left in. The other seams are all worked on the "longwall"
system, with walls about go feet long. Where coal is presently
being worked, the depth under the sea bed varies from 360
to 900 feet.
WINDING.
The winding engines are coupled and vertical with the drum
overhead. The cylinders arc 25 inches in diameter with a stroke
of 6 feet, and the drums are 10 feet in diameter on the "Great"
Seam side, and 13 feet 3 inches in diameter on the "
Jewel" side.
PUMPING.
The shaft pumping is performed by a Cornish engine, with a
single cylinder 70 inches in diameter with a stroke of 12
feet. There are four plunger lifts, three of 22 inches in
diameter, and one 17 inches in diameter with a stroke of 10
feet. The dook pumping is performed by compressed air and
hydraulic pumps. There are two air compressors on the surface,
having each a 20-inch steam and 18-inch air cylinder with
a stroke of 4 feet. These drive dook pumps in the "Great"
Seam. There is a Brown hydraulic pump in the " Jewel"
Seam, driven by surplus water, which requires to be run down
from the "Great" Seam to the "Jewel" to
balance the shaft pumps.
An hydraulic installation was recently erected with the intention
of supplementing the shaft pumps and taking the place of the
compressed air pumps. The power plant consists of a pair of
coupled horizontal engines, with cylinders 27 inches in diameter
by $ feet stroke driving pumps directly from the piston rods
to keep up a constant pressure of 1, 000 lbs. per square inch
in the hydraulic mains. The Brown pumps to supplement the
shaft pumps are, one in "Great" Seam to pump 500
gallons per minute to a height of 100 fathoms vertical, and
one in "Jewel" Seam to raise 200 gallons per minute
to a vertical height of 36 fathoms.
HAULAGE.
All the engine haulage underground is on the endless rope
system with single hutches, the speed being about 1 1/3 mile
per hour. The rope is under the hutches, and the mode of attachment
to the rope is by Smallman's clips.
The engines are on the surface, and are coupled horizontal
engines \\ith cylinders 22 inches in diameter by 5 feet stroke.
The driving clip pulley is of the Thorncliffe type with mild
steel liners in the cheeks. It is 8 feet in diameter and is
on the crank shaft. It is intended ultimately to drive these
engines at 21 revolutions per minute, giving a speed of 6
miles per hour to the band rope. At present the speed is 14
or 15 revolutions per minute, giving the band rope a speed
of fully 4 miles per hour. The band rope is |-inch diameter,
galvanised patent improved steel, and has been on twenty-six
months, during which time the splice has been renewed three
or four times. It has travelled about 55, 000 miles, and is
in fairly good condition. Including the driving pulleys, it
passes over eight pulleys 8 feet in diameter and one 12 feet
in diameter.
There is gearing in both seams for reducing the speed of the
haulage ropes to one-third of that of the band rope. In the
"Great" Seam this is done by passing the band rope
round a 12 feet pulley driving a "C. " pulley 4
feet in diameter for the haulage on the same shaft. In the
"Jewel" Seam where the haulage will ultimately be
heavy, the speed is reduced by spur gearing, all the clip
pulleys being 8 feet in diameter, so as to allow of a large
haulage rope being used. The underground haulage ropes at
present in use are all 2 1/12 inches circumference.
VENTILATION.
The ventilation of the colliery is produced by. a Guibal fan
22 feet diameter by 7 feet wide, running about 60 revolutions
per minute. The fan is driven by an engine with an 18-inch
cylinder and 18-inch stroke.
BOILERS.
Steam is generated for the colliery and brickwork at a range
often Lancashire boilers, each 28 feet by 7 1/2 feet.
The stalk is 200 feet high, 17 feet square outside at the
base, and 9 feet square inside at the top. The steam pressure
is 70 lbs. per square inch.
>On account of the saltness and hardness of the pit water,
condensers have been erected to obtain a supply of hot distilled
water for the boilers.
PITHEAD SCREENING AND WASHING PLANT.
On the pithead, the loaded hutches gravitate to the tumblers,
and the empty hutches are brought back to the back scaffold
by a creeper. There are six self-acting tumblers, five of
which
are used for coal, and one for fire-clay. There are five double
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