556 
DEPOSITS OF IXDIA : MINING. [PaRT III: 
constructed as illustrated in figure 29, to be of considerable thick- 
ness, say 50 feet. In figure 30 it is shown dipping at an angle of 
40°, and in figure 31 at an angle of 80°, the slope of the bill on the dip 
side of the deposit being in each case about 30°. We can also suppose 
that the hill is in each case about 300 feet high as referred to the low 
ground at the base. The difference in the dip of the deposits may produce 
a radical difference between the methods of work to be adopted in each 
case. In the case illustrated in figiu-e 30, there is little doubt that 
the deposit should be quarried, at least down to the level of the low 
ground. This quarrying could probably be most systematically carried 
out by working the deposit in horizontal slices of a convenient thickness, 
say 5b feet— AA', BB', CC, etc., in figure 30. Work should be started 
at the summit of the hill with the removal of the overburden AA'^O 
along the whole length of the ore-body down to the level of the bottom 
of the fiiTst 50-foot slice, AA'. On AA" a level or bench should then 
be constructed parallel to the whole length of the ore-band, and 
tram lines laid down. To remove the ore to the bottom of the hiU 
on the dip side, gravity inclines (tramways) or aerial ropeways, 
one or more according to the length of level A, should be constructed, 
with the loading station just below level A, so that the ore in the trucks 
on this level could be tipped direct into the trucks or buckets of the 
incline or ropeway. With the slope of the hill given, inclines would 
probably be better than ropeways ; an incline also has the advantage 
of a greater carrying capacity than a ropeway. From level A the waste 
should be rim out on to the scarp side, OF', of the deposit, through 
openings made by deepening the original prospecting cross-trenches down 
to the 50- foot level AA'. It would be advisable to start work on the out- 
crop, 0, before the level A and the incline are finished, so as to have 
a supply of ore ready to despatch to the bottom of the lull at the earliest 
possible moment. With the level A constructed and the dip slope 
OA" of the ore-band exposed, it would be an easy thing to remove the 
ore down to the level A and transport it expeditiously to the foot of the 
hiU. It would probably be advisable to remove the country on the foot- 
wall side also of the deposit down to the 50-foot level. It would be 
as well to arrange to work away the first slice of ore sooner at one end 
of the deposit than at the other, so as to allow the removal of the country 
AA" B"B and the preparation of level B at this end before the ore had 
been completely removed from the other end of level A. Arrangements 
would have to be made for moving the loading stations of the inclines 
down slice by slice as the work progressed. In this way work would be 
