756

THE COLLIERY GUARDIAN.

April 20, 1916.

CURRENT SCIENCE

Cost of Upkeep of Electric Safety Cap Lamps.

Figures are given in Coal Age, showing the entire cost
of upkeep of an electric cap lamp service for a year,
with an estimate on the cost of maintenance for a
station with 250 lamps. The test was made at the
Vulcan Mine, Newcastle, Colo., of the Rocky Mountain
Fuel Company, of Denver, in the same State. The
installation was not large, and the lamps were tended
by the regular lampman of the mining company. The
Vulcan Mine dips at an angle of over 45 degs., and the
lamps are consequently operated under the most
unfavourable conditions, being subjected to the roughest
usage. The total number of delivered lamp shifts
during the 12 months was 6,350, making a total of burn-
ing hours of 61,700. The number of lamp months was
324, and the cost of upkeep, excluding labour, was 65-52
dols. net, or 0-2022 dol. per lamp per month. This
figure, which is a trifle more than 20c., included all
material needed to keep the lamps in good working
condition. The average number of lamp shifts was 19-6
per month. Thus the upkeep per shift per lamp was
only 0-0103 dol. Including the 27 bulbs furnished with
the lamps, 113 bulbs were rendered valueless during the
year. Of these, 34 were destroyed by the miners. These
may be figured as being half-consumed before they were
destroyed, and the same assumption is made about the
27 bulbs in use at the end of the period. Thus 61 bulbs
may be figured as half-consumed, which is equivalent to
about 31 bulbs wholly burned out. Thus it is fair to
declare that the requirements of the year’s running were
82 bulbs. These delivered, as stated,' 61,700 burning
hours, or 753 hours per bulb. It is interesting to note
that no battery plates had to be renewed during the
whole year, and the mine reports that all the electrodes
are still in first-class condition. It will be noted that
82 bulbs were sufficient for 27 lamps, SO' that less than
three bulbs served for each lamp for one whole year.
Forty-nine cable lengths had to be renewed during the
trial year. Let it be assumed that the 27 cables were
half-worn out when the year was concluded. This will
make the equivalent number of cables a trifle under 63.
In other words, as the total number of delivered lamp
shifts was 6,350, a cable lasted for over 100 shifts, or
as 19-6 shifts were delivered per month, it lasted for
over five months, a long life for a part under such stress.
A new fastening has been introduced, which appears
likely to prove, from actual tests now being made, 100
per cent, more durable than the old.

It has been found that 250 lamps can easily be tended
by one lamp master at 75 dols. per month and one
assistant at 45 dols., or for 120 dols. per month. Grant-
ing that each lamp is operated for 19-6 shifts, the 250
lamps deliver 4,900 shifts, for a cost of labour of 120
dols., or 0-0245 dols. per lamp shift. Adding the cost
of upkeep to this, the charge for both upkeep and labour
of maintenance per lamp shift would prove for the first
year 0-0348dols., or roughly 3|c.

Coal in the Philippines.

An interesting account of the coal measures of the
Philippine Islands, by W. E. Pratt, Chief of the Divi-
sion of Mines, Bureau of Science, Manila, has recently
appeared in Coal Age. Coal was first recognised .in the
Islands in 1827, and it is now known that practically
every one of the larger islands contains coal, some of it
of good quality. Up to now its exploitation has been one
long tale of failure, notwithstanding that the Spanish
Government, and later, the United States Government
have persistently endeavoured to encourage the develop-
ment of the native industry. At the present moment,
while the imports of coal amount to 500,000 metric tons
annually, there is no active coal mine in the Philippine
Islands, and the total production has been only 125,000
metric tons. This condition of affairs is due, Mr. Pratt
believes, to the following principal causes :—(1) The
discontinuity of the coal beds as a result of extensive
minor faulting and, to a lesser degree, to non-uniform
conditions of sedimentation at the time the coal beds
were laid down, with consequently restricted lateral
extension of the beds; (2) the steep angle at which the
beds are commonly tilted; (3) prevailingly bad roof and
floor conditions; (4) the fact that much of the coal
cannot be stored because of its liability to spontaneous
cambustion and to disintegration or slacking; (5) the
inaccessibility of some of the best coal and the generally
poorer quality of the coal in the beds which have been
least disturbed by dynamism, and which are conse-
quently most available to the prospector-miner; (6) the
lack of adequate capital.

Philippine coal is now generally conceded to be of
Miocene age, the earliest deposition having taken place
perhaps in the Oligocene. It has been noted that where
the Miocene beds contain petroleum, as they do in
Southern Luzon and in Leyte, no coal is found. There
is a suggestion that the one class of hydrocarbon is sub-
stituted for the other; however this may be, coal is
f.und at one place and petroleum at another in the yane
series of rocks and in about the same stratigraphic
position.

Coal has been found on practically all of the larger
islands of the archipelago, and in some of them at
numerous places. The following list includes the
principal known fields :—

Polillo field (off the eastern coast of central Luzon).

Ba tan field (off the eastern coast of South-Eastern
Luzon); East Batan; West Batan; Gatbo, Sorsogon (on
adjacent mainland).

Mindoro field (South-Eastern Mindoro).

Masbate field (South-Eastern Masbate).

Cebu field; Compostela-Danao, including Cujuma-
jumayan Valley (North Central Cebu); Uling (South
Central Cebu).

Mindanao field (Western Mindanao).

F. A. Dalbrug has estimated the tonnage of the

AND TECHNOLOGY.

several coal fields in the Philippines, basing his calcu-
lations on data obtained by various members of the
Division of Mines throughout a period of years. He
concludes that the presence of 4,201,000 metric tons is
demonstrated with reasonable certainty, and that the
probable total tonnage of the principal fields is
67,000,000. Of this total about 5,000,000 tons is bitu-
minous coal, 31,000,000 tons is sub-bituminous, and
31,000,000 tons is lignite. Practically all the coal,
including the lignite, is black with a brilliant lustre.
The lignites slack rapidly on exposure, and are subject to
spontaneous combustion in storage. They also dis-
integrate upon heating, after they have been exposed
for a time, and in burning them in ordinary fireboxes
there is an important loss through the escape of
unburned fines into the ashpit. Thej? can be burned
with fair economy, however, on.grates of special design,
and their fuel value can be utilised with high efficiency
in gas producers of proper construction. Philippine coal
is generally low in sulphur and in ash, but is high, of
course, in moisture and in volatile combustible matter.
Ill the following table are proximate analyses and
calorific values of representative samples from the
principal fields.

Proximate Analyses and Calorific Value of

	Philippine	] Coals.			
Field.	n/r • Volatile 7'01os“ combustible tu,e- matter.	Fixed carbon.	Ash. Sulphur. B.t.u.		
	Per	Per	Per	Per	Per	
	cent.	cent	cent.	cent.	cent.	
Polillo		8 28 ... 4L35 ...	46-31 '.	,. 3-88..	. 0 32 .	..12,200
E. Batan...	18-09 ... 36-24 ...	38-44 ..	.. 7-23..	. 0 84 .	.. 8,360
W. Batan..	5-76 ... 39 64 ...	51*76	2’84..	. 0’18 .	..12,100
Gatbo 		13-62 ... 42-93 ...	41'35 .	.. 2- 0..	—	.. 9,240
Mindoro ...	15’34 ... 46*02 ...	32-50	6-14..	—	.. 9,800
Masbate	4-87 ... 46-50 ...	44-18 .	.. 4-45..	.' 0-45 :	—
Uling, Cebu Compostela,	17’84 ... 34 ; 1 ...	43'03 .	.. 4-62..	— .	/ 9,910
Cebu 	  Danao,	8-60 ... 36-95 ...	5175 ..	. 2-70..	. 0’71 .	..11,495
Cebu	  Cajuma-	9-01 ... 43-46 ...	43'18 ..	.. 4-35..	. 2-40 .	..11,235
jumayan, Cebu		13-88... 40 87 ...	41-74 .	.. 3-41..	.. 0-65 .	...10,390
Duman-					
quilas, Mindanao	1-85 ... 10 43 ...	82-34 .	.. 5’38..	.. 0-82 .	...13,845
Sibuguey,					..12,026
Mindanao	6-81 ... 45’45 ...	45-92 ..	.. 1-82..	. 0-43 .	

Lack of capital has operated more effectively than
any other one factor, perhaps, to prevent the develop-
ment of the Philippine coal fields. Only the prospector,
or the man of limited means has attempted to mine coal
in the past, if exception be made of the inconclusive,
because unfinished, venture of the United States Army.
Most of the difficulties would lose their deterring influ-
ence in the face of capital; none of them appears to be
insurmountable.

Coal Dust Explosion at an American Mine.

Coal Age gives an interesting account of an explosion
near Kempton, West Virginia, which arose from a blown
out shot, and was limited in scope by the condition of
the mine. In the disaster 16 men lost their lives. No
gas has ever been detected in the mine. The mine,
being situated along the synclinal axis of the. Upper
Potomac basin, is naturally fairly moist. The air shaft
is somewhat wet, and the water falling for a consider-
able distance is practically atomised, thus dampening
the air current. There is no doubt in the minds of the
managers that the zone of the explosion was limited by
barriers of wet and moist workings, which lay between
the origin of the explosion and the other parts of the
mine. The explosion was caused by a blown out shot,
which had in turn resulted in a secondary dust explo-
sion, which was'confined to the workings along the first
left entry, and which was prevented from spreading
farther by the moist condition of these entries. The
universal'rule at this mine, and the general practice, has
been to use only permissible explosives, and to detonate
them with an electric battery, and a miner violated
the rules of the company by using short fuses and high
explosives. It was found that a dynamite hole had been
drilled 12 in. on the solid. The rescue parties and the
investigators found no sign of gas whatever in any part
of the mine. Only a, dozen air stoppings were displaced
by the concussion.

The Movement of Coal in Hoppers.

An account of a research into the movement of grain,
coal, etc., in the hoppers of bunkers and silos, published
in the Genie Civil, contains particulars likely to be of
interest to central station engineers who have under their
charge bunkers filled with slack or other small coal. The
experiments were carried out with the aid of a model
representing a vertical section of a hopper. The front
consisted of a sheet of glass, on which were ruled squares
to serve as datum marks, and the side walls were of
sheet steel, either .straight or curved, and could be
placed at various inclinations. The substance used for
the experiments consisted of sand of two colours, which
was charged into the hopper in layers, either vertical or
horizontal, so as to indicate the progressive deformations
of the originally parallel slices. The opening at the
base of the hopper could be regulated to any desired
width.

It was shown clearly that it is always the uppermost
layer which moves from the periphery towards the
centre of the hopper, where it gradually sinks, whilst
the next following layer tends to flow over it, and this
holds good, no matter whether the orifice is large or
small, the walls more or less inclined, straight, convex,
or concave; the sand resting in the neighbourhood of
the walls does not move until it becomes a surface layer,
owing to the descent of all that has previously covered it.
It is only when the walls are very sharply inclined that
the whole of the mass of sand commences moving, and

this is not a practical case, such a hopper being exces-
sively high in comparison with its capacity.

Small coal, coke, etc., obeys the same laws, as one
can easily prove by whitening with chalk the surface
layer of the coal in a bunker, and noting the moment
when the whitened pieces appear at the outlet.

It has also been observed, when vertical iron pipes are
driven deeply into the coal in a bunker, for the accom-
modation of thermometers to ascertain the temperature
in the body of the coal, that these tubes remain vertical
so long as the bunker is not in great part emptied,
because the surface layer alone slides past them without
dragging them with it, the mass of the coal remaining
motionless, and continuing to hold the pipes in their
original vertical position, until the discharge of the coal
eventually removes their support. The fact that the
sloping walls of bunkers when empty show little evidence
of friction, further indicates that only the very last
particles have slid upon them.

To summarise : The column of water ■which stands
upon the outlet is the first to be discharged; then the
successive surface layers; and finally the parts that
were at the bottom, but against the walls, and not
immediately over the outlet.

To provide against the formation of voids in the mass,
due to the jamming and arching of the larger pieces,
which it is often awkward to get rid of, the best plan
is to put the discharge valve at the very bottom of the
hopper without any throat, and to give the outlet the
full width of the base of the funnel; otherwise the pieces
of coal find support in the dead angles at the bottom of
the hopper, and stay there, holding up those above
them.

MINING INDUSTRY AND MILITARY
SERVICE.

Before the Glamorgan colliery tribunal a question arose
in which the miners’ leader (Mr. Hodges) challenged the
action of the colliery representative. It was as to surface-
men for whom the Aberbaiden company did not seek
exemption; and Mr. Hodges made appeal, stating that
clearance could not be effected owing to surface arrange-
ments. He said that when one of the men was idle some
time ago the company had to take a fireman from under-
ground to do his work. Mr. Kerridge, for the management,
said that men over military age could be got to do the work
of the coal tippers; but Mr. Hodges retorted that men
unused to the work might endanger the lives of others.
Upon the tribunal deciding to refuse exemption in the first
case, Mr. Hodges said that the men could not be dispensed
with, for skilled men were necessary at the top. He would
not hold himself responsible for anything that might happen
at the colliery, and would see that no man took on the
job unless he was capable of doing the work. Mr. Kerridge
said he hoped there would be no friction. They were’merely
going to replace those men from another gang. When
the tribunal decided to refuse exemption in a second case,
Mr. Hodges said that- trouble would be caused at the
colliery, for the lives of the men 'depended upon that kind
of work being properly done. In subsequent cases—there
being 14 refusals altogether—Mr. Hodges made further
protest, alleging discrimination in one instance and sug-
gesting virtual victimisation in another. The reply of the
management was a direct contradiction, it being pointed out
that selection had been made of the younger men, and that,
there was not an atom of evidence to support the idea of
victimisation.

With regard to Coytrahen Colliery, Mr. Hodges said that
the company were dispensing with men they really required,
and that eight and even ten turns a week were being worked,
and added, “ You -are going to get trouble if you expect
men to work for 1.6 hours.” After he had spoken at- some
length, Dr. Atkinson said, “ I am afraid your eloquence
will not prevail wrhen the company say they can do without
a man, or can replace him with some one unfit for the
Army.”

Mr. Jones, the agent of the Enginemen’s, Stokers’, and
Craftsmen’s Association was appealed for, at the Gelligaer
tribunal, by the association as his employers. They repre-
sented that his work was of national importance, more so
than if he were in the Army, as he was empowered to effect
settlements in cases of dispute, and was that very day
engaged in such work in the Pontypool area. It was sub-
mitted on his behalf that in the list of certified occupations,
those who were in charge of organisations that might
through some cause effect a stoppage of collieries should be
kept in that occupation. If the decision was adverse it
would upset the whole work of the association. It W’as
stated that the advisory committee had failed to get a rulingz
on this point. The chairman of the tribunal said that
no doubt Mr. Jones’ position was important, and that
if they could contribute to maintaining harmonious relations
between employers and employed they would be doing a
national service. Conditional exemption was granted so
long as the man remained in his present employment.

The Monmouthshire tribunal had before it on Friday the
case of the Celynen Colliery upon a second hearing. At the
previous hearing it had been stated that as the men were
on strike they were consequently not in the employ of the
colliery company, and therefore the single men were not
released from the operation of the Military Service Act.
Since then, however, wrnrk had been resumed; and this was
reported to the tribunal on Friday, when the manager
appealed for the retention of 21 men. He stated that these
had not been asked for at the first hearing because in com-
piling their list of appeals he had assumed that, in the
national interest, other collieries would relieve men with
whom it was possible to dispense. But other collieries had
not taken that course, and therefore he had to appeal, seeing
that their coke ovens were now in full swing. He had been
compelled to put on female labour, and he thought that
these men should be exempt.—The chairman said that the
action of other collieries could not be considered, and that
the Celynen company could not come applying for exemption
for men whom they had previously stated they could do
without.—The manager stated that as the ovens were now
in full operation, all the men were employed, and if they
were to carry out the wishes of the Government they could
not spare any men.—Several total and some temporary
exemptions were granted; but part of the appeals were
refused.

Tn order to obtain for military service more of the men
now engaged in tin-plate mills, the Swansea tribunal has