SMRSL - 1984
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- item: Conference-Full-textSymposium on mineral resources of Sri Lanka and its developments (Pre Text)(Department of Mining and Mineral Engineering, 1984-05-28)
- item: Conference-Full-textMineral resource assessment and long term supply of minerals(Department of Mining and Mineral Engineering, 1984-05-28) Jayawardena, DE de SMineral Resource Assessment means the estimation of a nation’s mineral resources and their classification into appropriate categories. The term resources is used to refer to quantities of foreseeable economic interest that are available for exploitation. The main objective of embarking on a mineral resource assessment programme is to plan-out the strategy for the long-term supply of minerals for existing mineral based industries taking into consideration the expansion programmes of such industries. In Sri Lanka, the mineral sector industries are broadly categorised into (a) industries based on local minerals and (b) the exploitation of minerals available locally for the export market. An attempt has been made in this paper to outline the basic principles of mineral resource assessment based on increasing degree of geological assurance and economic considerations. Such a resource classification scheme called the “Mckelvey Box” as adopted by the U. S. Bureau of Mines and the U. S. Geological Survey is attempted and the adequacy of local mineral resources to sustain mineral based / industries is described. Since mineral resources are non-renewable, the optimuny' utilization of such resources is emphasised keeping in mind the impact of exploitation on the environment.
- item: Conference-Full-textImprovement of brightness of Sri Lankan china clay(Department of Mining and Mineral Engineering, 1984-05-28) Dharmaratne, PGR; Marasinghe, BS; Perera, GPChina clay is widely used in many industries such as ceramics, paper, paints, plastics and rubber. As most of these industries require clay having high brightness, a number of techniques have been developed to achieve that. This paper briefly reviews the methods used in other countries and discusses the possibility of developing an electrolytic method to brighten Sri Lankan china clay. An instrument to measure brightness of powders has been designed and fabricated in this department. The principle involved is the measurement of reflected light from specimens at an angle 45° electronically.
- item: Conference-Full-textThe present trends in the gem industry(Department of Mining and Mineral Engineering, 1984-05-28) Hettiarachchi, LGem Industry cannot be studied in isolation. It has to be studied along with the Diamond Industry in particular and Jewellery industry. With the Jewellery Indus-. try coming into the scene, and with precious metals involved, it gets connected with the supply and demand of money. This is particularly so as diamonds, gems and gold have sometimes been considered as items comprising investment portfolios throughout the world. Supply and demand of diamonds, gems and gold therefore over the years reveal interesting areas of study. Technological development, scientific advancements and changes in consumer, tastes have always played their part in the gem industry too. An attempt has been made, therefore - in this paper to show as far as possible the different interactions in these areas. It is very appropriate to discuss at this stage, the present
- item: Conference-Full-textAn assessment of aluminosilicate refractories from in-situ deposits(Department of Mining and Mineral Engineering, 1984-05-28) Fernando, WLWIt is possible to predict the behaviour of Aluminosilicates prior to its use in iron and steel practice. The methods adopted by the author comprise extraction of the material from bore holes, bcneficiation and fabrication into suitable specimens for carrying out specific tests. Particular care was taken for the grog preparation, size grading, mixing and powder pressing prior to the heat treatment. In short, this paper summarises the test methods developed by the author to examine the grade of in-situ specimens, recovered from bore hole surveys.
- item: Conference-Full-textProcessing of gem minerals(Department of Mining and Mineral Engineering, 1984-05-28) Jayasinghe, SThe processing of Gem Minerals includes identification, selection for variety and grading for quality, size and use etc. It also includes identification of rare stones, identification and selection of stones which need to be treated (heat or otherwise) prior to cuttiug, polishing and other forms of treatment. The author also stresses the following The various stages of cutting and polishing, carving of ornamental items, making abrasives, grading and grouping of cut and polished stones for marketing to the traders, related industries or to the ultimate user
- item: Conference-Full-textMining of Graphite in Sri Lanka(Department of Mining and Mineral Engineering, 1984-05-28) Gregory, NThe first mention of the presence of graphite in Sri Lanka dates back to 1675. The industry grew mainly during the 19th century and it peaked in ! 899 with a production of 31,761 mt coming from about 3,000 pits. The graphite of Sri Lanka commanded, at that time, a high premium due to its exceptional quality. However, in 1912, shallow deposits which matched in quality those of Sri Lanka, were discovered in Malagasy. This resulted in stiff competition, the Malagasy graphite being extracted at a lower cost. The Sri Lanka production declined slowly but inexorably, with some outbursts of revival during World Wars I and XI. The share of Sri Lanka, which was half the world trade in graphite prior to 1912. had fallen to less than 2 per cent in 1980. The main reason of this decline, apart from the foreign competition, is probably that the graphite occurrences of Sri Lanka are in thin veins of small extension scattered over a large area. This structure was favourable to manual methods of mining by cheap labour, as long as mechanization was not very developed world wide. However, as the pits had a very small production and as their owners did not have the means to invest in a minimum of mechanization when the time came to be so. their exploitations became unprofitable. Furthermore, the labourers were attracted by the tea plantations where the work was less painful. Only the mines of the Bogala, Kahatagaha and Kolongaha complexes resisted this trend because they had a concentrated higher production and their sales allowed them to invest in shaft sinking and equipment purchasing.
- item: Conference-Full-textSurveying for marine minerals(Department of Mining and Mineral Engineering, 1984-05-28) Wijesinghe, NSA survey chart or plan is only as useful as it may be used to accurately locate places, objects oi interest etc. Land survey plans can be prepared accurately and can be used as a guide to the user. There are many types of surveys. Aerial surveys enable a pictorial man of a vast area in a small time. Underground surveying is used in mining. All the plans prepared from each application must have one basic quality-accuracy and reliability so that of these maps or charts may not waste time in locating features shown in the map. The first step to assessing marine minerals is to accurately survey the geology of the submarine terrain and record the results on a survey chart. The inherent inaccuracies in offshore hydrography are many. What constitutes a hydrographic seismic survey ? Instrumentation demands familiarity with sophistication in electronics, personnel require specialised training, surveying costs a lot of money. We may not in our lifetime either fully measure or benefit from our efforts to assess marine minerals but we can and must set in motion a plan for posterity so that mankind may use their mineral resources more wisely than they have done of the resources on land.
- item: Conference-Full-textMathematical modelling of mineral processing operations(Department of Mining and Mineral Engineering, 1984-05-28) Subasinghe, GKNSDuring the last few decades, efforts have been made to describe the various unit operations involved in mineral processing by mathematical models. These models are of great importance in the design of new equipment and improving the efficiency of existing industrial plants. Also, the models have been used in the computer simulation and control of various processing operations which otherwise require, and depend on, highly experienced and skilled operators to ensure their profitability. This paper briefly outlines the various models and/or the methods used in their development, in relation to a number of mineral processing unit operations such as screening, crushing/grinding and flotation.
- item: Conference-Full-textA study of pinched sluice concentrator(Department of Mining and Mineral Engineering, 1984-05-28) Jeyadevan, BThe pinched sluice concentrator is a device for the separation of heavy minerals particularly beach sands. They come in a variety of sizes and shapes and have been used extensively overseas in the beach sand industry for over a century. Previous work to study the mechanisms of separation of these units have been of a purely empirical nature and thus required experienced and skilled operators to achieve acceptable level of separation. More recent work has shown that the performance characteristics of a pinched sluice could be analysed using the established theories of fluid mechanics and mineral processing. This paper outlines the work published up to date and also the progress of research in this field at the Department of Mining and Mineral Engineering, University of Moratuwa.
- item: Conference-Full-textComputers in mining industry(Department of Mining and Mineral Engineering, 1984-05-28) Senaratne, CPJWith the advances made in Computer Technology during the recent years, computers have come into use extensively in mining operations. Companies have specially developed minerals industry software which offer mining Engineers, data processing from exploration through to mine planning. One branch in which computers could be used even in Sri Lanka where the mining is more labour oriented, is in mine ventilation. This paper discusses the use of computers in the mining industry and takes an example from the branch of mine ventilation to show the advantages in using computers to plan out the day to day mining activities.
- item: Conference-AbstractUp-grading of Sri Lankan ilrnenite(Department of Mining and Mineral Engineering, 1984-05) Ismail, MGMU; Amarasekera, J; Kumarasinghe, JSNIlrnenite, rutile and leucoxene are the only naturally-occurring titanium bearing minerals that have been seriously considered as suitable feed stock for either the metal producing or pigment industries. The existence in many places in the coast of Sri Lanka of natural concentrates of titanium bearing mineral sands such as ilrnenite and rutile with a high degree of purity has been known as far back as 1903. These deposits are found as beach sands on the east and north-west coast and occur in association with others, namely, rutile, zircon and monazite. The beach sand industry of the country, operated by the Ceylon Minerals Sands Corporation produces about 70.000 tonnes of ilrnenite per year and about 10,000 tonnes per year of rutile. If Sri Lanka were to convert the ilrnenite produced here into a value added product, instead of exporting the raw material as such, it would enable us to make sizeable strides in industrial development. The work carried out showed that Sri Lankan ilrnenite can be converted to synthetic rutile containing about 95 % Ti02 by oxidation-reduction-leach process. The oxidized ilrnenite was reduced with carbonaceous materials to reduced rutile and ' iron. Iron can be leached out using dilute HC1 acid. Reduced rutile phase was calcined to obtain synthetic rutile. The paper will discuss the main steps involved in this process.
- item: Conference-Full-textThe effect of feed concentration on the performance of hydrocyclones(Department of Mining and Mineral Engineering, 1984-05-28) Marasinghe, BSHydrocyclones have found wide application in many areas such as solid/liquid separation, powder classification and purification of minerals. The effect of solids concentration on separation performance of hydrocyclone is well recognised in practice but very little quantitative information exists in the literature. A brief review of the current knowledge in the area is followed by a proposal of a semiempirical dimensionless correlation which relates the reduced cut size to the operating variables including the solids concentration. The validity of correlation is shown by comparison with the results of tests performed with 125 mm and 50mm diameter hydrocyclones at varying feed concentrations. The equation proposed here allows scale-up and predicting of performance in application with feed concentration higher than 8 % by volume when available theories cannot be applied.
- item: Conference-Full-textGem industry & its development(Department of Mining 8c Mineral Engineering, 1984-05-28) Perera, DCSri Lanka is endowed with a galaxy of Gem minerals. This great opportunity provided by natural processes should be harnessed to the maximum to bring much needed foreign exchange to Sri Lanka while generating job opportunities vast number of people in Sri Lanka. Hence the need to streamline this industry.