58 MALLET : COAL-FIELDS OF THE nXgI HILLS. 



struck by boring through the alluvium at short distances from the 

 foot of the hills,* and there is no assignable reason why the Jaipur 

 measures should, as a whole^ be inferior to those of the other fields, as to 

 either the total thickness or the quality of the contained coal. But the 

 unknown depth of the alluvium leaves it problematical whether coal 

 could be profitably raised from beneath it, this being a point that can 

 only be settled by boring. 



The data, then, on which to form an estimate of the total quantity 

 of available coal are insufficient, although it may be safely said that there 

 is a large quantity. The known seams in the northern part of the field 

 include the following thicknesses of coal :— 



Ft. In. 



At Tipam tea garden (4' 10" + 4' 7") ,.. .. 9 5 



„ Dihing river ,•, .. ... .. 10 



„ Hukanjnri path ... ... ... ... 9 



but only the very top of the measures is visible. In the nallas half-way 

 between the last locality and the Disang no useful seams were exposed ; 

 this, however, cannot be taken as proof of their absence. In the fullest 

 section obtainable — that in the Disang itself — 30 feet of workable coal is 

 known to exist; but even here part (and, judging from the thickness 

 exposed in other fields, the greater part) of the measures is obscured. 

 In the imperfect section at Boruarehali 9 feet of available coal is known. 

 The above figures give an average known thickness of 13 feet 6 inches : 

 taking the above considerations into account, therefore, it is certainly 

 not extravagant to estimate the mean available thickness at five yards. 

 As the measures, however, only occur along the skirts of the hills, they 

 seldom or never rise to any considerable elevation above the plain, and 

 the greater portion of the accessible coal is therefore below the alluvium 

 level, and could only be mined towards the deep or by vertical pits. 

 Taking this into account, together with the high dips often met with, 



* The testing of such highly inclined measures would, of course, require a larger 

 numher of horeholes than would he necessary in strata more nearly horizontal. 

 ( 326 ) 



