426

THE COLLIERY GUARDIAN.

August 21, 19141.

WATER IN SAND PULP FOR MINE FILLING.

In sand filling it is possible to transfer the sand
residue to the pump by shovelling from the tanks
through the discharge doors into a launder down which
water flows (Journ. Chem. Met. and Min. Soc. of South
Africa, September 1913). "While trial has shown this
method to be practicable, yet the limited grade avail-
able for launders in most existing sand plants requires
a much higher ratio of water to solid for the pulp to
flow by gravity than is needed for subsequent pumping,
and, of course, still more than is desirable for lowering
underground. The same consideration applies to
hydraulicking the sand out of the tank, in addition to
the liability of driving slime through the filter cloth.
If discharge to the dump is necessary at times, it is
essential that cars or belts under the tanks should not
be interfered with by launders.

An excess of water is undesirable as causing a non-
uniform deposit of sand underground; in addition, when
surface transport by pumping is practised, the power
consumption is increased by superfluous water; and
both in pipes and in launders a more fluid pulp increases
the velocity and the wear by abrasion. A pipe has
been in use with thick pulp at the Simmer and Jack for
upwards of three years without appreciable signs of
wear. The amount of drainage water underground
increases rapidly with fluid pulp; nearly three times as
much has to be handled from a pulp containing 50 per
cent, as from pulp containing 30 per cent, moisture.

In the transport of sand residue as pulp, the water
serves essentially as a transporting medium, and its
ratio to solids should be kept as low as compatible with
serving this purpose. A sand pulp may be pumped by
a centrifugal pump up a short vertical pipe with as low
a ratio by weight as one of water to one of sand, but
for pumping any distance on an incline, it is usually
necessary to employ a 2 : 1 ratio. Where the velocity
is insufficient the pyritic particles are liable to settle,
and periodical pumping of water is necessary to prevent
choking. The delivery pipe on the down grade works
well with a fall of 3-5 per cent., so that acting as a
launder it may clear itself on cessation of pumping. In
a rising pipe the vertical component of the velocity
should be greater than the rate of fall of the coarse
pyritic particles. A horizontal delivery pipe is unde-
sirable, as a high velocity of pulp is required to prevent
settlement. Pipe grade and water ratio are, within
limits, inversely proportional; the steeper the grades
practicable, the less water need be used. The coarse-
ness of the sand residue is also a factor, since the finer
the particles the lower the velocity required. When
possible a vertical rising pipe from the pump, with a
uniform down grade from its highest point, constitutes
a satisfactory arrangement, as does also a steep up
grade to the point of delivery. It is, of course, essen-
tial that there should be no pockets or flats, as any
unfavourable grades affect the whole operation.

The launder grade required for the sand pulp is
dependent upon the size of the sand particles, the ratio
of water to solids, the volume of the pulp, and the
internal shape and surface of the launder, while the
head of a launder and any curves require a higher grade
than the average. In general, an ordinary sand pulp
containing 30 per cent, moisture will flow slowly but
without difficulty on a 30 per cent, grade, with 40 per
cent, moisture on a 20 per cent, grade, and with 60 per
cent, moisture on a 10 per cent, grade.

The water ratio in pulp, besides determining the size
of pumps and piping and the power consumption, also
affects the number of dewatering cone classifiers
employed. With an inflow pulp having a 2 : 1 water
ratio, a diaphragm cone, 8 ft. in diameter by 10 ft. deep,
will deliver 10 tons to 12 tons of sand as a thick, 30 per
cent, moisture, pulp underflow per hour, if slime has
been adequately removed from the sand before its
cyanide treatment. If, however, the sand residue con-
tains much colloidal slime, so as to form a viscous
deposit in the cone, the capacity of the classifier may be
reduced by one-third or more. If a return of the over-
flow by pumping is necessary, any additional water
necessitated by unfavourable pipe line grades constitutes
a constant source of expense.

MINING AND OTHER NOTES.

Mr. Gustav Edward Jaeger, of The Oatlands, Grove Hill,
Middlesbrough, a director of Messrs. Jaeger Brothers Limited,
iron merchants, of Middlesbrough and London, who died
March 30 last, left estate of the gross value of £9,230 Ils. 10d.,
of which the net personalty has been sworn at <£6,585 17s.

Mr. Theobald Fitzwalter Butler, of Barrow-in-Furness,
of T. F. Butler Limited, and a director of the Whitehaven
Coal and Iron Company, who died June 16 last, left £36,724
gross and £22,007 net.

Sir C. P. Lucas, in his address to the Geographical Section
of the British Association, which is now holding its annual
meeting in Australia, dealt mainly with the results of
human agency on the earth’s surface, and he concluded :—

More than half a-century ago Buckle, in his f History of
Civilisation,’ wrote : ‘ Formerly the richest countries were
those in which Nature was most bountiful; now the richest
countries are those in which man is most active. For in
our age of the world, if Nature is parsimonious we know
how to compensate her deficiencies. If a river is difficult
to navigate, or a country difficult to traverse, an engineer
can correct the error and remedy the evil. If we have no
rivers we make canals; if we have no natural harbours we
make artificial ones.’ The greatest revolution that is being
worked in human life is the elimination of distance, and
this elimination is going on apace.”

The Port of London Authority has recently issued an
interesting volume dealing with the past and present
history of the Thames and its docks. The letterpress is by
Mr. Douglas Owen, and the illustrations, which are numerous
and artistic, are by Mr. Charles J. De Lacy. The book
briefly traces the rise of the Port of London from its earliest
days, and relates the circumstances which eventually led up
to the creation of the Port of London Authority. The first

enclosed dock area was the Howland Dock, at Rotherhithe,
which flourished as early as 1703. Its site now forms part
of the Surrey Commercial Docks. It was, however, nearly
a century later that the value of enclosed docks for the
handling and protection of cargo came to be fully appre-
ciated, and the West India Dock, the precursor of many
others, was opened for trade with the active support of the
great William Pitt. In addition to dealing with the many-
sided activities of the Port Authority, the book deals fully
with their great scheme of improvements now in course of
execution, and in particular indicates by pen and picture
the general character and importance of the fine new deep-
water dock which is now being constructed^ between the
Royal Albert Dock and the river. Several of the illustra-
tions of the new dock are in colours, and very effectively
suggest the great part which the enterprise is likely to
play in the future commercial history of London.

Presiding at the half-yearly meeting of the South
Metropolitan Gas Company, in London, on the 12th inst.,
Dr. Charles Carpenter dealt at some length with the ques-
tion of the coal supply, and advocated the adoption by the
collieries of the co-partnership system. He said that if it
was necessary for gas undertakings—as he believed it was—
it was still more important for collieries which were a more
important part of the country’s industries.

The Panama Canal Zone celebrated the opening of the
Canal on Saturday. The principal event was the passing
through the Canal of the United States War Department
steamer “ Ancon.” The “ Ancon ” went through the Gatun
locks in 70 minutes and was followed by several other
vessels, and the commerce through the canal was officially
started.

Bulletin 57, issued by the United States Bureau of
Mines, tells us that tunnel accidents in 16 important works
have averaged 4*7 deaths annually and nearly three times as
many serious and 13 times as many slight injuries per
thousand men employed. While most of the accidents
were caused by ore or rock falling from the roof or walls of
the tunnel, many of them were the result of ignorance or
gross carelessness and could have been avoided. Many of
them occurred from the improper use of explosives. To
reduce the number of accidents it was recommended that
roof blasts should be made with as small charges of explo-
sives as practicable ; that men be detailed to remove loose
pieces of roof immediately after the blast; that each man
carefully inspect the roof under which he works ; and that
any doubtful piece of rock be tested by impact, and if
vibrations can be detected by touch or through a stick, the
rock be immediately removed.

Investigations discussed by O. C. Derby in a bulletin
published by the University of Wisconsin, had in view:

(1)	The determination of the temperature limits between
which tars are distilled from the various classes of coal;

(2)	the temperature limits of the maximum rate of evolu-
tion of tars ; and (3) the relative quantities of tars distilled
from various general classes of coal. Briefly stated, the
results show that with any coal, tar commences to distil at
about 300 degs. Cent, and are completely distilled at
550 degs. to 600 degs. Centigrade. The greatest evolution
of tar vapours occurs (on the average) between 375 degs.
and 475 degs. Centigrade. The amount of tar produced
depends not on the relative amount of volatile matter in the
coal but upon the ratio of carbon to the hydrogen, as shown
by an ultimate analysis.

According to United States consul W. F. Doty, at Nassau,
New Providence, Bahamas, it has just been learned from
interested persons that, acting upon a recent favourable
report, a British syndicate will very soon establish a coal
and oil depot on one of the Caicos Islands, presumably
Providentialis. This island, he says, is particularly well
located, being adjacent to the course to be followed by
vessels en route from Europe up to the Panama Canal.
The Caicos group is situated about 400 miles south-east
from New Providence. American vessels on their way to
the canal are likely to take their bearings from the strong
light on Watlings Island, quite close to Providentialis, and
accordingly will be interested in this proposal. Formerly
a supply of coal was kept at Nassau, but recently there has
been none of a suitable sort.

“SAFETY FIRST” DEVICES ON THE RAND.

At the Alining Exhibition recently held at Johannes-
burg, handsome prizes were offered by the Rand Mutual
Assurance Company for the best exhibits of a safety
device, appliance or method of procedure, the bond fide
idea of the inventor, which was calculated to prove of
practical value for the purpose of preventing accidents
to workers.

In Class A. the following prizes have been awarded :
First prize of £25. and silver medal, Mr. E. Nowag,
Dynamite Factory, Modderfontein, for a safety clip for
the prevention of misfires, etc. Second prize of £15
and bronze medal, Mr. A. W. Lindberg, Ferreira Deep
Limited, Johannesburg, for an overwinding device for
electric hoists. Third prize of £10, Mr. Otto E. Dick,
Geldenhuis Deep Limited, Cleveland, for a safety bar
with pegs for locking hanging stamps in position. In
Class C the prize of £10 for the best exhibit of an
enclosed lamp is awarded to Mr. G. C. Carter, P.O.
Box 94, Johannesburg. The devices that won the
second and third prizes in Class A have already
been recommended by the “ Safety First ” Committee
in conjunction with the Mine Managers’ Association,
for adoption on the mines.

In Mr. Nowag’s device, the clip holds detonator and
fuse firmly in primer cartridge, preventing misfires
which are frequently caused by the pulling away of fuse
and detonator from primer cartridge while charging and
tamping hole. The clip is very small and simple.

The Lindberg overwinding device consists of three
principal parts, viz. :—(1) Electrical contacts in the
headgear for rock hoisting; (2) electrical contacts above
the collar of the shaft for men hoisting; (3) a three
point controller operated by the driver. On either the
men or rock contacts being operated by the skip or cake,
the main switch of the winder is opened by the “ no
volt ” coil, and the post brakes are automatically
applied. When rock is being hoisted, the controller
lever is placed in the “ rock ” position, and then only

the contacts in the headgear are in circuit. When the
signal is given to raise men, the driver places the con-
troller in the “ men ” position, and, until he has done
so, he cannot give the return bell signal. The plunger
of the contacts at the collar of the shaft is at once
pulled out by a solenoid, which acts in place of a spring.
On the resumption of rock hoisting, the first skip passing
the solenoid plunger pushes it back out of reach of
succeeding skips, thus saving wear and tear. Should an
overwind take place when the controller handle is in
either the “rock” or “men” position, the driver cannot
close the main switch or release his brakes until the
handle of the controller is brought to the “ off ” position.
A bell will then automatically ring until the skip has
been moved from the danger point, and the driver can
then bring the handle of the small controller to the
correct position for further operation. The advantages
of the device are that the contacts are operated directly
by the skip, which is independent of stretching of ropes,
faulty indicators, etc., and is therefore applicable as
well to Whiting hoists as to drum hoists. Four sets
have been at work since February 1913, so far with every
satisfaction.	1

Carter’s flame protector, which won first prize in
Class C, consists of a metal cylinder 2 in. outside
diameter by 4 in. high; the top of the cylinder is cut
away and wire gauze is fixed; the bottom is provided
with a hole a in. diameter to allow it to fit over the
burner protector of the Wolf lamp, this bottom may
be perforated or covered with gauze. Three openings
are cut in the periphery of the cylinder to allow the
light to penetrate, the metal being cut and folded in
such a manner as to form slides or sashes into which
mica sheets are fitted. Approximately the front panel,
which is twice as wide as the side panels, is the same
width as the metal left at back of cylinder to act as
reflector. A clip is riveted on to this reflector portion
by means of which it is attached to the reflector bracket
of any Wolf lamp. It is necessary to make provision
for re-lighting in the event of the flame being extin-
guished by concussion from blasting in the vicinity; for
this purpose the right-hand side panel should be used,
and a sketch is shown of the small hinged door (mica
covered); as an alternative this mica might be fixed in
a metal frame and made to slide in top and bottom
sashes towards the reflector clip. A further addition
is shown on sketch of a tin cap (asbestos protected) and
method of fixing. The whole device is packed in a tin
canister of such size that the protector does not shake
about; this enables the device to be kept in the pocket
or tool box without damage.

WORKMEN’S COMPENSATION.

(Specially Contributed.)

Contracting-Out.

Leaf v. Furxe.—In this case (Leeds, April 1) it
appeared that applicant had been employed at Messrs.
Charlesworth’s Robin Hood Colliery for about 11 years,
and had been a paying member under a contracting out
scheme. He had been able to earn about £2 a week.
At the end of 1911 his working place became worked
out, and it was suggested to him that he should con-
tinue to work, but as a “ market ” man. He did not,
however, care to attend the pit as a casual worker,
and he sought another position. On January 4 he saw
the officials of Topcliffe Colliery with the object of
obtaining work. He was then asked to “get liberty ”
from the Robin Hood management and to submit him-
self to examination by the certifying surgeon in
Topcliffe. Accordingly, on January 5 he signed off at
the Robin Hood. On the following day he submitted
himself to examination, and the surgeon refused him
permission to work at Topcliffe, because he was suffering
from a bad form of nystagmus. The doctor had
certified that he was disabled from following his
employment as a miner from January 6, this certificate
having been sent to the defendant on January 20.

For the defence it was contended that they were not
compelled to pay compensation under the Industrial
Diseases Section of the Compensation Act, inasmuch
as the plaintiff had left his employment a day before
being certified as disabled.

His Honour, therefore, had to decide a question
which, he said, bristled with difficulties, owing to the
fact that the Act did not provide that an accident had
taken place until there was certification of disablement;
and the surgeon explicitly stated that the “ disable-
ment ” began on January 6, the day following that on
which plaintiff signed off from Robin Hood Pit. But
it seemed very probable that if it were not for this
contracting out scheme the plaintiff would by the nature
of his disease have been able to recover from Messrs.
Charlesworth under the Compensation Act. There was
no doubt that the plaintiff had gone without compen-
sation for a long time when, roughly speaking, he was
entitled to it. He awarded compensation £50.

“ Disease from Gas ” Treated as an “ Accident.”

Derbyshire v. Ellerbeck Colliery Company.—In this
case (Chorley, May 15) it appeared that the applicant
had been incapacitated as the result of an injury caused
by coal gas from the coal face. A doctor came to the
conclusion that the man was suffering from gas poison-
ing, and the claim was for six weeks’ compensation.

For the respondents it was urged that the place was
ventilated as well as possible, and if it could have been
improved it was the applicant’s duty to report it. This
was undoubtedly an attempt to get disease from gas in
mines included for compensation as an accident, because
it was not scheduled.

His Honour found for the applicant.

*#* IFe shall oe pleased to answer in this column questions
relating to Workmen's Compensation and Employers’
Liability. All communications must be authenticated by the
name and address of the sender, whether for publication or
not. No notice canbe taken of anonymous communications.