788

THE COLLIERY GUARDIAN.

April 9, 1914.

MANCHESTER GEOLOGICAL AND MINING
S CIETY.

A meeting of this society was held on Tuesday last at
the society’s rooms, 5, John Dalton-street, Manchester.
In the absence of the president (Sir Thomas Holland),
the chair was occupied by Mr. Charles Pilkington.

Mr. John James Reynolds, mining engineer, Parr’s
Bank-buildings, Manchester, was elected a member
federated, and Mr. Thomas Hopkin Thomas, 30,
Gilmour-street, Tonypandy, South Wales, was elected
as an associate member federated.

Deepening a Shaft by a Rise Method.

Mr. Hugh Brocklehurst Pilkington read a
paper on this subject as follows :—

At the No. 2 pit of the Newtown Colliery, belonging
to the Clifton and Kersley Coal Company Limited, two
mines only used to be worked—viz., the Trencherbone
and Cannel—and many years ago a level tunnel was
driven in each direction, seating the Trencherbone
mine to the south and the Cannel mine to the north.
As the Trencherbone mine was getting exhausted, and
also the rise coal in the Cannel mine, it was decided to
deepen the shaft and drive another tunnel immediately
under the first one, but 65 yards lower, seating the lower
part of the Cannel mine to the south of the pit and the
Plodder mine to the north. As, however, the Mo. 2
shaft was at that time very busy winding coal, it was
decided to open out in narrow work in the Lower Cannel
mine, and drive the tunnel above mentioned from the
Cannel to the Plodder in such a position that when the
shaft was deepened it would intersect this tunnel.

When the time came for deepening the shaft, a con-
siderable difficulty arose, as there were only a few hours
in the night available for sinking—the shaft being an
extremely busy one—as the following will show:—Coal-
winding started at 6 a.m., and continued throughout the
day until 5.30 p.m.; at 6 p.m. a nightshift was let down,
and also between that time and 10.30 p.m. waterwinding
had to be resorted to, when 200 tons of water were
usually dealt with; at four o’clock next morning the
firemen had to be let down ; and further, between
10.30 p.m. and 4 a.m. portions of the night shift were
constantly coming to the bottom of the shaft wanting
to be wound out. It will therefore be seen that there
was practically no time for sinking in the ordinary
manner, for even had it been possible to protect the
sinkers from coal falling down the shaft, the debris from
the sinking could not be wound out when any other
work was being done. With these difficulties confronting
them, the management had to consider the advisability
of deepening the shaft by a rise method. They obtained
what information they could from mining papers as to
how this had been accomplished before, but they could
find no way which to their minds was satisfactory or
safe, the methods, so far as they could learn, up to then
being very crude, the particular danger being that men
were always liable to injury from falls of debris while
being wound up the shaft, unless there was some
permanent covering. The difficulty was to design a
covering which should be easy of access, convenient, and
safe to work both under and above, and yet be able to
withstand the shock of shotfiring and accompanying
falls of debris.

After a good deal of thought, however, Mr. Percy
Wood invented the scaffold which the writer is about to
describe, and which he thinks overcomes the difficulty
and danger hitherto existing with this class of shaft
driving. Mr. Wood wishes to state that much of the
success of this scaffold was due to Mr. James Files, who
acted as draftsman, and arranged many of the details.

It was decided to commence operations in the shaft
from the Cannel Mine, which was 40 yards below the
bottom of the existing No. 2 shaft and 12 yards above
the lower tunnel. This had the advantage of leaving
both the pit bottom and the tunnel untouched; the pit,
therefore, was free to wind coal, and the traffic through
the lower tunnel to be sent forward without any
interruption.

Another important feature, which helped in no small
degree to the success of the scheme, was the putting
down of a 10-in. borehole from the bottom of the existing
shaft to the road driven in the Cannel mine from which
the shaft was to be started. This borehole served three
purposes : it enabled a plumb line to be put through,
so that the new shaft should coincide perfectly with the
old shaft; it formed an excellent means of ventilation
for the rising shaft, and by lowering the capstan rope
from the surface through this borehole it enabled the
sinking scaffold to be moved as and when required.
Had it not been possible to get the capstan rope to the
scaffold, it would have been necessary to have raised it
from time to time with hydraulic jacks, which would
have considerably delayed the sinking. Except when
blasting or winding water, the capstan rope was always
kept in this borehole ready to be attached to the scaffold
each time it was required.

As this borehole did not make a great amount of
debris, it was found possible to keep it going while the
pit was working by putting a strong protection across
the bottom of the shaft to protect the workmen, the
debris being piled round the bottom of the shaft and
wound out in the short time that was available at night.

So as to enable water to be wound while the sinking
was being carried on below, a pipe was placed in the top
of the borehole, sticking up some distance above the
bottom of the shaft. This pipe was secured by clay and
concrete to keep the water back, thus making a water-
tight sump for the tanks to dip into while keeping the
borehole quite dry. The first operation when the bore-
hole reached the road in the Cannel mine was to blast
a quantity of roof down so as to enable the sinking
scaffold to be erected in position under the borehole.

The scaffold itself is a double-decked one, the upper
deck being the working floor for drilling the roof and
trimming the sides, the lower deck being used as a
banking level and bricking scaffold. The top deck was
built 16 ft. 9 in. in diameter, the finished diameter of the
pit being 16 ft., and always rested on the brickwork
during drilling and blasting operations. It was con-
structed with a square opening 5 ft. in size on one side
of the centre line. The framework consisted of three
parallel baulks of pitch pine, 12 in. by 9 in., planked
over with 3 in. planks covered with old boiler plates.
The lower deck was 6 ft. 3 in. below the top deck,
and was secured by four main posts at the corners
of the opening previously referred to, and also by eight
2 in. iron bolts round the edge of the framing. This deck
was built 15 ft. 8 in. in diameter, being 4 in. less than
the inside diameter of the finished pit—viz., 16 ft. Two
openings were provided here 5 ft. square, one being
directly below the opening in the top deck, and the
other symmetrically opposed to it on the other side of
the centre line, and through this this hoppet was raised,
and the men and materials landed on to the lower deck
by means of two small pulleys fixed above it to take the
winding rope used for the hoppet. This opening was
protected by three movable bars. The other opening,
which had the four posts at each corner, was planked in
from the lower to the upper deck, thus forming a box.
Two small rectangular manholes were cut in two sides
of this box, and these formed the means of reaching the
top scaffold. The floor of this box was formed by two
doors, which opened downwards, and as the safety of the
workers, both on the scaffold and at the bottom of the
shaft, depended on these doors, special precautions were
taken to keep them shut. In the first place, they were
heavily counterweighted until they could support more
than the weight of a man, even if not secured in any
other way; secondly, they were fitted with a powerful
screw brake, which was always kept screwed hard on;
and thirdly, there were two trigger catches, which were
operated by a hand lever, and which advanced under the
doors when they were shut. The doors themselves were
of solid construction and armoured with iron plates.
These precautions were necessary to prevent any debris
falling on to the men when ascending after blasting, or
when working below the scaffold filling out the debris.
There were also two small emergency doors to get from
the bottom deck to the top, in case the main way was
impeded by any large stones.

The lower deck was also fitted with six ordinary prids
of substantial design, and which were used in the
ordinary method. Four diagonal stays were fitted from
the framing of the lower deck—and these were also
bolted to the top deck as they passed through—to take
the weight of the scaffold when attached to the bridle
chains, which were attached to the capstan each time
the scaffold had to be raised for putting in a new length
of brickwork; after this was finished the scaffold was
packed up and the main baulks allowed to rest on top of
the brickwork, and the prids on the lower deck knocked
into holes left for them. When the scaffold was thus
doubly secured in this position, the capstan rope was
detached, and the chains let slack on to the top deck so
as to leave a free and open space for work, and to remove
the capstan rope away from any danger from blasting.
At a later date a strong iron girder and two under tie
bolts were added underneath the lower framing.

As the engine required for this work had only to raise
and lower the men and bricking materials to and from
the scaffold, a 7 in. coupled engine with drum was quite
sufficient, and this was placed in the Cannel level some
35 yards away from the pit, the rope passing under a
pulley at the mouthing and so up the side of the shaft
and over the two small pulleys previously mentioned,
and then down to the hoppet. An electric signal bell
was connected from the scaffold to the engine.

To facilitate filling the loose debris into tubs, plates
were laid on the floor, level with the Cannel mine. The
tubs when full were removed by the main downbrow
engine at convenient times, and sent into the workings.

As a good light on the roof was a sine qua non,
portable electric lamps were used, each box of batteries
having two 8-candle power lamps on flexible hose 1 yard
in length. These could be put in any position, and gave
a good light in all directions. Two boxes (four lights)
were used at a time, and there is no doubt these
contributed in a very large measure to the safety of the
men.

The procedure during a complete cycle was as follows:
The top deck of the scaffold would be resting on the
completed brickwork, and the prids on the lower deck
would be in holes some 6 ft. below the top of the brick-
work. The sinkers, on arriving at the bottom of the
shaft at the Cannel mine, entered the hoppet and
ascended to the scaffold. Then they examined the gear,
saw that the doors were locked and the brake was on.
All being correct, the foreman—after making sure that
the roof immediately above the box was sound-r-would
then enter the box. As a matter of fact, the roof nearly
always came to a good bed over the centre of the
scaffold. He would then sound the rest of the place
with a long pole kept for that purpose, and also used
for knocking off any overhanging flags.

The sinkers, to protect themselves, used to set props
off the top deck of the scaffold to the roof before drilling.
They then put in their shot-holes, and these, through
being for the most part almost vertical, went in with
surprising rapidity, as the drills always cleared them-
selves whether hollow or spiral ones were used. The
holes were then charged, and the wires coupled up to a
permanent cable attached to the lower deck, and which
was led down to the mouthing. The sinkers then left
the scaffold and connected the permanent cable at the
bottom to a large magnet machine, which was always
kept locked. The shots were then fired all together, four
shots being the maximum that were fired at once.

After the prescribed interval the sinkers went up
again, and, exercising due caution, entered the box and

climbed up on to the scaffold, removing, with the long
pole mentioned above, any dangerous pieces and making
their roof secure. The scaffold was then cleared by fill-
ing the box. When the box was sufficiently full, the man
on the lower deck signalled down to the bottom for
anyone to stand clear, and, having received a signal
that all was safe below and above, he would then open
the triggers, release the brake, and let the debris fall to
the bottom. The doors were at once shut and locked,
and the process repeated till the scaffold was clear.
The sides were then trimmed and everything made
ready to move up.

The capstan rope was then rung for and the chains
connected up. The prids on the lower deck were
knocked in, and the scaffold lifted until the bottom
deck was level with the top of the brickwork, when the
prids were knocked out and the scaffold lowered on to
them. Next, the shaft was bricked between the decks
until the top scaffold was supported by the brickwork
and made to share the weight with the prids. The cycle
was then repeated.

A bell was connected from the level in the Cannel mine
to the pit bottom, but generally when the sinkers wished
to have the capstan rope raised or lowered they would
shout to the hookers-on at the pit bottom through the
borehole, which acted like a megaphone.

The last few yards below the sump were left in as a
protection while sinking through the ground below the
Cannel mouthing in the ordinary way, using the scaffold
as a headgear ; and this intermediate strata also served
as a water dam, the water winding being continued until
they broke through, which they did from the top.

The contract price for the top portion was £10 a yard
for the finished pit 16 ft. diameter, including 14 in. brick-
work, and £11 a yard for the lower section, which included
bell-mouthing the pit to 20 ft. for the new pit bottom.
It will be seen from these figures that the driving of the
shaft by this rise method was practically as safe and as
cheap as sinking in the usual method. This, the writer
thinks, is ample proof as to the success of this method
of sinking under these circumstances.

The total cost of the extension, including 20 yards of
arching at the bottom and putting wooden rods and
bearers in the new portion of the shaft, worked out
approximately to £25 a yard for labour and materials.
This is not really a high figure, and it should be
remembered that the winding of both coal and water
was not interfered with in any way, either at the pit or
in the tunnel, until the last moment.

During the sinking only one accident occurred, and
that was not serious nor of a nature unusual in ordinary
tunnelling, and was in no way due to the sinking
scaffold.	,

The writer is of the opinion that if the same work had
to be done again by his company, the same method
would be adopted, with the exception that the frame of
the scaffold would probably be of steel.

Safety Air Doors for Coalmines.

Mr. James Ashworth, of Vancouver, contributed the
following paper:—Whilst examining No. 5 Mine of the
North-western Improvement Company’s coalmine at
Ronald, in the State of Washington, U.S.A., the writer
came across a simple and ingenious arrangement
whereby the opening of the main separation doors
between the intake and return air, and the surface and
the fan, were so controlled that both doors could not be
open or opened at the same time.

It seems opportune to send a model of this arrange-
ment with a few descriptive notes, to follow Mr. William
Clifford’s paper on “ Some Experiences in Reversing
the Main Air-Currents in Coalmines.”

Under ordinary circumstances, if the air in a mine is
reversed, a most serious and dangerous condition is at
once established, because the air will be sure to short-
circuit at the first doors between the intake and return
airways. The Ramsey patent is a cure for this,
although it is self-evident that a small leakage would
still occur.

The whole subject of air-reversal is such that the
course to pursue cannot be settled by any written or
printed instructions; but one thing is certain, and that
is, that to reverse the air-current is a most dangerous
operation, and may result in a greater disaster than the
original disaster. The writer has only seen one
instance of this, and that was the second explosion
at the Burley Colliery, in North Staffordshire. He
was at the time on his way to visit the mine
after the first explosion, which resulted from a
shot which killed every living thing in the mine,
excepting one horse. Exploring parties had been down
the mine and recovered most of the bodies, but then,
for some reason which the writer does not now recollect,
they were withdrawn, and it was decided to fill up the
upcast shaft until a certain mouthing, through which
some of the return air entered this furnace shaft, was
covered. Throwing dirt down the shaft reversed the
air, and after this had proceeded for some time a line
was lowered down and measured by an engineer, who
reported that the mouthing was covered. A party of
engineers was'then organised to go down the downcast
shaft to make further explorations. This party were
actually on their way to the top of the shaft, when the
mine exploded the second time, with very great force,
throwing great volumes of smoke and dust out of the
downcast shaft only, killing the one horse and smothering
a large number of horses in another mine which had not
been affected by the first explosion. In explanation of
the second disaster it was thought that a blower of gas
.or some material had been burning in the upcast shaft,
and that the firedamp which had accumulated during
the reversal of the air had been carried to this flame and
thereby ignited. This is just one of those instances of
what might happen in consequence of the reversal of