COAL Final.pptx

Coal its origin,varieties, distribution

1. COAL ORIGIN ,VARIETIES and distribution OF COAL SARMISTHA NAIK M Sc. 1 st year (Geology) Roll no.22geol014

2. CONTENTS 1.Introduction 2.Origin Of Coal 3.Insitu Theory and its Evidences 4.Drift Theory and its Evidences 5.Varieties Of Coal 6.Distribution Of Coal in India

3. COAL It is an organic sedimentary rock that forms from the accumulation and preservation of plant materials,usually in a swamp environment. Scientifically “Coal is a solid stratified rock composed mainly of hydrocarbons. It is one of the chief fossil fuels.

4. ORIGIN OF COAL Two theories have been put forward to explain the origin of coal seams. 1.In situ Theory 2. Drift Theory.

5. IN SITU THEORY This theory suggests that the vegetal grew at the same place where we now find the coal seams and it is said to be Autochthonous in origin.

6. Evidence in support of in situ theory There are large accumulations of vegetal matter forming in swamps at the present day. Some of them gave rise to coal seams. The purity of coal seams and uniformity in composition indicates that the deposition of the vegetal matter in still waters and from nearly the same source material. The numerous tree trunks were found with their roots firmly fixed in the underlying clays that lie beneath the coal seams. These clays represent the original soils on which the vegetation grew.

7. DRIFT THEORY According to this theory the vegetal debris have been transported by water from their original site of growth to the present site of coal seams.This is said to be Allochthonous in origin.

8. EVIDENCES OF DRIFT THEORY Large quantities of tree trunks are being transported downstream by present day rivers particularly in regions of forests. Beds of peat have been found in the process of formation at the deltas of some rivers at the present day. e.g., Delta of Ganga. The rocks associated with coal are distinctly sedimentary and coal seams themselves behave like sedimentary beds. Absence of clays and coal seams lie directly on sandstones , shale’s or conglomerates.

9. VARIETIES OF COAL Macroscopically there were two general varieties of coal 1. Humic Coal(Banded Coal) 2. Sapropelic Coal(Non Banded Coal) Microscopically coal is made up of organic grains called macerals .These are of 3 types: 1. Vitrinite 2. Inertinite 3.Liptinite

10. HUMIC COAL The Humic coals are the most important and are mainly formed from there mains of the wood and bark of the original plants and they generally give a banded look . Humic coal have 4 lithotypes constituents: 1. VITRAIN : Essentially bright black, glassy in lustre and homogeneos component of coal having a massive texture. 2. CLARAIN : Bright component of coal in overall appearance,but lesser than VITRAIN . It is a heterogenous material with a banded structure. 3. DURAIN : Essentially dull component of coal with slight greassy black lustre . It is heterogenous material and has a firm granular texture . 4. FUSAIN : It occurs in pockets or as patches rather than uniform band of fibrous material resembling charcoal.

11. SAPROPELIC COAL The sapropelic coals are formed from non-woody matter as leaves ,spores,enrich of plants and also from organic oozes , algae,fungi. These coals contain less carbon but rich in Hydrogen compared to Humic Coals.

12. TYPES OF SAPROPELIC COAL 1.BOGHEAD COAL 2.CANNEL COAL Composed largely of algal materials. Extremely rich in Hydrogen. Brown in colour. Feels greesy in hand. Inorganic matter <25% Also called as TORBANITE. Formed by sub aquatic plants. Has a good hydrogen content. Black in colour,sometimes shades to Brown. Dull and Hard in lustre. Also called as PARROT COAL .

13. MODERN CLASSIFICATION OF COAL The following varieties of coal were recognised based on the physical and chemical changes that transforms the vegetal matters to coal. This relatively comes under the varieties of Humic coal. Those are: 1.Peat 2.Lignite 3.Bituminous Coal 4.Anthracite

14. PEAT LIGNITE Not regarded as coal 1 st stage of coal It is a compact fibrous matter of Plant. Lower to Dark Brown in colour. Moisture ~=80% Carbon~= 5% It is Brown in colour. Here the vegetal matter is in consolidate form. Carbon~=30% Moisture~=30 to 60%

15. BITUMINOUS ANTHRACITE It burns like Bitumen with yellow flame ,so the name Bituminous Coal . Black in colour. Banding is present of dull and bright colour. Moisture <10% Carbon=69 to 86% Last stage of coal. Metallic Black colour. Also known as Stone Coal. Burning is difficult but when burns it burns with blue flame with no smoke. Carbon=92 to 98%

16. MICROSCOPIC COMPONENTS OF COAL On microscopic level , coal is made up of organic grains (smallest unit of coal) called macerals . Macerals are organic entities produced under highly variable physio-chemical conditions from different parts of plants such as woody tissues , leaves , spores , pollens , resins etc. Different macerals have different optical properties and have variable concentration in mineral matter. Macerals are separated into 3 groups- inertinite , vitrinite and liptinite.

17. VITRINITE Vitrinite group macerals are mainly derived from cellulose, woodyparts. Vitrinite has a high oxygen content compared to other maceral groups. Capable of producing hydrocarbon gas but only small amounts of oil.

18. LIPTINITE Liptinite is common in dull coal bands. It originates from spores, pollen, algae, fats, bacterial proteins. Many of the volatiles, including methane, emitted by the coal comes from the liptinite. These macerals have the potential of producing hydrocarbon gases and oil.

19. INERTINITES All Inertinites have high carbon and low Hydrogen content. Has relatively more carbon content than other Macerals . Only small amount of volatile component are generated by Inertinites.

20. DISTRIBUTION OF COAL IN INDIA Coal deposits of India belongs to two geological periods: 1. Gondwana Coal: About 98% of annually extracted coals in India belongs to Lower Gondwana age. It is mainly Non-coking Bituminous type. It is Interbedded commonly with Sandstone,Shale and sometimes Limestone. Gondwana coals comprises of Coal fields of Bihar,West bengal, Odisha,Chattisgarh,Jharkhand,Andhra Pradesh,Madhya Pradesh. 2. Tertiary Coals: These coals are found in Assam,Arunachal Pradesh,Meghalaya and J&K.

21. COAL FIELDS OF ODISHA Odisha has only 2 coalfields out of 57 Gondwana and 14 Tertiary coal fields for the National Inventory of coal. Yet its share in the reserve is so far established in the country amounts to 24.78% (58.01B.T). Talchir coal field is having the pride of highest geological reserve of 51.220 BT in the country. Ib River coal field has the third highest geological reserve of 29.620 BT in the country .

22. COAL FIELDS OF WEST BENGAL Raniganj Coal Field: This coal field is named after the town of Raniganj which is the mining centre. This coal field is about 1554 Sq.Kms. in area and is one of the largest coal fields of India. The Gondwana formations in this coalfield are extended over an area of 1000 Sq.km.

23. COAL FIELDS OF JHARKHAND Jharia coal field: It is the most important productive of the Indian coalfields located in Dhanbad district of Jharkhand. The lower Gondwana rocks are very well developed in this field. It exhibit a characteristic banding of alternate bright and dull layers of coaly matter. Bokaro coal field: The Bokaro coalfield is situated in the Hazaribagh district and is the second largest coal field in Jharkhand. All the formations of the lower Gondwana System from Talchir to Panchet series occur in this fields. Usually the coals are of coking varieties.

24. COAL FIELDS OF ASSAM Makum , Nazira , Mikir Hills , Dilli-Jeypore and Lakhuni are some coal fields of Assam. Makum coalfield in Sibsagar district is the most developed field. Assam coals contain very low ash and high coking qualities but the sulphur content is high , as a result of which this coal is not suitable for metallurgical purposes. But these coals are best suited for hydrogenation process and are used for making liquid fuels.

25. COAL FIELDS OF JAMMU & KASHMIR Coal fields in Udhampur & Kalakot area which extends from Jangalgali in the east to Jigni in the West , falling in Districts of Udhampur and Rajouri. This coal which is semi anthracitic in rank occurs as black in form though about 10% of the production is in the form of Steam coal. The coal is of generally of high heat value.

26. LIGNITE DEPOSIT OF INDIA Nyveli Lignite field: It belongs to the tertiary coal fields of India. This lignite field is centered around the Nyveli Station and it is 43 Km west of Cuddalore part and about 241 Km from Tamil Nadu. The lignite deposits in Nyveli occur in a sequence of clays and Cuddalore Sandstones of Miocene Age. It is the largest Lignite deposit of India.

27. CONCLUSION Although coal is one of the chief source of our energy requirements but it is a non renewable resource of energy. So the over extraction and over consumption of it may lead to harse effect of it like global warming,acid rain and other natural phenomenon. Hence ,the extraction and consumption of it should be done in a sustainable manner so we could make a safen place for the future times.

28. REFERENCES Principles Of Engineering Geology by K.M. Banger(Chapter-9 Ore deposits) Wikipedia (Coal in India) Economic Geology by Umeshwar Prasad(Chapter-5 Non Metallic Minerals)

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