January 1, 1915.

THE COLLIERY GUARDIAN.

35

The reloaders have the duty of receiving coal from the
conveying system and then making delivery of it to
vessels. As the latter will vary a good deal in respect
to size and the location of hatches, it is necessary that
the reloading arrangements shall be flexible. Conse-
quently, the unloader is provided with a hopper, which
receives coal from the general conveying system,
and an individual conveying system by means
of which coal is taken from the hopper to the
discharge end of the reloader, where an adjustable boom
controls a telescopic chute. By means of these arrange-
ments the unloader is able to take care of big ships and
others not so big, and to deal with their individual
peculiarities. The reloaders operate on the reloading
wharf, where they may be moved back and forth on
rails provided for them. These machines have a rated
capacity of 500 tons per hour.

The general conveying system provides for the local
transportation of coal to and from various points within
the plant. It connects different parts of the storage
pile, and puts the pile in connection with unloaders
and reloaders. Further, the conveying system puts the
wharf bunkers into touch with the storage pile and the
unloaders, and it is said that it permits two vessels to
unload coal destined for the same part of the storage
pile at the same time.

On the loading wharf a steel and concrete bunker
will be constructed having a capacity of 1,500 tons.
There are three compartments of equal size, each pro-
vided with two valves. The delivery openings which
may thus be brought into service have a cross sectional
area of 6 sq. ft. The floors of the individual bins are
tilted at an angle of 45 degs., which is sufficient to
provide a good rate of flow. The openings through
which coal is delivered from the bins are 28 ft. above
the wharf. By means of a folding chute, delivery may
be made at a level 7 ft. below it. This is the lowest
delivery point of the chute. Its highest is 14 ft. higher
up. In addition to these arrangements, each bin has a
second chute which delivers coal at a constant level of
5 ft. above the wharf. The wharf bunker provides for
the coaling of barges, tugs, and such vessels.

At Balboa, on the Pacific side, the coal plant will be
not so large as its companion. There will be unloading
towers and other apparatus similar to that which is to
be installed at the larger plant. But instead of employ-
ing specially designed and constructed bridges for the
purpose of reclaiming coal and stocking it, the cable-
ways which have been employed at Miraflores in con-
crete construction, will be modified and brought into
service. As these originally cost about $300,000, the
incentive to their utilisation will be readily understood.

Coal handling plants no doubt fall into several general
classes, in each of which certain elements or features are
more or less fixed. And yet, on the other hand, nearly
all situations, or at least very many, call for special
arrangements to meet the special conditions. Panama
has been no exception. Here the perhaps not unusual
requirement that the several units be mutually inde-
pendent has been transcended. What had to be taken
into account was not merely the vicissitudes to which
an ordinary commercial plant might be expected to be
subject, but, in addition, the eventualities of war.
Cristobal and Balboa are going to be great naval coaling
stations. It is proposed not simply to have coal on
hand in storage, come what may, but to have a loading
and unloading plant which should be on hand ready to
perform its duties. So, for one thing, the towers are
not to be operated by electricity from a central station.
Such an arrangement would result, in the event of a
hostile capture of the station, in putting the handling
plant entirely out of commission.

The six towers therefore are to be operated by steam.
Each will be a self-contained unit in respect to power.
The engines, located in the large quadrangular space in
the tower just below the big hopper, will get their steam
from a boiler equipment situated in this same space.

There will always be coal. So if, at Balboa for example,
three towers should be demolished or captured, there
would still be a fourth unit capable of operation.
Further, the towers are independent of the conveying
system. If the latter is, for any reason, out of com-
mission, the towers are competent, without its assist-
ance, to load vessels from the storage pile and to unload
vessels and deposit the coal on the pile. Indeed, coal
may be transferred from one. vessel to another by means
of the tower alone. The outboard portion of the boom
has a reach of 61 ft., so that a coal barge and a ship
may be abreast close up to the wharf—in this way
making it possible to reach hatchways in both.

The towers are structures of considerable size, as may
be gathered from some of their dimensions. All six
will have a height of 150 ft. above the rails, which
means the elevation above the concrete floor, as the
rails will be sunk so as to have their heads flush with
the general surface. The inboard reach of the boom
from the framework of the tower will be 71 ft. The
outboard reach, as already said, will be 61ft. The
boom will be 79 ft. above the rails. The four-wheeled
trucks which support the entire load will run on two
tracks, either of which will have a gauge (centre to
centre) of 3 ft. From truck track to truck track,
centre to centre, will be 34?, ft.

Two of the trucks, one on either track, will drive,
while the others will trail. The transmission will be
by worm gearing.

Altogether, there are to be four different power units
to each tower. The main engine is the hoisting unit,
a double-cylinder 18 in. by 24 in. machine. This engine
is direct connected. The engine which effects the
traversing movement of the trolley is of 12 in. by 14 in.
size, and is also of the double-cylinder reversing
variety.

A third engine, 10 in. by 12 in. geared unit, performs
the duty when necessary of raising and lowering the
boom and of effecting the propulsion of the driving
trucks. A 6 in. by 8 in. double-cylinder engine operates
the 42 in. conveying belt.

THE “ FLUVER1T ” FUSE SYSTEM.

Until recently, most engineers in charge of electrical
installations experienced a difficulty in finding a
satisfactory fuse. It is generally known and admitted
that the requirements of the engineer had not been
fully considered by the manufacturer in the past, for
there are still in use defective fuses such as the 4 in.
porcelain tubular handle type, and the hand shield type.
The defective features of these fuses are their small
metal contacts fixed by screws, long length of fusing
wire which has considerable resistance and inherent
heating troubles, together with arcing from contact to
contact.

These troubles have been fully appreciated by Messrs.
Parmiter, Hope and Sugden Limited, Manchester. The
fuse system which they have developed and placed on
the market embodies the results of a long study of the
conditions existing in power work, and meets the
required demand in a thoroughly reliable manner.

The design and construction of the fuse system seems
to be sufficiently substantial and well suited to the
conditions met with in mining practice. In this connec-
tion we append some descriptive notes and illustrations
of the system.

The fuse consists of a T shaped porcelain block with
large metallic contacts secured to the sides instead of

Fig. 1.—“Fluvent” Fuse

Fig. 2.—Row of Bases and Cover
Plates.

Fig. 3.—Iron-clad Box Containing Fuses.

at the ends as in the usual hand-grip type; the front
portion has a vertical tube, the fuse wire passing through
this tube obliquely instead of down the same. The
wire when straightened is threaded through small holes
from one contact to the other (fig. 1). The fuse block
is inserted as a wedge into a porcelain base provided
with corresponding metallic contacts which are
connected to round bus-bars. Fig. 2 shows a row of
bases viewed from the back.

In the fuse system the bases, together with the
spacing blocks at the ends, are threaded on steel rods,
which are insulated at the ends in an iron-clad box
(fig. 3). This design gives a rigid form of fixing, and
has the advantage of keeping the whole space behind
the bases clear of any supporting pillars, and allowing
ample freedom for the bases to expand, thus preventing
any injury to them through heating.

It will be noticed in fig. 3 that all “live” parts are
most carefully covered: even when the fuse blocks are
withdrawn the bus-bars and contacts are still covered.
When the steel rods are withdrawn any base may be
turned on the bus-bar, which acts as a hinge, and by
this means contacts may be added from the front of
the board without any difficulty. The fillets on which
the spacing blocks rest are made of non-hygroscopic
and incombustible material. The box is also provided

with a ventilator, which prevents excessive temperature
rise in the box. The notable advantages of this fuse
system are :—

Short length of fusing wire, and thereby no heating
troubles when the fuses are placed in a closed box*

No arcing from contact to contact, as the blow-out
effect of the vertical tube tends to blow the arc away
from the contact instead of towards them.

The very short length of wire that has to be
volatilised on short-circuiting entails a very low watt
loss.

The fuse will clear- the line when subjected to really
heavy short circuit. +

Fuses easy of access and free from danger when
replacements are necessary.

* This is most clearly demonstrated, when this fuse and
a 4 in. handle type are in series and subjected to a current,
using same size of wire for both: the former will be
comparatively cold while the latter will be red hot.

t This is borne out by the tests made under exceptionally
severe conditions by Mr. S. L. Pearce, chief engineer for
the Manchester Corporation. In all the tests, Mr. Pearce
says “the circuit was broken immediately without any
signs of arcing or burning- of the contacts.”

TELESCOPIC GAS-TESTING ROD.

In the course of his reply to the discussion on his
paper on “ A few Practical Observations on Gas
Testing”* read before the South Wales Institute of
Engineers, Mr. John Roberts described a telescopic
gas-testing rod, the accompanying illustration of which
we take from the current issue of the Proceedings.

The rod consists of three aluminium tubes—an outer,
intermediate, and inner tube. The outer tube is
36 in. long, in. outer diameter, and made of metal
in. thick. The lower- end (a) is made solid and of
brass, to resist wear and in order that it may be used
for testing the roof. At the upper end a brass milled-
head conical nut (6) is fixed. Slots (c) are cut in the
tubes, as shown, so as to enable the inner rods when
extended to be tightened in any position by means of
the conical nuts. The inner- rod carries at its upper-
end a brass pear-shaped loop to receive a lamp hook
when testing for gas ; the swinging of the lamp being
reduced to a minimum on account of the shape of the
hole. The outer tube is graduated in inches upwards
from the bottom, the inner tube being graduated from
the top downwards. The total weight of the rod is
If pounds. The rod is made by the Spring Bod
Company, Cherry Tree, near Blackburn.

* See Colliery Guardian, October 9, p. 778.

LETTERS TO THE EDITORS.

The Editors are not responsible either for the statements
made, or the opinions expressed by correspondents.

All communications must be authenticated by the name and
address of the sender, whether for publication or not.
No notice can be taken of anonymous communications.

As replies to questions are only given by way of published
answers to correspondents, and not by letter, stamped
addressed envelopes are not required to be sent.

FIREDAMP DETECTORS.

Sirs,—In your issue of the 18th inst. mention is
made of my gas detector (recently described in your
paper) by Mr. Percy Lee Wood, at the meeting of the
Manchester Geological and Mining Society.

It was stated that my instrument gave correct
indications for methane, but was unsatisfactory in a
mixture of methane and carbon dioxide. This is far
from being the case. As a matter of fact, the instru-
ment will now measure both the CH4 and the CO2 in
any mine mixture of these gases.

Again, Mr. Ralph states that diffusion instruments
all require pure air for their use. Until the present
time this has been the case, but with my instrument
continuous readings can be, and have been, accurately
taken under the worst conditions possible underground
without the use of fresh air.

Horsforth, near Leeds.	H. R. Webster.

December 29, 1914.

Reference to the discontinuation of the coal explorations
by the Peruvian Corporation Limited was made by Mr. G-.
Acton Davies, at the annual meeting, on the 29th ult. He
said he assured the proprietors last year that they should
not proceed hastily or without convincing themselves that
the coal was really of such a character as would ensure a
sale at profitable prices. This, as time went on, was more
and more confirmed, and had the coal been present in
adequate quantity there could be no doubt that the
profit from the working would have been very remunerative.
But their hopes of success were shattered by the further
explorations made, and the board reluctantly came to the
conclusion that it would not be prudent to continue any
further outlay, inasmuch as the doubtful prospects as
regarded quantity more than outweighed the undoubted
excellence of the quality. They had, therefore, discon-
tinued all expenditure, and had written off the whole debit
balance.