COMPOSITION OF INDIAN COAL 



COAL 



Properties 



4-35; Unit.Ml Kingdom 4-42; Victoria 4'44 ; Imliu l< ins- 



il 14-47 ; New South Wales 17'67 ; Cape Colony L'4 li ; Xat.-il i'; 99 ; 

 Hritish ('olumhiii ( . ( J'48. India is thus by no mean* the country in 

 British Kinpiiv tliat shows the worst result. 



The almost universal practice in Indian coal-mines is to extract the indun 

 il on the system variously known as the " bord and pillar," " post and 



or "stoop and room" system. Although this system in Europe 

 fast being superseded by the more economical " long-wall " method, 

 ii.u' to the thickness of most of the Indian seams, it is not easy 

 It-vise any more suitable plan of working. It is undoubtedly wasteful, 

 the pillars form from 25 to 65 per cent, of the available coal, and at the 

 t time except in certain mines, where local-trained labour and efficient 

 supervision are possible, their extraction is not even contemplated." 



Holland points out that the strong roof in the Gondwana rocks, the 

 freedom from disturbances, and the comparative lightness of the over- 

 len are features of strength and safety not fully appreciated by those 

 10 have gained their experience in countries where these advantages do 

 jt prevail. In the Giridih coalfield the system of working thick seams 

 ;re pursued, which is a modification of the South Staffordshire method Mr. w*rd's 

 Bested by Mr. T. H. Ward, allows of 90 per cent, of the coal being 5 

 loved. Adamson (Trans. Min. and, Meek. Engin., 1903, lii., 202) has 

 scribed fully the " working of a thick coal-seam in Bengal." " In 

 le Makum field a highly inclined seam, 75 feet thick, is worked also 

 a modification of the South Staffordshire system of 'square work.' 

 ic coal is removed in two, or sometimes three sections, the top section 

 ig removed first, and a parting of stone and coal being left untouched 

 stween each pair of sections. In the Dandot and Khost mines, thin seams 

 worked in one operation, on a modified ' long-wall ' system." 



PROPERTIES AND USES. It is difficult, if not impossible, to give a Properties. 

 Bneral statement of the properties of Indian coal : the two great geological 

 jups already established differ in almost every essential, and, moreover, 

 le coal varies not only between mines within the same formation but 

 ren within the seams of one and the same mine. Averages are therefore 



an very misleading. The late Mr. H. B. Medlicott accordingly very D.E.P., 

 ;htly observed, " In both regions the quality of the coal varies much, " *79. 

 in all coal- measures ; but the best in both reaches a very high standard, 

 lost if not quite up to that of high-class English coals. In the Gond- 

 ina (Bengal) coal the general defect is an excess of ash, and also in some Excess of ASU 

 excess of moisture ; while in the Tertiary (Assam) coal the percentage 

 ash is low, but that of the volatile combustible matter high, producing 

 lighter fuel." Medlicott then furnished a table to show the results 

 various chemical examinations, and, as little of material importance has 

 ice been learned, it may be here reproduced : 



339 



