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Economic Geology 6 Year Integrated M. Tech. Geotechnology and Geoinformatics e-Learning Material PAPER CODE: MTIGT0601 ECONOMIC GEOLOGY Dr. J. SARAVANAVEL Assistant Professor Centre for Remote Sensing Bharathidasan University Tiruchirappalli- 620023 Email: [email protected] e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. [email protected] 1 MTIGT0601- ECONOMIC GEOLOGY 1. Economic ore mineral deposits: Ore and gangue minerals – Hypogene (Primary) and Supergene (Secondary) deposits – concentration of elements in the crustal rocks - Classification of ore mineral deposits (Lindgren’s, Bateman’s and recent classifications). Metallogenic provinces and epochs – Distribution pattern of ore resources in the world – review of crustal evolution and metallogeny and evidences from Indian shield- Geologic Thermometry – Non isotopic methods – Direct and indirect methods – Isotopic methods – Principles of ore microscopy – microtextures of ore minerals and their significance. 2. Processes and environment of ore formation: Magmatic Deposits – Contact metasomatic deposit – Hydrothermal deposits- Sedimentary and residual deposits – Metamorphic deposits – Oxidation and supergene enrichment – Paragenesis of mineral deposits. 3. Physical properties, Chemical composition, mode of occurrences and Indian distributions of native elements and metals (Gold, Silver, Platinum), semi metals (Arsenic, Antimony) and non metals (Diamonds, Graphites) – Sulphides (Sphene, Molybdenite, Cinnabar, Aresenicpyrite, Stibnite, etc.) – Halites (halites, fluorite) – Oxides (Rutile, Corundum, Iluminite, Cassiterite, Columbite, Tantalite, Spinel, Franklinite, Chrysoberyl, Beryl) – Tungstates (Wolframite, Scheelite) – Talc, Steatite, Asbestos, Tourmaline. 4. Metaliferous deposits: Mineralogy, mode of occurrence and distribution of Iron, Manganese, Aluminium, Lead and Zinc, chromium and Gold in India. 5. Industrial Minerals: Mineralogy, mode of occurrence and distribution of minerals used for Abrasives, Fertiliser, Paint, Refractory, Glass, Ceramic and Cement. e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. [email protected] 2 Text Books: 1. Bateman, AM and Jonsen, M.L., Economic mineral Deposits, John Wiley 2. Gokhale & Roa, Ore Deposits of India, Thomson press, 1972, 3. Krishnaswamy,S., Indian Mineral Resources, Oxford IBH, 1980, References: 1. Alkinson, Ore Deposit Geology Chapman & Hall,1985 2. Craig, 1985, Ore Petrology and Petrography, Wiley, 1981. 3. Desppande M.L., Gemstones and Semiprecious stones. Indian Minerals, Vol-32 No.1 Geol. Survey of India Pub. 1978. 4. Iyengar, N.K.N. Mineral wealth of Tamilnadu, Madras Govt. 5. Karanth, K.V., Gems and Gem Industry in India, Geol. Soc., 2000. 6. Krishnan, M.S. Mineral Resources of Madras, Geology Society of India Pub. 7. Laford,S.J., Industrial minerals and Rocks, AIME Pub., 1975. 8. Lindgren, W, Mineral Deposits, McGraw Hill, 1942. 9. Nancy, & Ron Perry, Practical Gem Cutting, David & Charles, 1982. 10. Prasad, V., Economic Geology, CBS Pub., 1994. 11. Ram Dohr, P., Ore Deposits and their Relationship, Springer Verlaz, 1960. 12. Stanter, R.L. Ore Petrology, McGraw Hill, 1972. 13. Sinha RK & Sharma, N.L., Treatise on Industrial Minerals of India, Pub, 1967. 14. Subramanyan, K.S. Geology of Tamilnadu and Pondicherry, Geol Soc. India, Pub., 2001. 15. GSI, Geology and Mineral Resources of Tamilnadu, Geol. Survey of India Pub. e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. [email protected] 3 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] ECONOMIC GEOLOGY e – Learning Material: Unit-1 ORE AND GANGUE MINERALS 4 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] Economic Geology is an important branch of Geology which deals with different aspects of economic minerals being utilized by mankind to fulfill his various needs Economic Minerals are those which can be extracted profitably This subject deals with • Minerals and their origin •Processes of mineral formation • control of localization •Metalogenic epoch and provinces, etc. What is a mineral? A solid naturally-occurring compound having a definite chemical composition Examples: quartz - SiO2 (an oxide) hematite - Fe2O3 (another oxide) chalcopyrite - CuFeS (a sulphide) 5 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] MINERAL DEPOSITS The term Mineral Deposit refers to any accumulation of useful minerals of the mineral kingdom. Such deposit may be classified as metalliferous (Copper, lead) or non-metallic (Bauxite) The elements that enter into the constituents of the mineral deposits are derived either from the rocks of the earth crust or from the molten bodies (magma) Metallic Mineral Deposit: The concentration of metals in the deposit is called Metallic Mineral Deposit. These metals generally associated with other elements such compounds are said to be ore minerals Non-Metallic Deposits: The non-metallic deposits consist of solids, liquids and gases. The term ‘ore’ is not generally used to refer such deposits. They called by the name of the substance itself such as Mica, Petroleum, Coal, Asbestos The unwanted material is simply called as ‘Waste’ and not as gangue The price is generally low compare to metallic deposit, they are common substances Except Gemstones, most of the non-metallic deposits are free of waste or little waste Feldspar, Barite, etc. have a considerable waste 6 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] What is an ore? An occurrence of minerals or metals in sufficiently high concentration to be profitable to mine and process using current technology and under current economic conditions. A high grade lead deposit in Antarctica may not considered as ore at present, since it can not be commercially utilized To be an Ore, there are two factors 1) The cost of production and 2) the market value Single ores contain a single metal and complex ore (ore minerals) consist of more than one metal Molybdenum – single metal in Molybdenite Chalcopyrite – Copper association with Iron and Sulphur 7 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] Most ore minerals are combinations of metals with sulphur, oxygen and other non-metals Some metals like gold, plattinam, copper are occur in native form Single metals may form many ore minerals or single metal can be extracted from the number of ore minerals. For example:- Copper as a native metal – Cuprite as a Silicate – Chrysocolla as a Sulphides – Chalcopyrite, bornite, covellite, chalcocite as a Carbonates – Malachite, azurite Gangue: The ore minerals are usually associated with non-metallic materials or rock forming silicates which are not desired . These unwanted materials are called as Gangue Gangue is mainly composed of rock forming minerals like Quartz, feldspar, Calcite However, certain gangue minerals are collected as byproducts and utilized. For example: rock Gangue may be utilized as road metal, fluorspar and limestone as flux, quartz as abrasive, pyrite for manufacturing sulphuric acid 8 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] The tenor of ore is the metal content of the ore. Which is required to give profit The tenor is usually expressed as • Weight percentage (base metals) • Grams/tonne (precious metals) The tenor varies with the Price of the metal , cost of production, ores of different metals, different ores of same metals The Higher price of the metal, the lower the metal content is required to make it profitable Most of the iron ore is profitable – tenor of 35 – 50% The tenor of copper is 0.8% Gold 1/1000 of 1 % Economically Important Metal Concentrations in Earth’s Crust Concentration Metal (% by weight) Aluminum 8.0 Note for comparison: Iron 5.8 Silicon 28% Copper 0.0058 Oxygen 46% Nickel 0.0072 Zinc 0.0082 Uranium 0.00016 Lead 0.001 Silver 0.000008 Gold 0.0000002 9 e-learning Material – Economic Geology Dr.J.Saravanavel, Assistant Professor, Centre for Remote Sensing, Bharathidasan University. Email: [email protected] Mineral Resources 'Mineral Resource' is a concentration or occurrence of material of intrinsic economic interest in or on the Earth's crust in such form and quantity that there are reasonable prospects for eventual economic extraction. The location, quantity, grade, geological characteristics and continuity of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge. Mineral Resources are sub-divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories. • Inferred: That part of a Mineral Resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. • Indicated: That part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can
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