174

THE COLLIERY GUARDIAN.

January 26, 1917.

to the Bradford disintegrator, an efficient machine built
for breaking coal. At the Joliet plant of the Illinois
Steel Company, a Bradford disintegrator, 11 ft. in
diameter and 25 ft. long, with screen openings of If in.
diameter, breaks Illinois lump coal so completely that
less than 3 per cent, oversize is discharged, and this is
mostly hard refuse. Practically all the coal is broken
during its passage through the screen. Although the
diameter of the disintegrator is 5 ft. greater than that
of the ordinary roller screen, and although ribs are
placed inside to lift the coal and secure extra height of
drop, the general parallelism of action holds.

Breakage in Loading : Passage Over Loading Chutes,
Aprons, or Booms.—Because of the price of labour and
low value of the coal at Illinois mines, coal must be
loaded mechanically or automatically, even at the
expense of slight breakage. Since most tipple screens
have considerable slope, inclined chutes are constructed
to lower the various screened products into- the railroad
cars. Such chutes may be fixed, hinged, shaking, or
movable, or may consist of a moving or travelling adjust-
able steel loading boom, belt, or apron, with
which is often combined the picking belt. Most of the
tipples built within the last five years have been
equipped for loading the lump and egg sizes of coal with
these travelling adjustable loading booms, or with some
other form of movable loading chute which can be
lowered into the empty car and raised again when that
end of the cars fills.

Loading chutes may lend directly into the car at right
angles to the track, or, if they have bends or right angle
turns or drops, they may lead into- the car in a direction
parallel with its length. Chutes which discharge
straight into the car at right angles to the track, unless
flat and shaking, shoot the coal into the car. At one or
two of the older mines in which these chutes are still
in use, a sheet steel buffer is hung over the opposite side
of the car in order to prevent spilling, and since the coal
comes with considerable force, even trimming 'and hand
picking are rendered difficult. In a chute with curved
bottom, the lumps slide down only in the lowest part,
and one at a time, so that a swiftly moving piece may
overtake and break the piece ahead. Otherwise, these
chutes give good results, especially if bends are neces-
sary, because they turn the direction of the1 coal
gradually.

At most new‘installations the loading chutes are
placed parallel with the track, since from this position
the coal can be loaded with less breakage, the chutes
can be lowered into the cars, spilling of the coal over
the sides of the car can be eliminated to a great extent,
hand-picking can be conducted efficiently and with
greater safety, and the coal1 can be trimmed more
uniformly. Whether or not the flow of coal in such a
chute should be with or against the direction in which
the loading car is moving is open to argument. Most
chutes in Illinois are placed so that the coal moves in
the same direction as the car. Advocates of this system
claim :—(a) If movable loading booms are used, it is
possible to get them well down into the empty car; (b)
lumps can be examined and picked with safety. Those
in favour of the other system claim :—(a) More regular
trimming is possible, especially if the cars are moved by
hand or by gravity;, (5) less breakage occurs, since the
coal is always moving in the direction of the slope of the
coal in the car.

Breakage in the loading of the smaller prepared sizes
—egg and nut—is not so severe, oh account of their
smaller size, lighter weight, and greater uniformity. In
order to meet the demands of domestic trade., these
sizes must be unusually free from degradation products.
A number of mines have recognised this fact, and have
installed small degradation or 'secondary screens in the
bottom of the loading chutes for these sizes. These
screens, bar, round hole, wire screen hole, or lip, are
usually stationary, and form the bottom of the chute
for their length. They usually have less than 1 in.
openings, but they remove the last trace of accidental
fines, and allow only the clean, sized coal to enter the
car. The undersize usually passes into the screenings
car or to the boiler room.

The perforations in the lip screens (fig. 5) are long
in comparison with their width, and they become
slightly wider at the lower or discharge end. A slight
drop in the screen at the end of each series of slots
allows wedged pieces to be released at these points.
This screen also aids in removing small flat impurities
which have been sized on the round hole shaker with
the.more cubical pieces of coal.

Loading and Trimming Railroad Cars.—If all railroad
cars were of the same dimensions as regards height, it
would’be. a simple matter to- regulate a chute, so that
loading might take place with a minimum of breakage.
Coal cars differ greatly in design, in height, and in capa-
city. They consist of three classes :—(a) Gondola cars,
with or without dumping devices; (b) hopper bottom
cars; (c) box cars. The special loaders of the box cars
will be treated later. Open gondolas and hoppers are
the common classes, and at present range in capacity
from 25 to 50 tons, and in height,or clearances of sides
above the rails they vary from about 7 ft. to- more than
lift, in the newer “high sides.” Such a range of
clearance seriously affects the successful loading and
trimming of the cars, especially if the chutes are not
easily and quickly adjustable, since in “ spotting” the
cars one with steel sides is likely to be followed by a
low wooden gondola. At some of the old mines, screens
and chutes are so low that the highest cans cannot be
loaded on the lump track. In such a case, they are
usually switched under the screenings chute, where more
headroom is available, and breakage not so important.
Also, by this practice, excessive shifting of the loading
devices is avoided.

There is a -wide difference in the inside height of coal
cars. They range from 3 ft. 6 in. in the smaller flat-
bottom gondolas to 9 ft. in the deepest part of ai modern

steel hopper car. The difference in breakage in loading
two such cars from a chute of the same height is
•evident. At one mine the loading chute had been
raised to a height of about 14 ft. above the tracks in
order to load properly and trim a high side car. The
next car was only 8 ft. in height, and, therefore, the
coal dropped about 10 ft. before striking the bottom of
the car. Another measurement showed that the- end of.
the lump coal chute had a clearance of 8 ft. above the
car being loaded at the time.

In general, coal loading without breakage is an engi-
neering problem which has been practically solved.
Frequently the loaders do not take advantage of the
adjustable features of the chutes by following the load-
ing closely, and often no attempt whatever is made to
use them. In some cases bad balancing makes the
Eshifting of the automatic loading devices laborious. The
newer inclined loading belts or booms are generally cone-
troll ed by small electric hoists, which make adjustment
easy.

When loading a car under the tipple, first the end
shbuld be filled to the full height of the car, and then
the car gradually and slowly moved along, preferably
only a few inches at a time. In this way the coal
coming from the loading chute strikes near the top of
the loaded pile, and after dropping a. minimum distance,
rolls gently down the slope of the pile into the- car. .
Sometimes the cars are pinched by. hand while being
loaded, along a grade which has become somewhat irre-
gular by reason of long service, while on other tracks
the grade is sufficient to start the car on releasing the
brakes; in either case, there in danger of excessive
breakage from lumps dropping ihe full distance to the
floor if the car is allowed to move too far. At the
more modern and larger mines the cars are retarded
and moved either by means of a car puller, which is
simply a wire rope attached to a power-driven drum,
or by a patented car retarder, which consists of a rope
attached to a small friction drum under control of an
operator. This allows the car to be moved forward as
desired, and ensures a uniform unbroken lump.

Of late years a number of mechanical devices have
been perfected, called box car loaders, which load the
coal evenly in the car, or where desired.

A modern box car loader in the tipple should fulfil
the following requirements :—(a) A capacity equal to
that of the shaker screen :—(a} ready adaptation to the
regular coal chutes; (c) mobility—can be moved in and
out of the cars quickly; (d) freedom of injury to the Car
ends; (e) freedom from breakage in conveying and
depositing the lump coal in the ends of the cars. The
first four requirements will come properly in the dis-
cussion of the engineering features of the tipple. The
fifth feature, breakage, is being overcome in the newer
designs.

At a number of the tipples the box car loaders, which
had been installed several years previously, and were of
older designs, were rusty and unused. Enquiry revealed
that the main reason for this was “ too much breakage
of coal,” another objection being that no inspection or
picking is possible in the car. At many mines, how-
ever, the loaders are used constantly, and the fact that
some of the newest plants have installed them is proof
that they fill a need.

Much of the breakage in connection with a box car
loader is due to sliding the coal from the shaker screen
down the steep chute necessary to bring the lump coal
to the box car'loader. Mr. A. J. Reef describes the
difficulty as follows :—“ It has been the universal prac-
tice to feed box car loaders over stationary chutes, and
even .when shaking screens are used, the oscillating por-
tion is at such height as to load open cars, and for the
loading of box cars, a long and rather steep chute is
always employed. The coal necessarily attains such
speed in passing through this latter that it is certain
to splinter more or less on striking the loader.” Recent
installations in Illinois have improved this obvious
defect.

Grimsby Coal Exports.—There were 3,069 tons of coal
exuorted from Grimshv during the week ended January 19.
The total for the corresponding week of last year was 4,664
tons.

Output and Wages in 1916.—By means of the inflow of
labour, fuller working, and more regular attendance of
miners, the output of coal in the United Kingdom last year
showed an increase on that of the previous year (approxi-
mately 256.135,000 tons, against 283,179.000 tons), but the
total is still substantially below the 287,412.000 tons in
1913, and the 265.643,000 tons in 1914. The decline is largely
owing to the enlistment of miners. The net. increase of
wages in the coal miffing industry last year was £226,500,
compared with £277,800 in 1915. These figures include
increases granted to men, boys, women, and girls, but the
average increase is highest in the case of men. The number
of disputes declined from 79 in 1915 to 61 last year, when
57,018 workpeople were affected, and 287,400 working days
lost. In the previous year 297,801 workpeople were affected,
and 1.640.899 working days lost.

British Coal for France.—M. Henriot (Minister of Trans-
port and Supplies), at the conclusion of an important con-
ference with a number of French coal importers, declared
that, although French coal importers had been mostly in
favour of each acting separately to obtain the best freight
terms, at the end of the conference they had agreed that it
was. impossible in the existing circumstances to continue
isolated and independent chartering. . The necessity to
organise convoys under proper escort, said the Minister, bad
for complement the absolute submission of the importers to
the special conditions of such journeys. Under the terms of
the convention entered into . with Great Britain,, the charter-
ing of neutral vessels will be centralised in an Inter-Ally
Bureau in London. A recent conference in London had for
its object to fix the powers of this bureau. M. Herript paid
a high tribute to the loyaltv’ of Great Britain in this diffi-
cult and delicate matter, and added that the British Govern-
ment had agreed, to give France at least 50 per cent, of these
neutral charters.

THE CHALMERS-BLACK INDICATOR.

In Scottish mining circles considerable interest has
been aroused in the singularly successful results obtained
by the Chalmers-Black non-accumulative visual signal-
ling indicator. During the past few weeks a series of
interesting demonstrations have been carried out with
the indicator at. the Nos. 2 and 3 pits, Motherwell
Colliery, belonging to Messrs. John Watson Limited,
and as these demonstrations have been attended by coal
owners and managers from iall parts of Scotland, as well
as representatives of the Scottish Colliery Enginekeepers’
Association, a detailed description of the arrangement
will not be without interest.

The .indicator is made with three pointers, one of
which is for action signals, the second for cautionary
signals, and the third for destination signals. The
pointers are so arranged as to move round the dial step
by step with every stroke of the signalling system.
Actuation is obtained from a rod in direct contact with
the signal hammer. Mounted on this rod which is con-
nected to the signal hammer is a pawl, which serves to
give step-by-step rotation to a ratchet wheel loosely
mounted on a revoluble shaft, and engaging with the
latter by means of a one-way clutch connection. Secured
to this shaft is the active signal ratchet wheel and
painter, the latter being fitted with a tongue acting as.a
driver, and engaging with the lateral edges of the
cautionary and destination signal pointers. The last-
mentioned pointers are respectively mounted on sleeves
with ratchet wheels, surrounding loosely the shaft. By
virtue of the clutch connection on the free ratchet wheel,’
and the tongue on the signal pointer engaging with the
lateral edges, the cautionary and destination signal
pointers are adapted to participate in clockwise move-
ment round the dial. The free ratchet wheel is sus-
tained temporarily against counter clockwise rotation by
a detent co-operating with a time wasting device, com-
prising a train of wheels regulated by a governor, which
serves on each stroke of the signal hammer to main-
tain temporarily a rod having a pin and slot connection
in a state of flotation. As will be readily understood,
the temporary detention of the1 free ratchet wheel from
counter clockwise rotation is to allow the engine-operated
detent to feed up until the number of signals have been
given. "When the predetermined time elapses after the
onsetter has given his last signal, the free ratchet wheel
returns to zero, ready to repeat a signal or register any
signal that may be given.

The formation of the active signal pointer ratchet
wheel is such that the engine-operated detent is opera-
tive only when the pointer occupies a position at Nos.
1 or 2 indications on the dial. As this particular pointer
drives the other two, only one pointer is visible when
the signal 1 or 2 has been given. The cautionary signal
pointer, ratchet wheel is so formed that only one notch
is provided, and is operative only when the pointer indi-
cates 3 on the dial. The destination signal pointer is
fitted with a ratchet wheel and an engine-operated
detent. It is operative from the 3 indication on the
dial till maximum travel has been reached. The ratchet
wheels of the three pointers in reality only comprise one
complete ratchet wheel, and they are so loaded as to
return the pointers to zero when released.

When the action signal pointer and the cautionary
signal pointer pass the position they ought to take on
the dial, their detents are put and held out of action
until the pointers are returned to zero, independent of
any movement of the bell whatever. This ensures per-
fect action of the pointers. The destination signal
pointer ratchet wheel is so formed that the engine-
operated detent comes into action at the indication of 3
on the dial, and remains operative . to indicate every
signal given. It becomes disengaged only when contra-
dictory signals are given. The outstanding feature of
the device is that it automatically and without any
human agency-—that is, without the intervention of the
enginekeeper-—cancels all contradictory signals and those
that do not necessitate the moving of the cage. With
regard to the cautionary action signals — which may
require the cage to be moved a few inches only—these
are cancelled by the stop signal. The latter in turn is-
also cancelled, and the dial indicates zero.

The indicator is so constructed as to admit of easy
cancellation, between the decks of cages. It can also be
arranged to cancel the action signals when decking men,
and still retain at the same time the cautionary signal—
“ Men.” The indicator is strong and durable, and can
be adapted to suit the requirements at any colliery, and
be fitted comparatively easily to existing hammers,
wines, etc. The weight of the signal hammer in the
downward stroke is responsible for the travel of the
pointers round the dial. An important feature in con-
nection with the indicator is the cancelling gear, which
is positive in action, and is connected to the engine, and
fitted to cancel between decks. The indicator has been
working at Motherwell Colliery, Motherwell, for nearly
two years, and has given so much,satisfaction that appli-
cations to see it in operation have come from all the
colliery districts in Scotland. Messrs. Johnston and
Company, engineers, Cleland, Lanarkshire, Scotland,
are the manufacturers on behalf of the patentees, but
the indicator can be seen at work bv arrangement with
the management of Motherwell Colliery, Motherwell.

Hull Coal Exports.—The official return of the exports
of coal from Hull to foreign countries for the week ended
January 16 is as follows:—Aarhus, 157 tons; Dunkirk,
1.635; Gothenburg. 2,536; Harlingen, 591; Leghorn, 800;
Rouen, 4,415 ; Rotterdam, 477 ; St. Valery. 209—total, 10,820
tons, as compared with totals of 23,720, 36,909, 60.934, and
70.869 tons in the corresponding periods of 1916. 1915, 1914,
and 1913 respectively. These figures do not include bunker
coal', shipments for the British Admiralty, nor the Allies’
Governments.