18 Petrographic Investigation of Two Gondwana Seams from Madhya Pradesh, India Downloaded via UNIV OF CALIFORNIA SANTA BARBARA on July 17, 2018 at 21:01:15 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
S. K. BABU and RUSSELL R. DUTCHER Department of Geology and Geophysics, The Pennsylvania State University, University Park, Pa. The basic petrographic composition of two seams of Gondwana age, collected from Chirmiri Colliery, Central India, has been determined. The petrographic work was undertaken to delimit petrography, to allow comparison with coals from the United States, Africa, and Australia, and to apply the information gained to future studies of other Indian coals. The two seams from India of Gondwana age vary considerably in their petrography, chemistry, and physical properties from many of the coals of the United States.
Further, the two
seams are characterized by macerals of varying types and by a high "inert" content, both of which point to the heterogeneity of organic debris forming the macerals and to changes in environment during the formation of the coal swamp consistent with the "Drift" theory of origin for Gondwana coals. Jhe two seams, namely Seam N o . 2 and Seam X o . 4, of Gondwana age collected from C h i r m i r i Colliery, Central India, were studied to ascertain their basic pétrographie composition, chemical variation, and other physical properties i n order that the information gained from these studies might be applied to future studies of Indian coals. There is no significant pétrographie data available for these specific coals. T h e study of these two seams was sponsored by the Fulbright-Smith F u n d grants for a period of nine months. T h e studies were carried out at the Organic Sediments Laboratory, Department of Geology and Geophysics, T h e Pennsylvania State University. General
Geology
The two seams are located along L o n g . 82° 24' and L a t . 23° 13' at the town of C h i r m i r i i n Central India. It lies east of the Hasdo River i n Korea 284 Given; Coal Science Advances in Chemistry; American Chemical Society: Washington, DC, 1966.
18.
Β ABU AND
DUTCHER
Gondwana Seams
285
State and covers 48 square miles of hilly country. Fermor (6) has recognized two colliery; he treated the field in two sections. That to the east of the road, southward from Kurasia to Dabchola, he named the Kurasia area while that to the west he termed the C h i r m i r i area. The coal bearing beds are known as "Barakars," of lower Permian age of the Gondwana formations. These Barakars are completely isolated and almost entirely surrounded by Talchairs ( U p p e r Carboniferous) on which they lie almost horizontally. T o the north of these coal fields near Chitajohr there is a belt of dolerite and basalt which overlies both Talchairs and Barakars. This igneous rock is of Deccan trap age, and there seems to be little doubt that in this region it is all of intrusive character. As regards the C h i r m i r i areas from where the two seams have been col lected, Fermor (6) considered the most important exposure as that at the waterfall known as Karar Khoh in the Korea nala, where 36 feet of coal i n seven beds occur in 48 feet of strata. The coal seams are underlain and over lain by coarse to medium grained sandstones and black carbonaceous shales. Seam 2 is at the top of the section while Seam 4 is below. The two seams are separated by 40 feet. Seam 2 is 4 feet thick, while Seam 4 is actually 12 feet thick, but in the mines the mined portion is only 6 feet thick. Pillar columns were collected from these two seams for the present investigation; they form the subject matter of this paper. Techniques and Importance
of Study
T h e studies carried out consist of the megascopic description of the master columns study of thin sections for maceral assessment, determination of maceral composition on polished blocks in reflected light, determination of mean maxi mum reflectance values on polished pellets, proximate analyses of selected pétrographie zones, hot stage studies on vitrinoids to determine the thermal behavior at various temperatures, electron microprobe and spectroehemical studies of selected zones to determine the nature of ash forming elements, analyses of certain zones petrographically important to determine the variation of total carbon, and hydrogen and microhardness determinations on certain macérais. E m p l o y i n g various research techniques, we undertook the pétrographie work on these two seams to delimit their petrography, to compare w i t h coals from the United States, Africa, and Australia, and to apply the information gained to future studies of other Indian coals. W e also wished to explore the possibilities of better industrial exploitation from the pétrographie information. Finally, we hoped that the results would contribute to the basic knowledge of Gondwana coals and the problems associated with the origins of these deposits. Chemistry
of the Seams
A l l the samples were air-dried before analyses. Chemical analyses were conducted according to standard techniques; in the case of total carbon and hydrogen, the samples were sent to E n g l a n d for analysis. T h e average values for the chemical analyses for both the seams are presented in Tables I and II.
Given; Coal Science Advances in Chemistry; American Chemical Society: Washington, DC, 1966.
286
C O M SCIENCE
Table I.
Average Values Obtained from Duplicate Microchemical Analysis Fixed Carbon
Volatiles
Ash Content
Moisture
Sulfur
Hydrogen
Total Carbor
Seam No. 4 % 1. 53.43 2 50.84 3. 47.88 4. 51.73 5. 53.46 6. 51.50 7. 56.83 8. 54.98 9. 59.03 10. 60.73 11. 49.99 12. 54.20 13. 54.30 14. 55.42 15. 52.69 16. 57.32 17. 54.61 18. 53.24 19. 52.95 20. 51.00 21. 45.58 22. 49.34 23. 51.65 24. .58.73 25. 54.18
% 31.52 29.60 41.40 26.80 28.80 24.80 31.04 24.80 29.20 28.00 26.00 32.40 28.20 30.40 29.80 33.20 26.80 30.00 28.92 29.60 35.20 35.20 37.40 26.80 30..56
% 12.68 17.60 8.60 18.96 15.60 17.60 10.00 14.00 9.20 8.80 14.00 11.00 15.40 11.80 15.40 7.40 17.32 14.48 15.68 17.40 17.64 13.32 9.24 12.76 13.60
% 2.37 1.96 2.12 2.51 2.14 6.02 2.13 6.22 2.57 2.47 10.01 2.40 2.10 2.38 2.11 2.08 1.27 2.28 2.45 2.00 1.58 2.14 1.70 1.71 1.66
% 0.24 0.48 0.36 0.40 0.28 0.24 0.04 0.08 0.20 0.20 0.20 0.20 0.20 0.28 0.26 0.26 0.44 0.24 0.20 0.28 0.48 0.60 0.60 2.68 0.48
% 4.19 3.83 5.15 3.57 3.89 3.50 3.95 3.49 4.04 3.92 3.96 4.08 3.46 3.91 3.76 4.05 3.49 3.79 3.60 3.78 3.72 4.04 4.45 4.15 3.99
70.92 63.34 73.92 62.33 69.77 64.58 71.77 68.86 73.05 72.04 68.46 74.18 66.22 69.83 66.80 73.75 64.60 66.53 66.52 62.71 62.09 69.17 71.54 67.04 67.97
Seam No. 2 % 1. 48.88 2. 47.92 3. 48.30 4. 51.53 5. 44.87 6. 46.78 7. 38.49 8. 44.50 9. 45.81 10. 47.12 11. 45.77 12. 48.08 13. 48.98 14. 47.05 15. 47.97
% 36.96 37.96 36.76 34.88 36.36 37.00 35.16 39.32 40.16 37.40 39.96 36.08 37.00 41.08 41.04
% 11.48 10.32 10.60 10.52 11.88 10.84 16.88 12.40 10.00 11.40 10.00 12.44 11.84 9.80 8.04
% 2.68 3.80 4.34 3.07 6.89 5.38 9.47 3.78 4.03 4.08 4.27 3.40 2.18 2.07 2.95
% 0.63 0.52 0.75 0.52 1.70 0.58 0.72 0.75 0.64 0.48 0.52 0.44 0.46 0.62 0.51
% 4.29 4.48 4.33 4.04 4.09 4.36 3.97 4.40 4.63 4.36 4.31 4.25 4.28 4.13 4.21
% 66.10 67.38 67.35 67.80 63.83 66.98 62.27 65.26 66.94 66.94 67.44 66.49 66.96 65.28 66.56
Zone No.
%
T o t a l C a r b o n . T h e total carbon i n Seam 4 varied between 62.09 and 7 4 . 1 8 % , while i n Seam 2 it varied between 62.27 and 6 7 . 8 0 % . T h e total carbon presented i n Table I is not on an ash-free basis, but on a moisture-free basis. T h e total carbon does not vary widely i n either of the seams. However, it appears to vary more i n Seam 4 than i n Seam 2. Volatile. T h e volatile percentages range from 24.80 to 4 1 . 4 0 % i n Seam 4, and from 34.88 to 4 1 . 0 8 % i n Seam 2. According to the volatile percentage proposed by Moore ( 1 2 ) , these coals fall under the category of medium to high volatile coals, Seam 2 being distinctly i n the high volatile range. These two coals are poorly coking as evidenced from the character of the residue left after volatile determinations.
Given; Coal Science Advances in Chemistry; American Chemical Society: Washington, DC, 1966.
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Ash Content. T h e ash percentages vary from 8.6 to 18.9% i n Seam 4 and from 8.04 to 16.88% i n Seam 2, the average ash content being 13.21% for the two seams. T h e ash content is relatively more i n Seam 4 than i n Seam 2. T h e ash colors vary from ash-gray and bluish-gray to brown a n d chocolate brown. Sulfur. These coals are generally low i n sulfur and seldom exceed more than 1.5%. T h e sulfur percentage varies from 0.04 to 2.68% i n Seam 4 a n d from 0.44 to 1.70% i n Seam 2. T h e high percentage values—namely, 2.68 a n d 1.70%—are confined to one zone of each seam where megascopically recog nizable pyrite grains are present. Table II.
Average Values Obtained from Duplicate Microchemical Analysis on daf Basis
Zone No.
Carbon
Volatiles
Seam No. 4 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
% 62.89 63.20 53.63 65.90 64.99 67.43 64.68 68.92 66.91 68.44 65.78 62.59 65.82 64.58 63.88 63.32 67.08 63.96 64.67 63.28 56.42 58.36 58.01 68.66 63.94
% 37.11 36.80 46.37 34.10 35.01 32.57 35.32 31.08 33.09 31.56 34.22 37.41 34.18 35.42 36.12 36.68 32.92 36.04 35.33 36.72 43.58 41.64 41.99 31.34 36.06
Seam No. 2 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
56.94 55.80 56.78 59.63 55.24 55.84 53.26 53.09 53.29 55.75 53.39 57.13 56.97 53.39 53.89
43.06 44.20 43.22 40.37 44.76 44.16 46.74 46.91 46.71 44.25 46.61 42.87 43.03 46.61 46.11
Total Carbon
Hydrogen
0.28 0.60 0.40 0.51 0.34 0.31 0.05 0.10 0.23 0.22 0.26 0.23 0.24 0.33 0.31 0.29 0.54 0.29 0.24 0.35 0.59 0.71 0.67 3.13 0.57
A 83.48 78.74 82.79 79.37 84.82 84.55 81.68 86.31 82.79 81.19 90.09 85.66 80.27 81.37 80.98 81.47 79.35 79.92 81.25 77.80 76.86 81.82 80.33 78.38 80.21
7c 4.63 4.49 5.51 4.19 4.42 3.68 4.22 3.52 4.26 4.11 3.75 4.41 3.91 4.25 4.28 4.22 4.11 4.25 4.07 4.42 4.39 4.49 4.78 4.63 4.50
0.73 0.60 0.88 0.60 2.09 0.69 0.95 0.89 0.74 0.56 0.61 0.52 0.53 0.70 0.57
77.00 78.46 79.18 78.46 78.58 79.95 82.31 77.86 77.86 79.20 78.66 79.00 77.88 74.07 74.78
4.76 4.73 4.53 4.40 4.10 4.49 3.86 4.75 4.86 4.63 4.48 4.60 4.70 4.42 4.36
Sulfur
