Charles George Warnford Lock.

Economic mining: a practical handbook for the miner, the metallurgist and ... online

. (page 13 of 76)
Online LibraryCharles George Warnford LockEconomic mining: a practical handbook for the miner, the metallurgist and ... → online text (page 13 of 76)
Font size
QR-code for this ebook

which the bearings may be moved to disengage the gear-wheels. The
construction is very simple, and the hoisting work is all the time
under the control of the operator.

In the case of rapid hoisting, a direct-acting hoisting engine is
essential. Various forms are described at length in * Mining and
Ore-dressing Machinery.'

The Koepe system of winding consists in substituting for the
ordinary cylindrical drum a grooved pulley round which the rop
makes rather more than half a turn, and thence passes over the pit-
head pulleys and down the two divisions of the shaft. The balance
rope beneath the cage is not a peculiarity of the system, as it has
been applied for a long time to winding-engines where ordinary
cvlindncal drums are used. Experiments on tbe Eoepe system have
shown that with the rope passing only one-half turn round tbe
driving-pulley, the coefficient of adhesion between steel rope and
wood rim is in practice 80 per cent., which admits of a great excess
being placed on present ascending loads before any slip can oocur.
That no slip actually results in practice (under the vaual working
conditions) is shown by the fact that at Bestwood colliery the winding
takes place at the upcast shaft which is cased in, and the cages are
entirely out of sight of the engineer, who has to rely entirely on the
indicator, and under these circumstances has no difficulty in Icuiding
the load. It is, however, evident that when the cages reach the land-
ing-places and rest on the stops (if any are used) the weight is
removed from the rope, and sufficient adhesive power may not exist
on the rim of the motive-pulley to enable the loads to be re-started.
This can be guarded against by dispensing with stops altogether (as
is done at the Sneyd colliery), or by continuing the rope past lie
cages by means of cross-heads above and below each cage, con-
nected together by side pieces passing outside ; the bridle chains are
hung from the top cross-head, and when the cage rests on the to[»
the weight of the winding- and tail-ropes still remains on the motive-
pulley. This is the arrangement used at Bestwood. The single
winding-rope at the HanoYer colUery has been found to last more
than twice as long as the two ropes formerly adopted. The chief
advantage of the system, apart from the perfect equalisation of the
load, which can also be obtained in any engine with ordinary cylin-
drical drums, consists in doing away with the drum, which in many
instances weighs 60 tons, and has of course to be bet in rapid motion
and stopped in a short space of time, causing a large waste of energy.
The Koepe system of winding has been adopted at Oberhausen and
Westhausen in Westphalia, Stassfurth in Upper Silesia, and Best-
wood and Sneyd collieries in England, but has since been abandoned

Digitized by



at Oberhausen and Westhausen, possibly because breakage of one
rope would cause the stoppage of both sides of the pit. After 7 years'
sDooeflBful working, Koepe's system has been lately abandoned at
Bestwood for two reasons : the management do not consider it safe,
and slipping of the rope takes place every time it is oiled ; this
slipping oommenoes immediately oil is applied, and after a time
ceases altogether, to re-start, however, at the next oiling. This
action is very objectionable at Bestwood, for, as before stated, the
engineman has to rely entirely on the indicator for landing the cages,
as he cannot see them when they reach the surface, owing to the top
of the shaft being cased in. Against these abandonments we have
the fMxX that no aoddent has occurred at the Hanover pit since the
instiJlation was put down in 1877 ; indeed, the life of winding-ropes
is increased as before stated. This system is also giving every satis-
&cfcion at the Sneyd colliery in North Staffordshire.

The improved Bobey mining engine, made by Eobev (& Co.,
Limited, Linooln, is one of the most modem types, and is well
spoken of.

The following notes on ropes, obligingly contributed by Felten
k Chxilleaume, of Mulheim-on-Bhine, though their English agents,
W. P. Dennis A Co., London, will be read with interest as conveying
the experience of the foremost rope-making establishment in Euro^.

Mining ropes may be classed as winding, hauling, and guide
ropes. For winding and hauling purposes the most common con-
stmction is 42 wires and I hemp, or 36 wires and 7 hemps; but
the makers do not confine themselves to these constructions, and it
is desirable if possible to furnish particulars of the conditions under
whidi the rope is required to work, so that they may use their discre-
tion in case they consider it advantageous to alter the construction.
The two constructions before-named are tusually supplied by English
n>pe-makers, which simplifies their work, but it is not always to the
advantage of the buyer.

The class of wire employed depends more or less upon the con-
ditions of working, and the principal factors to be considered are : —

(1) Dimensions of drums and pulleys, as small pulleys generally
tend to shorten the life of a rope unless the rope can be made more
flexible, in which case however it is more apt to suffer from friction
or abrasion.

(2) The presence or absence of guide-rollers, in the case of hauling
ropee, and their dimensions ; it is injurious to ropes to work without

(3) The angle made by the rope in passing from the drum and
going round the pidley ; tne sharper the angle the more injurious it
is to the rope.

(4) Whether the rope is wound on the drum in one or more layers ;
if in more than one layer, the rope sufifers.

(5) Whether the shaft \b dry or wet ; in the latter case, especially
if the water is acidulous, the rope must be selected differently and
very carefuUy treated. Qenerally in such cases the size of wire must
be as large as conveniently possible, and sometimes it may be prefer-
able to have the wire galvanised ; but in every case the ropes must

Digitized by



be well dressed with a good grease free from acid or creosote. This
greasing is always beneficial also for ropes working in dry mines, but
is indispensable in wet or acid shafts.

The class of wire too may be different as regards the material
employed to ensure a lower or higher breaking strain. Bopes of iron
or steel are supplied with a breaking strain of 20 to 40 tons per sq. b^
but are now very little used.

The quality mo^t employed for winding and hauling ropes is
patent cast steel with a strain of 80-85 tons per sq. in., but in cases
where it is desirable to get the rope in the smallest compass with the
highest attainable strength, other classes of wire are employed, with a
breaking-strain of 110-120 tons per sq. in. — so-called "plough" steel

The prices of ropes usually increase with the reduction in size of
the wires employed, and for the purpose of simplifying matters
Dennis & Co. give in their general price list for wire ropes the gauge
of wires usually employed and the corresponding prices in the differ-
ent qualities.

Guide-ropes for mines are usually composed of 7 to 19 wires of
soft, tough material, ** homo " steel or iron.

Felten & Guilleaume's ropes have a high reputation, and give
great satisfaction wherever introduced, all over Europe and in the
Colonies. They also supply ropes on the principle of Albert or so
called *' Lang's lay " (wires and strands stranded in one direction),
which is especially adapted for haulage and will usually outlive the
ordinary construction ; as well as the '* lock coil " rope, which is com-
posed of round and sectional wires, the latter so shaped that they
interlock, preventing a broken wire from rising out of its place.
They can be used of spiral construction for guide-ropes where the
ordinary construction of rope would require to be stranded, and are of
less weight strength for strength by the reduction of section, as com-
pared with the old style.

In the United States the wire ropes manufactured by the John A-
Eoebling's Sons Co., Trenton, New Jersey, are the standard through-
out the many mining fields for lifting and hauling plants. The sus-
pension bridges at Niagara and at East Biver are built with the wire
of this firm. Their electrical copper wires have a remarkable repu-

The drums or reels of hoisting machinery are made for either
round or flat cables or rope. Where the shaft is inclined, and the
hoisting is done by cars, round rope is used. In vertical shafts, where
cages are used, flat rope is preferred. The drums should be of large
diameter, to reduce the bending strain to which the rope is subjected-
Bopes are of iron or steeL Where lightness and strength are especiallj
necessary, as in the case of deep hoisting, steel is preferred.

Bopes used in inclined shafts are subjected to more Motion, and
consequently last a shorter time than ropes used in vertical shafts.

Bopes hoisting 80 to 100 tons a day last about one year. After a
wear of 6 months, however, the rope should be moved to the side of
the shaft which is not used for the purpose of lowering the men,

Bules for the selection and care of ropes, and for calculating the

Digitized by



siza of drains, &c., are folly given in the author*8 * Miners' Pocket

In hoisting through vertical shafts, the gallows frame upon which
the sheaves are supported should be 50 ft. or more in height. The
additional height reduces the liability of over-winding. There are
several automatic devices, connected with the hoisting hooks from
which the cable is suspended, for preventing over-winding.

An excellent arrangement at the Lens Colliery, near Lille, consists
of an arrangement of valves, which come into play directly the cage
reaches a certain point in the shaft and, if the engine should at that
moment not be under control, immediately apply a powerful air-brake.
This, however, allows the cage to proceed at a certain speed; but
fihoold another point in the shaft be passed, and the engine be still
out of control, the brake is increased in power, steam is entirely shut
off, and the cage is brought to a standstill.

Qage*. — Every cage ^ould have a spring or buflfer for taking the
strain off the winding rope at the moment of commencing the hoist.

In vertical shafts, the cages run upon guide-timbers. The cages
are provided with safety catches, which operate when the tension of
the rope is suddenly released, and hold the cage fast in the guides.
The safeti^ should be frequently tested.

Double-deck cages are preferable when hoisting from great depths,
aa their use increases the capacity of the shaft. .

When the shaft is steep but not vertical, cages may be used,
nevertheless, by having an adjustable platform, which ensures a con-
stantly horizontal position of the platform. Cages of this design are
Tisefol where there is a departure from yerticality at any point of the

The adoption of some form of balance to the cage or skip equalises
the strain on the winding gear and leads to great economy in reducing
the wear and tear of rope and machinery and conserving power. A
simple method consists mainly in coupling the shaft of an auxiliary
winding drum or " spider " to the shaft of the main winding gears,
and in attaching to this auxiliary drum or spider a rope or chain of
increasing weight to act as a counterpoise to the cage and haulage
r*>pe. This rope or chain may hang either down the pump-shaft or
down a blind shaft or bore-hole, in any convenient position adjacent
to the winding gears.

The counterbalance chain is made in lengths, the weight of each of
which is relatively greater than that of the length next above it. The
upper end is secured by a light rope to the auxiliary drum or spider.

^1:^. — Self-dumping skips are often used in vertical shafts instead
of cages. They are useful for moderate depth, and especially for
nnking, as they can raise rock and water at the same time. When
the skip reaches the surface, wheels arranged on either side are forced
to pass between the inclined guides, as a consequence of which the
skip is tipped suflBciently to dump its contents.

In incline shafts, self-dumping skips are run upon tracks. Where
the incline is flat, cars are generally used. There is an economy in
having large cars of about 1^ tons capacity; as large, in fact, as are
easily handled.

Digitized by





The Frongoch skip shown in the accompanying illoBtrationa
(Figs. 56-66) is worthy of special mention, as it empties itsdl
automatically on reaching the top of the shaft, and then rights
itself without the aid of a lander, as soon as it is lowered. The time
occupied in lowering the skip on to a door, knocking up a bolt so as
to discharge its contents, closing it again, and raising the skip so
that the door may be drawn back, is all saved, and the servioee of
the lander are entirely dispensed with. The skip is the usual box a,
made of sheet iron or sheet steel, with 4 wheels h running on the
vertical wooden conductors \ and prevented from leaving them by
the back guide ^, at or near the bottom. The bow or loop e, instead


Figs. 56-60.— Fbongoch Sku».

of being attached to the top of the skip, reaches down, and is attached
to the axles of the bottom wheels. It rests against the axles of the
upper wheels, and the skip is thus prevented from falling away from
the guides. At the surface, each perpendicular conductor terminates
in a curved piece, and a front guide A is added on each side. When
the skip comes up, these front guides press upon the top wheels and
turn them on to the flat ends of the conductors. The partial cutting
away of the conductors at i enables the back guide to pass through,
and the bottom end of the skip is now raised, and the contents are
tipped or '* dumped " into a large bin or pass, from which the ore can
be drawn away at pleasure. If the engineman does not stop at onoe.

Digitized by



the slcip is simply drawn a little way tip, resting upon the front
g:aide8 c, the stop or stud / preventing it from assuming a wrong
pofdtioD. As soon as the engineman begins to lower, the top wheels
drop upon the flat ends of the conductors, and pivoted upon these top
wheels the tail end of the skip drops, the back guide passes through
the slot i, and the skip, resuming its upright position, descends the
shaft. One great recommendation of this system is that it can be
applied to existing shafts, whether perpendicular, inclined, or crooked*
It is the Hubject of a patent.

Coal Dumps, — There is a special feature about coal dumps in that
it is essential to avoid breakage of the coal so far as possible. Per-
haps the best form yet introduced is Wilson's automatic safety dump,
as furnished by John Davis & Son, Derby, and shown in Fig. 61.
The safety-horns A, placed at any given point or at any dibtance
behind the dump, prevent a second wagon from entering on the
damp till desired. Push and pull rods are attached to the horns, and

Fig, 61.— Automatic Safety CJoal Dump.

connected by a T-iron D and spreading-rod C to a lever B. The
notch E in the push-rod extending from D and intersecting the latch F,
holds the safety-horns open until the rear wheel of the wagon has
passed the horns A, when the front wheel strikes the projecting part
of latch F, lifting it from notch E, allowing spring G to close the
horns A immediately behind the rear wheels, and preventing another
wagrm from entering the dump until desired by the operator. A
press-lever H has connection through rod I with T-iron J, whose
arms reach the dump-horns K. Thu8, when the bottom of the wagon
begins to lide upon the press-lever H, giving it a downward move-
ment, the lever pulls backward on rod I and through J spreads apart
the dump-horns K so as to allow the empty wagon to pass between
them on a down-grade to a return track. When the empty wagon
has passed the dump-horns K the rear end of the full or approaching
wagon has passed the press-lever H, allowing springs L to close the
damp-honis K, holding the wagon in place until it is dumped in

Digitized by



turn. The break rails have a slot M in the rear end, and are hinge<}
at their forward end N, giving them a lengthening and shortening
motion as required in the np-and-down motion of the dump. The
motion of the dump is regulated by the lever O, having connections
with point of weight-lever Q and arm P, extending to brake B, and
held in place by weights S. The dump-brake has a smooth, regular^
rocking motion, and has none of the jarring and jerking produced by
other dump -brakes now in use.

Coal Conveyors, — The conveyance or transfer of coal from the mine
to distributing centres such as railway stations and river piers, without
undue breakage, is an operation demanding particular care, and has
called into existence special appliances whose adoption may be use-
fdlly extended ontside the coal trade. The construction of what are
known as '* river tipples " in America requires various precautions to
be taken against sudden freshets, drifts, and ice-gorges, and generally
something more than the building of mere breakwaters.

The first method adopted for river transfer was a simple incline,
with a movable cradle, which could be raised or lowered to suit the
different stages of water. This system, though limited to a small
capacity, and to cara not larger than tho.<4e commonly used under-
ground, possessed two advantages. The first cost was comparatively
small ; and, since the structure did not obstruct the channel, there
was little risk from freshets, the utmost damage from which could be
repaired at small expense. Its disadvantages, however, were many,
the principal among them being the breakage of the coal by reason
of the necessarily high dump ; the damages to barges from the same
cause ; and the difficulties of screening and distributing the different
sizes into separate barges. Hence this system has been almost aban-
doned in favour of the basket-arrangement, lowering vertically into
the barge, with the aid of counter-weights, which return the empty
basket; while pipes or shutes convey the small coals into other
barges, from a complete set of screens, which this method will readily

The latter system is now generally employed along all the
tributaries of the Ohio.* It has been elaborated to meet enlarged
outputs, until the cost of construction, in many cases, has reached
8000-1 0,000L Where mines have been connected with the river by
railway, necessitating the transfer into larger cars at the drift-mouth,
the same system has been employed to lower the railway cars, so as
to avoid the breakage from an extra dumpage. Owing to the fact,
however, that a barge mnst be laden uniformly, to avoid damage, it
has not been found advisable to dump more than 2-3 tons on any
one point ; and the largest car used in this manner has a maximum
capacity of about 6 tons, dumping from the centre upon a roofed
cage, so as to distribute the load. The Winifrede Coal CJo. has an
arrangement of this kind, with a maximum capacity of about 1300 tons
in 12-14 hours, and costing about 5000-6000/., including the struc-
ture for its protection. At the Faulkner Mines, 30 miles above
Charleston, a regular basket-arrangement has been erected, at a cost
of about 5000/.; and the Crescent Mines, 2 miles lower, have a
* W. N. Page, Tr. Am. Inst. Min. Engs.

Digitized by



dmilar arraDgement, coetdDg about 40001. Neither of these tipples
ain transfer more than 400 tons per diem.

Since the hest devised Btructnres, upon snch waters as the Ohio,
ire liable to be washed away, and become a total loss, it is clear that
)ne of the first considerations should be economy in construction, and
that as little resistance as the conditions will admit should be opposed
to the current. Where breakwaters are used, they mast be raised, to
kfford absolute protection, at least 60 ft. above low water. Such a
rtTQcture, in stone, would be beyond the means of most coal operators ;
md in timber, they are not only expensive, but depreciate rapidly at
md above the water-line. Bearing the above conditions in mind, and
^nfining his remarks to the transfer of bituminous coal into barges.
Page names the following desiderata in order of importance.

Fig. 62. — Coal Conveyor.

(1) The arrangement should permit a structure accommodating
my car ; and, since the majority of the mines, in the future, must
•each the rivers over lines of railway too extensive for the economical
we of small cars, the requirements of the standard railways should be

(2) All bituminous coals, being more or less damaged by breakage,
ibould be handled as gently as possible. Since breakage occurs not
mly from the shocks and friction on the bottom and sides of a shuts,
!)Tit from the weight and grinding of the superincumbent mass when
n motion ; hence it is clear that any method by which the coal can
i>e literally carried, while it remains at rest, will best meet this

(3) The barge should be loaded uniformly ; otherwise its timbers
»nU spring, and leakage will become a source of constant expense.

Digitized by



The cost of a barge is too great to permit the neglect of any pre-
caution for its preservation.

(4) The cost of transfer should be reduced to a minimum, and the
machinery should not be so complicated for a large capacity, as to
make a small output disproportionately expensive.

(5) The capacity shoula be practically unlimited, since gravity
fumiuies unlimited power.

(6) Above all, the structure should be a protection in itself
against high water, or subject to such damage only as may be qoickiy
repaired at a small cost.

Fig. 63 — Coal Conyktob.

After a careful study of the conditioDS and requirements — whick
are of course slightly modified by circumstances — Page ventured ^tek
make a departure from the conservative methods now in use, amA
erected a transfer on the Kanawha, for the Mt. Carbon Compaay^
Limited, which is described below, and illustrated in Figs. 62 to 65L.

As will be seen, it is a simple application of a flexible steel bc~
A ft. wide, with C-in. flanges, and 95 ft. from centre to centre
sprocket-shafts. The 3 chains are made of j^ x 2 in. steel bars, wHi
£-in. steel pins, 6 in. from centres. Each alternate link has a " ^

Digitized by VjOOQIC



flange, to which is bolted a segment of the belt, as shown in Fig. 60 ;
oonsequently every other link is an idler, which increases the flexi-
knlitj of the belt. The segments are made of No. 12 gan^e soft steel,
and lap I in. The lower lap is cnrred downwards, for which the idle
link is notched.

The hopper underneath the car holds less than a ton ; conse-
qnently the belt practically draws the coal direct from the car after
this hopper has been once filled. The feed-apron is narrower than
the belt, and is adjustable so as to feed automatically, the coal on the
belt regulating the charge. No difficulty is encountered in regulating
the feed to any desirable load ; and no attendant is required. The
links of the loaded chain run in small flanged rollers, placed every
4 ft on 6-in. girders, 24 ft. long, with fish-joints at every point of
■Qspension. There are 4 such points within the 95 ft., using eight
2-ton difierential blocks, four on each side. It was first proposed to
ue ooonterweigbts at these points ; but upon estimation blocks
proyed cheaper and more satisfactory.

I ® "^^m^

Fios. 64, 65. — Details of CJoal Conveyor.

The total weight of belt and attachments, exclusive of the upper,
^ fixed, shaft and sprockets, is 5 tons ; and the level load is 5 tons ;
wnaequentiv each revolution of the belt conveys a little more than
10 tons. The arrangement for returning the empty portion of belt
ttnaists of 3 pulleys, 2 ft. diam. by 12 in. face, set on tiie shaft so
that each pulley supports a chain. To suit the different stages of
▼ater, the entire system can be readily raised or lowered at one end,
by one man, care being taken to have the ^ders in line when the
pnrper elevation is reached. The guide on £e movable end is an arc
of the circle to which the belt is radius ; though, to cover any in-
•qnalitiee, or spring in the timbers, the fixed ends of the girders are
pfo^ided with movable connections to the main shaft, which is also

Online LibraryCharles George Warnford LockEconomic mining: a practical handbook for the miner, the metallurgist and ... → online text (page 13 of 76)