ctric transmission in mine work, while in certain
phases beneficial, has not decreased the perplexity which arises
from many added alternatives, none of which are as yet a complete or
desirable answer to any mine problem. When a satisfactory electric
drill is invented, and a method is evolved of applying electricity
to winding-engines that will not involve such abnormal losses due
to high peak load then we will have a solution to our most difficult
mechanical problems, and electricity will deserve the universal
blessing which it has received in other branches of mechanical
engineering.

It is not intended to discuss mine equipment problems from the
machinery standpoint,--there are thousands of different devices,--but
from the point of view of the mine administrator who finds in the
manufactory the various machines which are applicable, and whose
work then becomes that of choosing, arranging, and operating these
tools.

The principal mechanical questions of a mine may be examined under
the following heads:--

1. Shaft haulage.
2. Lateral underground transport.
3. Drainage.
4. Rock drilling.
5. Workshops.
6. Improvements in equipment.

SHAFT HAULAGE.

WINDING APPLIANCES.--No device has yet been found to displace the
single load pulled up the shaft by winding a rope on a drum. Of
driving mechanisms for drum motors the alternatives are the
steam-engine, the electrical motor, and infrequently water-power
or gas engines.

All these have to cope with one condition which, on the basis of
work accomplished, gives them a very low mechanical efficiency.
This difficulty is that the load is intermittent, and it must be
started and accelerated at the point of maximum weight, and from
that moment the power required diminishes to less than nothing
at the end of the haul. A large number of devices are in use to
equalize partially the inequalities of the load at different stages
of the lift. The main lines of progress in this direction have
been:--

_a_. The handling of two cages or skips with one engine
or motor, the descending skip partially balancing
the ascending one.
_b_. The use of tail-ropes or balance weights to compensate
the increasing weight of the descending rope.
_c_. The use of skips instead of cages, thus permitting of
a greater percentage of paying load.
_d_. The direct coupling of the motor to the drum shaft.
_e_. The cone-shaped construction of drums,--this latter
b