ERE - 2016

Permanent URI for this collectionhttp://192.248.9.226/handle/123/18296

Browse

Now showing 1 - 15 of 15

item: Conference-Full-text
Proceedings of the ERE 2016 Annual Conference on Earth Resources Management [Pre Text]
(Department of Earth Resources Engineering, 2016-07) Hemalal, PVA
item: Conference-Full-text
Critical evaluation of blast- induced structural damage criteria for buildings around metal quarries at Thudugala, Kaluthara
(Department of Earth Resources Engineering, 2016-07) Hettiarachchi, MM; Priyasanka, IDP; Herath, HMWD; Mohanaruban, G; Dharmaratne, PGR; Hemalal, PVA
Quarrying can generate a number of on-site and off-site environmental effects as a result of blasting, excavation, crushing, screening, stockpiling and transport activities. Blasting is necessary for recovery of ore and production of aggregates in most underground and open cut mines, as well as in quarries. However, blasting can cause noise and ground vibration, which can have an impact upon nearby structures and people living close by. Hence, proper control of blasting practices is necessary to ensure both the safety of employees and the protection of the community from adverse effects. In Thudugala, in Kaluthura district, people those who are living close to quarries are highly subjected to these effects due to quarry blasting. In these circumstances, it was decided to conduct a research into the ground vibration impact in the area. Due to complexity of structures ranging from wattle-and-daub structures which do not have proper foundations to those built with good foundations, the applicability of single criteria of 5 mm/sec PPV level of vibration which is currently being used in Sri Lanka is inadequate. It is also noted that the above vibration criteria has been adopted in Sri Lanka without a proper theoretical foundation. In this research program, the propagation of cracks due to the blasting was assessed at the initial stage of the project. At the final stage, the optimum PPV values will have to be found for different types of structures by constructing them. In this area soil overburden is less. Therefore most of the structures have been constructed on rock. When blasting takes place, rock tends to vibrate and the intensity perceived is very high. Therefore crack propagation is high in these particular structures. It is also noticed that the cracks have further developed between the period between pre-blast crack survey and post-blast crack survey. It is due to large number of un-monitored blasts that have been conducted during that period. Therefore to solve this problem, it is recommended to carry out continuous monitoring of blasts.
item: Conference-Full-text
Stope productivity improvement through application of cut-and-fill mining method variant at Bogala graphite mines, Sri Lanka
(Department of Earth Resources Engineering, 2016-07) Abeykoon, AGTBB; Lanka, KASS; Ovitigala, IR; Wijerathna, KS; Hemalal, PVA; Dharmaratne, PGR; Hemalal, PVA
Vein graphite mining is more often carried out by underground mining in Sri Lanka due to its mode of occurrence. Bogala underground mine is one of the major graphite mines in the country, where overhand cut-and-fill mining method is used for the extraction of graphite since the ore bodies are steeply dipping, with considerable vertical extent and clear and stable ore boundaries. According to the standard practices at the mine, ectraction is carried out at the stope by blasting of both rock and graphite vein in the exposed face, followed by hand sorting to collect graphite. Blasting the host rock and veins are carried out separately. Waste rock generated is used to fill the lower bench. Simultaneously, stope support is carried out and the working platform prepared. In this practice one cycle extends for four shifts and the research was launched with the objective of improving stope productivity by reducing the cycle time. In the proposed methodology, blasting of the face (graphite vein and rock) was carried out simultaneously resulting in the reduction of cycle time to two shifts. Therefore, in the research carried out, with the proposed alternative stope technique followed by froth flotation relevant performance indicators or parameters of productivity, cost and safety were analysed.
item: Conference-Full-text
Identification of the most suitable locations for rock quarrying to supply aggregate requirements of the Colombo Port City development project
(Department of Earth Resources Engineering, 2016-07) Nayanthara, PGN; Rosairo, KDARP; Gunawardana, GMSM; Sanjeewa, WPG; Dissanayake, DMDOK; Vijitha, AVP; Hemalal, PVA
‘Colombo Port City Development Project’ aims at reclaiming a minimum of 269 hectares of waterfront sheltered by Colombo South Harbour Breakwater for mixed development activities. It has been estimated that a total requirement of 26.6 million m3 of dredged sand and 3.45 million m3 of quarry materials for the reclamation and construction of coastal structures. The main objective of the present study is to assess and characterize the capability of identified quarry sites to provide different categories of rock for the project. The quarry site assessment of eleven quarries were carried out by incorporating factors such as rock quality parameters, mineable rock volume, type of rock, jointing or racturing in the rock mass, licence category, mining, hydrogeological and socio economic aspects. The data were gathered using numerous sources. Having combined geographic information systems (GIS) and Multi-Criteria Evaluation (MCE), the present study sought to locate the most suitable areas for rock quarrying to supply rock materials to Port City Project. The findings of the research indicate that four quarry sites are most capable of supplying all categories of rock and rest are more suitable for supplying rock products below 500 kg. Further findings of the research include suitable transportation routes and capacities for rock materials, potential adverse impacts on supplying materials and corresponding mitigatory measures to be adopted.
item: Conference-Full-text
Identification of the most suitable location in Kaduwela area to establish a mega quarry site to supply aggregate requirements of mega projects in Colombo
(Department of Earth Resources Engineering, 2016-07) Banujan, B; Pathirana, GPDH; Ranaweera, DKL; Vijitha, AVP; Dissanayake, DMDOK; Hemalal, PVA
Western Megapolis Project is a massive scale development project. The scale of the project demands huge amount of coarse aggregates for its construction. Most of these projects are concentrated within or on the pheriphery of Colombo district. Hence, the requirement to find a coarse aggregate source within Colombo district, closer to metropolitan area is inevitable. This project was carried out in order to identify the most suitable location to establish a mega quarry to address the above issue. Initially a desk study was carried out to analyse spatial data in order to get a rough idea about suitable locations. Field visits were carried out to observe prospective lands, collect rock samples and to gather sociological data through a questionnaire survey. The suitable location was determined by considering the distance to Colombo metropolitan area, rock outcrops, current mining activities, existing settlements, land ownership etc. The quality of rock samples were investigated through Aggregate Impact Value (AIV) and Los Angeles Abrasion Value (LAAV) tests. The volume of aggregates that can be extracted was calculated and compared with estimated aggregate demand. It was concluded that the aggregate requirement of considered construction projects could be satisfied by implementing the Mega Quarry project.
item: Conference-Full-text
Slope stability analysis and design of open pit mine slopes for limestone mine at Aruwakkalu, Puttalam, Sri Lanka
(Department of Earth Resources Engineering, 2016-07) Kariyawasam, KMGS; Dauglas, DLPM; Amali, NPG; Samaradiwakara, GVI; Chaminda, SP; Hemalal, PVA; Jayawardena, CL; Hemalal, PVA
The largest open pit limestone mine in Sri Lanka which belongs to Holcim Lanka Limited is located at Aruwakkalu, Puttalam. The sub-surface of this site is comprised of an overburden of average thickness 24 m followed by a 9 m thick low grade limestone layer and a high grade limestone layer at the bottom which extends even below the seawater level.The overburden which is currently being excavated in five benches of near vertical cuts becomes unstable during the rainy season, which is a significant safety issue on this site. In this scientific investigation, the physical properties of each layer of material are determined by laboratory testing, in order to design optimum bench heights and slope angles for this open cast mine. Direct shear tests are carried out on undisturbed soil samples collected from the overburden, whereas rock-triaxial tests are carried out on the samples collected from low-grade and high-grade limestone layers, in order to determine design parameters: cohesion(c) and friction angle(ϕ) of these materials. The stability analysis is carried out by means of “SLOPE/W” software. The analysis of data for a three layer model reveals that the possible failures are confined to the overburden based on the outcome of this study. The overburden mine slopes could be optimized to three berms of each 8 m height, 6 m wide and of 700 slopes, having a sufficient safety factor which will enhance the safety and productivity of the future mining operations on this site.
item: Conference-Full-text
Removal of iron oxides in Meetiyagoda kaolin by chemical leaching to improve whiteness
(Department of Earth Resources Engineering, 2016-07) Azarudeen, MHM; Piranavan, S; Krishnakumar, S; Senanayake, IP; Rohitha, LPS; Weerawarnakula, S; Hemalal, PVA
Industrial grade Kaolin deposits in Sri Lanka are located in Boralesgamuwa and Meetiyagoda. Two distinct grades of Kaolin are produced at Meetiyagoda refinery, based on the whiteness index (WI). The presence of iron oxides significantly affects the WI of the Kaolin. Upgrading of the whiteness will result in a huge increase in the product prices as high as 35%. However, no effective methods are currently in place for the whiteness improvement at Meetiyagoda Kaolin refinery. Hence, this study was carried out to assess the whiteness enhancement capability of Meetiyagoda Kaolin by chemical leaching process using oxalic and citric acids. The treatment time (0–120 min) in steps and concentration of acids (0.01, 0.1, 0.2, 0.3, 0.4 and 0.5 M) were considered as the main variables of this study. Leachate and treated samples were analysed by using spectrophotometric and XRF methods respectively. The results depict that the oxalic acid is more effective in leaching iron oxides from Kaolin compared to citric acid for the Kaolin at Meetiyagoda. It was observed that 25% and 14% of Fe in Kaolin filter cakes can be removed by 0.4 M oxalic and 0.5 M citric acid respectively, within a treatment time of 120 mins at the room temperature.
item: Conference-Full-text
Analysing the relationship between skin and formation damage of an oil well (time depended)
(Department of Earth Resources Engineering, 2016-07) Ruwanpathirana, RS; Nagasinghe, RV; Welagedara, WWVP; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP; Vijitha, AVP; Hemalal, PVA
The concept of skin and formation damage play a vital role in productivity of an oil well. The objective of this study is to introduce the effect of skin into the well flowing equation in transient state. The effect of formation damage zone on the well flowing pressure was introduced to the original solution of diffusivity equation by considering three scenarios. In the first scenario it was assumed that oil is flowing through the reservoir with average (effective) permeability. In the second scenario it was assumed that the oil is flowing with the permeability of reservoir till the boundary of formation damage zone and within the altered zone, oil is flowing with the permeability of damage zone. The third scenario is similar to the second scenario, however it was assumed that the oil is flowing within the altered zone with an average permeability. By considering the difference between calculated reservoir permeability for all three scenarios and assumed values, scenario three was selected as the most suitable way to introduce the effect of skin in to the well flowing equation in transient condition.
item: Conference-Full-text
Development of a model to evaluate the settling time of mineral particles
(Department of Earth Resources Engineering, 2016-07) Jayasinghe, JMHD; Gunathilake, WADV; Lakshan, MGK; Rohitha, LPS; Hemalal, PVA
Settling time is one of the most important parameters in mineral processing industry, to design flow of processing and to define input data rate. It can be defined as a function of average particle settling velocity through a fluid medium and the target of this research is to develop a model to evaluate the settling time of mineral particulates. During this study, parameters which affect the settling time were identified, existing models were evaluated and error functions were introduced to coincide theoretical results and experimental results, a new function was formulated and verified to measure the settling time. Characteristics of particles such as shape, size and density as well as the characteristics of medium such as viscosity, density and the temperature were identified as the parameters that affected. Steel and glass particles in spherical shape were selected with known density for the experiment. Newton’s law and Stokes law that developed theoretically were referenced with their defined limitations to take experimental results on measuring the settling time of mineral particles. To reduce the gap between theoretical results and experimental results, new error functions were introduced to Newton’s law and also another relationship was derived theoretically to calculate the time taken to reach particles’ terminal velocity.
item: Conference-Full-text
Long term coastal erosion and shoreline positions of Sri Lanka
(Department of Earth Resources Engineering, 2016-07) Lakmali, EN; Deshapriya, WGA; Jayawardene, KGIA; Raviranga, RMP; Ratnayake, NP; Premasiri, HMR; Senanayake, IP; Hemalal, PVA
Coastal zone of Sri Lanka is key to the sustainable development of the country. However, the erosion of this coastal zone has been identified as a long term problem. Therefore, coastal sediment dynamics around the country has to be identified to develop an appropriate coastal zone management plan. Remote sensing and GIS techniques can be used for quantitative and qualitative analyses of coastal monitoring activities including understanding the coastal erosion and accretion trends. In this study, past and recent Google Earth satellite images have been used to analyze erosional and accretional trends in the coastal zone, all around Sri Lanka. Using these results, near shore sediment transportation directions along the coastline around the country were also predicted. Most of the south-western coastline of Sri Lanka shows considerable erosion during stormy conditions under south-western monsoon period, but mostly recovered during fair weather northeastern monsoon conditions. Therefore, no any severe long term erosion conditions prevail in the western, south-western and north-western coasts. However, isolated locations in the north-eastern and eastern coastline shows considerable erosion. Predicted nearshore sediment transportation directions proved that it is mainly governed by wind and waves of southwest and northeast monsoons.
item: Conference-Full-text
Geochemical aspects of serpentine bodies off Embilipitiya, Sri Lanka and their effect on human health
(Department of Earth Resources Engineering, 2016-07) Wickramasinghe, KO; Wijerathna, AVVP; Godawithana, CAP; Weerawarnakula, S; Premasiri, HMR; Abeysinghe, AMKB; Hemalal, PVA
Serpentine is a mineral rich with Nickel, Chromium, Cobalt and Iron. Weathering of Serpentine rock can liberate such elements into the environment. Excessive exposure to such elements can damage human health by means of skin rashes, redness of skin, and Kidney diseases. Previous studies carried out in the Ginigalpelessa area off Ambilipitiya has concluded that major part of the area is underlain by serpentinite bodies and high amount of such elements are present in the soil, weathered rocks and fresh rocks of the area. To identify health issues associated within the area, a questionnaire was carried out in Gingigalpalessa village and in Angunakolapalessa village which is located about 15 km away from Ginigalpelessa area, where similar weather conditions,cultivations and social activities are found but not geology. Data gathered from the questionnaire shows skin rashes are common among the people living in Ginigalpellassa area. The survey also revealed that 54% of the patients are children, age below 15 years and 38% of them are adults, age above 45 years. Furthermore such deseases are common among the families living in the area for a longer period. The results also reveal that majority of the patients live in highly concentrated zones of such elements in Ginigalpelessa area and no such cases are found in Angunukolapellessa village where geological conditions are different.
item: Conference-Full-text
Analysis of geological structures for road cut failures: a case study along Balangoda – Haputale main road
(Department of Earth Resources Engineering, 2016-07) Senarathna, CSS; Godaliyadda, DP; Disanayaka, KTD; Premasiri, HMR; Abeysinghe, AMKB; Weerawarnakula, S; Hemalal, PVA
This study is focused on the causes for the road cut failures and suggest a methodology to design road orientation to minimize cut failures considering geology of the rock present in the area. In the past few years, several road cut failures have been recorded in Sri Lanka and there are development plans to construct expressways in hilly areas of the country. Hence, this study is important to minimize and control road cut failures while designing road orientation in a scientific manner. Several of studies were carried out to find the relationship between rock properties of the slope and occurrence of cut failures. This study helps to create a forecasting model for different scenarios. In this study, in order to validate the outcomes, some software were used. “DipAnalyst 2.0” is one of them and is a slope stability analysis software, which is designed to perform kinematic analysis for rock slopes and also calculating factor of safety values for plane and wedge failures based on the limit equilibrium theory. In this study, we identified that rock of the study area mainly dip towards the road (dip direction is parallel to the road direction). It is the main cause for lot of failures.
item: Conference-Full-text
Soil nail wall design optimization by geotechnical applications and geophysical techniques
(Department of Earth Resources Engineering, 2016-07) Hettiarachchi, DAI; Fernando, HRW; Nanthahoban, E; Sameer, STM; Abeysinghe, AMKB; Premasiri, HMR; Samaradivakara, GVI; Hemalal, PVA
Soil nailing is a soil reinforcement technique which is used to stabilize slopes by insertion of slender elements, called nails. When steep slopes are to be stabilized by soil nailing, practical problems are encountered related to subsurface investigations, as drilling machines cannot be placed on such slopes. Hence, bedrock levels cannot be determined in advance, which is disadvantageous to produce cost effective designs. This research was focused on studying the methods that can be used for soil nail wall design optimization by applying geotechnical and geophysical techniques. The study was based on an unstable slope situated near Victoria dam. The physical properties of soil were determined by direct shear tests, and stability analysis was done by means of “Slope-W” software. Determination of the profile of weathered quartzite layer, inter-beded with Charnokite bands was the major emphasis of this research. Three techniques were used: Ground Penetration Radar (GPR), Earth Resistivity Measurements and Geological Mapping. This investigation scientifically showed that the existing slope is unstable, and to be protected. Further, it was identified in advance that the basement rock cannot be encountered at designed depths of the soil nails, which was subcequently proven as correct by the ongoing drilling for soil nail installations.
item: Conference-Full-text
Effect of physical and mineralogical properties of aggregates on quality of asphalt concrete
(Department of Earth Resources Engineering, 2016-07) Wijayarathne, GWLW; Thavaneeshan, S; Sameera, BHAT; Sandamali, IGV; Chaminda, SP; Jayawardena, CL; Premasiri, HMR; Samaradivakara, GVI; Hemalal, PVA
The major component of an asphalt matrix is rock aggregates usually consisting an amount greater than 95% by weight. One of the main reasons causing failure of asphalt paved roads during the expected service period of the pavement, is due to the shortage of the quality of aggregates being used. In the local asphalt industry, aggregates used to produce asphalt concrete, are tested and approved for the application only by evaluating physical parameters such as LAAV and AIV. In this research, mineralogical properties of aggregates have been systematically analysed along with the respective physical and asphalt properties. Testing was carried out for aggregate and lump samples collected from a number of metal quarries and asphalt plants, representing rock types from three major geological complexes; Wanni, Highland and Vijayan of Sri Lanka. Both single and multiple statistical linear regression analytical tools were adopted to analyse the relationship between mineralogical properties with physical and asphalt properties. Findings of the research proposes to consider the collective influence of both physical and mineralogical properties of aggregates when selecting competent materials for asphalt concrete manufacture.
item: Conference-Full-text
Integration of direct and indirect techniques to optimize subsurface exploration
(Department of Earth Resources Engineering, 2016-07) Wijesinghe, LV; Ineshka, WSS; Sutharsini, S; Jayawardena, CL; Samaradivakara, GVI; Hemalal, PVA
Subsurface exploration is one of the major activities conducted to extract information for Geotechnical applications. Borehole construction is the most common direct exploration technique which provides exact information on a particular location whereas, Electrical Resistivity Method is one of the commonly practiced indirect exploration techniques. Since the exploration costs are relatively high, minimizing the cost while obtaining adequate information is of everyone’s interest. For larger constructions with deep foundation requirements, determining the overburden thickness (bedrock level) and water table is a mandatory requirement. Hence, the use of a proper combination of direct and indirect subsurface exploration methods could result a considerable cost reduction and time saving. This study was conducted to find an optimum integration of resistivity method and borehole construction for selected subsurface exploration activities currently in progress. Accordingly, resistivity surveys were conducted at sites proposed for a twelve storied residential tower at Malabe and Matara – Kataragama Railway Extension Project, near piers for new railway track. Apparent resistivity data were gathered using ABEM – Terrameter SAS 1000 instrument, were interpretated using “IP 2 Win” software. The results were validated using the borehole information. The resistivity survey information revealed a close relationship with the borehole data and resides within the statistically acceptable range. Hence, an optimum combination of resistivity surveying and borehole construction can be proposed, for cost controlling at large-scale subsurface explorations.

Browse

Recent Submissions