about coal - copy

7/26/2019 About Coal - Copy

1/32

BOUT CO L

M. Arifin


2/32

INTRODUCTION

Coal is a readily combustible

rock containing more than 50

percent by weight ofcarbonaceous material, formed

from compaction and

indurations of variously altered

plant remains similar to those

in peat. Most coal is fossil peat.

Peat is an unconsolidateddeposit of plant remains from a

water-saturated environment

such as a bog or mire

structures of the vegetal matter

can be seen, and, when dried,

peat burns freely.

Adapted from AGI's Glossary of

Geology. Forests from the Carboniferous Age which were transformed into

coal over millions of years


3/32

Coal is formed by the physicaland chemical alteration of peat

!coalification" by processes

involving bacterial decay,

compaction, heat, and time.

Coal is an agglomeration of

many different comple#

hydrocarbon compounds,some of which owe their origin

to the original constituents in

the peat.

Peat deposits are actually $uite

varied and contain everything

from pristine plant parts !roots,bark, spores, etc." to decayed

plants, decay products, and

even to charcoal if the peat

caught fire.

RESOURCES

Coal Formed


4/32

Peat deposits typically form in a waterlogged environment where plant debris is accumulatedpeat bogs and peat swamps are e#amples. %n such an environment, the accumulation of plant

debris e#ceeds the rate of bacterial decay of the debris. &he bacterial decay rate is reduced

because the available o#ygen in organic-rich water is completely used up by the decay

process. 'naerobic !without o#ygen" decay is much slower than aerobic decay.

%n order for the peat to become coal, it must be buried by sediment. (urial causes compaction

of the peat and, conse$uently, much water is s$uee)ed out during the first stages of burial.Continued burial and the addition of heat and time cause the comple# hydrocarbon

compounds in the deposit to start to break down and alter in a variety of ways. &he gaseous

alteration products !methane is one" are typically e#pelled from the deposit and the deposit

becomes more and more carbon-rich !the other elements drop out". &he stages of this trend

proceed from plant debris, peat, lignite, sub-bituminous coal, bituminous coal, anthracite coal,

to graphite !a pure carbon mineral".

(ecause of the amount of s$uee)ing and water loss that accompanies the compaction of peat

after burial, it is estimated that it took vertical *0 feet of original peat material to produce one

vertical foot of bituminous coal. &he peat to coal ratio is variable and dependent on the original

type of peat the coal came from and the rank of the coal.

RESOURCES

Coal Formed, cont


5/32

Coal were formed from plants and animals that lived +00 million years ago in primordial

swamps and oceans (left). ver time the plants and animals died and decomposed undertons of rock and ancient seas (middle). ventually, many of the seas receded and left dry

land with coal buried underneath it (right). &en feet of prehistoric plant debris was needed to

make one foot of coal.

RESOURCES

Coal Formation


6/32

Coal, an organic deposit, is madeup of organic grains called

macerals, which under the

microscope is separated into three

maceral groups, and each of it is

composed of several maceral

types. &hese groups are liptinite,

vitrinite, and inertinite and aredefined according to their grayness

in reflected light liptinites are dark

gray, vitrinites are medium to light

gray, and inertinites are white and

can be very bright.

/iptinites were made up of hydrogen-rich hydrocarbons derived from spores, pollens, cuticles,and resins in the original plant material. itrinites were made up of wood, bark, and roots and

contained less hydrogen than the liptinites. %nertinites are mainly o#idation products of the

other macerals and are conse$uently richer in carbon. &he inertinite group includes fusinite,

most of which is fossil charcoal, derived from ancient peat fires.

RESOURCES

Coal Components


7/32

/iptinites were made up ofhydrogen-rich hydrocarbons

derived from spores, pollens,

cuticles, and resins in the original

plant material. itrinites were

made up of wood, bark, and

roots and contained less

hydrogen than the liptinites.%nertinites are mainly o#idation

products of the other macerals

and are conse$uently richer in

carbon. &he inertinite group

includes fusinite, most of which is

RESOURCES

Coal Components, cont

fossil charcoal, derived from ancient peat fires.

Microscopic view of coal yellow area is vitrinite white grains are inertinite gray shapes are

liptinites !plant spores" dark brown areas are tiny grains of vitrinite.


8/32

Coals can also be divided into twotypes based on their macroscopic

!not microscopic" appearance

banded and non-banded. 1on-

banded coals include cannel and

boghead coals, both of which are

dull and blocky.

Cannel is derived from the word

candle, because pencil-shaped

pieces were used as candles in

the past. (anded coals grade

RESOURCES


from dull banded !splint coal" to bright banded coals, depending upon whether dull bands or

bright bands are dominant.

&he bands are divided into lithotypes. 2ull bands are called durain satiny bands are clarain

charcoal bands are fusain and black, glassy bands are vitrain. (right coals have lots of

vitrain and clarain dull coals are rich in durain bands. 3usain generally occurs only in thin

and sporadic bands.


9/32

4plint coals are durain-rich and can bemassive !non-banded" or banded. Most

vitrain- and clarain-rich banded coals

break into small blocky pieces along

oints called cleats. itrain and clarain

are brittle and break easily. 6(lock

coals6 are dull coals that break into

large blocks because they have fewervitrain and clarain bands, but have a

composition higher in liptinite macerals,

which are tough. 6(one6 and 6bone

coals6 have a high ash content in the

form of clays and silts they form part of

a continuum between dark shale and

dull !banded or non-banded" coal in the

following se$uence dark shale, bone

!greater than 50 percent ash", boney

coal !less than 50 percent ash", dull coal

!cannel, boghead, or splint".

RESOURCES



10/32

RESOURCES

Coal Tpe

Coal is generally classified bywhat is known as 6rank6

which is based on the degree

of transformation of the

original plant material to

carbon.

Low rank coal: Lignite Sub Bituminous

Hard coal: Bituminous Anthracite


11/32

Coal Tpe

&hese classes are furtherdivided into subclasses

based on their degree of

alteration !measured by

volatile-matter content,

calorie, or by petrographic

means".

RESOURCES

i i t di


12/32

/ignite - also known as brown coal - is

a dark brown to black combustible

mineral formed over millions of years

by the partial decomposition of plant

material subect to increased pressure

and temperature. /ignite is coal withlow organic maturity. %t is characteri)ed

by its high moisture content and low

carbon7energy content compared to

high rank coals such as anthracite.

2ue to its high moisture content and

relatively low calorific value, lignite isusually consumed at or close to where

it is produced7mined.

minin!tradin!.com

Coal Tpe

"i!nite

RESOURCES

minin!tradin! com


13/32

4ub-bituminous coal is the ne#t highest

coal in rank after lignite. %t is softer than

bituminous coal and contains more

moisture, making it less economic to

transport long distances. 4ub-bituminous

has typical bed moisture levels ofbetween *0-809 and a carbon content of

between :*-::9.

4ub-bituminous coal can be dull, dark

brown to black in colour and soft and

crumbly in $uality, to bright, et black, hard

and strong. ;sed primarily as fuel forpower generation and industrial

processes, sub-bituminous coal has

properties ranging from those of lignite or

bituminous coal.

minin!tradin!.com

Coal Tpe

S#$%$it#mino#s Coal

RESOURCES

minin!tradin! com


14/32

(ituminous coal is classified as

coal which in terms of rank falls

between sub-bituminous and

semi-anthracite. olatile matter

can vary widely and bituminous

coal is typically divided intothree sub-groups - low volatile,

medium volatile and high

volatile.

(ituminous coal can be

metallurgical !also known as

coking coal" or thermal !alsoknown as steam coal".

minin!tradin!.com

Coal Tpe

&it#mino#s Coal

RESOURCES

minin!tradin! com


15/32

'nthracite is the highest rank coal and

is characteri)ed by low volatile matter

!always less than *09" and high carbon

content - it contains about


16/32

Mining is classified by the method needed to reach the coal seam. =hen the coal is found

close to the arth>s crust and taking away the overlying layers of material is not too

e#pensive, surface mining is used to remove the top layers of materials and e#pose the

coal.

%f coal is found in layers far from the surface, underground mining is the preferred techni$ue.

ertical or slanted holes !6shafts6" are cut down to the mining area underground for

ventilation for the workers and for transporting the miners, e$uipment, and coal.

MININ(


17/32

4urface mining is accomplished byremoving overburden from the

coal seam and then blasting and

removing the coal. &he ratio of

overburden e#cavated to the

amount of coal removed is called

the overburden ratio. &he lower

the ratio, the more productive the

mine.

$uipment used in surface mines

include draglines, shovels,

bulldo)ers, front-end loaders,

bucket wheel e#cavators and

trucks. %n large mines, draglines

remove the overburden while

shovels are used to load the coal.

%n smaller mines, bulldo)ers and

front-end loaders are often used to

remove overburden.

MININ(

Strip Minin!


18/32

(ucket wheel e#cavator belt conveyor

?ydraulic e#cavator 2ump truck(ulldo)er

MININ(

S#rface Coal Minin! E)#ipments


19/32

Common types ofunderground mining

are the drift, shaft,

and slope mining

methods. (ased on

the mining system,

underground mining

consists of longwall

mining and room and

pillar mining.

MININ(

Under!ro#nd Minin!


20/32

%n longwall mining, acutting head moves

back and forth

across a panel of

coal about @00 feet

in width and up to

:,000 feet in length.

&he cut coal falls

onto a fle#ible

conveyor for

removal. /ongwall

mining is done

under hydraulic roof

supports !shields"

that are advanced

as the seam is cut.&he roof in the

mined out areas

falls as the shields

advance.

MININ(

"on!*all Minin!


21/32

Coal shearer Face conveyor elt conveyor

MININ(

"on!*all Minin! E)#ipments

!ydraulic support

minin!tradin!.com


22/32

%n longwall mining, a cutting head moves back and forth across a panel of coal about @00 feet in width

and up to :,000 feet in length. &he cut coal falls onto a fle#ible conveyor for removal. /ongwall mining is

done under hydraulic roof supports !shields" that are advanced as the seam is cut. &he roof in the mined

out areas falls as the shields advance.

MININ(

Room and +illar

minin!tradin!.com


23/32

Coal preparation, also know

as coal beneficiation, is the

stage in coal production

when the raw run-of-mine

coal is processed into a

range of clean, graded, and

uniform products suitable for

the commercial market.

+RE+ARATION


24/32

+RE+ARATION

3irst, the mined coal is loaded

into a stockpile, with a reclaim

tunnel beneath it. &hen, the coal

is transported to a raw coal silo,

usually *0,000 ton capacity, for

feed to the plant at a constant

rate.

%n this instance the first stage is a crushing7screening plant, with heavy media processing !for

coarse coal si)es - 86 # *0 mesh", spirals for the middling si)es !*0 mesh # A0 mesh",

flotation for the -A0 mesh fine coal feed. &he cleaned coal is then transported to the ne#t

plant, which is a series of thermal dryers for reducing the moisture content and thereby

raising the (&; value of the coal. &he final dried coal product is then transported to the clean

coal silo>s for loading onto a train for transport to the end user.

minin!tradin!.com


25/32

Coal Transport

nce coal has been e#tracted it needs to be moved from the mine to the power plant or

other place of use. ver short distances coal is generally transported by conveyor ortruck, whereas trains, barges, ships or pipelines are used for long distances.

by train by truck


26/32

Coal properties and uses

The chief uses of coal minedare electricity generation, heat,and coking coal for iron andsteel making. Electricitygeneration far surpasses theother uses of Kentucky coal.Each of these uses has specicrequirements, but generally ahigh Btu value, and a low sulfur,ash, and moisture content aredesirable. The important

properties of coal aredependent upon the specicindustrial use of the coal.ndesirable chemicalconstituents in coal such assulfur, chlorine, sodium, andvarious ha!ardous air pollutantsmay be important for some

uses of coal.

The washability of a coal is a property that determines how easily these chemical constituents

and the ash content of the coal can be reduced through preparation before the coal is used."mportant handling properties include grindability, content of scaling agents #chlorine and sodiumcause scaling in boilers$, and ash fusion. %sh fusion is a property that indicates whether the ashtotally melts #low ash fusion$ and must be removed from the boiler as a liquid, or forms &clinkers&or cinders #high ash fusion$ that must be removed as a solid. Boilers are designed to burn coalswith specic ash fusions for this reason.

minin!tradin!.com


27/32

Coal has many important uses, but most

significantly in electricity generation, steel and

cement manufacture, and industrial process

heating.

Coal is the maor fuel source for electric power

generation worldwide. More than half of total

world coal production provides around +@9 of

the world>s electricity.

Coal is also indispensable for iron and steelproduction almost :09 of total global steel

production is dependent on coal. 'bout A00

million tons of coal - e$uivalent to appro#imately

*A9 of total hard coal production - is currently

utili)ed by the steel industry.

USES

USES

minin!tradin!.com


28/32

USES

+o*er (eneration

USES


29/32

Steelmain!

USES

minin!tradin!.com


30/32

Coal Mining Cycle

coal mining

coal stockfilling

coal mining areapra 7 post mining area

coal transportingcoal utili)ing

MININ(


31/32

%n longwall mining, large

rectangular blocks of coal aredefined during the development

stage and are then e#tracted in

a single continuous operation.

ach defined block of coal,

know as a panel, is created by

driving a set of headings from

main or trunk roadways, some

distance into the panel. &heseroadways are then oined to

form the starting face of

longwall face.

Coal is e#tracted mechanically

from longwall faces. 's the coal

is cut the longwall face is

supported with hydraulicallyoperated supports. &he functionof these supports is to provide a safe working environment by supporting the roof as coal is e#tracted as

well as advancing the longwall e$uipment. 's the face advances the immediate roof above the coal is

allowed to collapse behind the line of support forming the goaf.

MININ(

"on!*all Minin!

MININ(


32/32

%n longwall mining, large

rectangular blocks of coal aredefined during the development

stage and are then e#tracted in

a single continuous operation.

ach defined block of coal,

know as a panel, is created by

driving a set of headings from

main or trunk roadways, some

distance into the panel. &heseroadways are then oined to

form the starting face of

longwall face.

Coal is e#tracted mechanically

from longwall faces. 's the coal

is cut the longwall face is

supported with hydraulicallyoperated supports. &he functionof these supports is to provide a safe working environment by supporting the roof as coal is e#tracted as

well as advancing the longwall e$uipment. 's the face advances the immediate roof above the coal is

allowed to collapse behind the line of support forming the goaf.

MININ(

Room and +illar Minin!

about coal - copy

Documents