896

THE COLLIERY GUARDIAN.

May 11, 1917.

the tension carriage sheave, and round the deflecting
and headgear sheaves, faster than the actipn of gravity
on the empty skip would overcome the inertia of these
idle wheels; the result being that the grip of the rope
in the reel grooves was reduced each time the engine
started in this direction.

The first method adopted to overcome the last objec-
tion was to put a false bottom and dead load into the
deflecting pulley skip to increase the effect of gravity.
By this arrangement, the dead rope was pulled away
much quicker, and the grip of the rope in the reel
grooves increased.

The objection, however, to this was the slight reduc-
tion of tonnage hauled by this one skip. The final
method adopted to overcome this difficulty was to equip

D

E

B

M

E?

P

A.	Headgear sheaves (ball

B.	West skip. [bearing).

C.	Deflection sheave.

Fig. 3.—Side Elevation

D.	Ball bearing pedestals.	G.

E.	Bridle.	H.

F.	Steel balls in grooves.	I.

the tension carriage sheaves with Skefko ball bearings,
which were specially made for this purpose.

For the first few months after these bearings were
installed it appeared that all the difficulties were over-
come, as slip disappeared entirely, irrespective of the
direction in which the engine was running, although
the dead weight in the deflection pulley skip had been
removed. There was also a very decided reduction in
the power consumed at starting, and it was possible
to cut off the current considerably earlier in the wind,
the saving in power being approximately two units per
trip.

It was, however, only a few months before it was
found that the ball bearings would not stand up to the
very severe load under which they were working, the
dead pull on each bearing being about 19 tons, in addi-
tion to any extra load due to starting and braking.

The authors are, however, convinced that with more
amply designed ball bearings on the tail carriage
sheaves, together with the extended use of ball bear-
ings to the headgear sheaves, this system of Whiting
winding will be perfected. Ball bearings for these
purposes are ordered. However, owing to the light-
ness of the design, it was necessary to discard the ball
bearings^ after running some months, and for the time
being revert to the original solid bearings.

The authors were, therefore, still confronted with
periodical slipping, and various other schemes had to
be tried to improve matters. The reels of one engine
were fitted with wood treads, and although the follow-
ing different woods were used, namely—Cape pine,
English oak, and iron wood, each in turn proved
unable to stand up to more than one day’s run. This
was more or less to be expected, as the pressure of the
rope in the groove is equal approximately to one ton
per foot at the bottom of the groove, and this pressure,
together with the embedding action of the wires of
the rope, destroyed the treads.

After this, solid cast iron grooves were fitted
throughout, displacing the wood treads, and the
experiment was then made of altering the shape of the
groove, since it was felt that the area of contact of
the rope in it might be increased. Theoretically,
owing to the groove being of larger diameter than the
rope, the latter actually runs on a line in the bottom
of the groove. A small groove was therefore cut at
the bottom of the main groove, which doubled the lines
of contact of the rope in the groove. The result of
this experiment had the desired effect of reducing the
slip, and the engines have both been running under
these latter conditions for the last 18 months. They
have often done 36 trips in a single hour, and an
average of 32 trips per hour has been kept up during
an eight-hour shift, the maximum speed of winding
being 3,600 ft. per minute. This amounts to 1,280
tons per hoist for the eight hours shift, raised from
a depth of 4,100 ft.

The wear in the groove of both reels was now found
to be almost equal, being at the rate of in. per
month; which would give a life of about five years.
The cost of a complete set of treads made locally is
£120.

During the time that these observations were being
made, it became apparent that the relative weights of
the winding rope and the tail rope were of consider-
able importance, and that the latter should be some-
what heavier than the former. This became neces-
sary for the same reason that ball bearings had been
put into the tail carriage sheave, and that a weight
in the deflection pulley skip had been experimented
with earlier in these investigations, namely—for assist-
ing the action of gravity on the down-going skip during
the acceleration period. The weights of the two ropes
which proved most satisfactory were:—Winding rope,
4-25 lb. per ft.; tail rope, 4-6 lb. per ft. This differ-
ence amounts to a pull of 1,4701b. in favour of the
down-going skip at starting.

and Plan of Keels.,

Tail carriage wheel (ball
Spring balance. [bearing).
East skip.

K.	Balance rope sheave.

L.	East compartment rope.

M.	West compartment rope.

The final conditions as regards loads on these
engines are as follow : —

Loaded side. Empty side.

	Lb.	Lb.
Rope 		17,850 ...	... 19,320
Skip 		9,500 ...	...	9,500
Rock 			10,000 ...	—
Half weight of tail pulley...	1,140 ...	...	1,140
	38,490 ...	... 29,960

The sum of these loads is the stress pulling the two
reel shafts together when the single turn is used, and
when two or three turns are used the stress increases
approximately in proportion to the number of turns.

In order to get an idea of the actual stresses between
the reel shafts under various running conditions, a

U

U
a

z

CD

•n

CD

0.

225Q

ZOOQ

1500.

<00Q

1750-

1250.

25QC

’50.

500.

X-

/ I
J

NUMBER Of TURKS OF WQPE ROUND REELS.

Fig. 4.—Curves Plotted from Winding Tests.

scale model was made, and a series of experiments were
carried out. The model is shown in fig. 3, and is a
miniature of the complete Whiting system to th
scale.

The model was made as frictionless as possible, all
the engine bearings, and the bearings of deflecting,
tension carriage, and headgear sheaves, being of the
Skefko ball bearing type.

The front reel shaft bearings were bolted firmly to
foundations, and the back reel shaft bearings were
mounted on a self-contained sliding frame, which was
free to travel on ball slides. This frame was connected
to one end of a 5 to 1 lever, the other end of which
was connected to a spring balance. The fulcrum and
all connections were on knife edges.

The reels were fitted with a sufficient number of
Walker rings to take five turns of the rope, and these

were most carefully made and arranged, so that any
degree of slackness could be given them, or that they
could be locked entirely, and so represent solid grooved
treads.

The model differed from the actual hoist, inasmuch
as the coupling rods had to be discarded in order that
the back reel could move to allow the pull between the
two shafts to be measured, and it . therefore became
necessary to do all the driving through one shaft only.

Whiting hoists have been worked under these con-
ditions, and it was obviously impossible, for the reason
given above, to make the model exactly similar to the
Turf engines.

The model was^erected at a disused vertical shaft,
and the skips were allowed to run without guides, so
that shaft friction was entirely eliminated, thus giving
as perfect conditions as possible.

The length of wind was made proportionately with
the model, namely—y^th of the actual winding depth,
or 340 ft. A J in. diameter flexible rope was used, and
the loads were fixed in proportion to the breaking
strain of this rope in relation to that of the winding
ropes used in actual practice.

The loads used in these experiments were 145-4 lb. on
each rope, plus 54-6 lb., representing the rock on the
loaded side, so that when one skip was loaded the total
weight hanging on both ropes was 345*4 lb.

The results showed that the pull between the reel
shafts was roughly in proportion to the number of
turns, the winding conditions as regards loads and
direction of wind being the same. Fig. 4 represents
certain of the tests, curve A representing the pulLin
pounds between the shafts at the end of the trip after
raising the normal load in the deflection pulley skip ;
curve B represents the same condition as A, but with
double the normal load; curve C represents the pull in
pounds between the shafts at the end of the trip, after
raising the normal load in the engine skip ; and curve
D represents the same conditions as C, but with double
the normal load.

In bringing this subject before the institution, it was
not the intention of the authors to advocate the adop-
tion of this system of winding in all cases, but rather
to draw attention to certain advantages which it offers
under special conditions, particularly when winding
from great depths.

The engines described above were at one time con-
sidered quite unsuitable for the work they were doing,
owing to the weaknesses which they had shown when
running with three turns, but to-day, winding with
one turn of rope, they are proving highly satisfactory
and quite economical. It will be evident also that an
engine designed on these lines would cost consider-
ably less than any other type of engine capable of doing
the same work.

A distinct advantage of this system of winding is the
reduced risk of damage in case of an overwind, it being
apparently impossible to break a rope when winding-
under these conditions, and if the over-wind is not of a
violent nature, the damage will be negligible. Bearers
have been fixed about 4 ft. below the loading position
of the skip at the bottom of the shaft, in order to
ensure its weight being taken off the engine, and the
grip of the rope on the reels thereby reduced should the
driver exceed his distance when coming into the tip.

In conclusion, the authors are of the opinion that,
with a single turn of rope, these hoists as they stand
could be used for winding from vertical depths up to
6,000 ft., and even more if the difficulty of obtaining
ropes of sufficiently high breaking strain can be
overcome.

Donetz Basin Coal Production in 1916. — The South
Russian Mining Congress publishes the following statement
on the production of coal, etc., in the Donetz basin in the
year 1916:—The production of ordinary coal amounted to
1,373,450,000 poods, compared with 1,316,540,000 poods in
the year 1915; and the output of anthracite 378,800,000
poods, against 310,040,000 poods. The corresponding
figures for coke were 269,430,000 poods, against 254,800,000
poods; and for briquettes 18,970,000 poods, against
23,840,000 poods. Thus, the production of coal in 1916
exceeded that of 1915 by 56,910,000 poods, or 4-3 per cent.;
the anthracite production exceeded that of 1915 by
68,760,000 poods, or 22 per cent.; and the coke produced
exceeded that of 1915 by 14,630,000 poods, or 5-8 per cent. ;
whilst the production of briquettes, on the contrary*
declined 4,870,000 poods, or 20-4 per cent. The number of
workmen engaged in the coal and anthracite mines
averaged 237,000 per month, against 180,600 in 1915—
figures which indicate a serious decline in the production
per man in 1916 compared with the corresponding produc-
tion in 1915. This is explained principally by the fact
that many miners were taken for the war, and prisoners of
war put in their places. The decline in production per
man was progressive from month to month.

Coal, in Argentina. — The Argentine Government has
authorised a firm to extract coal from the harbdur and
river beds of Argentina, where it has been dropped in the
unloading of vessels. It is thought that a large quantity
of coal may be recovered by means of diving devices. The
Decree in the Boletin Oficial authorising the extraction of
the coal specifies that the National Treasury is to receive
50 per cent, of the value of the coal extracted. Other
sources of coal, in Argentina now under investigation are
the coal deposits in the province of Mendoza and the
newly discovered mines at Malanzan, in the province of
La Rioja. The Malanzan mines are said to yield coal of
good quality,. while the Mendoza coal, which has been
used in experiments in. Buenos Ayres, is not wholly satis-
factory, but could be improved by sorting and screening.
The coal shortage and the excessive cost of fuel imported
from the United States have caused capitalists of Buenos
Ayres to take an interest in the possible development of
coal, deposits in Peru. An investigation of various pro-
perties in that, country is being carried out, and a study
made of the mining and transportation problems involved.
It is reported that Great Britain is considering placing an
embargo against coal exports to Argentina, says the Coal
Trade, Journal, unless the wheat embargo which the latter
country has maintained is raised. It is reported that the
United States Government may back up Great Britain.
In any event, the United States Government is taking steps
to assure itself that none of the American coal exported
to the Argentine in the future will be supplied to German
raiders.