Departmental Conferences

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item: Conference-Full-text
Design of a low cost magnatic separator for local beach sand separation.
(2014-07-09) Boralugoda, BPD; Udowita, UGKBP; Sayathan, K; Rohitha, LPS
Study had been carried out to identify beach sand minerals available locally. Principles, cost, and design feasibilities of industrially used magnetic separators were reviewed. As the best suit for requirements permanent drum , magnetic separator was chosen. Software aided separator design was prepared based on reversed engineering concept, in the purpose of building fully functional prototype. Material selection was carried out. According to basic CAD drawing, prototype was built with necessary design adjustments. Magnetic drum is 20 em (0) x 40 em, which yields a magnetic force field nearly 0.1 T. Prototype proven to separate ferromagnetic minerals in beach sand. Flow rate is nearly 15 kg/hour. Recovery of magnetite in silica-magnetite mixture is about 50-60% in single batch process. Using drum direction of rotation opposite to flow direction, highly magnetic susceptible material was removed with a higher recovery.
item: Conference-Full-text
Designing and evaluating a casing program for petroleum wellbores
(2014-07-11) Wijesinghe, KADR; Hewavitharana, TD; Mahsoom, MSM; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP
Due to high operational and financial risks associated with the investments in the petroleum industry, all precautions are taken by the operators to achieve a safe and cost effective well completion. Casing design of a drilling program is a critical element which contributes greatly to safety and cost of the operation. The objective of this research was to develop a casing design program which enables the user to evaluate casing design proposed or implemented in a drilling campaign. The developed casing design program consists of sequential criteria to select casing setting depth and establish optimum casing strength. Knowledge on local pore pressure gradient and facture gradient are essential to select the casing setting depths. Since both the factors are regional stratigraphy dependants, casing setting depth selection was designed in the way it allows user to assign variables for these parameters. Developed casing design program was validated with the casing design done by Rahman, S. Sand Chilingar, G. V(1995). Validation results shows that the casing design of Rahman and Chilingar and the casing design done with the use of developed program are having similar casing setting depths except in the case of conductor casing.
item: Conference-Full-text
Development of an Algorithm to find the Optimum Dredging Region for Short Term Scheduling
(2014-07-11) Fernando, JMMP; Cooray, TMJA; Dissanayake, DMDOK
This research focuses on the short-term scheduling of the vertical slicing method applied dredge mine sites. An algorithm was developed to outline the region to mine, when the block model, optimum pit limit, topography limit and the market demand are given. The algorithm is based on the concepts. of dynamic programming and zero-one integer programming to avoid repetitive solutions and memorize the previous stage outcome for the next stage process. It utilizes 3D matrix to store previous and next stage solutions with three integers representation for "possible future mining", "already mined" and "never mine" conditions. The algorithm is used on 2D resource block model, which is obtained by pre-processing optimized 3D block model to 2D plan-view block model. The developed algorithm was faster and required less data storage over the conventional method due to exclusion of repetitive solutions in the processing.
item: Conference-Full-text
Digital image processing technique for partical size, shape and mineralogical, textural analysis.
(2014-07-10) Siriwardana, MUVA; Deshapriya, NL; Abeysinghe, AMKB; Weerawarnakula, S; Premasiri, R
Aggregate size and shape measurements are extremely important issues in mining and construction industry because of it directly affect the performance of aggregate products, also there is a prime need of textural analysis in many fields including g~ological and geotechnical studies. Traditional methods are time consuming and complex. In the present research, we applied DIP (Digital Image Processing) techniques for grain size analysis. Mainly, there are four sections which are unattached particles/fragment analysis, Attached particles/fragment Analysis, Moving particles/fragment Analysis and Colour, texture based classification. In unattached particles analysis, particles were spread without contacting each other and then analysis was done. In attached particles analysis, watershed transformation was applied to distinguish particles and then analysis was done. Moving particle analysis were performed by acquiring a video of free falling particles and generating contact-less flow of particles using video processing techniques. Colour and Texture based classification was done by separating the RGB (red, green, blue) bands and calculating mean, standard deviation and smoothness and then k-mean classification were performed. Finally results from Image processing methods were compared with the conventional methods. The method developed by the research was successfully applied in aggregate and sediment analysis.
item: Conference-Full-text
Distribution of gaphite mineralizations in south- western part of Sri Lanka and the identification of suitable locations for mining.
(2014-07-10) Batagalla, YMAS; Senewimala, EH; Rajapaksha, PV; Weerawarnakula, S; Premasiri, HMR; Abeysinghe, AMKB
Exploitation and utilization of extremely pure vein Graphite in Sri Lanka have been known since seventeenth century. Sri Lanka is rich with highpurity variety of lump graphite .. The graphite mineralization is more noticeable in the south western part which is underlain by granulitic facies of high-grade metamorphic rocks belong inthe Highland Complex (HC) of the island. Past mining sites were identified through the literature survey, collection of historical data and field investigations. Hundreds of abandoned mines and pits were identified throughout the region. Veins found in this region follow the direction of foliation pattern, fold axes and the fracture pattern. Foliation varies from 3200 to 3400 bearing and fold axes in major anticlines and synclines also follow the same directions. Major fracture patterns are in a direction which varies from 400 to 70°. General dips of the veins are around 450. Vein thickness varies from 10cm to about 1m (lenses). Some of the major veins found in the area show over 90% carbon content. Three major areas have been identified as most suitable- locations for further investigations to be followed by mining. They are Aluketiya-Meegahatenna, Delgoda-Kalutara and Watareka-Padukka.
item: Conference-Full-text
Finding a new sampling methods and studying its characteristic with respect to existing methods.
(2014-07-09) Kumarasinghe, KJMD; Nanayakara, SS; Yapa, YHPSM; Rohitha, LPS
In mineral processing industry, quality of minerals has to be measured in several stages of processing. In measuring the quality, obtaining accurate samples is of prime importance in representing the bulk material. There are number of sampling methods which are industrially used for mineral sampling. But each of these methods has their own weaknesses that make some of them inappropriate in using as the most suitable sampling method. Most of them are human biased. Some sampling methods have simple protocol, but their sample accuracy is low. More accurate methods require advanced instruments and involve high cost and more time. Any sampling method to be successfully used should not only be of highly accuracy, but should be simpler, more cost effective, less time consuming and easier to be applied in the field as well. If any sampling. method with the above characteristics could be introduced, it will be a good substitute for many existing methods. Through literature studies combined with innovative ideas, it was possible to introduce a new sampling method. This sampling method developed has the characteristics of being simple and quick in operation, minimal effects due to segregation, high accuracy, lesser equipment usage, cost effectiveness and less bias to operator experience.
item: Conference-Full-text
In Search of future construction material- recycled aggregates for concrete production.
(2014-07-10) Premasiri, ESY; Kariapper, ABY; Abeysinghe, AMGGMB; Karunarathne, S
Properties of the recycled aggregates and the suitability of the same in structural concrete were studied and compared with those of natural aggregates. The results showed that the particle size distribution of recycled aggregates is compatible with those of natural aggregates. The recycled aggregates had abrasive and impact values of 48.7% and 27.10%,respectively while those of the natural aggregates were 29.5% and 11.45, respectively. Bulk density of recycled aggregates was 1065 kg/ m3 with compared to 1296 kg/ m3 of Natural aggregates and the water absorption was 2.82% with compared to 1.22 of Natural aggregates. The mix design proposed for concrete was grade 30. Properties of concrete made fewer than three testing scenarios consisting different proportions of natural aggregate to 'recycle aggregate as 50% -50%, 25%-75%, and 0%-100% were compared with those of 100% natural aggregates. With increasing percentage of recycled aggregate content, compressive strength, flexural sttength, tensile splitting strength and workability were decreased. According to the results, grade 30 concrete properties could be achieved with mix proportions of 50%natural aggregate and 50% recycled aggregate, without significantly affecting the concrete properties, indicating a 50% saving of natural aggregates thus reducing environmental impacts and enhancing sustainability.
item: Conference-Full-text
Interference of natural coastal sediment dynamics due to the Colombo harbour expansion project
(2014-07-17) Bandara, MSD; Keegle, PV; Mallawaarachchi, MAKM; Ratnayaka, NP; Premasiri, HMR; Amalan, K
Man-made coastal structures directly affect sediment balance in the surrounding beaches. Ongoing South Colombo harbour expansion project has created 5 km long breakwater affecting the sediment dynamics of the Colombo beaches. Present study is focussed on quantitatively and qualitatively analyse the effect of Colombo harbour expansion project on economically important beaches in an around Colombo city area and to forecast possible consequences to the Colombo harbour itself. We have taken monthly variations of beach width, beach profile and the mean grain size of the sediments at mean sea level from selected 8 beaches. Data was processed and analysed to establish sitespecific erosion vulnerability. Results shows cumulative beach erosion has high affinity to erosion causing drastic reduction of beach width after the construction of the breakwater. This study highlights necessity of proper mitigation plan to protect the beaches affected by the construction of southern Colombo harbour expansion project.
item: Conference-Full-text
Mine cost control through effective mine drainage at Bogala mines-phase 1.
(2014-07-11) Uddika, JI; Samarakkody, IC; Harinth, PR; Dharmaratne, PGR; Hemalal, PVA; Thanansayan, G
The Bogala Graphite Mines in Sri Lanka is experiencing a considerable water flow problem for more than two decades which has resulted in increasing total production cost due to high dewatering cost. This case study was basically carried out to optimize the mine dewatering cost by preventing water inflow where possible. This paper describes only the phase 1 of the study, which is "The identification of water recharge sources in to the mine". Major water seepage takes place above 72 fathom (fm) levels and a significant inflow is at 52 fathoms level which discharges water at a rate of 8.5 liters/so Initially, major joints/fractures above 72 fathom were measured and the fracture network in the problematic area of the mine was developed. Interpretation of the fracture model provided valuable data on water recharge locations. Simultaneously environmental isotopes (2H and 18() analysis on surface, subsurface water bodies and underground seepage locations were carried out to identify the exact water recharge locations. The 2H and 180 contents were plotted in graphs in various suspected combinations with local meteoric water lineto identify interconnections. Even though, some solutions were presented to reduce the mine dewatering cost, further analysis is needed with continuous sampling of data to confirm the tentative conclusions.
item: Conference-Full-text
Modelling of pollutant removal rates in constructed wetlands under varying hydraulic rates.
(2014-07-11) Udukumburage, RS; Ariyasena, MADN; Rupasinghe, GGMBMB; Karunarathne, S
subsurface horizontal flow constructed wetland located at University of Moratuwa was observed from January 2012 to November 2012 in order to derive empirical equations for the treatment efficiencies of BOD, COD, Nitrate-N, Nitrite-N and Total Phosphorous with varying hydraulic loading rates. Source of polluted water was the grey water effluent from the Staff canteen which is located near the constructed wetland. BOD, COD; Nitrate-N, Nitrite-N and Total Phosphorous, turbidity and conductivity measurements were taken to ascertain the water quality. Overall treatment efficiency of the wetland cell is above 75% for all parameters. Regression technique was used to derive the empirical equations. IBM SPSS statistics -20 software was used in analysing the experimental data. The derived equations exhibit a high level of accuracy since predicted data and actual data shared a strong correlation of 79.1% for. COD, 93.2% for BOD, 85.1% for Nitrate-N, 84.1% for Nitrite-N and 86.2% for Total Phosphorous. Constructed wetlands in tropic environments are capable of using these equations' with relevant adjustments to the original.
item: Conference-Full-text
The Optimization of field parameters of non-explosive demolishing agent.
(2014-07-10) Silva, DWGSL; Wickramage, KMJP; Vithanage, KS; Hemalal, PVA; Dharmaratne, PGR
Demolition of concrete and rock is a common pI:.ocess in many construction, renovation and rehabilitation projects. Non-explosive Demolishing Material (NEDM) has been a popular alternative for explosive or mechanical demolishing activities due to the lack of noise and vibration. NEDM is a dry, powdery material that expands considerably when mixed with water. When two consecutive drill holes in rock or concrete are loaded with NEDM, the pressure developed by NEDM gives rise to stress concentrations among the holes causing the rock to fracture. However, NEDM is not yet economically competitive, with explosives and any means of optimizing on their use is considered desirable. This study examines the factors affecting the performance of NEDM in the laboratory environment using unreinforced concrete blocks by ana lysing crack initiation and crack expansion. It was found that the performance of the NEDM is a function of water content, water temperature, field temperature and the brand used. Further Research was conducted to examine the possibility of adding an inert material to the NEDM in order to reduce the cost. Research was also conducted to improve the workability of the NEDM by the addition of super plasticizer to the slurry. .
item: Conference-Abstract
Performance evaluation of emulsion/water gel explosives and comparison with dynamite in Sri Lankan quarrying/mining practices.
(2014-07-11) Kumarage, P; Edirisuriya, EMTG; Wanniarachchi, AM; Hemalal, PVA; Dharmaratne, PGR
In the Sri Lankan context, Gelatin Dynamite has been one of the widely used explosives far rock blasting purpases. Water-gel (WG) explosive is in the process of being introduced to. the Sri Lankan mining industry. So. far there had been only a very few tests conducted to.assess the suitability and to. evaluate the performance of this explosive with ather available explosives. Complaints made by the users as regard to.the performance of WG have been a cause of concern. In this research, performance comparison of WG with Dynamite as regards rack break-aut in underground tunnelling has been carried aut. Comparison of fragmentation with the evaluation of particle size distribution in concrete block blasting, using three types of explosives (WG, Dynamite &Emulsian) has been one of main tests. Gap sensitivity, density and the determination of Velocity of Detonation has also.been carried aut.
item: Conference-Full-text
Use of the block punch and point load tests to predict the compressive strength of gneissic rocks; with particular reference to the size effect
(2014-07-17) Pitawela, EWMHRB; Priyan, SPD; Kumara, HMAP; Vijayarathan, K; Maduranga, HGS; Dassanayake, ABN
Various correlations have been established with regard to rock strength indices for different types of rocks around the world. In Sri Lanka, having several types of sedimentary and metamorphic rocks, least attempt has been made in relation to the particular subject area. In order to fulfil the need to a certain extent, this research was carried out to study correlations between rock strength indices specifically in Sri Lankan gneissic rocks. The study reveals information with regard to an emerging, yet powerful rock strength index known as Block Punch Index, which could be used with same significance as that of Point Load Index, while predicting Uniaxial Compressive Strength. The study further compares the strength indices and their variations in relation to size effect. It finally presents conclusions drawn relating to strength indices of Sri Lankan gneissic rocks with several recommendations.

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Browsing Departmental Conferences by Conference "ERE 2013"