DCTAILED DESCRTPTFONS OF TFIE RESPECTIVE COALFIELDvS. 
part of the measures is visible at tlie surface, the remainder being 
sunk beneath the alhivium of tlie phiins. 
The thickest section of the rocks is to be seen in the Disanj^ 
river where a thickness of 45 feet of workable coal in six seams 
has been measured. Mallet ^ estimated that between Tipam and 
Boruarchali (a distance of 15 miles) within 450 feet of the out- 
crops of the seams, and allowing that there is an average work- 
able thickness of 15 feet, there is a total quantity of 20 million 
tons of coal. This may be looked upon as a minimum estimate 
for the outcrops of lower seams probably underlie the alluvium, 
whilst there is the probable extension of the field south-west from 
Boruarchali to be taken into account. 
R. R. Simpson considered the outcrops near the Disang river to 
be the most promising and estimated that, over a mile of outcrop, 
1| million tons could be profitably extracted. 
The quality of the coal is somewhat inferior to that from the 
Makum field, the average analysis of eight samples being as 
follows : — 
Moisture . . ' 5-9 
Volatile matter ....... 34-7 
Fixed carbon ....... 55-0 
Ash 4-4 
Much of the coal is soft and crumbling at the outcrop, but 
seams of harder coal are found. As in the Makum coal, the sulphur 
content is somewhat high. A few quarries have been worked for 
local purposes on the outcrops of the seams but the total quantity 
of coal which has been mined is insignificant. A small mine was 
commenced at Hapjan in 1910 and a tramway 4 miles in length, 
conveys the coal to Namrup, Assam-Bengal Railway. 
As the measures seldom or never rise to any considerable eleva- 
tion practically the whole of the coal lies below the level of the 
alluvium and the sinking of deep pits will be necessitated when 
the field comes to be worked on a large scale. 
Nazira.^ — The Nazira coalfield lies some 20 miles south-west 
of the Jaipur field and 11 miles east of Nazira and is drained 
by the Saffrai, Tiru and Dikhu rivers. The coal-measures have 
a total length of about 16 miles and are highly inclined in a 
1 Op. cit, p. 59. 
« R, R. Simpson, Rec, O.S.I., XXXIV, pp. 2I.5-24I (1006). 
c 3 
