THE COLLIERY GUARDIAN

AND journal of the coal and iron trades.

Vol. CV.

FRIDAY, MAY 23, 1913.

No. 2734.

THE CADEBY MAIM COLLIERY EXPLOSION.

Home Office Report.

The report to the Home Secretary on the causes of
and circumstances attending the explosions which
occurred at the Cadeby Main Colliery on Tuesday,
July 9, 1912, by Mr. R. A. S. Redmayne, C.B., H.M.
Chief Inspector of Mines, has been issued as a Blue
Book [Cd. 6716.] It may be recalled that 88 persons
lost their lives—viz., 35 by the first and 53 by the second
explosion.

The Colliery.

The Dena by and Cadeby Main collieries are situate in
the Don Valley, in South Yorkshire, and are about
2,000 yards apart from each other, being nearly midway
between the towns of Doncaster and Rotherham. The
area of the mineral tract being worked by the colliery
company comprises about 10,000 acres.

The two shafts of the Cadeby Main mine, which is
situate close to Conisborough Railway Station, are sunk
to the Barnsley Bed—the only seam worked at this
mine—at a depth from the surface of 763 yards, on the
• dip side of a large fault, which has a throw to the south
of 126 yards (see fig. 1), the coal on the north side of
the fault being won by a pair of headings driven through
the fault. Both shafts are 16 ft. in diameter, and 752 and
738 yards in depth respectively. Coal is wound at the
No. 1 shaft from the bottom. At the No. 2 shaft the
coal wound is brought to a temporary inset on a level
with the seam on the north side of the fault. An inset
is, however, being made at the bottom of this shaft, and
is practically completed, to which all the coal drawn at
this shaft will in future be brought. A portion of the
coal worked on the north side is brought to the No. 1
shaft, being lowered down by means of a staple pit sunk
from the north side level to the south side level.

The thickness of coal worked is 7 ft. 3 in., and
2 ft. 4 in. of coal, or 2 ft. 10 in. of coal and dirt, is left up
last and allowed to fall between the packs in the goaf or
waste. The under-manager of the colliery, however,
stated that 6 ft. 6 in. was the height of coal generally
.got, and that from 10 to 20 inches was left. But of this
coal about 40 per cent, appears to have been recovered
-from the waste and sent to the surface. In the roads,
-the bags and day beds are ripped down and sent to the
surface. About 49 ft. above the Barnsley bed is a seam
of coal 2 ft. 2 in. in thickness, a fact which has an
important bearing in respect of part of the enquiry.
'The top coal of the Barnsley bed is of inferior quality
: and mixed with dirt. The roof of the seam is bind,
variable as to hardness, being harder in the south
district area than in some of the other districts of the
mine. It constitutes a moderately good roof. The
^Barnsley Bed is a gassy seam, and though, at any rate at
Dadeby, not subject to blowers or sudden irruptions of
gas, the under-manager stated that a weight coming on
in No. 2 pit some years ago, it was found necessary to
withdraw the whole of the men from the pit on account
of gas. In South Yorkshire this seam is peculiarly
liable to spontaneous combustion—at this particular
colliery there have been no less than 35 fires due to
-spontaneous combustion—to work it safely requires,
therefore, the greatest care and vigilance on the part of
the management. The dip of the seam is at the rate of
. about 1 in 14 to 1 in 12 to the south-west.

The workings of the mine are divided into five main
districts. The system of working practised is the long-
wall, the distance between the gate roads being usually
40 yards. Packs are built on either side of the roads of
a width of 7 ft. 6 in., and every 7 yards a gob pack is
built and made 6 ft. wide. The material used for
building the packs is stone obtained from the waste and
from the ripping in the gates. In the main roads a good
deal of ripping has to be carried out in the bind roof,
which has the effect of contributing to the formation of
stonedust—a fact which had an important bearing in
limiting the extent of the explosions. All the coal was
got by hand, there being no mechanical coal-cutting;
nor were mechanical conveyors used for transporting

the broken down coal along the faces ; as, however, the
coal is fairly friable, a certain amount of dust was made
at the face, but not in an unusual quantity.

The total volume of air circulating in the mine was,
at the time of the accident, about 163,000 cubic feet
per minute, under a pressure (water-gauge) of about
3|in. This is drawn through the mine by a Schiele
fan, 21 ft. in diameter, and making about 119 revolu-
tions per minute. A Waddle fan, 9 ft. in diameter,
electrically driven, which is kept as a stand-by in case
of breakdown of the Schiele fan, is being replaced by a
reversible Sirocco fan. Although the Cadeby mine is
connected with the Denaby mine by means of an
emergency outlet, the ventilation system of the two
mines is quite separate, and the iron doors in this outlet
are kept locked.

With the exception of some of the lamps carried by
officials, and a number of electric lamps, used when
working at fire-holes, the type of safety lamp in use at
the colliery is the Marsaut. It may be mentioned
incidentally that the safety lamps found in the pit after
the disaster were examined, and the vital ones were

Fig. 1.—Plan of the Cadeby Main Colliery.

found to be intact. Several on the 14 level were broken,
and one on 19’s crossgate had been broken from the
outside.

The surface arrangements are admirably designed
towards preventing the floating dust produced by
movement of the coal at the tipplers, screens, conveying
belts and hoppers, from being carried down the downcast
shaft and so on to the roadways of the mine. The dust
is collected where made by means of funnels attached
to pipes connected to an exhaust fan which creates a
partial vacuum (2| in. water-gauge), the current of
dust-laden air passing from the fan into a cyclone, where
it enters a steamy atmosphere maintained by a steam
jet from the boilers; this prevents any of the lighter
dust from escaping by the chimney to the outer
atmosphere. Where necessary, the screens and hoppers
are almost entirely enclosed. This arrangement, which
has been in operation for about five years, has proved
very effective in clearing the air about the heapstead of
dust, and practically no dust is carried by the ventila-
tion down the downcast shaft into the underground
workings.

The two mines—the Denaby and Cadeby Main
Collieries—are under the general control of a managing

director, Mr. W. H. Chambers. There was one agent
over the two collieries, Mr. H. S. Witty, who, before
September 1911, had been manager of the Cadeby Main
Colliery. Under Mr. Witty, as manager of the Cadeby
Main Colliery alone, was Mr. 0; Bury (who was seriously
injured in the second explosion, and died a few days
afterwards). There was one under-manager at the mine,
Mr. Bridges, an assistant under-manager, Mr. Cusworth
(killed in the second explosion), and Mr. Eli Croxhall
(who also lost his life in the second explosion) acting as
under-manager in the afternoon shift. The mine was
worked by three shifts, viz., two coal-getting shifts and
one repairing shift.

The South Plane District.

It is with this district that the enquiry was almost
entirely concerned, as the explosion, which originated in
the east side thereof, was limited in its effects to this
district. The position of the district in respect of the
rest of the mine is shown in the small scale plan (fig. 1).
The district may be described as dry and moderately
dusty. The coal was filled into tubs at the face with
shovels (not forks as is common in some collieries in

South Yorkshire), so that there would not be more fine
coal or dust at the face than is usual at collieries in the
neighbourhood and rather less than at some.

The volume of air entering the south district was
21,661 cubic feet per minute, about half of which quan-
tity went along the 14 level to ventilate the district in
which the explosions happened, returning by way of
33 level, which crosses the south plane at a point about
967 yards from the shaft, the other half going into the
straight-on portion of the south district to ventilate the
workings there.

A fault, coursing roughly north and south, and with
an upthrow to the east of from 4 ft. 6 in. to 5 ft., cuts
off the workings at the northern extremity of the eastern
portion of the district. The tract of coal being worked in
the eastern portion of the district was a strip between
7’s and 131’s gates (stalls), and the continuity of this
coal face was broken by a fault between 12’s and 14’s
gates, coursing roughly at right-angles to the fault
already mentioned. This fault has a downthrow from
the south of about 6 ft. Parallel to this is a third fault,
cutting the face at 131’s and also downthrowing from
the south about 5 ft.

Gob fires had been known in the neighbourhood of