IMPROVEMENTS IN DRESSING METALLIC ORES OR SEPARATING METALLIC ORES FROM EARTHY MATTERS, WHICH IMPROVE. MENTS ARE APPLICABLE TO THE SEPARATION OF OTHER SUBSTANCES." PROVISIONAL SPECIFICATION
Year: 1879

page_text: LETTERS PATENT to John Thomas Dawes, of Mold, in the County of Flint,
Mining Engineer, for the Invention of "IMPROVEMENTS IN DRESSING METALLIC
ORES OR SEPARATING METALLIC ORES FROM EARTHY MATTERS, WHICH IMPROVE.
MENTS ARE APPLICABLE TO THE SEPARATION OF OTHER SUBSTANCES."
PROVISIONAL SPECIFICATION left by the said John Thomas Dawes at the
Office of the Commissioners of Patents on the 3rd May 1879.
#1
JOHN THOMAS DAWES, of Mold, in the County of Flint, Mining Engineer.
'IM-
PROVEMENTS IN DRESSING METALLIC ORES OR SEPARATING METALLIC ORES FROM
EARTHY MATTERS, WHICH IMPROVEMENTS ARE APPLICABLE TO THE SEPARATION OF
OTHER SUBSTANCES."
In the ordinary method of dressing metallic ores or separating metallic ores from
the earthy matters with which they are associated in nature the crude ore is
crushed, and the coarse powder thereby obtained is exposed to the action of a stream
of water. By the action of the stream of water the lighter earthy particles are
carried away, the heavier particles, consisting of the metallic ore, being left behind.
In treating metallic ores according to one of my improvements I reduce the
crude ore to a powder, more or less fine, according to the nature of the ore. I intro-
duce the powered ore into a strong vessel filled with water, and by means of a
force pump or other compressing agent I compress the water in the said vessel
until its density is so far increased as to exceed that of the earthy matters of the
ore under treatment, while being less than that of the denser metallic portion of
the ore.
The particles of earthy matter rise to the upper part of the vessel, while
the heavier particles containing the metal remain at the bottom. The two portions
of the crude ore being thus separated are preserved separate by mechanical arrange-
ments in the closed vessel, and the pressure being removed the upper portion of
the water with the lighter earthy matter is drawn off and the pure ore afterwards
removed. The degree of fineness to which the crude ore to be operated upon is
reduced, and the amount of compression to which the water is exposed, vary
according to the nature of the ore to be treated.
According to another of my improvements I introduce the crushed ore with a
stream of water into a vertical hollow cylinder in which is a rotating vertical
archimedian screw, on the broad thread or blade of which the stream of crushed
ore is delivered. The screw rotates in a direction proper to raise anything falling

page_text: on its blade. The obliquity of the blade is such that it does not prevent the heavy
particles of the pure ore falling to the bottom of the bottom of the cylinder, while
it raises the lighter particles of earthy matter which pass away at the upper part of
the cylinder. In order to effectually separate the ore from the earthy matter it
may, where necessary, be subjected to the treatment described two or three times.
Although my Invention is particularly applicable to the separation of metallic
ores from earthy matter, yet my said Invention is also applicable to the separation
of other bodies of different specific gravities.
In special cases where the use of water is incompatible with or injurious to the
material to be treated other liquids may be substituted for water with like effect.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Thomas Dawes in the Great Seal Patent Office on the 30th
October 1879.
"IM-
JOHN THOMAS DAWES, of Mold, in the County of Flint, Mining Engineer.
PROVEMENTS IN DRESSING METALLIC ORES OR SEPARATING METALLIC ORES FROM
EARTHY MATTERS, WHICH IMPROVEMENTS ARE APPLICABLE TO THE SEPARATION
OF OTHER SUBSTANCES."
In the ordinary method of dressing metallic ores or separating metallic ores from
the earthy matters with which they are associated in nature the crude ore is
crushed, and the coarse powder thereby obtained is exposed to the action of a
stream of water. By the action of a stream of water the lighter earthy particlos
are carried away, the heavier particles, consisting of the metallic ore, being left
behind.
In treating metallic ores according to my Invention I reduce the crude ore to a
powder, more or less fine, according to the nature of the ore, and I introduce the
Baid powdered or crushed ore with a stream of water into a vertical hollow
cylinder, around which and rotating with it is an archimedian screw, on the broad
thread or blade of which the stream of crushed ore is delivered. This rotating
hollow cylinder and scrow are contained in a fixed hollow cylinder. The screw
rotates in a direction proper to raise anything falling on its blade. The obliquity
of the blade is such that it does not prevent the heavy particles of the pure ore
falling to the bottom of the cylinder while it raises the lighter particles of earthy
matter, which pass away at the upper part of the cylinder. In order to effectually
separate the ore from the earthy matter it may where necessary be subjected to the
treatment described two or three times.
Although my Invention is particularly applicable to the separation of metallic
ores from earthy matter, yet my said Invention is also applicable to the separation
of other bodies of different specific gravities.
In special cases where the use of water is incompatible with or injurious to the
material to be treated other liquids may be substituted for water with like effect.

page_text: I will now proceed to describe, with reference to the accompanying Drawing, the
manner in which my Invention may be performed.
Figure 1 represents in sectional elevation, and Figure 2 in plan, the apparatus
which I employ for dressing metallic ores or separating metallic ores from carthy
matter according to my Invention, the said apparatus being constructed so as to
operate three times upon the ore to be dressed.
The same letters of reference indicate the same parts in both Figures.
a, b, c, are three fixed hollow vertical cylinders, into which the crushed ore or
other material carried by a stream of water is introduced and operated upon.
These fixed cylinders are open at top and bottom and are fixed upon the tank or
reservoir k, into which their lower ends open; d, e, f, are three vertical axial shafts
in the hollow cylinders a, b, c, respectively. Each of the shafts d, e, f, carries a
hollow cylinder; these hollow cylinders are marked respectively d, e, f, and
rotate with their respective shafts. The shafts are supported on pivote at the
bottoms of the cylinders a, b, c, and in bearings at their upper ends. About mid-
way between the tops and bottoms of the hollow cylinders d², e³, f, are openings
marked 8, t, u
Each of the rotating cylinders d, e, f, carries an archimedian
screw. These archimedian screws are marked respectively g, h, i, the peripheries
of the said screws being enclosed in and connected with the cylindrical cases g³, h³, i³.
These cylindrical cases are of somewhat less diameter than the interior of the fixed
hollow cylinders a, b, c, and rotate therein freely. The axial shafts d, e, f,
are geared together by toothed geearing l, m, n. The toothed wheel on the
shaft d is driven by the pinion p on the shaft q, which lattor is worked from the
steam engine r or other prime mover. By an examination of the gearing l, m, n,
it will be seen that the shaft d rotates with the highest velocity, the shaft e with a
lower velocity than the shaft d, and the shaft with a lower velocity than the
shaft e.
v is a feed water tank communicating by the pipe with the tank k; and wis
a waste water tank. This tank w is in communication with the feed water
tank v.
The apparatus is used as follows:-
The feed water tank v is filled with water through the pipe, the tank k being
also full of water. The crushed ore or other material is carried by a stream of water
from the crusher along the channel x, Figure 2, and is delivered into the first hollow
cylinder d³, and passes out by the openings 8, 8, into the space enclosed between the
thread or vanes of the screw g and the hollow cylinder g³. The screw thread g rotates
in such a direction as to raise the water contained in the space between the vanes of
the screw.
The ore or other material to be treated carried into the apparatus by
the stream of water falls upon the vanes of the screw, and while the heavier
particles work their way slowly down the screw and fall into the tank the
lighter particles are carried by the combined action of the screw and the upward
motion of the water to the top of the cylinder g³, and are conveyed by the over-
flowing water into the trough y. The said lighter particles of the ore and over-
flowing water from the hollow cylinder g are delivered by the funnel into the
second hollow cylinder e, which has a slower rotation than the first hollow
cylinder d'. Here a further separation of the ore or other matter under treatment
takes place, the heavier particles working their way downwards into the tank k
and the lighter particles passing with the overflow water out of the top of the
cylinder h³. The said overflow water and lighter particles pass by the funnel 2
into the hollow cylinder f", which has a slower rotation than the hollow cylinder e³
and are here exposed to a third treatment, the heavier particles falling into the
tank k and the lighter particles overflowing the top of the hollow cylinder i³, passing
with the stream of water along the trough 3 into the waste water tank w.
they fall to the bottom of the tank w, and the waste water from the said tank w
is conveyed by a pipe to the feed water tank v, so that the same water is used
over again. Any portion of the ore or substance and the water by which it is
carried which escapes, falling through the funnel into the cylinder e*, will wholly
Here

page_text: or for the most part fall through the funnel 4 into the funnel 2 of the hollow
cylinder f'.
Although I have represented an apparatus to be used in carrying my Invention
into effect, in which the ore is operated upon three times by screws rotating with
progressively diminishing velocities, yet I do not limit myself to the use of an
apparatus coutaining threo or other particular number of screws. Neither do I
limit myself to any particular rate of rotation of the screws, as the rate of rotation
must be determined by the nature of the material being operated upon and the
degrees of fineness into which it is wished to separate the crushed ore or other
material.
In some cases, especially when the matter operated upon has a tendency to stick
or attach itself to the vanes of the screw, it is desirable to give a variable motion
to the shafts of the several screws, so that by the temporary more rapid rotation of
the screws, any attached particles may be detached. This may be effected by
mounting the toothed wheels of the gearing excentrically on their shafts d, e, f,
that portion of each toothed wheel of longest radius engaging with that portion of
the wheel it is geared to, which is of shortest radius, as is well understood. Or a
rising and falling or jarring motion may be given to the screws for the purpose of
detaching any particles adhering to them by having projections or grooves in the
foot plates, or by means of cams over or under the centre upright shafts and
actuated by the driving power. These machines may be constructed of light and
strong material, such as steel, mounted upon wheels, to render them portable to
move from place to placo as required.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I do not limit myself to
the precise details herein described and illustrated, as the same may be varied
without departing from the nature of my Invention.
But I claim as my Invention the improvements in dressing metallic ores or
separating metallic ores from carthy matters, and separating other substances of
different specific gravities herein before described and illustrated in the accom-
panying Drawing, that is to say, effecting the said dressing or separating by
causing the crushed ore or other matter to be delivered by a stream of water into
one or more rotating hollow cylinders carrying screws rotating with them as
described, the stream of water and material being delivered upon the threads or
vanes of the screws below the surface of the water in the said cylinders, the said
cylinders and screws having rotation in a direction proper to lift the matter and
water in which it is suspended vertically, so as to raise the lighter particles with
the ascending current of water, and permit the heavier particles to fall down the
threads or vanes into a receptacle at the bottom of the said screws, substantially as
described and illustrated.
In witness whereof, I, the said John Thomas Dawes, have hereunto set my
hand and seal, this Twenty-third day of October, in the year of our Lord
One thousand eight hundred and seventy nine.
Witness,
CHARLES ATKIN HOLLOWAY,
Assistant to Mr. J. T. Dawes,
Mold,
Flintshire.
JOHN THOMAS DAWES. (L.S.)