ter 8
CLASSIFICATION AND
ORIGIN OF COAL
8.1 INTRODUCTION
Numerous system of coal classification has been proposed by
different authors since the later part of the 19,f1 century. Most of the
classification are based on the chemical and technical properties of
the coals.
Following these various schemes the classification of
Bapung coals is tried on the basis of proximate analysis, ultimate
analysis and petrographic composition.
Chapter 8
123
According to the physical properties, the Bapung coal can be
classified as bituminous as it is black to dark black in colour with dull
to glossy lustre.
8.2
CLASSIFICATION BASED ON PROXIMATE ANALYSES
The difficulty in determining the ultimate analysis of coal and
due to the simple nature of the proximate analysis, many systems of
classification have been devised using proximate analysis alone.
Moreover, proximate analysis includes a measure of the proportions
of volatile matter and the range of calorific value, both points of
practical importance in relation to the utilisation of coal.
The parameters generally used in classification are moisture,
volatile matter or fixed carbon, fuel ratio and calorific value.
8.2.1 Fraser's classification
It is one of the earliest classifications of coal proposed by
Fraser (1877) in the USA.
He devised a system based on the fuel
ratio, i.e., the ratio between volatile matter and fixed carbon content.
His scheme of coal classification is given in Table 8.1. As the fuel
ratio is in between 1.10 and 1.42 (Table 8.2), the Bapung coal can be
termed as bituminous coal according to the Fraser’s classification.
8.2.2 Parr’s classification
The coal classification system as introduced by S. W. Parr
Chapter 8
124
(1928) is mainly based on the proximate analysis and calorific value
of the coal. The calorific value of the pure coal is plotted against the
percentage of unit volatiles as shown in Fig. 8.1.
' In this classification, the Bapung coal mostly falls in the western
type of bituminous although it ranges from western type of bituminous
to black lignites.
8.2.3 A.S.T.M. Classification
Classification by proximate analysis of coal has been a
favourite method in USA for more than a century. The A.S.T.M
(American Society for Testing and Materials) system is generally used
here, being a development of the best features of the systems based
upon proximate analyses by Parr and others.
The ASTM
classification uses bases the fixed carbon or volatile matter for high
rank coals, and the calorific value of the moist, mineral matter free
coal for the low rank coals which contain high proportions of
moisture.
The coals are classified into a series of classes and groups. In
this classification which is numbered, commencing with the higher
rank coals.
Coals of higher rank than No. 4 high volatile - B
bituminous coal, i.e., coals containing less than 31% of volatile matter,
in dry mineral matter free basis, are classified according to their fixed
carbon contents. Coals containing more than 31 % of volatile matter in
dry mineral matter free basis are classified according to their 'moist
125
Chapter 8
calorific value’.
Moist calorific value (moist B.Th.U) means the
calorific value of the coal containing its 'natural bed moisture’, but not
including visible water on the surface of the coal. The scheme of
ASTM classification is given in Table 8.3.
In this classification Bapung coal falls in the bituminous - High
volatile A group (Table 8.4).
8.2.4 Indian Standard Classification
The coal classification system adopted by the Indian Standard
Institute is mainly based on the yield of volatile matter and calorific
value (on dry mineral matter free basis) together with the moisture
content and caking nature of the coals.
The classification is
presented in Table 8.5.
The calorific value of Bapung coal ranges from 13471.34 to
14612.32 B.Th.U/ib with average value of 14007.65 B.Th.U/lb in dry
mineral matter free basis. In this classification, Bapung coal falls in
the high volatile bituminous (non-caking) group (Table 8.6).
By plotting the percentage of volatile matter as abscissa against
the calorific value, a figure is obtained for the ISI classification. The
data of Bapung coals are plotted in Fig. 8.2 and the plots mostly fall in
the bituminous region.
Chapter 8
8.3
126
CLASSIFICATION BASED ON ULTIMATE AND PROXIMATE
ANALYSES
8.3.1 Seyler’s classification
Seyler’s classification is one of the outstanding historical
classifications of coal based upon ultimate analysis. As originally
presented in 1900, coals were grouped into a series of species
according to carbon content and into series of genera according to
hydrogen content.
The carbon and hydrogen as determined by
ultimate analysis, were corrected for moisture, ash and combustible
sulphur. The lowest carbon content included was 75%, thus excluding
lignites, whilst the hydrogen range was too small to include such coals
rich in hydrogen as cannels and bogheads. Seyler’s classification in
tabular form (in part) is presented in Table 8.7. In this classification
the prefix ‘ortho- indicates ‘true’, ‘typical’ or ‘normal’, ‘sub’ means
‘less than normal’, whilst ‘per’ means ‘more than normal’.
In Seyler’s chart, a narrow band is drawn between the carbon
limits 70.0-97.0% and hydrogen 2.0 to 5.8% which is believed to
include the composition of all normal (humic) bright coals within this
range of carbon content.
Later on Seyler has produced a series of graphical
representations of his classification in the form of charts with carbon
and hydrogen as rectangular co-ordinates, with further axes indicating
calorific value and volatile matter at right angles to each other, but
inclined at about 60° to the carbon axis (Francis, 1961).
Chapter 8
127
In Seyler’s coal chart, the Bapung coal falls in the ortholignitous species (Fig. 8.3). According to hydrogen content the coat
ranges from per-bituminous to bituminous genera and the average
hydrogen content (in dry mineral matter free basis) falls in the
bituminous genera.
8.3.2 Mott’s Classification
Mott has made an intensive study into the subject of
classification based upon ultimate and proximate analyses, and his
classification covers a wide variety of coals. The construction of the
chart representing Mott’s classification is on somewhat similar line to
that of Seyler, except that the volatile matter and calorific value
determinations are used as the principal rectangular co-ordinate,
whilst hydrogen and carbon are subsidiary co-ordinates, inclined at an
angle of approximately 40° to the main co-ordinates. The ultimate
and proximate analyses are calculated to the dry mineral matter free
basis. The Mott’s classification is tabulated in Table 8.8. The chief
merit of Mott’s classification lies in the recognition of the coal outside
the coal band of Seyler.
Classification of Bapung coal according to the Mott’s
classification is tabulated in Table 8.9. From the table it is seen that
Bapung coal ranges from high volatile bituminous to lignitic
transitional group but the average composition falls in the lignitic
transitional group. The data are plotted in the coai band (Fig. 8.4)
Chapter 8
128
and observed that the plots mostly fall in the lignitic region.
8.3.3 Hickling's Classification
Hickling (1927) proposed a classification and constructed a
chart by. plotting .the percentage of carbon against oxygen (unit coal
basis).
The carbon and oxygen contents of Bapung coals as per this
system are plotted in Fig. 8.5 and it is observed that coal is
bituminous.
8.3.4 Williamson’s Classification
Williamson (1957) plotted the percentage of carbon against the
calorific value in B.Th.U/lb in dry ash free basis to have a coal
classification.
It is observed that the plots of Bapung coal in this system falls
in the bituminous type and thereby confirming the bituminous nature
of the Eocene coals (Fig. 8.6).
8.3.5 Classification by International Geological Congress
In the classification proposed by International Geological
Congress letters are substituted for names (Table 8.10).
The
parameters used are V.M., fuel ratio, calorific value and carbon. In a
general way the classification conforms to the nomenclature used in
America as follows :
129
Chapter 8
Ai = Anthracite coal
A2 = Semi-anthracite coal ■
B1 = Anthracite coal and high carbon bituminous coal
B2 = Bituminous coal
The classification of Bapung coals as per IGC system is given
in Table 8.11. It is observed that all the samples of Bapung belong to
B2 type (bituminous).
8.3.6 Basic curves by Francis
On the basis of carbon, hydrogen and oxygen contents of coal,
Francis (1961) has drawn basic curves for the Humic coal series from
Peat to Graphite.
The
data
of
these
elements
of
Bapung
coals
are
plotted on These curves and observed them to be of bituminous type
(Fig. 8.7).
8.4
PETROGRAPHIC CLASSIFICATION
8.4.T Classification based on vitrinite
An attempt has been made by Sen (1978) to classify and codify
Indian coals on the basis of petrographic analysis. Vitrinite has been
chosen as the most important parameter for classification as
proposed in Table 8.12. Here coals have been divided into a number
of coal types such as per-vitrinous, meta-vitrinous, ortho-vitrinous,
para-vitrinous and sub-vitrinous according to decreasing proportion of
vitrinite content (in visible mineral matter free basis) of coals. For the
Chapter 8
130
purpose of codification the coal types have further been divided into
groups as shown in Table 8,12.
The vitrinite content of Bapung coal varies from 76.9 to 87.26%.
On
the
basis
of
vitrinite
percentage
Bapung
coal
ranges
from per-vitrinous (B) to meta-vitrinous (A) types and average
vitrinite percentage (82.15%) falls in the meta-vitrinous (A) type
(Table 8.13).
8.4.2 Classification based on exlnlte
Sen has also classified the Indian coals on the basis of exinite
content.
Coals have been grouped into eight genera with
corresponding group numbers according to exinite content (volume %
on the basis of VMMF basis) as shown in Table 8.14.
Exinite content of Bapung coal varies from 1.25 to 4.46% in
visible mineral matter free basis with an average of 2.26%. On the
basis of exinite per cent, Bapung coal falls in sub-exinous to paraexinous genea and the average content falls in the sub-exinous
genera (Table 8.15).
8.4.3 Classification based on reflectance and volatile matter
(rank)
Rank is of paramount importance in deciding the chemical,
physical and technological properties of coal. In some classifications
in addition to maceral composition,
rank is also taken into
131
Chapter 8
consideration. This may be achieved by considering the reflectance
of vitrinite.
Mean maximum reflectance (in oil) of vitrinite is
recommended for this purpose. Reflectance values of vitrinite have
been divided into reflectance numbers and group numbers based on
carbonisation properties as deduced from correlation of volatile matter
per cent and carbon per cent with maximum reflectance per cent. The
span of bituminous range has been divided between reflectance of
0.51% (volatile matter approximately 40-50%) and reflectance 2.1%
(volatile matter 13%). The entire range of bituminous coal has been
divided into 5 groups each having equal range of reflectance of 0.30%,
except the last one which has a span of 0.40%. In this classification
provision has been made for placing anthracite and low rank coals.
— The scheme of this classification is given in Table 8.16.
The
volatile matter content (in air dried basis) and
corresponding reflectance value of Bapung coal are given in Table
8.17. From the table it is seen that Bapung coals are non-caking coal
having Group no. 2.
8.5
PETROGRAPHIC CODIFICATION OF BAPUNG COAL
Sen (1978) has employed three different parameters of
petrographic classification for petrographic codification of Indian coal.
When only maceral composition of coals is known, the same
can be expressed by two digital code numbers in which the first digit
relates to coal type (vitrinite %), while the second one denotes the
Chapter 8
132
genus (exinite %). Following two digital code, the Bapung coals are
plotted in Fig. 8.8 and observed that the code for most of the samples
is 71.
Sen (1978) employed the reflectance number of coals as the
third parameter in petrographic codification.
Group members of the three parameters arranged in the
sequence, coal type (vitrinite %), genus (exinite %) and reflectance
number (R0%) are used to form a code number.
Using these three parameters the Bapung coals are codified in
Table 8.18.
Considering the average value, the Bapung coal is
codified as 712.
8.6 SUMMARY OF COAL CLASSIFICATION
The different classifications of Bapung coals are summarised in
abstract form in Table 8.19 for chemical composition and in Table
8.20 for petrographic composition. It is observed from the summary
tables that Bapung coal is of bituminous type, whether it is classified
on the basis of proximate or ultimate composition.
The petrographic composition places the coals to be metavitrinous (A) - Group no. 7 on the basis of vitrinite per cent and subexinous - Group no. 1 on the basis of exinite per cent.
8.7 ORIGIN OF COAL
During the last century there was lengthy controversy as to the
133
Chapter 8
actual mode of accumulation of coal deposits. On the one hand, they
were considered to have accumulated from vegetable matter which
remained more or less in the place of growth as in situ or
autochthonous deposits. Alternatively it was argued that much of the
vegetation had been eroded and redeposited many miles from source
to form drift or allochthonous coals.
The principal evidences relevant to the drift or allochthonous
origin of the coal seams of the Bapung coalfield are enumerated
below:
1. The rocks associated with coal are distinctly sedimentary
and the coal seams directly rest over sandstone and shale,
i.e., coal seams are interstratified with shale and sandstone.
2.
Fire clay or lithomargic clay is absent on the floor of the
coal seams.
3. The repetition of regular sequence of sandstone, shale and
coal seams suggest continuous deposition in a sedimentary
basin.
4.
The coal measures of Bapung area (Lakadong sandstone)
is overlying by Sylhet limestone and this is another
evidence for sedimentary basin.
From the above discussion, it can be concluded that the
present coal seams of the Bapung area are of drift origin. The ash
percentage is very low as compared to the Gondwana coals of India.
This favours the short distance transportation of the vegetable matters.
134
C h a p te r 8
Table 8.1
Fraser’s Classification of Coal
Type
Fuel ratio (FCA/M, unit coal basis)
Anthracite
100-12
Semi-Anthracite
12-8
Semi-bituminous
8-5
Bituminous
5-0
Table 8.2
Bapung coal in Fraser’s classification
Sample No.
Fuel ratio
Type
1
1.32
Bituminous
2
1.40
Bituminous
3
1.31
Bituminous
4
1.28
Bituminous
5
1.14
Bituminous
6
1.15
Bituminous
7
1.21
Bituminous
8
1.39
Bituminous
9
1.25
Bituminous
10
1.13
Bituminous
11
1.38
Bituminous
12
1.24
Bituminous
13
1.20
Bituminous
14
1.29
Bituminous
15
1.42
Bituminous
16
1.42
Bituminous
17
1.28
Bituminous
18
1.29
Bituminous
19
1.19
Bituminous
20
1.10
Bituminous
21
1.22
Bituminous
22
1.14
Bituminous
23
1.26
Bituminous
24
Average
1.22
Bituminous
1.26
Bituminous
135
Chapter 8
Table 8.3
A.S.T.M classification by rank
Limits (VMMF basis)
Class
Anthracite
Group
Volatile
matter%
1. Meta anthracite
98+
2-
2. Anthracite
98-92
2-8
3. Semi anthracite
92-86
8-14
1. Low volatile
86-78
14-22
2. Medium volatile
78-69
22-31
3. High volatile A
69-
31+
Bituminous
Subbituminous
Fixed
carbon%
Moist B.Th.U.
4. High volatile B
14000-13000
5. High volatile C
13000-11000
Sub-bituminous A
11000-13000
Sub-bituminous B
9500-11000
Sub-bituminous C
8300-9500
Lignite
Less than
8300
Less than
8300
Lignite
Brown coal
Requisite
physical
properties
Nonagglomerating
Either
agglomerating
or non
weathering
Both
weathering and
nonagglomerating
Consolidated
Unconsolidated
136
Chapter 8
Table 8.4
Classification of Bapung coal by A.S.T.M system
F.C. %
V.M. %
Sample No.
Class
Group
DMMF basis
1
56.59
42.73
Bituminous
High volatile A
2
58.46
41.90
Eituminous
High volatile A
3
57.08
43.47
Bituminous
High volatile A
4
56.32
44.03
Bituminous
High volatile A
5
53.50
46.99
Bituminous
High volatile A
6
54.13
46.46
Bituminous
High volatile A
7
55.12
45.28
Bituminous
High volatile A
8
58.50
42.12
Bituminous
High volatile A
9
55.91
44.64
Bituminous
High volatile A
10
53.59
47.27
Bituminous
High volatile A
11
58.26
42.37
Bituminous
High volatile A
12
55.69
45.06
Bituminous
High volatile A
13
54.73
45.56
Bituminous
High volatile A
14
56.63
43.74
Bituminous
High volatile A
15
58.90
41.52
Bituminous
High volatile A
16
58.96
41.56
Bituminous
High volatile A
17
56.28
44.29
Bituminous
High volatile A
18
56.64
43.85
Bituminous
High volatile A
19
54.51
45.89
Bituminous
High volatile A
20
52.78
47.82
Bituminous
High volatile A
21
55.19
45.17
Bituminous
High volatile A
22
53.82
47.21
Bituminous
High volatile A
23
56.18
44.56
Bituminous
High volatile A
24
Average
55.34
45.25
Bituminous
High volatile A
Bituminous
High volatile A
55.96
44.53
137
Chapter 8
Table 8.5
Type
General classification
Standard Institute)
Subdivision or
Group
of
Range of
volatile
percentage
at
900°C±15°C
Anthracite
A,
3-10
Semi­
anthracite
a2
10-15
Low volatile
(caking)
Bt
15 to 20
Medium
volatile
b2
20 to 32
b3
32+
&4
32+
Bg
32+
Sub-.
No caking
bituminous Slacking on Be
coals
weathering
32+
Anthracite
Bituminous
coals
(caking
High volatile
strength
(caking)
increasing
from Bs to
B2)
High volatile
(semicaking)
High volatile
(non caking)
Lignites or
brown
coals
Normal
lignite
Li
45 to 55
Canneloid
lignite
1.2
55 to 65
* A = Near saturation at 96% RH at 40°C
* B = Air dried at 60% RH at 40°C
Indian
coals
Range of
calorific
value
Kcal/kg
(B.Th.U/lb)
(unit coal
basis)
8330 to
8670
(15000 to
15600)
8440 to
8780
(15200 to
15800)
8670 to
8890
(15600 to
16000)
8440 to
8780
(15200 to
15800)
8280 to
8610
(14900 to
15500)
8060 to
8440
(14500 to
15200)
7500 to
8060
(13500 to
14500)
3940 to
7500
(12500 to
13500)
6100 to
6940
(11000 to
12500)
6940 to
7500
(12500 to
13500)
(Indian
Range of
moisture
percentage
(mineral free
basis)
*A
*B
1 to
2 to 4 3
1.5 to 1 to
3.0
2
0.5
1.5 to to
2.5
1.5
0.5
1.5 to to
2.5
2.0
5 to 1 to
10
3
10 to 3 to
20
7
20 to 10 to
30
20
30 to 10 to
70
25
30 to 10 to
25
70
138
Chapter 8
Table 8.6
Sample
No.
Bapurtg coal in general classification of Indian coal
Volatile
matter %
Calorific
value
(B.Th.U/lb)
Type
Name
Group
symbol
in DMMF basis
1
42.73
14044.32
Bituminous
2
41.90
14360.61
Bituminous
3
43.47
14215.21
Bituminous
4
44.03
14019.12
Bituminous
5
46.99
13648.17
Bituminous
6
46.46
13759.92
Bituminous
7
45.28
13840.99
Bituminous
8
42.12
14396.61
Bituminous
9
44.64
13876.95
Bituminous
10
47.27
13695.73
Bituminous
11
42.37
14319.12
Bituminous
12
45.06
13987.40
Bituminous
13
45.56
13818.70
Bituminous
14
43.74
14106.02
Bituminous
15
41.52
14597.78
Bituminous
16
41.56
14612.32
Bituminous
17
44.29
13967.19
Bituminous
18
43.85
14121.95
Bituminous
19
45.89
13993.02
Bituminous
20
47.82
13471.34
Bituminous
21
45.17
13837.46
Bituminous
22
47.21
13807.31
Bituminous
23
44.56
13906.73
Bituminous
24
45.25
13869.68
Bituminous
Average
44.53
14007.65
Bituminous
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(semi-caking)
Highly volatile
(semi-caking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Non-caking,
slacking on
weathering
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
Highly volatile
(noncaking)
b
5
b
5
b
5
b6
b5
B5
b5
Bs
b
5
b5
Bs
Bs
Bs
Bs
b
4
Ba
Bs
Bs
Bs
Bs
B5
Bs
Bs
Bs
Bs
i
■
Semianthracitic
species
Orthoanthracite
Anthracitic
genus
Hydrogen
<4%
*
Carbonaceous
Hydrogen 4.04.5%
PseudoMetabituminous
bituminous
sp ec ies
Sem i; Subbituminous
bituminous
sp ecies
(sub-m eta(ortho-semi; bituminous)
bituminous)
i
......
C arbonaceous Pseudosp ecies
carbonaceous
(sub-m eta(orthocarbonaceous) bituminous)
Pseudo­
Pseudoanthracite
antracite
(sub(sub-m etacarbonaceous) bituminous)
Carbon %
91.2-89.0
Perbituminous
(per-metabituminous)
Carbon %
93.3-91.2
i
Pseudocarbonaceous
(sub-parabituminous)
Pseudo­
anthracite
(sub-parabituminous)
j
Carbon %
80-75
Ortho-
Meta
Per-iignitous
Carbon %
84-80
Meta
1
.Q
3
CO
i
Parabituminous
L____ __ _ __
Subbituminous
(sub-parai bituminous)
Carbon %
87.0-84.0
Perbituminous
(per-parabituminous)
Meta-
Ortho
Ortho
to
zs
o
•*«*
'c
Pseudocarbonaceous
(sub-orthobituminous)
Pseudo­
anthracite
(sub-orthobituminous)
Subbituminous
(sub-orthobituminous)
Orthobituminous
Carbon %
89.0-87.0
Perbituminous
(per-orthobituminous)
Para-
CO
O
c
CD
Li
Semibituminous
Hydrogen 4.55.0%
Perbituminous
Hydrogen
>
5.8%
Bituminous,
Hydrogen 5.05.8%
0)
Carbon over
93,3%
S
Genera
Ortho-
Lignitous
|
r
C arbonaceous
i
t e
Bituminous
p
Anthracite
a
S p e c ie s
Seyler’s Classification of coal (dry mineral matter free basis)
h
i
Table 8.7
C
8
139
140
Chapter 8
Table 8.8
Mott’s classification of coal
Group limits
Class
Anthracite
Bituminous
(Agglomeratic)
Transitional
.Group
Lignite
Peat
Group
Volatile matter %
(in DMMF basis)
Anthracite
Semi-anthracite
Low volatile
Bituminous
Medium volatile
Bituminous
High volatile
Bituminous
2-8
8-14
Calorific value
(B.Th.U/lb in
VMMF basis)
14750-15750
16000-15500
14-20
16000-15500
20-31
16000-15500
31-47
15750-14000
38-47
14000-13500
47-56
14000-13500
Lignitic
Per-hydrous
lignitic
Lignite
Per-hydrous
lignite
Super-hydrous
lignite
Per-hydrous peat
Super-hydrous
peat
38-47
47-56
13500-10000
56-75
65-75
75-85
11000-85000
141
C h a p te r 8
Table 8.9
Bapung coal in Mott’s classification
Calorific
value
(B.Th.U/lb)
in DMMF basis
Sample
No.
Volatile matter %
1
42.73
14044.32.
Bituminous
2
41.90
14360.61
Bituminous
3
43.47
14215.21
Bituminous
4
44.03
14019.12
Bituminous
High volatile
Bituminous
High volatile
Bituminous
High volatile
Bituminous
Lignitic
5
46.99
13648.17
Transitional
Lignitic
6
46.46
13759.92
Transitional
Lignitic
7
45.28
13840.99
Transitional
8
42.12
14396.61
Bituminous
9
44.64
13876.95
Transitional
Lignitic
High volatile
Bituminous
Lignitic
10
47.27
13695.73
Transitional
Lignitic
11
42.37
14319.12
Bituminous
High volatile
Bituminous
12
45.06
13987.40
Transitional
Lignitic
13
45.56
13818.70
Transitional
14
43.74
14106.02
Bituminous
15
41.52
14597.78
Bituminous
16
41.56
14612.32
Bituminous
17
44.29
13967.19
Transitional
18
43.85
14121.95
Bituminous
19
45.89
13993.02
Transitional
Lignitic
High volatile
Bituminous
High volatile
Bituminous
High volatile
Bituminous
Lignitic
High volatile
Bituminous
Lignitic
20
47.82
13471.34
Transitional
Lignitic
21
45.17
13837.46
Transitional
Lignitic
22
47.21
13807.31
Transitional
Lignitic
23
44.56
13906.73
Transitional
Lignitic
24
Average
45.25
13869.68
Transitional
Lignitic
44.53
14007.65
Transitional
Lignitic
Class
Group
Chapter 8
142
Table 8.10 Classification of coal by International Geological
Congress
C.V.
B.Th.U/lb
DMMF basis
Carbon%
V.M.%
Fuel Ratio
A,
3-5
Over 12
14500-15000
93-95
A2
7-12
7-12
15000-15500
90-93
Bi
12-15
4-7
15200-16000
80-90
b2
12-26
1.2-7
14000-16000
75-90
Type
Table 8.11 Classification of Bapung
Geological Congress
Sample
No.
V.M.%
Fuel Ratio
1
42.73
1.32
2
41.90
3
coal
C.V.
B.Th.U/lb
DMMF basis
by
International
Carbon%
Type
14044.32
77.06
b2
1.40
14360.61
74.30
b2
43.47
1.31
14215.21
79.15
Ba
8
42.12
1.39
14396.61
78.32
b2
9
44.64
1.25
13876.95
76.58
b2
10
47.27
1.13
13695.73
78.13
b2
11
42.37
1.38
14319.12
79.65
b2
12
45.06
1.24
13987.40
76.63
b2
13
45.56
1.20
13818.70
76.85
b2
17
44.29
1.28
13967.19
74.68
b2
18
43.85
1.29
14121.95
75.74
b2
19
45.89
1.19
13993.02
78.47
b2
24
45.25
1.22
13869.68
76.39
Average
44.18
1.28
14044.35
77.07
Ba
Ba
143
Chapter 8
Table 8.12 Classification of coal based on vitrinite per cent
(V.M.M.F. basis)
Coal types
Vitrinite (% volume in
visible mineral matter
free basis)
Group No.
Per-vitrinous (A)
More than 95
9
Per-vitrinous (B)
95-85.1
8
Meta-vitrinous (A)
85.0-75.1
7
Meta-vitrinous (B)
75.0-65.1
6
Ortho-vitrinous (A)
65.0-55.1
5
Ortho-vitrinous (B)
55.0-45.1
4
Para-vitrinous (A)
45.0-35.1
3
Para-vitrinous (B)
35.0-25.1
2
Sub-vitrinous (A)
25.0-15.1
1
Sub-vitrinous (B)
15.0-5.1
0
144
Chapter 8
Table 8.13 Bapung coal
vitrinite
classified according to percentage of
Sample
No.
Vitrinite %
(V.M.M.F. basis)
Coal types
Group No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Average
87.26
82.80
84.79
79.99
81.51
86.11
79.25
84.73
84.53
84.84
83.16
83.09
84.11
82.11
83.33
77.86
80.72
84.27
76.90
81.47
80.71
77.14
80.77
80.26
Per-vitrinous (B)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Per-vitrinous (B)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
Meta-vitrinous (A)
8
7
7
7
7
8
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
82.15
Meta-vitrinous (A)
7
145
C h a p te r 8
Table 8.14 Classification of coal based on exinite per cent
(V.M.M.F. basis)
G e n e ra
E x in ite (V o lu m e % in
V .M .M .F . b a s is )
G ro u p No.
N o n -e x in o u s
0 -0 .9
0
S u b -e x in o u s
1 .0 -2 .5
1
P a ra -e x in o u s
2 .6 -5 .0
2
O rth o -e x in o u s (A )
5 .1 -1 0 .0
3
O rth o -e x in o u s (B )
1 0 .1 -1 5 .0
4
P e r-e x in o u s (A )
1 5 .1 -2 0 .0
5
P e r-e x in o u s (B )
2 0 .1 -2 5 .0
6
P e r-e x in o u s ( C )
M o re tha n 2 5 .0
7
146
Chapter 8
Table 8.1S Bapung coal classified according to exinite content
Sample No.
Exinite %
(V.M.M.F. basis)
Genera
Group No.
1
2
3
3.47
1.61
Para-exinous
Sub-exinous
2
1
3.13
Para-exinous
2
4
1.31
Sub-exinous
1
5
1.34
Sub-exinous
1
6
7
2.25
2.05
Sub-exinous
Sub-exinous
1
1
8
1.76
Sub-exinous
1
9
1.29
Sub-exinous
1
10
11
2.31
Sub-exinous
2.33
Sub-exinous
1
1
12
1.25
Sub-exinous
13
14
1.29
1.41
Sub-exinous
Sub-exinous
1
15
2.19
Sub-exinous
1
16
3.29
Para-exinous
2
17
1.62
Sub-exinous
1
18
19
1.89
4.46
Sub-exinous
Para-exinous
1
2
20
2.59
Sub-exinous
1
21
22
23
24
1.70
3.77
2.16
3.87
Sub-exinous
Para-exinous
Sub-exinous
Para-exinous
1
2
1
2
2.26
Sub-exinous
1
Average
~
1
1
147
C hapter 8
Table 8.16 Classification of coal
volatile matter
based
on
reflectance
Approximate
range of
volatile
matter % of
vitrain
Remarks
More than 50
Scanty data
Reflectance
No.
Range of
reflectance
R0 max%
0
0
1
Less than
0.20
0.20-0.50
2
0.51-0.80
2
50-42
3
0.81-1.10
3
42-32
4
1.11-1.40
4
32-24
5
1.41-1.70
5
24-18
6
1.71-2.10
6
18-13
7
2.11-2.50
7
13-8
8
2.51-3.00
More than
3.00
8
8-5
9
Less than 5
9
Group No.
and
1
Mainly non­
caking
Caking
property
increases
from 0.81 to
1.10
Strongly
caking (high
volatile)
Strongly
caking (low
volatile)
Caking
property
diminishes
form 1.71 to
2.10
Semi­
anthracite
mainly
Anthracite
Meta­
anthracite
148
C h a p te rs
Table 8.17 Classification of Bapung coal based on reflectance
and volatile matter
Sample
No.
Vitrinite
reflectance Reflectance Group
No.
No.
(max %)
Volatile
matter %
Types
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
Mainly
non-caking
1
0.66
2
2
42.15
2
0.62
2
2
40.25
3
0.58
2
2
41.20
8
0.67
2
2
40.10
9
0.59
2
2
42.75
10
0.61
2
2
44.10
11
0.65
2
2
40.25
12
0.63
2
2
42.35
13
0.57
2
2
44.20
14
0.64
2
2
42.23
15
0.56
2
2
40.02
16
0.66
2
2
40.02
0.58
2
2
45.25
21
0.50
1
1
43.07
22
0.55
2
2
44.25
Average
0.60
2
2
42.15
20
'
149
Chapter 8
Table 8.18 Petrographic codification of Bapung coal
Sample No.
Vitrinite %
with Group
No.
Exinite %
with Group
No.
Reflectance
with Group
No.
Code
1
87.26(8)
3.47 (2)
0.66(2)
822
2
82.80(7)
1.61(1)
0.62(2)
712
3
84.79(7)
3.13(2)
0.58(2)
722
8
84.73(7)
1.76(1)
0.67(2)
712
9
84.53(7)
1.29(1)
0.59(2)
712
10
84.84(7)
2.31(1)
0.61(2)
712
11
83.16(7)
2.33(1)
0.65(2)
712
12
83.09(7)
1.25(1)
0.63(2)
712
13
84.11(7)
1.29(1)
0.57(2)
712
14
82.11(7)
1.41(1)
0.64(2)
712
15
83.33(7)
2.19(1)
0.56(2)
712
16
77.86(7)
3.29(2)
0.66(2)
722
20
81.47(7)
2.59(1)
0.58(2)
712
21
80.71(7)
1.70(1)
0.50(1)
711
22
77.14(7)
3.77(2)
0.55(2)
722
Average
82.80(7)
2.23 (1)
0.60(2)
712
150
Chapter 8
Table 8.19 Summary of coal classification based on chemical
analyses of coal
System or
author
Parr
Fraser
A.S.T.M.
I.S.I
Seyler
Mott
Hickling
Williamson
I.G.C.
Francis
Classification of
Bapung coal
Parameters
Volatile matter and calorific
value
Fuel ratio
Fixed carbon, volatile matter
and calorific value
Volatile mater and calorific
value
Carbon and hydrogen
Volatile matter and calorific
value
Carbon and oxygen
Carbon and calorific value
Volatile matter, fuel ratio,
calorific value and carbon
Carbon, hydrogen and oxygen
Black lignites
Bituminous coal
Bituminous - High
volatile A
Bituminous (high
volatile, non-caking)
Ortho-lignitous
Lignitic transitional
group
Bituminous
Bituminous
Bituminous
Bituminous
Table 8.20 Summary
of
coal
classification
petrographic analyses of coal
Author
Parameters
Type
based
on
Group No.
Sen
Vitrinite
Meta-vitrinous (A)
7
Sen
Exinite
Sub-exinous
1
Sen
Vitrinite reflectance Non-caking
and volatile matter
2
151
Chapter 8
aO
Calorific value in DMMF basis
(B.Th.U/lb)
- -------- -—s----Anthracite;
aO
1
i
|
1
iOt
Semianthracite
i Canal coal
Eastern type of
bituminous
•
Sem ibituminous
Western type of
A . bituminous
.... - ..............
.
•
Black lignites
-
io
O
uO
j
Brown lignites
---------------- 1--
0
10
~1--------------~1--------------- --------------- 1---------------
20
30
40
50
Volatile matter % (DMMF basis)
Calorific value (B.Th.U/ib in
Fig. 8.1 Plots of Bapung Coal in Parr's Classification
60
152
Chapters
-J
Lignitous
Meta
o>
Ortho
%
Bituminous
•
.
•
•* .
••
*
o<
•
.
Semi-Anthracite
Anthracite
t
o
w
Hydrogen %
(in dry mineral matter free basis)
Carbonaceous
100
95
90
85
80
75
Carbon % (in dry mineral matter free basis)
F ig . 8.3 B apung coal in S e y le fs coal band
70
153
§ 3
S
S &
Volatile matter % (DMMF basis]
§
S
Chapter 8
17000
16000
15000
________________
14000
13000
12000
11000
10000
9000
Calorific vaIue(B.Th.U/Ib,DMMF basis)
Fig. 8.4 Plots of Bapung Coal in Mott's coal band
8000
154
Lignite
Sub-bituminous
*
•
•
Bituminous
*
*
*
•
•
Anthracite
Carbon % (unit coal basis)
Fig. 8.5 Plots of Bapung Coal in Hickling's
classification
o
80
O
70
co
o
Oxygen % (unit coal basis)
C ha p te r 8
Chapter 8
Calorific value in DAF basis (B.Th.U/lb)
155
!
50.00
60.00
70.00
80.00
90.00
Carbon % (DAF basis)
Fig. 8.6 Plots of Bapung coal in Williamson's
diagram
100.00
156
Oxygen (per cent)
Hydrogen (per cent)
Carbon (per cent)
Chapter 8
Figure 8.7
Plots of Bapung coal in basic curves of Humic coal
Chapter 8
''C o a l
157
P e r -v i t r i n o u s
\ ly p e s
A
G e n e ra \
B
B
A
8
9
O rth o -
M e t a -v i t r i n o u s
7
A
6
P a r a -v i t n n o u s
v it r in o u s
B
5
A
4
B
3
S u b -v itr in o u s
B
A
2
1
Non­
e x in o u s
■
0
Sube x in o u s
•» *
, * »•
1
P a ra e x in o u s
*
• *#
2
O rth o e x in o u s
3
A
O rth o e x ln o u s
4
B
P e re x in o u s
5
A
P e re x in o u s
6
B
P e re x in o u s
7
C
Fig. 8.8
Codification of Bapung Coal on the basis of vitrinite
and exinite per cent
6