838

THE COLLIERY GUARDIAN.

October 22, 1915.

a room is so definitely set aside for the use of a steam
engine as to make it a steam engine room within
section 59 of the Coal Mines Act.

Reports were received of the result of proceedings
taken by owners against 599 workmen, showing an
increase of 15 cases over the figures for the preceding
year.

Coal Dust.

In addition to the removal of coal dust from the floors
of the haulage roads a certain amount of brushing of
roof and sides has been done. At a few collieries com-
pressed air is used for clearing coal dust from roof and
sides, the blown dust being collected by different experi-
mental methods.

The use of stone dust for rendering coal dust unin-
flammable is extending, and at a number of collieries
plant for crushing shale for this purpose has been laid
down; and in a few cases flue dust from the boilers
is used. The stone dust is usually distributed by hand,
but in a few cases experiments are being made for its
distribution by means of compressed air or mechanical
apparatus. As stone dusting seems to be the most
practicable method of dealing effectually with the coal
dus-t danger, Dr. Atkinson thinks it is very desirable
that regulations on the subject should be framed as soon
as possible.

Rescue Stations and Ambulance Work.

There are now eight central rescue stations in South
Wales and Monmouthshire, and two more in contempla-
tion in the western part of the Division. The stations
in operation are situated at Aberaman, Crumlin,
Rhymney Valley (New Tredegar), Swansea, Rhondda,
Llynfi Valley, Brynmenin, and Abercynon.

Signalling.

The regulation code of signals is in use throughout the
district. Considerable difficulty has been experienced in
obtaining reliable and otherwise satisfactory appliances
for automatically indicating the nature of the signals in
a visible manner, as required by the regulations. This
difficulty is being reduced by improved appliances and
greater experience in their use.

Horses.

The improvement in the care and treatment of horses
underground, due to the observance of the requirements
of the third schedule of the Coal Mines Act, continues
to be maintained. The horses generally are well fed
and kept in good condition. Improvements have been
made in the construction and ventilation of a number of
underground stables during the year.

to be held. The examining authorities generally are
considering how they can more fully comply with the
Home Office requirements as to the air measuring tests.

Explosives Used.

The following are particulars of explosives used :—
Quantity used, 2,401,728. Estimated number of shots
fired.—By electricity, 2,918,872; by fuse, 985,759; by
squibs, 269,475; total, 4,174,106. Miss-fire shots.—
With electricity, 3,241; with fuse, 1,341; otherwise, 95;
total, 4,677.

Safety Lamps.

The following particulars relate to the safety lamps in
use :—Flame safety lamps.—Number in use, 167,446.
Method of locking.—Lead rivets, 76,703; magnetic,
76,850; screws, 5,216; other, 8,677. Kind of illuminant.
—Colza or colza and petroleum, 95,383; petroleum,
1,033; volatile spirit, 3,970; other illuminant, 67,060.
Method of lighting.—By electricity, 102,373; otherwise,
65,073. Electric safety lamps.—Number in use, 23,066.
Method of locking. — Lead rivet, 1,195; .magnetic,
21,866; other, 5.

Of the flame safety lamps in use, 106,667 were of the
Clanny type, and 46,747 of the Marsaut type. The fol-
lowing shows the number of each type of electric lamp
in use:—Ceag, 16,057; Oldham, 5,753; Wolf, 1,033;
Float, 99; Gray-Sussmann, 80; Varta, 42; Bristol, 2.

Electricity in Mines.

The following is a summary showing aggregate horse-
power in use :—Number of mines, 291. Surface.—
Winding, 16,372J; ventilation, 17,924; haulage, 14,693-J-;
coal washing or screening, 9,528|; miscellaneous 35,314;
total, 93,832|. Underground.—Haulage, 42,783; pump-
ing, 55,095-p, portable machinery, 799J; miscellaneous,
1,765|; total, 100,443J.

Of the total horse-power, 63,480| were used in
Glamorgan, and 31,217 in Monmouth.

COLLIERY TUB BEARINGS.

By T.E.C.H.

The application of the ball bearing to the axles of
colliery tubs continues to gain favour, the reason for such
being due to the following actual truths proved in
practice :—(a) The saving in lubricant amounting to 80
per cent, of that required by the ordinary plain sliding
type of bearing; (b) the cost of haulage is greatly
reduced; (c) 30 to 40 per cent, more tubs can be dealt
with, the existing haulage plant requiring no increase;

case and the housing (wheel) in the other, owing to the
small diameter of the axles it is found advisable to hold
the inner race of the bearings, as shown, independently
of whether the axle or wheel revolve.

The hub of the wheel forms an excellent reservoir for
the lubricant in the design to fig. 1, while the bottom
cap of the pedestal housing, besides enabling easy inspec-
tion, also acts as a reservoir in the design to fig. 2. The
thrust duty is taken by the bearings themselves, and not
by plain washers, as is necessary in some designs of anti-
friction bearings.

Although the lubricant only requires renewing twice
per year, it is essential that the lubricant used shall be
free from acid and alkali or chalky matter. So impor-
tant is this that most ball bearings manufacturers
analyse any lubricant which it is intended to use free
of charge.

The all-round increased efficiency obtainable by the
use of the ball bearing results in such a high return on
the capital outlay, that wherever a trial order is placed
repeat orders generally follow.

Fuel Briquetting in the United States in 1914.—According
to Edward W. Parker, of the United States Geological
Survey, although the number of briquetting plants in the
United States was reduced from 17 in 1913 to 16 in 1914,
there was a substantial increase in the quantity of briquetted
fuel produced and sold. Of the 16 plants in operation, five
used anthracite culm as a raw material, two semi-anthracite,
two bituminous slack, two a mixture of anthracite culm and
bituminous slack, two petroleum residuum, two semi-bitu-
minous slack, and one a mixture of anthracite culm, bitu-
minous slack, coke, and lignite. Nine plants used coal tar
pitch for a binder, four used secret binders, and one used
petrolastic cement. No binder is required in briquetting
carbon residues from oil gas works. The production of
briquetted fuel in 1914 amounted to 250,635 short tons, valued
at 1,154,678 dols., compared with 181,859 tons, valued at
1,007,327 dols., in 1913, the increase amounting to 68,776
short tons, or 37-82 per cent., in quantity, and 147,351 dols.,
or 14-63 per cent., in value. The quantity of fuel briquettes
produced in 1914 was the largest in the seven years for
which these statistics have been collected by the United States
Geological Survey. In order to meet with popular favour
in the United States, briquettes must be of convenient shape
for shovelling and for permitting air to circulate in the fire

iWpli

Fig. 1.	Fig. 2.

The chief causes of complaint have been the working
of horses in an unfit state through sores caused by their
harness, and of horses being overworked. Other matters
to which the attention of colliery owners had to be called
included the adequate supply of food and clean drinking
water in the workings; the dimensions of horse roads;
the cleaning and ventilation of stables; the inadequacy
of horsekeepers’ reports; and many improvements were
thus effected.

Statistics respecting the horses employed underground
in mines under the Coal Mines Act are as follow :—
Number used, 16,299. Number died (exclusive of those
required to be destroyed) : From injury by accident,
478; from disease, 341 (including 31 from old age);
total, 819. Number required to be destroyed : In conse-
quence of injury, 334; in consequence of disease, 246
(including 52 from old age); total, 580. Number of cases
of injury or ill-treatment reported to manager (exclu-
sive of cases already included) : Injury, 3,148; ill-treat-
ment, 21; total, 3,169.

Firemen’s Certificates.

Examinations were held during the year by the Brecon-
shire, Carmarthenshire, Glamorganshire, and Monmouth-
shire Education Committees, and by the Borough Educa-
tion Authorities of Swansea and Merthyr Tydfil. In
some cases the arrangements for measuring an air
current with an anemometer, and by means of dust or
smoke, were not such as to admit of the latter test being
practically performed, owing to the absence of a gallery
with a current of air passing through it. To meet the
Home Office requirements fully as to air measurement,
two examining authorities now conduct this part of the
examination underground in a mine, and others in rescue
stations, where facilities for air measuring are greater
than in the county schools, where the examinations used

(d) the life of the tub as regards the axles and bearings
is increased many times; (e) practically no attention is
required by the ball bearing other than that the lubri-
cant shall be renewed twice in every 12 months; (/)
the danger of the ball bearing running hot is non-
existent. Correct fitting is of the utmost importance,
and although really a simple matter, does not always
receive its due share of attention, such telling unfairly
against the ball bearing, with the mounting shown in
figs. 1 and 2, the inner race of the bearing should be
an easy tapping fit on the shaft, which must be a reason-
able machine finish; the outer race of the bearing being
an easy push fit in the boss of the wheel. The distance
between the two end covers marked X is very important,
and prevents the housing loading the bearings very
excessively; this takes place when the outer race is
forced sideways should this difference be small. The
felt washer shown should be a reasonable fit on the shaft
and thus increase its efficiency in preventing dirt obtain-
ing access to the bearing.

To use the existing axles, the bearings are mounted
in the hub of the wheel, and two end covers used, as
shown by fig. 1; this arrangement is also advisable when
the track is very tortuous, and thus the many corners
are easily negotiated. The alternative method of placing
the bearings on the outside of the wheel is, from the
point of view of cheapness and inspection, an advantage,
with which arrangement a heavier type of bearing is
required. The ball bearing is made by all manufac-
turers for light, medium, or heavy duty, and thus no
difficulty arises on account of an increase in load, the
shaft diameter remaining constant.

It will be seen from figs. 1 and 2 that two nuts hold
the inner races of the bearings against the shoulders on
the axles, and although the shaft or axle revolves in one

box. They must be of sizes suitable for the purposes they
are intended to serve, and must possess sufficient cohesion to
resist fracture and abrasion under rough handling. Some of
the briquettes manufactured in European countries, parti-
cularly in Germany, are made very large, for easy stowage
in bunkers of steamships and tenders of locomotives, and are
not adapted for use in America, as the high cost of labour
prohibits such handling. The briquettes which appear to
meet with favour in the Eastern States are of the boulet type,
pillow- or egg-shaped, and about the size of anthracite nut.
In the Central and Pacific Coast States the popular type of
briquetted fuel appears to be the larger size, about that of
egg coal, for which the raw materials available seem to be
best adapted. The failure to make more substantial progress
in the production of briquettes from anthracite is probably
due to the fact that an absolutely smokeless product has not
been obtained, and consumers accustomed to smokeless
anthracite object even to the small amount of smoke emitted
from the briquettes. Slack from the non-coking bituminous
and sub-bituminous coals of the Middle Western and the
Rocky Mountain States is another cheap and abundant raw
material for the manufacture of briquettes. The quantity
now used in the manufacture of briquettes represents but a
drop in the bucket of available material. The vast and
almost untouched areas of lignite in North Dakota and Texas
contain enormous supplies of fuel that European practice has
taught is well adapted to briquetting, and is much more
usable in that form than in the raw state. The five estab-
lishments using binders other than pitch employ mixtures
whose constituents are principally of vegetable origin.
Inorganic binders, such as cement and lime, have not given
satisfactory results, for although they may be efficient in
cementing qualities, they have the serious objection of
increasing the ash and adding nothing to the combustible
matter of the fuel. Binders of organic material, however,
such as pitches from coal tar. gas tar. or asphalte, or mix-
tures of vegetable origin, contribute combustible matter, and
do not increase the percentage of ash.