3. •The Gondwana coals are largely
confined to the river valleys like the
damoder , Mahanadi , Godavari etc.
•The workable coal seams are confined
lower gondwana .
4. Introduction -
Coal -
• Coal may be defined as a solid
stratified rock composed mainly of
carbonized plants.
• Coal is the worlds leading mineral
fuel.
• It is burned to produce heat which is
used to generate electric power.
• On heating in air free atmosphere
such a coal converted to coke.
5. Chemical composition -
•Coal is composed chiefly of carbon , oxygen
,hydrogen , nitrogen , traces of sulfur and
phosphorous .
•Carbon being the major component .
•The chemical composition of coal may be in the
following range.
• Carbon (60-90 % )
•Oxygen (2-20%)
•Hydrogen (1-12 % )
•Nitrogen (1 – 3%)
6. Origin of coal-
•Coal are sedimentary rocks formed by accumulation
of plant materials in swamps , Hence the source
material of coal is the vegetation matter .
•The formation of a coal deposit require a large
accumulation of vegetation matter.
•There are two theories to explain the mode of
accumulation of plant materials to give rise to coal
seam.
1) The in situ theory
2) Drift theory
7. Type of coal -
•Coal is divided into four major classes –
Bituminous coal
Lignite
Peat
Anthracite
8. Peat -
•Peat is not considered as coal
though it is a fuel .
•It represent the first stage of coal
formation.
•Peat is a brown porous mass of
partly decomposed vegetable
material.
•Chemically it is very rich in
moisture and consist of carbon ,
hydrogen , sulfur and nitrogen as
important constituent.
9. Type of peat-
•There are two type of peat -
1) Bog peat –
•Which is evolved out of
lower type of vegetation
like masses .
2 ) Mountain peat-
•That is decomposed
and partially altered
form of higher type of
trees.
•It is found in sub-
mountainous regions.
10. Lignite -
•Lignite is also called brown coal as its
colour is often dark brown.
•It represent the second stage of in coal
formation .
•The lignite is composed of finely divided
plant tissue.
•The lignite burns freely with along smoky
flame .
• Lignite has a low calorific value(1100-
12500B.T.U )
11. The composition of Lignite –
•Fixed carbon-50%
•Oxygen-20-25%
•Hydrogen -5%
•Nitrogen-2-5%
•Sulfur – 1-2%
12. Bituminous coal –
•It is also known as common
coal .
•It is a dense coal of black
colour .
•Bituminous coal has compact
structure breaking almost
cubical fragment.
•It burn with a yellow flame.
•Its calorific value ranges
between 13500 to 16000 B.T.U.
13. Bituminous coal is distinguished into 3
types -
On the basis of carbon content –
•Sub- bituminous
•Bituminous
•Semi-bituminous
17. Anthracite-
•It is a coal of highest rank in which original organic source
has been completely transformed into carbonaceous
substance.
•Anthracite is a hard coal with an iron –black colour and
sub-metallic lustre .
•It is burns with short blue flame .
•Calorific value – 15000 to 15600 B.T.U.
18. USES -
•Coal is a primary source of heat and power (
thermal power )
•It is also used in the production of water gas.
•In metallurgical oporations , for the purpose of
oxtractions of metals like iron, zinc etc.
