t

22

THE COLLIERY GUARDIAN.

January 7, 1916.

The Fire at the Griff Clara Pit, Warwickshire, August 1915.

By F. POVEY=HARPER, Manager of the Collieries.

This pit is one of two pits owned by the Griff Colliery
Company Limited, Nuneaton, and a serious underground
fire broke out in the main intake haulage road, within
80 yds. of the downcast shaft, on August 27, 1915.

The seams worked at this colliery consist of the Two
Yard, Slate Coal, and Seven Foot. These seams lie at
a dip of about 1 in 5 to 1 in 6, and are illustrated on
the section (fig. 1). The shaft is sunk to the bottom
seam, and the seams are won to the dip by a cross
measures drift (the rise coal all having been worked
some years agt>). The cross measures'drift starts from
the bottom seam—the Seven Foot—and cuts the Slate
Coal seam, and then the Two Yard. The main “ hills ”
or inclines are then driven down in the different seams.

The Warwickshire coal field is subject to pillar and gob
fires, which generally originate near the seat of an old
head or on a fault side, and during the last few years
two serious fires have occurred in the pillars of coal left
to support the shaft and main roads at two other
collieries, which both had to be abandoned for a con-
siderable time before being re-opened.

At Griff Clara Pit, in working the rise coal years ago,
an airway was driven in the Slate Coal seam about

a

Fig. 1.—Sectional View^of the Seams.

about 18 in. thick, and from this, iron girders, 10 ft.
long and about 9 in. apart, had been erected to support
the roof. These were supported on the other end on
wood props. The side against the wood props was very
much broken, and if this had been disturbed there would
most likely have been a run of debris; so a 14in. wall
was run up all along on the opposite side to the concrete
wall, and all the timber was built in. Both the concrete
wall and the brick wall were extended to the emergency
stanks on each side, so as to get into good solid ground
and to shut off the air. As much concrete as possible
was rammed behind the brick wall, between and round
the timbers. The longitudinal section and the cross
section of the main drift, as illustrated in fig. 3, show
the position fairly accurately. Smoke was coming
through between the steel bars; and with the object of
stopping this, and to shut off the air, steel plates about
12 in. square were put in between the webs of the
girders, fine concrete was rammed in between each
girder, and another plate was then added, until the
whole length between each bar was rammed as tight as
possible with concrete. This work is illustrated by the
enlarged section on S N in fig. 3. The joints between

even more so .to make all the joints between the
numerous girders anything approaching airtight.

There has been another fire burning in the main Two
Yard cross drift for a number of years, and this had
been arched in, but owing to the heat, the arching has
often had to be renewed during the last 10 years. The
writer had frequently thought of pumping-in cement into
these fires with a view of putting them out, but the
difficulty was to know how to do the work. In the end
he went over and saw Mr. Albert Francois, of Doncaster,
who was conducting the cementation process in the sink-
ing of the Keresley pits close to Griff collieries, and
asked him to lend his pump and men who were used
to working it, to enable the Griff Company to see the
effect of pumping liquid cement on a fire. This was
immediately agreed to, and the necessary pipes and
valves were put into the roof between the steel girders,
some of these being shoved up through the timbers for
a distance of 10 to 12 ft. above the steel bars supporting
the roof.

The pipes used were 2 in. diameter ordinary steel
pipes. Water and cement were then pumped in by Mr.
Francois’ representatives, with every success. Although
it was thought that the place was fairly airtight, never-
theless, as soon as the cement and water was pumped
in, drippers came through in excessive numbers at all
the joints between the girders; but, as the mixture had
a large proportion of cement in it, these drippers gradu-
ally dried up, and after this process had been at work
about a week on the night shift, the fire, so far as can
be seen at the present time — four months after — is
extinct, and all traces of heat have disappeared. During
some shifts as many as 140 bags of cement were pumped
up in the eight hours. This work has been so successful
in dealing with this fire, that it is proposed to try it at
the Two Yard fire, referred to above, in exactly the same
way, and the preparatory work is now well in hand.

The chief cause of the fire was no doubt the old head,
which runs across the cross measures drift. A small
proportion of air had evidently been coming through this
head into the return, and as there has been a severe
weight all round the shaft bottoms and roads round
about, owing to the deep working approaching the shaft
pillar, this weight no doubt crushed the coal, and caused
a grinding movement, which, with a little air, would help
to start the fire.

I	'■’’Tn • WALL /rv

- h/ALL /rv Sf A

Fig. 2.—Plan, showing Seat of Fire.

Pontefract Coal Lease.—The draft lease of the coal under
Pontefract Park, comprising the Haigh Moor, the Silkstone,
and Beeston beds, from the Pontefract Corporation to John
Rhodes Limited, for a term of 60 years, was finally agreed
upon at a meeting of the Pontefract Corporation on
Wednesday. The Haigh Moor and the Silkstone seams have
been worked for many years at a minimum rental of .£600
per annum in each case, and the new lease is for. a term of
60 years, and includes the three seams mentioned. The
rental is to be £30 per foot per acre per annum for the Haigh
Moor and Silkstone seams, £25 for the Beeston seams, and
..£.‘■20 for all other beds. The minimum rent is to be £2,500
per annum for the first five years, or until the Haigh Moor
seam is worked or proved to be less than 2 ft. 3 in. in thick-
ness, when it shall be reduced to £2,000; when all the Silk-
stone seam has been worked or similarly proved, the minimum

80 yds. on the dip side of the shaft. When the dip coal
came to be worked, a cross measures drift was driven
under this from the downcast shaft, to be used as the
main intake airway and main haulage road. This old
head, although well dammed off with sand, has during
the last 10 or 15 years been practically forgotten; and
it was here that the fire occurred.

At the point where the cross measures drift cuts the
seams, the roof and sides for a considerable distance are
very much broken, and a large amount of timber has
been used in the roof for lagging. The cause of the roof
being so bad at this point is a very natural one, as the
clod and the strata underneath the coal leave the coal
seam, and then the seam drops. The cross measures
drift has been several times ripped right through.

Looking at the plan (fig. 2), it will be noticed that the
main return is driven in the Slate Coal seam, and is
situated about 15 yds. away, but on a different level, and
the old head or airway already referred to was connected
into this. Along this main cross measures intake drift
about 40,000 eu. ft. of air was passing, and therefore any
slight “ fire stink ” would not be very easy to detect.
The first indications of any smell were noticed at about
7 o’clock on Friday morning, August 27. At 10 o’clock
the smell was much worse, and at 1 o’clock smoke
started to come out in both the intake and return. The
men and horses were at once withdrawn, and the fan
stopped.

Work Done to Overcome the Fire.

In the return, which is in the coal, the side, which
consisted of Slate coal, was taken out for about 6 ft. in,
and short heads were put in about every 10 or 15 yds.
to cut off any breaks found to convey smoke and heat.
This was then filled in with about 6 ft. of sand for a
distance of 30 yds. The road was then ripped, and the
coal buried, about 2 ft. of sand being put on the floor.
This was successful in shutting off all smoke, and the
place gradually cooled down. In dealing with the intake
road, the first thing was to shut off the air from the seat
of the fire, and to do this two emergency dams were
put in at each end, where the ground was solid, and
a door was put in to enable material to be taken up to
the seat of the fire to supply the men who were working.
The necessary doors were put in at the upcast shaft,
so as to divert the ventilation and enable the pit to be
ventilated while the emergency dams were in. The
emergency dams or stanks consisted of brick walls about
18 in. thick, and these could have been made tight within
an hour in the event of the fire gaining the upper hand,
which would, of course, have stopped the pit from
raising any large amount of coal until it had been over-
come again. In the main drift along one side, before
the fire broke out, there was a reinforced concrete wall

te’/'i’cres S £ C r/OA/ OSV

s R

V«s

is

Fig. 3.—-Longitudinal and Cross Sections on Main Drift.

the girders and the iron plates on the under side were
then pointed up with cement, and in some places plaster
of paris, so as to make the whole as airtight as possible.
When all this had been completed, which occupied
about eight days, a coat of thin cement was put on with
a brush over the whole area.

The emergency stanks were then taken down, and the
pit resumed work. Only a slight smell was noticed for
several days, but shortly afterwards the bans became
hot, and it was obvious that there was great heat above.
To examine what was happening, a hole was made in
through the steel plates and concrete, and on looking
up through this, the mass above was found to resemble
a furnace. It was perfectly evident that the fire was
getting air from somewhere; and, of course, it is
impossible to make brickwork absolutely airtight, and



to be reduced to £1,500; when the Beeston seam has been
similarly worked or proved, to £1,000; and when the
Flockton, Stanley Main, and Warren House have been so
proved or worked, to £10. All abandoned coal is to be at the
disposal of the lessors. In addition, a wayleave of £5 per
acre is to be paid for each seam of “ foreign ” coal brought
through the roads under the Park estate. The lessees shall
have power to break the lease every 10 years, but this option
shall only be exercised if they have already abandoned their
lease of the coal belonging to the Duchy of Lancaster. The
lessees may erect an additional shaft in the Little Park on
payment of a shaft rent of £11 per annum, filling up at the
end of the lease, or paying £50 per acre in lieu. Much dis-
cussion centred round the excess payments made under the
existing leases, now amounting to over £6,000, but it has
been finally agreed to credit the lessees with all under-
gettings, less £2,500.