A Method of Sorting Minerals or other Bodies and Apparatus therefor.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
A Method of Sorting Minerals or other Bodies and Apparatus
therefor.
I, GEORGE KILGOUR, M.I.C.E. Civil Engineer 2 Victoria Mansions, Victoria
Street, Wostminster, do hereby declare the nature of this invention to be as
follows:
A common way of washing ores to separate metals or precious stones therofrom is
to crush the ore to a uniform.degree of fineness and to allow the crushed material to
be carried along by a stream of water which gradually decreases in velocity and so to
allow the material to settle-the heavier particles being the first deposited and the
lighter ones the last.
1 reverse this arrangement and use a body of air water or any other fluid com-
paratively at rest and with it I use a continuously moving bed or bottom-I use a
horizontal revolving disc or table which has a spiral coil standing up from its upper
surface and which is immersed in a body of the fluid used the vessel containing this
body of fluid may be circular and the disc form as it were a false bottom to it or
may be a stream or pond.
The spaces between the successive coils of the spiral being open at the top and
covered with a considerable body of water there will be but little flow along the
spiral channel but the fluid above the disc at its circumference will be considerably
agitated whilst above the centre it will be approximately at rest. The material to be
washed or sorted 1 cause to be fed on to the revolving table near its circumference
the heavier particles of solid matter will settle near to the circumference and the
lighter particles near the centre. At the centre an opening may be made through
the disc through which the finest materials the tailings may descend into a space below
the disc.
The same disc may also be employed in sorting into sizes bodies of the same specific
gravity.

page_text: COMPLETE SPECIFICATION.
A Method of Sorting Minerals or other Bodies and Apparatus
therefor..
I, GEORGE KILGOUR M.I.C.E. Civil Engineer 2 Victoria Mansions, Victoria
Street, Westminster do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:
The almost universal principle on which ores are "dressed " or rather separated
from particles of foreign matter (of different specific gravity but of approximately
similar volume) is based on the law that the carriage of all matter (not in solution) in any
fluid depends on the velocity with which such fluid is running, on this principle are
constructed buddles, long-Toms, cradles sluices, under currents, concentrators, blanket
strakes &c. &c. nay even the pan and the spoon act on the same. The water on
entering passes with a velocity sufficient to carry all with it, its velocity is then
checked by lessening the hydraulic mean depth, or the slope, or both, until at the
exit the velocity is only sufficient to carry off the lighter foreign matters and that
"dread" of the minor "float" metal all the metaliferous fragments of higher specific
gravity having been deposited in the channel at the point, where the current did not
run with sufficient velocity to carry them further with it. The chief disadvantages
(all in some methods, some in all) of this plan are.
1 The great length of channel with varying slopes necessary to ensure a sufficient
range of velocity which further demands.
'
a An embankment or cutting to ensure proper grades.
With the more valuable metals, a length of works that it is difficult to
protect efficiently and, the cost of such protection.
2 The difficulty of keeping up during long periods an equable flow of water and
velocity owing to
a The falling off or decrease of the supply.
ẞ The effect of wind on the surface of the water.
3 The enormous loss from "float" metal.
4 The large amount of water required.
5 The time lost and expense involved in cleaning up.
By my invention I greatly lessen or entirely do away with these disadvantages.
In place of a running stream of water or fluid I use a body of water or fluid usually
contained in a tank.
In place of a straight channel I use a channel formed by a spiral wall standing
up from the upper surface of a horizontal disc made to revolve around a central
vertical spindle and with a certain portion of its centre cut away.
1. In this way for example a channel of some 340 feet long and 1 foot wide will
only require a disc 20 feet in diameter.
a This can be placed in a room or on a level piece of ground 25 feet square.
Such room can be locked up, the material fed in continuously from above
and the metal collected and removed by one man periodically in a couple of
minutes.

page_text: སམ་སས
timed.
ẞ No wind can ever reach the channel even when in the open.
3 The crushed or 6. levigated" stuff will be delivered below the surface and thus
there is little chance of float metal-further if such occur an occasional revolution
of a radial blanket over the surface will gather it all.
4 The amount of water used when a tank is employed is extremely small.
The plan is of the simplest and depends on the fact that the effect of a channel
moving through still water is practically the same as that of water moving through
a channel so far as regards particles in such channel.
The revolving disc with the spiral channel upon its upper surface is immersed in
still water or other fluid the stillness being ensured by check boards or other means.
The disc is then revolved at the velocity found most suitable for the particular
class and character of ore under treatment, it will at once be plain that the velocity
of the channel at any point or rather the velocities at any number of points vary
directly as their distance from the central spindle, thus with a spiral 20 feet in
diameter a channel 1 foot broad and the central two feet cut away the velocity at
the periphery will be about 9 times as great as at tho central end of the channel.
The materials to be treated are fed into the channel near the periphery-the
metalliferous or heavier particles the larger are deposited in the channel near to the
circumference-the smaller ones nearer. the centre whilst all the lighter foreign
matters are gradually borne nearer and nearer to the centre falling thence through
the cut away aperture into the tank whence they may be removed where water is
scarce, by an elevator dredger or other mechanical means or where water is plentiful
by a stream.
In the drawings annexed Figure 1 is a longitudinal section of a hand machine
constructed according to my invention. Figure 2 is a plan view of the spiral channel.
Figure 3 is a side elevation. Figures 4, 5, 6, 7 and 8 aro cross sections of various
forins which inter alia the channel may be made to assume. Figure 9 is a plan view.
Figure 10 a section on the line C. D. Figure 9 and Figure 11 a side elevation of
a set of radial blades which are immersed in the water to impede it from revolving
with the disc. Figure 12 is a diagram view showing how two or more dises may be
mounted one under the other and used successively.
In Figure 1. A is an outer vessel or tank which may be square or circular or of
other form-B is a vertical spindle carrying a horizontal disc C on the upper surface
of which is a spiral channel D-E is an air chamber on the underside of the
disc to reduce the weight that has to be carried by the spindle. In large machines
provision night be made for pumping more air into the air chamber or allowing a
certain amount to escape from it according to the amount of ore which may be at any
time carried upon the disc. For large machines also the spindle instead of being
revolved by hand as shown would be driven by power in any suitable manner-F are
blades set radially and fixed to the sides of the outer tank to prevent the water in the
tank from revolving concentrically with the axis of the disc.
G is an inclined shoot by which the refuse tailings which descend through the
opening Cat the centre of the dise Care conveyed to one side of the tank. Il is
an endless chain elevator by which the tailings can from time to time or continuously
be raised up from the water and discharged. "I is an inclined shoot by which material
discharged from the outer circumference of the disc is conveyed to another side of
the tank or vessel-this material which contains the heavy metallic particles may be
raised up from the liquid by another endless elevator such as shewn at H or may from
time to time be removed in any other suitable manner.
K is a shoot by which the crushed ore to be operated on is fed continuously on to
the outer portion of the disc C as the disc is revolved.
Lis a bell by which warning is given when the channel has become filled with
solid matter and it is necessary-that the accumulated deposit should be removed.
The bell is operated by a lever L' the lower extremity of which carries a blade L³.

page_text: 1
When solid material has accumulated in the channel to such an extent that it rises
above the top of the spiral wall it is moved outwards by centrifugal force. When the
outer portion of the channel has in this way become filled it will come against the
blade L and cause the bell to be sounded. The channel may then be cleared by
lowering into it a scraper or scrapers M carried by one or more of the radial arins F
and capable of sliding to and fro along them. The direction in which the disc is
revolved should be reversed at the time when the scrapers are lowered into the channel
so that the deposit may be driven along the channel to its outer.end and discharged
from the circumference of the disc or the disc may be revolved in the opposite direction
without the scraper being employed.
Should it be found desirable to have a larger range of velocity than can readily be
obtained with one disc it may be obtained by placing two or more discs one below the
other so that the material carried to the centre of the upper one falls into the periphery
of one below and so on.
In the diagram figure 12 two discs are shown one below the other; as an example,
the velocity of the spindle B may be one fourth that of the spindle A, then if the
channel at the periphery of A moves at say 16 feet per second, the 'material falling
through the centre would then leave a channel moving (as drawn) 4 feet per second
and the peripheral channel of B into which it is conveyed by means of the shoot
will also move at the same rate whilst that portion of the channel whence it eventu-
ally would fall (through the central aperture of B) will have a velocity only of 1 foot per
second, in other words, assuming the ratio of the velocity of the peripheral and
central portions of the channel in a disc to be n by employing in the manner explained
above, 2 such discs a ratio of velocities of n² will be obtained, with 3 of n³ and so on.
The channel may be made with a horizontal bottoin as shown at figure 4 but
preferably I make it somewhat higher on its outer than in its inner side as shown at
figures 5 and 6 as the deposit tends by centrifugal action to accumulate on the outer
side.
The bed of the channel instead of being horizontal from periphery to centre may
be made to slope at any angle to the horizontal or as a curve, upwards or downwards,
thus bringing the force of gravity to add to or diminish the differential effect of the
spiral; for example if the bed be as shown in figure 7 such differential effect will be
lessened whilst if constructed as shown in figure 8 it would be increased.
The apparatus above described can not only be used merely for assorting but can
also be used for the treatment of (auriferous) crushed stuff direct from the mill in lieu
of ordinary mercury wells and plates in such a case the disc will be made of copper
and the surface amalgamated in the usual manner. The cleaning up of amalgam from
the channel will be effected by lowering into the channel a cleaner exactly fitted to it
as previously described which will sweep out ore amalgam &c. to the peripheral end of
the channel where it will be caught in a receptacle provided for the purpose or the
dise may be rotated in mercury.
I may state that it is not essential that the bottom of the channel should be smooth
it might with advantage in some cases be corrugated or made like the teeth of a saw
or otherwise formed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The herein described method of sorting or dressing mineral or other bodies in a
more or less uniformly pulverized state consisting in supplying the pulverized body
on to a spiral channel immersed in fluid and made to revolve around a central vertical
axis in such a direction that the matters of least specific gravity held more or less in
suspension in the fluid will be carried along the channel and be discharged at its inner
end through a, central hole whilst the matters of greater specific gravity will remain
at rest on the bottom of the channel or even he made to travel outwards by centrifugal
action. Or the converse of the above operation that is if particles of the same

page_text: material but of varying volume be placed on the peripheral portion of the channel the
larger and heavier particles will be deposited near the periphery thence graduating
to the smallest and lightest near the central outlet aperture.
2. The combination of the tank the spiral channel immersed in fluid contained in
the tank and carried by a revolving vertical axis means for supplying material in a
more or less pulverised state on to the spiral channel near its outer extremity, the
blades for keeping the fluid in the tank from revolving around the central vertical axis
of the spiral channel and the opening at the centre of the spiral channel for the
discharge of the lighter matters.
3. The construction of apparatus for sorting or dressing ores substantially as
hereinbefore described.