PART 2 .] 
Hughes : Borings for Coal in India. 
93 
The regions most carefully and most perseveringly explored within the last few years 
with the object of testing the occurrence of coal, its extent and its quality, have been those 
of the Wardha and Godavari valleys, and near or within the Satpura range of hills. Nearly 
200 borings have been carried out. As a rule, few of them exceed 300 feet; but at 
Khappa, one, under the immediate charge of Mr. Stewart of the Public Works Department, 
has already attained a depth of 710 feet. 
The method of boring most generally practised is that of jumping the rods by the 
agency of a windlass that works a rope passing over a sheave 
fixed to a set of shear legs of sufficient height to allow of two 
lengths of rods to be unscrewed at once. In the Wardha valley, to which my own experience 
of boring operations is confined, a spring-pole or a lever was rarely employed; the single 
jack-roller or winch doing the duty of raising the rods at each stroke, the sudden slackening 
of the rope on the drum allowing them to fall again. 
During the early stage of our explorations the attempt was made to secure the ad¬ 
vantages supposed to accrue from the employment of steam-power; and a Mather and 
Platts’ machine, under the charge of Mr. Mather’s son, was for some time put upon its trial. 
The essential principle of Mather and Platt’s system consists in the substitution of a 
flat rope for the iron rods employed in the ordinary methods, by which means a saving in 
time is effected in raising and lowering the cutting tools. In practice, however, it was found 
that for the shallow depths required for the holes in the Wardha valley, there was scarcely 
any appreciable saving in actual time of working. For deeper holes the steam borer would 
probably have answered, as then more scope would have been afforded for the display of 
those advantages which its system of working undoubtedly possesses. Shifting the 
machine was in each instance a tedious business, owing to the unfinished condition of the 
roads, and the consequent difficulty of procuring suitable carriage, and more time was lost 
at each removal than would have sufficed to put a shallow boring down by hand. 
Size of holes. 
The diameter of the holes varied from 5 to 3 inches. The larger of these dimensions 
was adopted at the outset, in order that better illustrative samples 
of the rocks passed through might be obtained than would have 
been procured from holes of the smaller size. When experience had familiarised the eye 
with the aspect of the debris characterising the respective horizons of productive and sterile 
measures, the diameter of the holes was diminished and with considerable advantage in 
respect to rapidity of sinking. 
The usual form of cutting or chipping tool was the flat chisel or straight bit. It was 
found to be most generally useful, being applicable to almost all 
varieties of strata and being easily re-sharpened—a quality that 
cannot be too highly estimated in a country where considerations of petty repairs are of 
much moment. For penetrating extremely hard rock a V chisel was occasionally used. 
Against trap, however, it was of little more avail than the ordinary straight bit. For 
clearing the ribs or snags that resulted from imperfect manipulation, a -|- or a T chisel was 
used, hut the latter is a precarious tool to trust in the hands of native workmen, as it 
requires careful management. One of the most important exploratory borings* in the 
Wardha field was lost by the jamming of a chisel of this form. 
Cutting tools. 
An objection sometimes urged against the claim of the straight bit to obvious superi¬ 
ority is the supposed necessity of employing a second chisel to round the hole. This need 
should not exist, if the chisel be continued upwards, for four or five inches, of the same 
* Mangli, 
