May 8, 1914.

THE COLLIERY 'GUARDIAN.

1011

The Wolf-Patterson Lamp.

The Wolf-Patterson lamp, the general design of which
is shown in fig. 23, is a double-gauze, flame, spirit or oil
lamp, with air feed through vertical holes in the middle
ring, and the bottom feed through slots situated below
the glass, protected by double gauzes. It consists of
the following essential parts :—

(1.) Bonnet or Shield of stamped steel, with reinforced
upper part, and with an additional securely fastened
steel or brass crown; furnished with outlet holes
immediately below the crown, provided that the bottoms
of the holes are not less than in. above the top of the
outer gauze.

(2.) Middle Bing of brass or iron, riveted to bonnet,
provided with vertical air-inlet holes of total area not
exceeding 1*2 square inches; pillars, of iron or steel,
four or five; bottom ring, of brass, of the type shown in
fig. 23, with a flanged ring forming a baffle against a
horizontal current entering the air admission slots.

Sectional

Elevation

Outside
Elevation

/°

O

\O

SB

Fig. 23.
Wolf-Patterson Lamp.

(Wolf Safety Lamp Company.)

Plan of bonnet ring with
bonnet removed half shown
in section through A B

Fig. 22.—Marsaut Safety
Lamp, Types B3 and B4.

(Patterson and Company.)

(3.) Gauzes, of not less than 28 S.W.G-. steel wire, 784
meshes to the square inch, with double-folded lap seams,
formed to fit flanges of the inner and outer base rings.
The arrangement of the gauzes in the lamp is that
shown in fig. 23.

Inner gauze.

in. ± | in.

in. ± | in.

in. ± a in.

Outer gauze.

4| in. ± | in.

2 in. ± i in.

2| in. ± a in.

Internal dimensions.

Height from shoulder of
hoop .................

Diameter at top ......

Diameter at bottom....

(4.) Glass :—

External diameter..........

Height.....................

Size mark .................

( + 0 mm.

59	mm. <	1

( — 1 mm,

60	mm. ± 4 mm.
59-60 or W. S. L. Co.

(5.) Glass Retaining and Air Admission Bing.—The
lamp is fitted with a combined glass retaining and air
admission ring, of the type shown in fig. 23, with six
slots of total area not exceeding 0’75 square inch, pro-
tected by double securely fastened brass gauzes of not
less than 28 S.W.G., 784 meshes to the square inch.

(6.) Spirit or Oil Vessel of stamped steel, with a
securely fastened brass screwed ring to fit the bottom
ring, with slots cut in the threads to engage the pawl
of the magnetic lock. Fitted with a flat to f inch
burner; and with or without a thumscrew wick adjuster
and an electric igniter of the type shown in fig. 23.

(7.) Locking Device.—One or other of the following:—
(i.) A magnetic lock of the type shown in fig. 23,
so constructed that the pawl which engages
with slots in the oil vessel can be withdrawn
only by a powerful magnet.

(ii.) A lead-rivet lock with a lug cast on the bottom
ring, and a second lug securely soldered to the
oil vessel.

(iii.) A lead-rivet lock with a loose lug riveted around
one of the lamp pillars, and the second lug
securely soldered to the oil vessel.

The lamp is made at the works of the Wolf Safety
Lamp Company, at Bank-street, Sheffield, or at the
company’s works in Zwickau, Saxony.

(To he continued.)

Under the title of “ A Possible Cause of Explosions in
Coal Mines,” W. A. Douglas Budge, of Cambridge, sug-
gested, in Nature of February 12, that coal dust might be
ignited by being projected in a cloud against an insulated
conductor. Laboratory experiments with various kinds of
dust showed him that the potentials might rise so high that
sparks several centimetres in length were produced. Walk-
ing in the Ludlow Pit at Radstock behind a train of wagons,
when carrying a Wulf electrometer provided with a radium-
tipped collector, he observed potentials of 280 volts and more,
but did not notice any sparks. But he rightly pointed out
that coal dust on mine roads is rarely pure, and that coal
dust contaminated with stone dust did not, in the laboratory,
give rise to a high charge. He scattered dust from boiler-
flues over the coal dust, and as the sign of the charge depends
upon the dust material, and as coal dust and this dust
imparted opposite charges to a conductor, the mixture was
relatively harmless.

Reports on the Senghenydd Explosion.

(Continued from page 955.)

Memorandum by Mr. Robert Smillie.

Mr. Robert Smillie, one of the assessors, adds a
memorandum, in which he says that with the main
body of the report he is in general agreement, but
on one or two of the points dealt with he feels it
necessary to offer some observations. He is of
opinion that communication doors should be
strongly built in order that they may be in a
position to resist considerable pressure, and also
that they should be formed of uninflammable
material. Had the rescuers not been forced to deal
with the fire at the doors, they might at once have
turned their attention to the most serious fire at
the end of the archway in the Lancaster level. On
the question of the reversal of the air current, he
differs most strongly from his colleagues, as he
thinks it would be admitted by everyone who took
part in the enquiry that the reversing of the air
current would have meant the saving of the lives of
all.of the men in the West York district. To him,
it is an amazing thing that for hours and hours
those in charge allowed the smoke to continue
going down from the fire in Lancaster level when
they must have known that it was finding its way
into all of the districts.

Mr. Smillie also calls attention to the fact that
there were two fan-men at this colliery whose duty
was to oil and generally look after the fan-engine.
They wTere supposed to read the water gauge everj^
10 or 15 minutes. The hours of these men were 84
per week, the man on the night shift being on duty
14 hours, and the man on the day shift 10 hours.
Once every fortnight each man required to attend
to his duty for a period of 24 hours when changing
shifts. He thinks that it is too much to expect a
person to be. alert during all the time on a .long
shift like this, and to examine in an intelligent
way every 15 minutes the water-gauge, or even to
pay adequate attention to the fan itself.. Again,
the enquiry revealed the fact that the districts of
some of. the firemen at this colliery were extra-
ordinarily large, in one. case the fireman having 44
stalls to examine. This man had 125 men under
his charge. He expressed the opinion that the
whole of the firemen’s districts in the section
covered by the explosion were far too.large; and
that they would still be too large even if the lamp
cabins were removed nearer to the district.

Mr. Williams’ Report.

In his report, Mr. Evan. Williams, the other
assessor, regrets that he is.unable to subscribe
to Mr. Redmayne’s report owing to differing from
him in greater or less degree upon several material
points. He points out that the Senghenydd Col-
liery is typical of the average steam coal colliery
in. South Wales. The seams of coal and the strata
lying immediately over and sometimes under the
seams are more or less charged with gas which
exudes, generally imperceptibly, at the face as the
coal is worked, and issues, .sometimes with force,
more often gently, but still perceptibly, from
fissures in the roof and floor when thev have been
exposed by the removal of the coal. The presence
of gas is, therefore, inevitable in the ventilating
current after passing through the working faces,
and the aim of good management is to keep the
percentage as low as is compatible with the avoid-
ance. of other dangers that may arise from the
forcing of air at too great a velocity through the
workings of the mine. The steam coal collieries
of South Wales are also liable to sudden outbursts
of gas in very large quantities accompanied by
falls of roof. In these cases, more often than not,
the gas under pressure, generally coming from an
unworked seam of coal lying some distance above,
is a contributory cause of the fall which releases
it, in volume so great sometimes as completely to
block the passage of strong currents of fresh air.
Such a fall as this occurred in October, 1910, at
Senghenydd, and is a contingency against which
no provision can be made.

One of the determining, factors in the. arrange-
ment of the ventilating districts of a mine is the
length of working face that the available quantity
of air in the split can pass through without becom-
ing so charged with gas as to cease to be harmless.
Judged bv this standard, Mr. Williams does not
consider that the arrangement of the ventilation in
the workings of the west side at .this collierv is
open to censure or .adverse criticism. As to the
actual quantity of air passing through the working
faces, there is no information as no measurements
had taken place. Amid the bewildering number
of new obligations laid upon managers bv the Act
amd General Regulations, this had no doubt been
overlooked though no actual breach of the law took
place.

The method of timbering known as open cogging
was much discussed at the enquiry, but the weight
of evidence, strongly backed b^ Mr. Dyer Lewis,
the inspector of mines with the longest experience
of South Wafles, was emphatically in. its favour as
being the best and safe.st for cavities in the roof.

Mr. Williams considers that the collierv was
well and efficiently staffed. With regard to the
controversy as to the size of the districts allotted
to the firemen and to the time occupied in the
examinations before the. commencement of shift,
the district which necessitated the longest walk is
the Mafeking West, the total distance to be

travelled, including up and down each stall road
and along the face, being 5,300 yds., and that has
the largest number of working places, viz., 46. The
actual walking of the distance can easily be done
in an hour, so that an hour, at least, w’ould be left
for stopping to examine the.working parts of the
district, and Mr. Williams is of opinion that an
efficient examination could be made in the time,
and all the more so in the other districts, with less
distance* and fewer working places. Provided the
first man was passed into the district by the fire-
man at. 5.40 a.m., no breach of the Act was com-
mitted in this respect. Work can be said to have
commenced in a district when the first man has
been, admitted into it by the fireman.

With regard to the position of the station it is a
question of balance of advantages. It was claimed
by Mr. Shaw that by his method the overman and
any other superior officials were able to meet and
confer with all the firemen of this side of the pit
together, and to learn at once its condition, and
were, thus able to decide what part or parts
required, their most urgent attention and to give
prompt instructions to all. On the other hand,
stations inbye would have the advantage of
enabling the inspection of the faces to be made
within a shorter interval of the time at which the
men actually entered them. No hard and fast
rule can be laid down, and it is a question that
must be left to the discretion of. the individual
manager to arrange within the limits laid down by
the Act. In this particular instance, it is not
suggested that this matter had any bearing upon
the explosion.

The method practised at this colliery of examin-
ing cavities in the. roof for gas by raising a lamp
on the end of a stick has been impugned unjustly.
As long as the flame of the lamp is in sight, at
distances of 7 ft. or 8 ft., it is possible, without
difficulty, to detect the presence of gas well below
the explosive point upon the ordinary flame of a
safety lamp. It is very necessary that a fireman
should have some indication of the condition of a
cavity in. the roof before he climbs into it to
examine it closely, and there is no method so con-
venient or safe as that under consideration. With
regard to the manner of reporting the presence of
gas, Mr. Williams agrees that the entries on the
report.books should be more specific as to the exact
condition of the. place reported upon. It would be
well, when gas is found, if more detailed informa-
tion were, given of its character—if a blower,
whether diluted as made or at what distance away;
if detectable in the body of the air, the percentage
present; if an accumulation, whether explosive or
not, and also the extent .of it. But section 64 (3)
of the Act does not require this detailed informa-
tion to be entered, as it does not specify that the
report shall be “full and accurate” as regards gas
in respect of anything more than “whether or not,
and where, if any, noxious or inflammable gas was
found,” while as regards roof and.sides, a descrip-
tion of the defects found must be given as well. On
the question of the record of the number of men
required by General Regulation 50 the .words
“ statutory report book ” do not occur in the
regulation, and no place has been provided in the
prescribed form of firemen’s report book for the
purpose. With regard to the recording of the
readings of the barometer, there, is one statutory
report book, No. 53, for each mine, in which the
daily records of barometer and hygrometer are to
be entered, and it can never have been contem-
plated that all the firemen were to record their
readings one after the.other at the beginning and
end of each shift in this book. Mr. Williams does
not agree that a breach of Regulation 60 had been
committed by the fireman of West Ladysmith, .in
that he had not travelled the return airway, which
was the second means of egress from his district.
This Regulation came into force on September 15,
and the requirement is as to once in every quarter,
and not a month had elapsed at the time of the
explosion.

Owing to the natural peculiarities of South
Wales coal in. deep, dry mines, it is to be feared,
says Mr. Williams, that no practicable method can
be applied to the. transport of coal from the faces
to the pit that will prevent the production of fine
dust in sufficient quantity to propagate an explo-
sion, and up to the present no system has been
proved to be efficacious in heavily timbered roads
of large area, such as those at Senghenydd, for
preventing such accumulation on roof and sides of
very fine dust as would carry on a violent
explosion, or of removing such accumulation to an
extent that would render the remainder harmless.
In the absence of knowledge of some means of the
kind adopted by Mr.Nicholas atTirpentwys for the
interception and collection of the dust, it cannot
be said that there was any system that could be
adopted that had any practicability at all in pre-
venting coal dust accumulating, and no.suggestion
to the contrary was made at the enquiry, by any
engineer or inspector of mines. The limit of
practicability was the prevention .of coal dust
accumulating on the floor, and as this was systema-
tically cleared, section 62 (3) was complied with as
fully as possible. These being the conditions in
South Wales, the solution of the problem seems.to
lie in spraying the journeys of loaded trams with
water at the farthest possible point inbye, and at
such intervals as may be necessary to keep the