ERE - 2010
Permanent URI for this collectionhttp://192.248.9.226/handle/123/18290
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- item: Conference-Full-textAnalysis of effect on vibration and air blast in rock quarrying(Department of Earth Resources Engineering, 2010-09) Senadeera, SMADSI; Erangika, MD; Herath, MHBCW; Wickramasmghe, WIUS; Chaminda, SP; Dharmaratne PGR; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SBlasting induced ground vibration occurring in the quarries has ecome a serious environmental issue in Sri Lanka. To achieve high production targets the number of blasts has increased in the quarries and, therefore, mitigate measures to minimize the detrimental effects of the vibrations have to be identified. This research project on rock blasting was carried out to design a suitable indicating system to predict the ground vibrations and air blasts. In order to assess the variation of intensity of the ground vibration and the air blast over pressure, ground vibrations and air blasts results from two different types of explosives on different types of rocks were monitored. Statistical analysis of the data sets found a high level of confidence on the best fitting empirical relationship between peak particle velocity and scaled distance. By that two site-specific factors were established. A comparison of the analytical work revealed that the level of ground vibration varies significantly with the changing of charge weight per delay, explosive type, rock type and the distance from blasting point to monitoring point.
- item: Conference-Full-textCleaner production assessment of a quarry mine(Department of Earth Resources Engineering, 2010) Wijegunawardana, DS; Sabesan, S; Karunagalage, KVS; Kumara, HMCR; Karunaratne, S; Rohitha, LPS; Kirunanayake, P; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunartne, SWastages, energy loses, low production and environmental impacts are the major problems associated with quarry mines and s. It is essential to minimize these problems to optimize profit and to make a better working place. A Cleaner Production (CP) assessment was performed in quarry and crusher plant located in Nochchiyagama, Sri Lanka. The objective of this project was to identify and provide suggestions to reduce wastages and energy losses, reduce environmental impacts, and provide optimum installation criteria of and to optimize the explosive usage of the quarry with enhanced profit/benefits. The whole operational process was divided in to five sections, i.e. material balancing, energy survey, chain survey for , assessment of environmental aspects and rearranging blasting parameters according to Uniaxial Compressive Strength of rock in quarry mine. After implementing the CP, the solutions / suggestions of turning off generator after starting the plant, introducing cone nozzles to the , covering the conveyor belts, reducing powder factor, etc, was made and they were given to client. The expected annual saving of the CP implementation was Rs.3, 168,895.89 with number of other intangible benefits.
- item: Conference-Full-textDemarcation of potential sites for construction material using RS and GIS techniques in Eastern Province, Sri Lanka(Department of Earth Resources Engineering, 2010-09) Palamaumbure, D; Colombage, HDP; Kodippili, TKA; Wickramasekara, KT; Premasiri, HMR; Abeysinghe, AMKB; Chaminda, SP; Dissanayake, DMDOK; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMRDemand for construction materials in the Eastern province of Sri Lanka has risen significantly due to accelerated construction work in progress to restore the destroyed infrastructures during the civil war. Ground surveying methods to locate quarries within this area are not applicable due to security reasons and inaccessibility. Thus a Remote Sensing method is suitable for this task. This study introduces a methodology to locate suitable quarries and sand mines for constructions in the Eastern province. LANDSAT ETM+ images were used for classification. Feasible rocks and sand deposits for quarry operations were located using Multicriteria Analysis (AHP). Four different criteria were used by assigning weights to each criterion. Proximity to roads, construction locations, important places and land use type were the four criteria used. Rocks and sand deposits were given a map value according to the suitability and divided in to four groups. The highly suitable rock quarries and sand deposits were considered in closest facility analysis. The results showed that the integration of Remote Sensing (RS) and Geographic Information System (GIS) can serve as an effective tool in demarcating suitable sites for construction material and this methodology can also be applied for projects of similar nature.
- item: Conference-Full-textDetermination of soil overburden on Panirendawa iron ore deposit for selection of appropriate mining method/s(Department of Earth Resources Engineering, 2010-09) Jayathilaka, BRPM; Perera, MSR; Jayasekara, DAIA; Liyanawaduge, CY; Abeysinghe, AMKB; Premasiri, HMR; Chaminda, SP; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SPanirendawa iron deposit consists of four isolated deposits namely A, B, C and D. The deposit D has potentially high magnetite concentration according to previous data. The main objective of the study is to carry out an electrical resistivity survey to determine the overburden thickness of the deposit D using the SAS 1000 Terrameter. Vertical Electrical Sounding (VES) was carried out at ten different locations around the deposit D. A single line parallel to strike was surveyed with six points of equal depth to the bed rock and the other two lines (west to east) were parallel to the dip as depth increases. The observed data were interpreted using the IX1D Interpex software in to ID and 2D formats to identify the underground layers/stratification with reference to the apparent resistivity values. The survey was preceded with mean depth about 6.5m of surface layer having about lOOOQm apparent resistivity overlying on a water baring surface with a mean thickness about 35m having about lOQm apparent resistivity; also about 41m below, the bed rock stood with an apparent resistivity about 44500m. According to present study, the most possible mining method would be underground mining.
- item: Conference-Full-textEffects of discontinuous properties on the stability of tunnels(Department of Earth Resources Engineering, 2010-09) Nawarathna, THK; Kulathilake, LKNS; Perera, HDH; Premalal, PAM; Dharmaratne, PGR; Chaminda, SP; Rohitha, LPS; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SMany failures of underground openings during excavation are closely related to discontinuous properties of the surrounding rock mass and they affect differently to the stability of underground openings. In this research, attempts have been made to study the effect of discontinuities over the rock mass stability with various infilling materials, dip angles and strikes by using laboratory scaled models. Specimens were casted using cement concrete mixture and five different dip angles (30°, 45°, 60°, 75°, 90°) and three infilling materials (quarry dust, kaolin and graphite) have been selected for the study. Models were tested to determine their uni-axial compressive strength. The results indicate that the dip angle of the joints and the orientations of the tunnel axis have significant impacts on the stability of the tunnel. The dip angle at 90°, perpendicular to the tunnel axis shows a higher stability while the angle at 45°, shows the lowest stability. The tunnels excavated with axis parallel to the discontinuous plane should be avoided as much as possible. If it is unavoidable in any circumstances, well designed support system should be used. Types of infilling materials also affect the stability of the tunnel with graphite being the most unfavourable among the selected materials.
- item: Conference-Full-textEvaluation of existing timber supports in Bogala mine and proposals for alternatives(Department of Earth Resources Engineering, 2010-09) Rathnapala, AVAOC; Perera, TSLC; Hetttiarachchi, DSW; Gangatheepan, B; Chaminda, SP; Daharmaratne, PGR; Senanayaka, IP; Ratnayake, NP; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SRock support is an important aspect in underground mining to stabilize the ground rock to provide a safe environment. As it directly influences the safety, it is very important to evaluate the supporting system. As cost is a major issue, it is important to reduce the support cost without compromising safety. Bogala Graphite Lanka Ltd is an important vein-graphite supplier in the world operating an underground mine using Over-hand-Cut-and-Fill mining method. Steel supports, Rock bolts and timber supports are currently used for supports. Eucalyptus Microcorys (Micro) is the main type of timber used for supports. The objective was to find a cost effective type of support with the required level of strength and durability in an underground environment. Rock mass classification using Rock Mass Rating (RMR) was initially used to evaluate the intact rock. Several timber types such as Eucalyptus Microcorys, Eucalyptus Grandis, Oil treated Eucalyptus Grandis, Teak, Eucalyptus Camaldulensis and Hora were selected and their mechanical properties were determined. Concrete beams and Steel beams were also considered. From mathematical and cost analysis, it was evident that Eucalyptus Camaldulensis satisfies the requirements. It was also found to be cost effective than the existing type with a minimum cost saving of about 44%.
- item: Conference-Full-textGold recovery from gem gravel(Department of Earth Resources Engineering, 2010-09) Sampath, JDS; Abyegunawardana, PH; Anojan, R; Gunasekara, RDI; Dharmaratne, PGR; Rohitha, LPS; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SThe combination of gold's relative scarcity and its elegant beauty has made it a very valuable commodity throughout the history of humanity. It is much evident that Sri Lanka is processing placer type secondary gold occurrences scattered with most of the alluvial gem gravel deposits in many areas. Unfortunately discards after panning for gem stones which contain finer particles of gold together with sand are thrown away as waste or sold out as a substitute to river sand. Therefore, it is important to find methods of recovering gold from gem gravel. In this study, Physical separation methods such as Table separation and Jig concentration were basically used for gem gravel as well as stream bed sediments from several parts of the country. After samples (about 300Kg) were processed, we were able to concentrate 71.2mg of gold particles and a relatively high amount of heavy minerals like Garnet, Rutile, Ilmenite, etc... Though the presence of gold in placer deposits exhibits relatively a low concentration, the high production cost in gold industry (630$ per ounce) elsewhere makes it a cheaper method to gold from gem gravel as a by-product of gem mining.
- item: Conference-Full-textModeling simple craters using gravity measurements(Department of Earth Resources Engineering, 2010-09) Henkel, H; Ekneligoda, TC; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SA study was carried out for two early Paleozoic impact structures in Sweden. These two impact structures (Granby and Tvaren) are located in the southern part of Sweden. Common features can be identified of these two structures as similar diameter of ca 2 km and a substantial post impact fill with Paleozoic sedimentary rocks. The Granby structure represents an almost completely preserved impact crater within a Paleozoic sedimentary rock sequence — only the uppermost part of the raised crater rim might be eroded and was subsequently covered by Quaternary sediments. The Tvaren structure is eroded below the surrounding pre-impact Paleozoic cover rocks into the underlying crystalline basement and has a Quaternary sediment fill. Gravity measurements were carried out on land and sea ice. The inverse gravity modeling shows a gradual change of density and the equivalent porosity with radial distance from the explosion center within the damage zone around and below simple craters.
- item: Conference-Full-textOccurrence and depositional character of monazite deposit in the offshore and coastal zone around South-West region in Sri Lanka(Department of Earth Resources Engineering, 2010-09) Egodawatta, EADMU; De Zoysa, GDP; Prasanna, DAKDG; Mohommedshiffa, J; Ratnayake, NP; Weerawarnakula, S; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SOnshore or offshore, ocean offers us a larger number of industrial minerals. Monazite is one of these minerals found on beach placers in north eastern and south western coastal region of Sri Lanka. Our study area, both onshore and offshore from south western region, encompasses Induruwa and Polkotuwa. This research is focused on analyzing the depositional character of monazite and to evaluate the suitability as an ore deposit. Our methodology comprised of in-situ sampling periodically in predetermined locations and laboratory testing for monazite concentration by grain size analysis and observation though microscope. Results show significant correlation between the monazite concentration in the coastal zone and monsoonal changes. Further, accumulation of this Monazite is significantly controlled by coastal morphology. However, the absence of monazite in the offshore region contradicts with United Nations Revolving Fund for Natural Resources Exploration results. In this study, we have identified three coastal areas; Maha Induruwa, Kalutara and Polkotuwa for exploiting Monazite as an ore deposit. In these hotspots, Monazite concentration ranges from 2.2 % to 9.1%, especially during south western monsoon. Therefore we propose to mine them only during south western monsoon, digging lm surface layer and extracting monazite by collecting only <256fim fraction.
- item: Conference-Full-textPneumatic sludge pump re-design for performance enhancement in the conditions of Bogala mines(Department of Earth Resources Engineering, 2010-09) Senarathne, DEN; Perera, KLHD; Madusanka, DAG; Muthukuda, MASL; Dharmaratne, PGR; Rohitha, LPS; Chaminda, SP; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SBogala Graphite mine is one of the well known high grade underground graphite mine in the world. Dewatering is one of tire major lost component in the mine. Diesel or electric pumps can not be used in underground mines such as in the case of Bogala due to safety issues. In such conditions, a reliable and economical sludge pump for underground mining operations is a prime necesscity. In this study it has been subjected to analyse underground dewatering process, available solutions for associated problems and selected types of pneumatic sludge pumps. A mathematical model was developed to explain the pump mechanism and a pump was re-designed. A cost analysis was carried out to find out the financial feasibility and the design was changed according to the available technology. Sand casting method was used to produce pump head. Other parts were produced according to feasible and cost effective methods. Performance evaluation was duly carried out using redesigned pump. Maximum efficiency and the maximum pump head were observed at inlet pressure of 20 psi. Problems and other issues were identified and with the results of the performance evaluation, pump design was developed. Finally we could conclude that we can fabricate the pump economically, by locally available technologies. In this paper, pump design, production and performance evaluation process and other associated problems which arose throughout were analysed.
- item: Conference-Full-textProceedings of the 5th Annual Conference on Earth Resources for National Development [Pre Text](Department of Earth Resources Engineering, 2010-09) Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
- item: Conference-Full-textSpatial properties of lineaments using a computer software(Department of Earth Resources Engineering, 2010-09) Ekneligoda, TC; Henkel, H; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SAn interactive software, Spatial Analysis of Lineaments, has been developed, that calculates the spatial properties azimuth, length, spacing, and unidirectional frequency of lineaments, provided that the starting and end coordinates of the lineaments are given. The software accepts a large number of lineaments. The different statistical properties are derived in series of steps and spatial outliers are removed in an interactive way. The software allows the user to sub-divide the azimuth group in to two or more if necessary. The nearest lineament is found based on the rules developed by Ekenligoda, & Henkel, 2004. The results are presented in graphical form for all spatial properties mentioned above together with mean, mode and standard deviation of each property and the number of lineaments involved for the derivation of spatial properties and the unidirectional lineament frequency.
- item: Conference-Full-textStructural mitigation for stabilizing rock slope failure at Peradeniya on Colombo- Kandy Main Road: geotechnical and constructional aspects(Department of Earth Resources Engineering, 2010-09) Premathilaka, KKW; Munasinghe, MPNJ; Kasthurirathna, KANS; Kumara, ALDP; Senapathi, LR; Abeysinghe, AMKB; Premasiri, HMR; Chaminda, SP; Puswewala, UGA; Wijewickrama, MIDH; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SRock slope failure at Kandy -Colombo highway near Peradeniya town has been identified as a major threat to the highway as well as the people and properties of the vicinity. This study proposes a permanent mitigation plan for the rock slope failures at this site. Study was initiated with the analysis of similar case studies and field studies on the site area and mitigation options. Two level surveys were carried out to collect topographical data for preparation of a 3D model of the slope. Material identification was done by using particle size analysis and plasticity tests; direct shear tests were carried out to determine the friction angle, cohesion and density of the material. Mitigation plan was designed according to the site conditions. The design was analysed for nine sections on the slope for its stability with the test results by using Geo-studio 2004 software. Reinforcements were proposed to improve the stability whenever needed. An appropriate drainage system was also designed having analysed the past rain fall data of the area. The proposed mitigation plan in this study is a highly stable, safe, trouble-free and economically feasible one, and that can be implemented on this site.
- item: Conference-Full-textSuitability of locally occurring clay as liner material(Department of Earth Resources Engineering, 2010-09) Indunil, HWI; Jayasekara, JMNP; Mahesh, TPC; Veenuganan, S; Karunarathne, S; Puswewala, UGA; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SThe lowest permeability and highest shear strength are desirable factors when designing a liner system. Adding additives such as coal or mixing with fine clays such as kaolin was also invented to improve the desirable properties of the liner. The fundamental soil experiments and tri axial tests were carried to determine the properties of original and mixed clay types. After analyzing, the particle size distributions of clay types, the mixing compositions of additive materials were determined. The compacted mixed clay samples of Bricks and Tile clays from Intermediate zone with kaolin clay to the 70:30 composition gave lowest permeability as 4.591 * 1008 cm/s. The friction angle is important when determining shear strength of liner.The internal friction angle that was improved by adding finely powdered roof tiles (from 12° 10' 8" to 17° 54' 14"). The cohesion between clay particles that was increased by adding lime (from 51.56 Kpa to 54.23 Kpa). Local abandoned clay can be improved as a liner materials.
- item: Conference-Full-textUse of electrical resistivity method for investigating geological and hydrological conditions at proposed site for Institute of Technology, University of Moratuwa(Department of Earth Resources Engineering, 2010-09) Wanasundara, WMAD; Siriwardena, KKGLI; Sajieve, Y; Chandrakumari, GR; Weerawarnakula, S; Abeysinhe, AMKB; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, SResistivity survey is one of the geophysical methods which can be used to identify subsurface ground conditions. The research is focused on determining the bed rock depth, variation of soil overburden thickness and areas suitable for ground water exploitations at the proposed site for Institute of Technology, University of Moratuwa by using the Vertical electrical sounding. The survey was carried out using Schlumberger electrode configuration along three main profile lines, with 18 resistivity points. The results of the survey were provided 2-3 distinct geo-electrical layers overlying the bedrock. The first thin upper layer represents of Sandy Silt/sandy gravel and second layer corresponds to lateritic soil. The third represents the saturated soil materials with less resistivity. The forth layer corresponds to the bedrock and the depth ranging from 8 to 26m from the surface. Geo-electrical results based upon 1-D models, which were created by IXlDv3 software, provide a satisfactory approximation of the various soil and rock components. Based on the above results, it is confirmed the soil overburden in the Northern part of the site, constitutes an aquifer, with a thickness of about 1.3m above the bed rock covering an area of about 100 m2.