearby. This industry has been creating new socio-economic situation in the area as this has been beneficial to many people in the area. This paper discusses present issues related to artisanal river sand mining in Mahaweli river- Mahiayangana area and remedial measures already adopted and proposals to ensure sustainable way of mining to minimize detrimental environmental affects to the ecosystem of river and the river banks.
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Landform planning - from void to vegetation
(Department of Earth Resources Engineering, 2019-08) Reynolds, T; Skok Muir, AA; Dissanayake, DMDOK; Samaradivakara, GVI
Iluka Lanka Resources has mineral resources within the Puttalam District of the North Western Province of Sri Lanka and is in the early stages of development of the Puttalam Mine and Industrial Development Project (PMIDP). At Iluka, we plan for rehabilitation of the open mine pits and subsequent final landform at the feasibility phase and continue throughout the life of the project from feasibility studies, execute, operations, closure through to close out. Iluka takes a multidisciplinary approach to rehabilitation with its technical ability in mine planning, survey and engineering in conjunction with applying knowledge from fields such as soil science, vegetation, ecology and hydrology among others to achieve the agreed final land use, which influences final landform. This paper discusses the planning process in terms of landform rehabilitation applied to Iluka's Australian operations at Jacinth-Ambrosia and Yoganup West, and how that knowledge is adopted in the rehabilitation planning for the Puttalam Mine and Industrial Development Project.
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Flyrock generation and social impact mitigation in local quarrying
(Department of Earth Resources Engineering, 2019-08) Ranathunga, RMSSL; Gurusinghe, AS; Kajenthiran, V; Daluwatta, WS; Hemalal, PVA; Dharmaratne, PGR; Ratnayake, NP; Dissanayake, DMDOK; Samaradivakara, GVI
Quarrying industry in Sri Lanka has expanded widely due to the rapid increase in the demand for basic of quarries are materia] in the construction industry. Thus, large number operating throughout the country. Major concerns related to these activities are the social impact and the impact on workers' health and safety. While blasting is carried out, blasted rock fragments could be projected out of the set boundaries (flyrock) and is a threat to human safety. Although precautionary and mitigation techniques have been in use for many years, impacts on workers safety and health have not shown any resulting reduction. This study focusses on raw measures many strategies to control flyrock and introducing controllable parameters (e.g. powder factor) based on past reports of accidents and related engineering parameters. Three different areas were selected based on the availability of data, considering consequences, distances and the powder factor for the study. Accordingly, collected data was tabulated for ease of analysis and buffer the distance for focused area was calculated statistically. Relationship of area of hazardous zones with different explosive charge was determined using statistical tools correlation co-efficient and R square and allowable powder factor for calculated buffer zone was determined based on statistical data. Recommendations and conclusions were made based on the calculated data.
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Analysis of beachrock samples along Southern and Western coasts of Sri Lanka by spectroscopic methods
(Department of Earth Resources Engineering, 2019-08) Edirisooriya, KVUI; Thilakarathna, MADP; Vijitha, T; Dassanayake, ABN; Jayawardena, CL; Dissanayake, DMDOK; Samaradivakara, GVI
Beachrocks are sedimentary structures commonly observed where there is warm sea water in tropical and subtropical regions as a result of cementation by CaCCb of coastal sediments in the tidal zone. Comprehensive studies have been carried out to determine the formation mechanisms of beachrocks specially Japan to improve an alternative countermeasure against erosion by man-made rocks. When focusing on formation mechanism of beachrocks elemental and mineralogical composition is vital. Considering this important application, we used spectroscopic techniques to understand composition of beachrocks in southern coastal region between Ahangama to Kaikawala and Uswetakeiyawa in the western coastal region of Sri Lanka. The presence of minerals in beach rock samples in southern coast were identified by FT-IR spectroscopic technique. The constituents of minerals present in the beach rocks are further confirmed by XRD technique. Elemental concentrations of beach rock samples have been analyzed using technique of WDXRF spectrometry. Uswetakeiyawa beachrock was mainly analyzed by using EDX in SEM. Beachrocks in southern coasts is comprise higher percentage of Aragonite which is the polymorph of CaCCb, frequently founded in most of the sites in the world. Further the composition shown similarities with Indian (Tiruchendru) and Japan (Okinawa) beachrock occurrences. Comparative to the composition of southern coast beachrock, XRD analysis did not indicate any CaC03 polymorphs Uswetakeyyawa, beachrocks. Instead it indicated the presence of Kutnohorite (Ca(Mn,Mg,Fe)(C03)2).
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Beachrock identification using geology and geophysical approaches in Indonesia
(Department of Earth Resources Engineering, 2019-08) Daryono, LR; Nakashima, K; Kawasaki, S; Titisari, AD; Barianto, DH; Suyanto, I; Rahmadi, A; Dissanayake, DMDOK; Samaradivakara, GVI
A unique carbonate rock developed naturally as a natural barrier presumably appropriate for advanced marine ecosystems including microbiotas in shorelines. A great deal of progress has been made in recent years to investigate the chemical characteristics of beachrocks. Beachrocks found in Krakal-Sadranan Beach can be categorized into non-beachrocks, unconsolidated beachrocks (similar to carbonate sands), and well-consolidated beachrocks, which mainly consist of rocks and minerals. A depletion of Sr concentration in the beachrocks indicates that the diagenetic processes have progressed from the land to the seashore, most likely post-deposition of the beachrock and carbonate sand. An increased concentration of Rare-Earth-Element (£REE), both heavy REE (Tb, Dy, Y, Ho, Er, Tm, Yb and Lu) and light REE (La, Ce, Pr, Nd, Sm, Eu and Gd) signals that the beachrock deposition process happened at oxidative environmental conditions. Unmanned aerial vehicle (UAV) drone mapping, geological analysis, and geophysical surveys were conducted to detect the underground structure of the beachrocks and to emphasize the coastal mapping based on targeted beachrock.The mechanism of beachrock formations obtained in this study would be a novel concept and applicable for the coastal zone improvements and preservations for further studies. on targeted beachrock. The mechanism of beachrock
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Assessment of sedimentation capacity in Rantambe Reservoir using acoustic methods
(Department of Earth Resources Engineering, 2019-08) Yasanga, SK; Udara, HMD; Dilantha, MGA; Rupasinghe, MGAR; Premasiri, HMR; Ratnayake, NP; Dissanayake, DMDOK; Samaradivakara, GVI
Reservoir sedimentation is a major problem for dam safety, water security and productivity. So, regular monitoring and assessment of sedimentation rate performances are paramount. Rantambe reservoir with an initial gross capacity of 21 MCM, constructed under Mahaweli Development Scheme is a multipurpose reservoir used for power generation (52 MW) and flood controlling. However, due to excess sedimentation through Uma Oya, the capacity of the reservoir is affected and therefore compromised the dam safety and water security. In this study, the sedimentation characteristics were assessed using acoustic methods for identifying the performance of reservoir sediment management measures. Hence, Sub-bottom profiler with 10 kHz and 3.5 kHz transducers were used as the main acoustic instrument to determine the height of the water column, the layering of the reservoir bed and the sedimentation pattern. Results show 1.93 MCM as the reservoir's existing volume and due to excessive sedimentation in the mouth of Uma Oya exceeding the dead storage level at the dam thus significantly decreasing the water depth limiting the reservoir capacity.
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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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Analysis of ground-borne vibrations due to piling operations and risk zonation
(Department of Earth Resources Engineering, 2019-08) De Seram, PSPSW; Indika, LGV; Athapattu, AMHSM; Samaradivakara, GVI; Hemalal, PVA; Dissanayake, DMDOK; Samaradivakara, GVI
Due to paucity of land for construction and the highest valuableness of lands in urban areas, construction activities are broadly carried out neighboring to existing buildings. Pile driving is the most common foundation technique used to transfer the load ol a building or a structure to the hard layer of soil or rock. These activities am source of ground vibrations affecting human life as well as existing buildings or structures. Ground-borne vibration and noise levels have been monitored at a pre-cast piling site closer to the Thermal Power Station at Kerawalapitiya using a blast vibration monitoring instruments in this study. The main objective of this research is to produce the risk zonation to the surrounding humans, buildings and infrastructures from the pile driving location. Nuisance to human and comfort level of workers are analysed as per British and ISO standards respectively, and possible damages to existing buildings and structures are discussed according to Swedish and Indian Standards, in this study.
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Application of hydrodynamics to assess coastal morphology to the north of Kelani River, Sri Lanka
(Department of Earth Resources Engineering, 2019-08) Ishankha, WCA; Kahawala, KKHB; Sandushan, JAC; Hewavidana, SM; Silva, KBA; Ratnayake, NP; Dissanayake, DMDOK; Samaradivakara, GVI
Studies on hydrodynamics are important since the hydrodynamic processes highly contribute to sediment transportation in the coastal regions. Erosion in Uswetakeiyawa coastal region of Sri Lanka has been a significant environmental issue since 2000. The Coast Conservation & Coastal Resources Management Department of Sri Lanka carried out artificial beach nourishment in 2012, and then a set of offshore breakwaters was constructed in 2013 to protect the nourished stretch of the beach. However, the beach was not developed to the desired extent. This research was carried out to assess hydrodynamics to forecast the noted coastal morphology in the Uswetakeiyawa coastal region. Wave data were gathered and analyzed using "SWELLBEAT" software for 12 months, covering both the monsoons. Further, "Delft3D" open source software was used to simulate the hydrodynamics in the study area, and seasonal changes of coastal morphology were analyzed for the study area using GoogleEarth images. The findings of this research indicated that due to the strong wave action perpendicular to the coast during the southwest monsoon, the beach was more vulnerable to erosion and there was no sediment transportation to the beach from longshore drift during inter-monsoon periods because sediments contributed from Kelani River were directly transported to the ocean. Also, the predominant sediment transportation to the study area was during the northeast monsoon.
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Socio-geological impact of Uma Oya multipurpose development project, Sri Lanka
(Department of Earth Resources Engineering, 2019-08) Gunawardana, KDC; Jayasingha, P; Ratnayake, AS; Dissanayake, DMDOK; Samaradivakara, GVI
Uma Oya Multipurpose Development Project consists of a 23 km long trans-basin tunnel which is to be built to generate hydropower and provide water to Hambanthota area. However, implementation of this project has caused huge geological, environmental and sociological impacts on the people in Badulla District. This study was carried out to investigate the socio-geological impact on the people in 13 affected Grama Niladari (GN) divisions in Bandarawela and Ella Divisional Secretariats. The data collected from the literature surveys and field surveys used to map and interpret the water availability, major events of hazards and landuse changes in the area. Non-structured interviews were carried out to analyze the opinion and mindset of the community towards the ongoing project and hence, to understand the socio-geological aspects. According to the literature, it was found that 5,279 houses have been damaged and 1,228 domestic wells have been dried in the selected 13 GN divisions. During the field observations, it was revealed that out of 323 observed domestic wells, 199 have been completely dried (61%). Some of the wells seem to be recovering after several rain spells received in the area. Ground instabilities like ground cracks and sinkholes were identified, especially in some of the valley areas. As a result of these geological impacts, the communities living in the area have experienced significant negative consequences in relation to their socio-economic contexts, such as loss of residential housing units, loss of income from various ways, loss of agriculture (dropped by nearly 45%), unexpected expenses for water and importantly loss of family life. In addition, due to the unplanned relief process conducted, most of the affected people have suffered from the evaluation and damage estimation activities. People's mindset has been adversely affected due to on the Uma Oya project, and also the service providing institutes mainly due to lack of proper awareness regarding geological impacts and other relief programs associated with the project. More importantly, psychological impacts due to this geological disaster have not been considered in the relief programs yet.
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Analyzing the seasonal variation of groundwater characteristics in the Attanagalu Oya basin
(Department of Earth Resources Engineering, 2019-08) Athukorala, DRM; Kohilan, C; Danushka, U; Jayarathna, WHDP; Chaminda, SP; Dassanayake, ABN; Hewavidana, SM; Dissanayake, DMDOK; Samaradivakara, GVI
Gampaha district which has the second largest population in the country consists of many industrial establishments and residential areas. Attanagalu Oya Basin which almost entirely the Gampaha district is a major hydrologic feature in determining the seasonal variations of groundwater characteristics in the region. In this study, the groundwater characteristics in the Attanagalu Oya Basin analyzed both quantitatively and qualitatively to identify variations in the pre and post monsoon periods. The qualitative parameters such as pH, conductance, turbidity, calcium, magnesium, nitrate, phosphorous, ferrous, and heavy metal concentrations were analyzed for samples taken throughout the entire basin for the two time periods: pre and post monsoons. The groundwater quantity variations were observed through data loggers and field surveys of water wells. These recorded values were used to model the groundwater resources in the region using two numerical models, MODFLOW by USGS and a self-written Fortran code. The qualitative and quantitative variations were then analyzed spatially and temporally to correlate with the upstream to downstream flow and the monsoonal recharge. The possible reasons for the observed trends and variations were also studied to provide recommendations for the sustainable management of the groundwater resources in the Attanagalu Oya Basin.
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Identification of soil property impacts on manufacturing of high strength soil bricks in selected areas of Hambanthota and Ratnapura Districts
(Department of Earth Resources Engineering, 2019-08) Batapola, NM; Hewarachchi, KG; Rimosan, R; Karunadhipathi, HL; Vijitha, AVP; Dissanayake, DMDOK; Dissanayake, DMDOK; Samaradivakara, GVI
Soil Cement Bricks (SCB) are cost effective, energy efficient and environmental friendly alternative building material which address the problems related to fired clay bricks such as costly masonry, high energy usage and other environmental problems. Characteristics of soil have a great influence on the strength and performance of SCB. This paper presents an experimental study carried out on the influence of soil properties on the characteristics of SCB. Eight soil samples, collected from the soil excavation sites located at Hambanthota and Ratnapura districts were used to produce bricks with 10% of ordinary portland cement and a 1.8:1 volume compaction ratio through a locally fabricated pressing machine. Dry and wet compressive strengths and water absorption of the bricks were analyzed with physical properties of the soils. In this study, it was depicted that well graded soils with high coefficient of uniformity and plasticity index lower than 15% are suitable for manufacturing high strength, durable and quality SCB.
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Upgrading low-grade graphite tailing into high-grade graphite in pilot scale using agglomeration
(Department of Earth Resources Engineering, 2019-08) Mushmika, PAS; Lakshitha, EDP; Kusumsiri, GARL; Dissanayake, DMDOK; Rohitha, LPS; Dissanayake, DMDOK; Samaradivakara, GVI
Froth floatation is the only beneficiation technique currently need for low-grade Graphite. Liberation of Graphite from Graphite bearing rocks for the froth flotation is more prominent using wet grinding techniques with grinding mills. This generates a high amount of Graphite fines of size less than 100 microns which ultimately mixed w i t h tailing and discarded as waste without further recovery of Graphite. This occurs as the froth flotation process is optimum for recovering a range of particle sizes between (100 to 200) microns. Agglomeration of Graphite fines has been proven to be a possible by size enlargement technique proven by previous studies. I n the initial stages of the study, the character of the low-grade Graphite tailing samples obtained from the column flotation plant of Ragedara Graphite mine was characterised by carrying out analysis on particle size distribution and the amount of fixed carbon according with the American Standards for Testing Materials (ASTM). In the latter stages of this comprehensive study, the amenability of the agglomeration of Graphite for the beneficiation of low grade Graphite tailing samples containing 23.4% to 25.5% of fixed Carbon from Ragedara Graphite mines was assessed by varying bridging liquid to tailing ratio for optimum purity and recovery of Graphite. The study continued with increasing the sample size from 1 kg to 25 kg for variations in purity and recovery of upgraded Graphite for a fixed bridging liquid to tailing ratio. The surface structural changes of upgraded Graphite was observed with comparison to Natural Vein Graphite (NVG) using Scanning Electron Microscope (SEM). The beneficiation study has been able to obtain a concentrate with 88% fixed Carbon at a recovery of 69.6% for 25 kg sample suggesting its amenability to be implemented i n commercial scale w i t h periodic iterations for upgrading over 99+% fixed Carbon. The results from the SEM study i n similar topographies using three different magnifications (xl20, xlOOO and xl2000) have suggested no significant changes between the untreated NVG and the agglomerated NVG. With respect to the froth flotation process, this novel processing method has a low water requirement and ability to process tailing w i t h any purity, while cutting off the time for the separation of Graphite and also reduce the loss of the Graphite fines to the tailing, while improving sustainability of the process.
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Remote sensing monitoring of recent morphodynamics in Kalido Beach - Kalutara, Sri Lanka
(Department of Earth Resources Engineering, 2019-08) Sandamali, KUJ; Chathuranga, KAM; Dissanayake, DMDOK; Samaradivakara, GVI
Kalutara is the major city in Kalutara District, Western Province, Sri Lanka. Kalido Beach is a strip of beach that runs between Kalu Ganga and the Indian Ocean. It is known for its unique ecosystem. Nonetheless, in recent years it facing challenges such as natural erosion from the sea, tourist visits, and pollutions. In addition to that recently it washed out from its original location due to the heavy flood i n May 2017. Southwest monsoon weather condition brought heavy rainfall to the southeastern parts of Sri Lanka and cause so many damages to people and nature. After the flood level has risen people excavated channel across the Kalido sand dune just for control flood and discharge extra water to the sea. As a subsidiary effect of that, the Kalido sand dune washed out and a new beach developed near to the country. I n this study, it investigates the incident in Remote Sensing and GIS perspective. Finally, it reveals that there were approximately 690 m of movement of the center of the new sand dune to the southeast direction respect to the previous Kalido sand dune
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The upgradability of beach ilmenite found in Sri Lanka by mechanically activated carbothermic reduction
(Department of Earth Resources Engineering, 2019-08) Wijewardhana, TDU; Ratnayake, AS; Dissanayake, DMDOK; Samaradivakara, GVI
A large amount of high-quality titanium ore minerals are required for future development of the titanium industry. Although ilmenite (FeTOs) is a type of low-grade titanium ore, it has a significant utility value in the production of titanium dioxide (TiOi). The existence of ilmenite percentage (70%-72%) is much higher than the rutile percentage (8%) i n the northeastern coastal area of Sri Lanka. The results of a large number of chemical and physical investigations have been published regarding the reduction of ilmenite but the effective and improved reduction of ilmenite is relatively limited. The long reduction time, slower reduction rate are the major problems in the existing electric furnace process. I n this study, the carbothermic reduction behavior and optimum temperature under specific conditions for milled ilmenite were investigated. Magnetically separated ilmenite sample was supplied by Lanka Mineral Sands, Pulmoddai. Activated carbon was used as a reducing agent. A mixture of ilmenite and activated carbon (4 to 1 ratio) was subjected to high energy ball milling for one to four hours separately. Subsequently, milled samples were heated for two hours at different temperature of 800°C, 900°C, 1000°C, 1100°C, and 1200°C. Phase identification and functional groups of the treated samples were determined using X-ray Diffractometer (XRD) and Furrier Transform Infrared (FTIR), respectively. The particle sizes of the initial and milled samples were determined using a dry sieving method. In contrast with initial ilmenite, relative peak heights, sharpness of peaks, the number of titanium dioxide (TiOi), XRD peaks in treated samples, and metallization of the iron were increased with the time during the studied four hours. Many corresponding ilmenite peaks were disappeared after four hours milling and annaling at 1000°C, 1100°C and 1200°C. FTIR analysis indicates initial ilmenite contains Fe-O and OH stretching vibrations. The upgraded ilmenite sample contains Ti-O stretching vibrations w i t h more broadness. The dso particle size of initial ilmenite sample and four hours milled samples were 0.10 mm and 0.075 mm, respectively. Mechanical activation significantly improve effiency of carbothermic reduction due to particle size reduction and increasing of specific area. The annealing temperature can be reduced up to 1000°C during the studied four hours. Therefore, beach ilmenite found in Sri Lanka can be upgraded by mechanically activated carbothermic reduction.
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The efficiency of iron oxide removal from laterite for industrial applications
(Department of Earth Resources Engineering, 2019-08) Goonetilleke, WALAT; Ratnayake, AS; Jayawardena, DT; Dissanayake, DMDOK; Samaradivakara, GVI
Laterite is used as the main alumina source for cement manufacturing process of some countries, and it decreases the lifespan of limestone deposits due to the high Fe content. This study focuses on the removal of iron oxide from laterite with studying the effect of pH, sonication time, and temperature. The iron removal from laterite was examined along with Cd and Mn. The raw and treated laterite were subjected to Loss of mass on Ignition (LOI), moisture, pH, Atomic Absorption Spectroscopy (AAS), X-ray Diffraction (XRD) and Fourier-Transform Infrared (FTIR) to understand the physical, chemical and mineralogical nature of the samples. The LOI, moisture, and p H of untreated laterite were 16.56%, 15.80% and 5.69, respectively. XRD results of untreated laterite revealed goethite and hematite as main Fe-rich minerals associated with gibbsite, kaolinite, and quartz. The solid to liquid ratio (1:10) and the particle size (63 pm) were constant, throughout the experiment. The optimal p H range for Fe, M n and Cd removal was examined with HCl (pH 1-5) and NaOH ( pH 6-10) at 300 K for 1800 s. pH 5.69 was the neutral pH value for this research. The Fe and M n removal efficiency were gradually increased when the pH from 5 to 1 and Fe had a sudden increment from pH 2 to pH 1. Cd removal efficiency was increased from pH 1-10. Therefore, the effective pH for Fe, Cd, and M n were 1, 7 and 1, respectively. Effective temperature and sonication time were conducted for pH 1 and 2. Fe removal w i t h temperature was examined with 313, 333, 353 and 373 K for 3600 s and 600, 900, 1800, 2700 and 3600 s at 300 K for sonication time. All elements removal efficiencies were increased with the temperature. Fe and M n had high removal efficiency at 900 s w i t h pH 1 , and Cd was recovered within 600 s w i t h pH 2 when sonication. The optimal condition of Fe ion removal for industrial applications is pH 1 w i t h 333 K temperature or pH 1 with 900 s sonication time. Under high temperature and basic pH conditions Cd can be removed effectively. The optimal condition for Mn is pH 1 w i t h 900 s sonication time. The goethite and hematite peaks can be identified in every XRD graphs of final treated laterite samples.
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Exploration of potential sources for extraction of rare earth elements (REEs) in Sri Lanka
(Department of Earth Resources Engineering, 2019-08) Dushyantha, NP; Batapola, NM; Premasiri, HMR; Abeysinghe, AMKB; Rohitha, LPS; Ratnayake, NP; Dissanayake, DMDOK; Ilankoon, IMSK; Dissanayake, DMDOK; Samaradivakara, GVI
Rare Earth Elements (REEs) are a set of seventeen chemically similar elements in the periodic table, including fifteen metallic elements of the lanthanide series. Yttrium and Scandium. REEs are significantly used in numerous high-tech applications in sectors, such as metallurgy, military, petroleum and agriculture. Therefore, REEs are considered as critical and strategic elements i n the industrial revolution towards a green economy i n the future. However, China is the world's largest producer, consumer and exporter of REEs, currently controlling more than 90% of the global supply. According to the recent Chinese industrial policies, they have reduced their REEs export in 2010 in order to build up a REEs stockpile for future domestic uses. As a result, currently, REEs supply is at a risk of disrupting i n the world market, which has created many concerns among REEs stakeholders. Thus, worldwide explorations for REEs are carried out to prospect new potential sources. In this context, Sri Lanka is a country, which has geological settings implying the presence of probable primary REEs sources (e.g. apatite in carbonatites, granitic and synitic pegmatites, granitic rocks and hydrothermal veins) and secondary REEs sources (e.g. mineral sand, gem gravel, stream sediments, clay deposits and laterite deposits). According to previous studies in Sri Lanka, considerable contents of REEs have already been identified in a few locations of the country, such as well-known monazite deposit in Pulmoddai containing Cerium (28%), Lanthanum (15%), Neodymium (10%), Promethium (3%), Samarium (2%), Gadolinium (2%) and Yttrium (1%).Therefore, aforesaid potential sources will be explored as a worthwhile approach to address the impending REEs problems i n both local and global context. However, available resources on land w i l l not be enough to cater the future demand, and therefore, offshore sources, including upwelling areas in southern coast of Sri Lanka are also needed to be investigated as a promising solution for future REEs scarcity. However, effectiveness of extraction of REEs depends on the quality of the resources and the degree to which the resources have been explored. Based on the REE concentrations in aforesaid sources, novel extraction technologies will be developed to get the maximum benefits to the Sri Lankan mineral industry and ultimately to the national economy of the country.

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