Browsing by Author "Rohitha, LPS"

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item: Conference-Full-text
Applicability of pre-heating techniques for recovery of garnet from garnet biotite gneiss
Jayakodi, JDSU; Weliwita, BY; Nishanthan, SS; Samaradivakara, GVI; Abeysinghe, AMKB; Rohitha, LPS; Vijitha, AVP; ; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
In mineral processing industry, the highest energy is consumed by crushing and grinding operations. However, if we can initiate micro cracks in the hard rock pieces in advance, we should be able to reduce the crushing energy and liberate useful minerals economically. Various pre-heating techniques have been tried by the scientists around the world to liberate minerals from rocks. In this investigation, pre-heating techniques were used to liberate Garnet from Garnet Biotite Gneiss. The market price of Garnet varies with the particle size. Hence, the samples were crushed and sized into industry needed three size fractions: (+250-850) μm, (+180-250) μm and (-180) μm. Afterwards, by means of Wilfley Table, Garnet was separated from rocks. Final Garnet recovery percentage was recorded for different temperatures. Furthermore, energy calculation was done for each sample to get an idea about the power consumption. It was observed that the crushing strength decreases with the temperature increment and it has been proven by identifying propagation of micro cracks in thin sections, prepared from rock samples pre-heat treated in Muffle Furnace and Microwave Oven. The analysis reveals that the preheat treated and quenched samples give higher Garnet recovery than Garnet recovered from as-received samples of Garnet rich Biotite Gneiss.
item: Conference-Full-text
Applicability of pre-heating techniques for recovery of minerals from rocks
(Department of Earth Resources Engineering, 2018-08) Dasanayake, RB; Jatheesan, N; Nissanka, NACM; Samaradivakara, GVI; Abeysinghe, AMKB; Rohitha, LPS; Abeysinghe, AMKB; Samaradivakara, GVI
In mineral processing industry, liberating of minerals is the most important involvement because it can enhance the purity of the mineral. However, if we can initiate micro-cracks in rock pieces in advance to these operations, it would be more economically viable. Hence, there is a trend i n the world to investigate less energy-consuming methods for propagating micro cracks within rock grains. Previous studies show that preheating techniques such as heating in muffle furnace, microwave preheating can enhance micro-cracks propagation in rocks and samples. Microwaves have several advantages over standard heat application methods namely that they heat only "responsive" phases. Microwaves also heat considerably faster than conventional heating methods as the heating on radiation and conduction heat transfer mechanisms. Therefore, in this scientific investigation, we applied microwave pre-heating technique to liberate Garnet from Garnet Biotite Gneiss for which samples were collected from Boulder Mix Pvt. Ltd quarry in Meepe. To create a weak zone i n between graphite and its gangui rock in graphite bearing rocks which were collected from Bogala Mines in Aruggammana have also tested. Industrial price of garnet vary w i t h the particle size. In general, higher the particle size, higher w i l l be the value. Hence, the recovery of Garnet in this study was considered focused on industry needed particle size which is less than 850 |xm. The analysis revealed that there is a possibility to produce low cost garnet sand which is cheaper than i n the international market with high purity, by means of microwave technology,. Also it is proved that creating a weak zone along the grain boundary of graphite and its gangue rock is possible w i t h microwave pre-heating.
item: Conference Full-text
Application of emulsion explosive and comparative study on water-gel explosives for rock quarrying in Sri Lanka
Dharmaratne, PGR; Hemalal, PVA; Rohitha, LPS; Herath, B; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Dynamite has been the premier and the only high explosive used for mining and construction activities in Sri Lanka for a long period of time. Negative environmental impacts, effect on health and security hazards led to the Government of Sri Lanka (GOSL) to issue directives to find a suitable substitute for Dynamite. Subsequently, Water-Gel explosive was introduced in the year 2011. The poor performance of Water-Gels in wet conditions and it’s low Velocity of Detonation encouraged the use of Emulsion explosives. This research was focused on performing a comparative study of the performance of both Water-Gels and Emulsion explosives by analysis of the ground vibration and the blast air over pressures. The methodology adopted was to conduct ten blasts at one single metal quarry site keeping all other parameters constant. Blasting tests were performed using Emulsion explosives and Water-Gel explosives and the resulting ground vibration and Air-Blast overpressures were measured with Blastmate 111model for each blast. Calculation of mean fragmentation was done and particle size distribution based on photographic evidence of each blast was analyzed. Analysis was carried out demarcating the resultant production pile of aggregates covering a cleared zone. Grid lines inserted on the muck pile facilitated particle counting using photographs and calculating the mean fragmentation.
item: Conference Full-text
Characteristics studies on engineering properties of river sand substitutes for conventional concrete and mortar works
Withanage, AK; Sugathadasa, AGMRP; Mithushan, T; Dissanayake, D; Rohitha, LPS; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
The main sand source of construction industry in Sri Lanka is river sand. However, being a developing country, the demand for river sand increases gradually. Based on engineering computations, sand demand for 2013 was estimated to be 12,266,186m3. The GSMB currently keeps records of all the licenses issued for sand mining and transportation, and according to these records the approximate annual sand supply is 7,132,631m3(GSMB records), which is far below the estimated demand. The difference may compensate by to illegal mining. Thus, this kind of unrestricted harvesting of sand is resulting in heavy rates of soil erosion; land degradation; increased river-water turbidity; lowered water tables; salinity intrusion in the lower reaches of rivers. Further, over use of river sand for construction industry has various undesirable social and ecological consequences. As a solution for this, various alternatives such as offshore sand, quarry dust, manufactured sand, dune sand, washed soil, waste building material, broken glass and blast furnace slag have been identified by various countries. Thus, this study attempts to identify suitable alternatives for river sand to mitigate the environmental issues related to river sand mining in Sri Lanka. In this project, we use manufacture sand, quarry dust, beach sand and off shore sand to test the suitability for conventional concrete and mortar works. Basically testing for concrete strength using uniaxial compressive strength and check grading of all river sand substitutes are performed. In addition to that two types of sand were mixed in various ratios and check those concrete and mortars for the compressive strength test to find the best mix ratio of sand for construction purposes. Finally those results were compared with strength of concrete for which river sand was used.
item: Conference-Full-text
Cleaner 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, S
Wastages, 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: Thesis-Full-text
Comparative study of emulsion and water gel explosives for rock quarrying
Herath, B; Hemalal, VPA; Dhramarathna, PGR; Rohitha, LPS
In the mining field, blasting is the predominant method for breaking of consolidated rocks and the main objectives are to extract the large quantity at both minimum cost and having minimum damage to the environment. Rock breaking , over the years , which was limited to just breaking of boulders for the use of building and road construction has developed vastly to various aspects of mining namely ,open cast, underground and underwater blasting. Manually drilled single shot bore holes are disappearing and making way to multiple bore holes of immense depth with the introduction of the latest blasting technologies. Result of the introduction of optimum blasting techniques and sustainable development criteria, mining industry has twisted in the path of eco-friendly mining. Explosives and blasting techniques that are used nowadays are based on the above concept. Use of Dynamite changed to lesser powerful explosives such as Water Gel and then to Emulsion explosives. Our country also discarded the use of Dynamite several years ago and Water Gel explosives was introduced. Water Gel explosives is eco friendlier than Dynamite but could not be substituted in areas underground and underwater blasting. Introduction of Emulsion explosives was mainly to overcome these disadvantages of Water Gel Explosives. Aim of this study is to carry out a comparative study in all areas of open cast mining and to ascertain the most appropriate high explosive type for optimum output.
item: Article-Full-text
A comparison of global rare earth element (REE) resources and their mineralogy with REE prospects in Sri Lanka
(Elsevier, 2020) Batapola, NM; Dushyantha, NP; Premasiri, HMR; Abeysinghe, AMKB; Rohitha, LPS; Ratnayake, NP; Dissanayake, DMDOK; Ilankoon, IMSK; Dharmaratne, PGR
Rare earth elements (REEs), a group of 17 elements comprises 15 lanthanides, scandium and yttrium, are largely attracting the world’s attention due to their importance in a wide variety of advanced technological applications. Global REEs production is mainly sourced from resources, such as carbonatites, alkaline igneous rocks, placers, laterites, and ion-adsorption clays. Recently, REE demand has been escalating, especially due to the REE applications in renewable energy and defense sectors, expecting a worldwide shortage of REE supply in the future. Therefore, REEs have been widely accepted as strategic elements in the world, which compels to prospect for new and alternative REE resources. In this context, Sri Lanka has a favorable geological setting which implies the presence of REE mineralization. Previous geochemical studies in Sri Lanka have reported significant concentrations of REEs in different geological formations and mineral resources. Accordingly, Pulmoddai and other beach placer deposits, Eppawala carbonatite, alluvial placer deposits, and pegmatites have been identified as potential REE resources in Sri Lanka. Monazite, apatite, allanite, and zircon are the primary rare earth (RE) minerals found in the preceding resources. The Pulmoddai mineral sand deposit is considered as the most potential REE resource in the island, which is enriched in monazite containing more than 61% of light rare earth elements (LREEs). Similarly, Eppawala carbonatite contains high concentrations of LREEs. However, despite their significant REE enrichments, to date, no attempt has been made to recover these REE prospects, which essentially conceals their potential of catering for both local and global REE supply chains.
item: Conference-Full-text
Design and fabrication of cable bolt for excavation in a fractured rock
(Department of Earth Resources Engineering, 2009-05) Dhanawardana, YLC; Siriwardana, HDPM; Henderson, SH; Kumara, HMCP; Indika, KAS; Dharmaratne, PGR; Welideniya, HS; Rohitha, LPS; Karunaratne, S
In fractured rock masses, large excavations have an unsupported stand-up times less than the minimum time required to support the roof after the excavation. Therefore, the principal objective in the design of a support system is to help the rock mass to support itself. The use of rock bolts is a very flexible supporting method that can be combined with wire mesh, shotcrete and concrete lining. During past years a wide variety of dowels and bolt types were developed but most of them failed within a short period and the cost were high. Advantages of cable strand supports have been well documented and include flexibility, strength, and ease of installation. Main objective of this project is to design rock bolts using discarded wire ropes or cables at a low cost. A detailed designing methodology was carried out to fabricate this bolt. The bolt consists of nearly 1.6m long cable and 16 cm of anchored part and cable tightening part. Outer diameter of bolt is 33 mm and inner diameter is 12 mm and used cable diameter is 5mm. Field data illustrated the amount of load measurements that the bolt can carry is 5 kN. Suggestions were made to improve the design, which will enhance bolt performance. Field tests carried out at Bogala Lanka Graphite Ltd proved that cable bolts are effective in Sri Lankan conditions.
item: Conference-Extended-Abstract
Design and fabrication of cable bolt for excavation in a fractured rock
(2009) Dhanawardana, YLC; Siriwardana, HDPM; Henderson, SH; Kumara, HMCP; Indika, KAS; Dharmaratne, PGR; Welideniya, HS; Rohitha, LPS
Most often in fractured rock masses, large excavations have an unsupported stand-up times less than the minimum time required to support the roof after the excavation. During past few years a wide variety of dowels and bolt types have been developed but most of them failed within a short period of time and the cost were high. Main objective of this research work was to design rock bolts using discarded cables at a low cost. The bolt consists of nearly 1.6m long cable and 16 cm of anchored part. Field data illustrated the amount of load that the bolt can carry as 5 KN. Suggestions were made to improve the design, which will enhance bolt performance. Field tests carried out at Bogala Graphite Lanka Ltd proved that cable bolts are effective in Sri Lankan conditions.
item: Conference-Abstract
Design and fabrication of cable bolt for excavation in a fractured rock
(2014-08-08) Dhanawardana, YLC; Siriwardana, HDPM; Henderson, SH; Kumara, HMCP; Indika, KAS; Dharmaratne, PGR; Welideniya, HS; Rohitha, LPS
In fractured rock masses, large excavations have an unsupported stand-up times Jess than the minimum time required to support the roof after the excavation. Therefore, the principal objective in the design of a support system is to help the rock mass to support itself. The use of rock bolts is a very flexible supporting method that can be combined with wire mesh, shotcrete and concrete lining. During past years a wide variety of dowels and bolt types were developed but most of them failed within a short period and the cost were high. Advantages of cable strand supports have been well documented and include flexibility, strength, and ease of installation. Main objective of this project is to design rock bolts using discarded wire ropes 01' cables at a low cost. A detailed designing methodology was carried out to fabricate this bolt. The bolt consists of nearly 1.6m long cable and 16 em of anchored part and cable tightening part. Outer diameter of bolt is 33 mm and inner diameter is 12 mm and used cable diameter is Smm. Field data illustrated the amount of load measurements that the bolt can carry is 5 kN, Suggestions were made to improve the design, which will enhance bolt performance. Field tests carried out at Bogala Lanka Graphite Ltd proved that cable bolts are effective in Sri Lankan conditions.
item: Conference-Full-text
Design and performance optimisation of graphite-based batteries for advanced energy storage system
(Department of Earth Resources Engineering, 2023-08-28) Liyanage, LDNM; Reval, SS; Madushan, IL; Rohitha, LPS
This research focuses on the development of a graphite-based battery, utilising the abundant graphite resources available in Sri Lanka while facing the challenges of limited access to advanced materials and technologies. The primary objective is to create a viable graphite battery that can potentially contribute to the advancement of energy storage technologies. Given the constraints in accessing certain materials and technologies, this study explores the electrochemical properties of graphite and investigates its potential application as a key component in battery design. Through systematic testing and optimisation processes, we aim to enhance the battery's performance and energy storage capacity. The outcomes of this research provide valuable insights into the potential of graphite-based batteries, serving as a stepping stone for future improvements and innovations in energy storage. Although the developed battery may require further enhancements, it contributes to the growing body of knowledge in sustainable energy solutions, benefiting both Sri Lanka and the global energy sector.
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
Design of a low cost magnetic separator for local beach sand separation
(Department of Earth Resources Engineering, 2013-07) Boralugoda, BPD; Udowita, UGKPB; Sayanthan, K; Rohitha, LPS; Hemalal, PVA
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 cm (0) x 40 cm, 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 fabrication of a low cost magnetic separator for beach sand separation
(Department of Earth Resources Engineering, 2011) Hettiwatte, MC; Siyanath, HAN; Amalan, K; Rohitha, LPS; Ratnayake, NP; Abeysinghe, AMKB
The heavy mineral deposits of Sri Lanka are widely spread over the coastal area. The mining industry is looking forward for an effective method for heavy mineral separation with the low cost equipments, which suit the local environment requirements to reduce the overheads. The major deposit at Pulmoddai, Trincomalee is a well known Ulmenite deposit in Sri Lanka. The state company is currently engaged in processing using imported separators, specifically magnetic separators for ore dressing. But they are expensive and also difficult in operating, due to their outdated mechanism. In this context, the research project was launched to design and fabricate a low cost magnetic separator for beach sand separation. Through literature studies, an effort was made to add new features with innovative ideas to suit the purpose of the design. A prototype was fabricated in laboratory scale. The model was fabricated with a low cost in the laboratory is light weight, more portable, easier to assemble & dismantle. Future modifications are also possible with variable parameters. The separator was optimized for beach sand separation.
item: Conference-Full-text
Designing suitable mining method and processing plant for Kukurampola magnetite ore body
(Department of Earth Resources Engineering, 2006-10) Amarasekera, HM; Sajirupan, S; Senanayake, IP; Sirisoma, RHANC; Chaminda, SP; Rohitha, LPS; Welideniya, HS; Karunaratne, S; Dissanayake, DMDOK; Ratnayake, N; Chaminda, SP
Evaluation of mining methods for the exploitation of Kukurampola ore body is considered in this report. Minerals take millions of years to form, but exploitation takes only few decades. Therefore, mineral deposit is a wealth which must be used for the maximum benefit of the country. Iron is one of the most important metals in the world for many industries. Therefore, exploitation of iron ore is essential for the industrial development of a country. The Magnetite deposit in Kukurampola contains high purity Magnetite; hence it is a valuable resource need rational exploitation. Mining methods evaluated include open pit and underground, and based on geological, engineering, environmental and economical factors combination of both open pit and underground mining are considered as the most suitable mining method. Consequent to open pit mining underground mining will commence for future ore body development and exploitation. A processing method is designed to produce feed material for palletizing those will include crushing, grinding and magnetic separation. If ample deposits are found in the future, there's a possibility of constructing a palletizing plant which need ore reserves for more than 25 years. Also, occurrences of magnetite in the neighborhoods are identified for further expansion of mining operations Special consideration is given to minimize environmental impacts. Remedial methods are proposed in this report to minimize adverse environmental impacts.
item: Conference-Full-text
Determination of percentage of mineral in beach sand using digital image processing techniques
(Department of Earth Resources Engineering, 2015-07) Abeyrathna, PMDGSK; Bandara, IMMS; Ranaweerasinghe, GA; Tharmakulasingham, K; Rohitha, LPS; Hemalal, PVA
Determination of percentage ofmineral is extremely important in beach sand mining industry. To select a site for extraction and processing heavy minerals it is important to assess the rough concentrations. The traditional methods are time consuming, costly, high labour intensive and difficult to handle the equipment. A method was developed to determine the percentage of minerals in raw sand by Digital Image Processing. HSV colour space was selected due to its wide range when compared to other colour spaces. Non over lapping samples were analyzed in this research. Most appropriate background was selected using colour analysis of HSV values. Background was differentiated from the minerals by using HSV values. By analyzing the pixels, area occupied by the minerals can be determined and using weight to area relationship, the weight percentage of minerals can be identified. Validation was carried out and using the statics accuracy was estimated. There are some limitations despite the benefits.
item: Conference Full-text
Developing relationships among grindability, chemical composition and particle size of raw material mix at Aruwakkalu Limestone for Cement Production
Mendis, BSM; Jayathunga, THGS; Madurapperuma, HH; Rohitha, LPS; Dharmarathne, PGR; Hemalal, PVA; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y.
In this research study, the relationship among chemical constituents (SiO2, Al2O3, Fe2O3, CaO, MgO, Cl-, SO3, Na2O and K2O) and raw meal grindability are investigated on raw meal samples taken from the output of ball mill. The X - ray Fluorescence analysis is used to check the chemical composition and grindability is checked in the form of residue test of No 212 sieve residue. The distribution curves of the variables were analyzed to examine the skewness of the distribution. The Pearson’s Coefficient of Correlation analysis was performed on each two variables to identify any linear mathematical relationship between variables. The time series analysis was carried out to find the best fitting curve between grindability and the variables. Scatter plot analysis was finally performed and the results show the effect of chemical components and particle size distribution of raw meal were found to be range correlated on the raw meal grindability. The most suitable chemical constituent range to improve the grindability of raw meal are given based on 68% , 95% and 99% confidence intervals. The quality parameters such as Lime Saturation Factor, Alumina Ratio and Silica Ratio also evaluated based on chemical constituent values of 68%, 95% and 99% confidence intervals.
item: Conference-Full-text
Development of a Model to Evaluate the Settling Time of Mineral Particles
(2016-08-22) Jayasinghe, JMHD; Gunathilake, WADV; Lakshan, MGK; Rohitha, LPS
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
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
Effects 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, S
Many 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.