554 
MANGANESE DEPOSITS OF INDIA : MINING. [PaET III 
small width, say orily 5 feet thick. Such a deposit could of course 
be opened up as a quarry. But it would be much better to ascertain 
if the deposit extend to any depth, either by a small prospecting shaft, 
calculated to strike the ore-band at 100 feet, by a small incline shaft 
on the ore, or by means of boreholes calculated to strike the deposit 
at depths up to 300 feet. For it would not be economically possible 
to follow such a thin band to a great depth by quarrying, on account 
of the enormous expense of the earthwork that would have to be 
done ; and if mining were necessary it might be better to start 
straight away on it. This case is illustrated in figure 33, which might 
well be taken to represent the Gowari Warhona deposit in the Chhindwara 
district. There must also be many deposits of characters intermediate 
between the large bodies of ore referred to above, and the thin 
band found at Gowari Warhona. Hence it is evident that in many 
cases it would be advisable to wait before opening up the deposit as a 
quarry, until it has been ascertained whether the ore go to any 
considerable depth or not, and then to decide if it would not be 
better to mine the deposit, instead of quarrpng it. I suppose, however, 
it is useless to mention this point, because the owner of a manganese-ore 
deposit always wants money returns with the greatest possible speed, 
and can never wait to have the deposit properly developed. However, 
by following the ore on an inclined shaft it i,« possible to prove the 
ore and win ore at the same time. 
Having determined the character of the deposit, at least to the extent 
of finding out something about its width, strike, and dip, and whether 
any considerable amount of ore be available, the operator can think 
about opening it up. 
If quarrying be decided upon then there are four main points to be 
Pour mistakes to be observed if the deposit is to be properly 
^^oided. worked. These are :— 
1. The waste must not be dumped on the line of strike of the deposit. 
2, The waste must not be dumped too near the sides of the deposit, 
assuming it to be longer in one direction than in the other ; and by 
preference the waste should be dumped on the side away from which the 
ore is dipping and not on the dip side. The distance to which the waste 
should be carried depends on the angle of dip of the deposit, and on the 
depth to which it is likely to be worth while to follow it by opencast 
work. The flatter the dip, the wider will the quarry have to be 
for the ore to be extracted down to a given depth, say 100 feet ; and the 
