274

THE COLLIERY GUARDIAN.

February 8, 1918.

face, but when the engine is at the delivery end, the
following advantages are gained : —•

(1)	The engine obtains better attention, as it is
easier to get at, and, being near the pack of the
gate, the roof is much better.

(2)	The loader can control the engine, and can
regulate the speed to suit the load. To run a
shaker conveyor unloaded, if persisted in, means
rapid deterioration.

a right and left hand worm wheel gear running in a
dustproof oil bath; and the second reduction by means
of a steel pinion meshing with an internally toothed
wheel within and protected by the belt drum. As the
gears are all machine cut and enclosed, the drive is
practically noiseless—an important feature in the case
of bad roofs. The belts used are of 20 in. canvas,
specially treated with hardened edges.

The electric drive (fig. 14) is, by means of an 8 horse-

Fig. 6.—Eickhoff Electrically-Driven Conveyor Engine.

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pc.

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repairs that have been necessary through wear and tear
were the re-bushing of the turbine rotors and the
drums.

The first method of securing, which was not success-
ful, was by setting props on the head, thus jamming it
solid, the result being that the frame had to stand
any movement of the roof and floor. The present
method is to hold the head in place by tension chains,
and since doing this no trouble has ensued.

The height of the seams has varied from 2 ft. 8 in.
to 18 in. No difficulty has been found in working in
the thin seam, with the exception of having to remove
a small portion of stone directly overhead, in order
to allow the large pieces of coal to pass. By using
low roller stands, which measure only 7 in., no diffi-
culty in filling on to the belt in the low section has
been experienced.

Some very difficult ground to work has been gone
through, in one case under a badly-broken roof, due
to a 5 ft. seam having been goafed underneath, which
caused falls on the belt, the largest of which was
over 20 yds. long and very thick. In this case none
of the belting was lost, and only about four of the
roller stands. The falls were heavy enough to com-
pletely smash a steel conveyor, but the only result
in the case of the belt-conveyor was to stop it running
until the fall had been cleared. The belt has also
run over a fault in the middle of the face that com-
pletely cut the coal out, the method of effecting this
being to take away about 8 in. of bottom and 8 in. of
top so as to form a gradient. A roller stand with
the bottom roller only was placed in such a position
that the belt just cleared the flzoor; it was certainly
more difficult to fill on the low side of the fault, but
the sag of the belt was sufficient to enable the men to
do so. During this difficulty over 400 tubs of 8 cwts.
capacity were passed in the 10 hours of work.

One of the faces had a “ swelly ” or depression of

Fig. 7.—Compressed-Air, Shaker-Conveyor, with Engine
Fixed Underneath Troughs.

Fig. 8.—Compressed-Air Shaker-Conveyor, Fitted with
Cross-Arm and Column.

Fig. 11.

If the engine should be attached at the top end, care
should be taken that all bolts are kept tight, otherwise
there will be lost motion at the delivery end, where the
speed should be greatest. Wherever the engine is
fitted, however, it should be so arranged as to receive
the full effect of the roller path and engine reversal at
the same moment.

The electric drive is usually effected, by means of a
rope and a bell crank, although the Diamond Com-
pany supply a cross-arm drive.

Belt Conveyors.

Fig. 12.

Ro

Head
&

TRak\ J:

Figs. 9—13.—Illustrating

OTHER FORMS OF DRIVE.

The belt conveyor has been in use for many years.
An angle iron framework is usually fitted to keep the
coal on the belt, the speed reduction being effected by
means of spur reduction gear from the electric motor
or air engine. Conveyors of this type were in use at
the Wharncliffe Silkstone Collieries, and a number of

power flameproof motor running at 720 revolutions
per minute, both the starter and the motor forming
part of the conveyor head. The power required to
drive a fully-loaded 100-yd. conveyor is only 4 brake

over 4 ft. in the centre of the face, but here again
the sag of the belt completely overcame the difficulty.

The belts, which average 90 yds. in length, take 2|
hours in which to flit or pull up. This work is car-
ried out by six men, who spend the rest of their time

■

■' ' A

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Fig. 14.—Meco Electric Belt-Drive.











in drawing the back timber and chocks.

For some considerable time two conveyors were
delivering on to one mothergate, one conveyor leading

Fig. 15.—Meco Compressed-Air Belt-Drive.







experiments were carried out there that have removed
a considerable number of previous difficulties. The
angle irons were removed, and the belt was carried on
light wooden rollers, supported on props. Light steel
frames are in many cases used to carry the wooden
rollers. The driving gear was entirely re-designed, the
frame made of built-up steel, the motor or air turbine
coupled direct to the frame, and the speed reduction
effected in two steps—the first reduction by means of

horse-power. The head is so arranged that the motor
and starter can be fixed on either side.

The compressed air drive (fig. 15) is by means of an
8 horse-power spiro-turbine, running at 1,200 revolu-
tions per minute. The first installation of this type
was at a Durham colliery, and the author is indebted
to the management for the following particulars : —

Two of the drives have been running nearly two years
with the same belt that was first put on, and the only

the other by about 40 yds. The primary haulage was
kept to within 100 to 200 yds. of the first conveyor,
and the whole of the coals (which sometimes amounted
to 850 tubs) was brought out by a small compressed
air secondary haulage. In every case an endeavour
was always made to keep the mothergate about 40 yds.
in advance of the conveyor, as shown in fig. 16.

The conveyors were pulled up each night, but a
minimum pull of 2| ft. was fixed. In pulling up, the