I'RODIICTION, THADK, r.AIJOUR, ETC. 
125 
of stone and coal boing left untoiiehed between each pair of flections. 
The work is exceptionally diflicult as the seam is very liable to 
spontaneous combustion ; and " bumps " due to the disturbance of 
equilibrium caused by the working of the coal occur. 
In the Dandot (Punjab) and Khost (Baluchistan) coal-mines, 
thin seams are worked in one operation on a modified " longwall " 
system which appears to be fairly successful. 
Except in a few localities the amount of water in Indian 
collieries is not large, and considering the shallow depths attained 
up to the present, docs not constitute a serious expenditure for 
pumping operations. In this connection, however, a word of warning 
may be given to mine-owners. The almost universal practice in 
India has been to work out the whole of the outcrop coal without 
leaving any barrier to prevent the influx of surface water. The 
result of this short-sighted policy must be that in the deeper work- 
ings of the future, the mine-owner will be burdened with the expense 
of pumping practically the whole of the outcrop water, an expense 
which will become greater the deeper mining operations are carried 
on. The evil is so great that Government have had to consider 
whether some form of State interference is not called for in order 
to prevent the possible loss of coal which may ensue. 
It is satisfactory to note that the use of machinery, particularly 
during the last ten years, is rapidly extending. 
Use ot machinery. ,i , n- ■ i i , r- i 
At the larger collieries modern plants ot good 
design are now the rule rather than the exception. At the smaller, 
chiefly native-owned mines, however, there is much need of improve- 
ment. It may be a surprise to many to know that, at the present 
day, within 120 miles of Calcutta, a coal-winding gin, driven by 
coolie women, can be seen in daily operation (Plate 16). 
During the quinquennial period of 1904 — 1908, the average num- 
^ ^ ber of persons employed in and about the coal- 
mines of India was 104,709. The great pro- 
portion of those employed are the aboriginal Dravidians from the 
mountainous country of Chota Nagpur and the Central Provinces, 
but a large number of other castes are employed, particularly in 
the outlying fields. The majority of the workmen are employed 
in agriculture as well as mining, and make a practice of returning 
to their homes during the periods of sowing and reaping ; the 
result being that, at such times, the output of many of the mines 
is greatly restricted. In certain long-established mining centres 
