Improvements in Ore Concentrators.
Year: 1898

page_text: Improvements in Ore Concentrators.
A communication by FRANK LESLIE BARTLETT, of Canon City, in the County of
Fremont and State of Colorado, United States of America, Chemist.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, 118, New Street, Birmingham,
in the County of Warwick, and 322, High Holborn, in the County of Middlesex,
Civil Engineer, 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:-
a
This invention relates to improvements in that well known class of ore concen-
trators known as "shaking tables," in which the ores are made to pass over
plane or corrugated surface where it is subjected to the action of a flow of water
which washes out the lighter and more worthless particles of material and separates
them from the heavy and more valuable particles.
Hitherto these tables have been made wholly or partially of plane or unriffled
surfaces and the separation has mostly been done on single tables where all the ore
and water were applied at once at the end and along the side.
The tendency in these tables was to pile up the ore and to wash the fine and
valuable particles into the tailings owing to the large amount of water used and they
had a limited capacity as the ore traversed the table in a comparatively narrow belt
whereby only a small portion of the surface did the actual work of separation.
According to the present invention the entire working surface of the table is
covered with riffles running in the same direction as the table reciprocates using no
plane surfaces for the separation of the ore and the riffles are extended to the
discharge end of the table so that the concentrates discharge at this point from the
ends of the grooves.
The table is constructed with a series of laterally inclined shelves with an
independent water supply for each shelf with spouts of peculiar construction for
carrying the unconcentrated material from the lower side of each shelf to the upper
side of the next shelf below. Means are also provided for grading the concentrates
as they fall from the ends of the grooves of the several shelves.
The invention is illustrated by means of the accompanying drawings in which,
Fig. 1 is an end elevation of the complete machine,
Fig. 2 is a side elevation of the same,
Fig. 3 is a cross section on the line
of Fig. 6,
Fig. 4 is a section on the line x x of Fig. 6,
Fig. 5 is a section on the line y y of Fig. 6 and
Fig. 6 is a plan of the table proper.
The shaking table proper, B, is constructed with a series of steps or shelves CC
in the present case, three, all extending from one end of the table to the other and
being placed at descending levels so that the water and waste material will flow or
may be mechanically conveyed from one to the other of the upper shelves of the
series.
These shelves are considerably inclined laterally so that the water will flow

page_text: across them and it is preferable to construct them substantially level from end to
end.
The water is admitted through pipes or boxes a a placed lengthwise beneath the
two upper shelves, the openings a a¹ for the discharge of water being along the
upper sides of each of said shelves so that an independent flow of water is secured
straight across each shelf.
The surface of each of the shelves is grooved or corrugated longitudinally, the
grooves being preferably in the form of right angled triangles, that is to say, one
side of the groove is vertical, the vertical side being that from which the flow of
water comes and the grooves extend to the end of the table where the discharge of
concentrates takes place. The several water boxes are supplied with water through
the pipes ww.controlled by valves w¹ and they connect with a water chest W which
receives its supply from a supply pipe w².
The ore is fed to the machine through the feed box or hopper 0 and the
concentrates are discharged as fast as they are formed over the end of the table and
are allowed to fall into the grading box D hereinafter described.
The waste and unconcentrated material is delivered over the side of each of the
upper shelves, to the next lower shelf, through the inclined spouts E, each of which
is pitched somewhat from the discharge end to the upper end and has in it several
inclined partitions e e (Fig. 5) the lower ends of which are left somewhat above the
bottom e¹ of the spout E. These partitions form a series of inclined passages by
which the waste and unconcentrated material from each of the two upper shelves is
conveyed to different points on the upper side of the next shelf below. The action
of this spout has a tendency to carry forward the process of concentration as the
lighter particles are swept by the action of the water toward the upper end of
the spout, while the heavier particles tend to drop into the partitions nearest
the discharge end of the table. Again, the motion of the water at the lower ends
of the passages as the table jars, tends to form a suction and to draw the material
down through.
This spout thus not only prevents the material which has once been separated from
being again mixed but it also carries on the process of separation while delivering the
material from one shelf to the other. A spout F carries off from the machine
the water and tailings from the lower shelf.
The table proper is here shown as supported on rollers 22 journalled to the
blocks ppl which are adapted to be raised and lowered by the supporting rods P and
adjusting nuts R.
The table is reciprocated in the direction in which the grooves run by an eccentric i
which is connected with the underside of the table by the eccentric rod k, the end of
the rod passing through a hole in the bracket u.
Secured to the rod on one side of the bracket is a buffer j and on the other side of
the bracket is a buffer t both of which it is preferable to make of heavy rubber;
although they may be made of other suitable material. The buffer t through which
the forward motion is imparted to the table is much more yielding than the buffer j
which imparts the return motion.
The motion given to the table by these unequally yielding buffers will carry it
forward with a gradually accelerating speed whereby the momentum of the table will
be gradually imparted to the ores on its surface with a short pause at the outward
end of the stroke. The table will then start quickly on its return, throwing forward
the ores and will gradually come to a rest at the rear end of the stroke. This
movement of the table will tend to move the ores rapidly forward, particularly those
fine and heavy concentrates which lie in the grooves.
The movement of the table is regulated by means of a. tension rod r which is
secured by one end to the table while the other end is yieldingly secured to the
frame of the machine by. a spring g held by a nut q. On one end of the rod is a hand
wheels by which the tension of the spring is regulated. It will be seen that the
action of the spring q is to assist the buffer t in throwing forward the table and the.
t nsion of this spring will therefore determine the amount of compression: of
e

page_text: the buffer and consequently its effect on the table and the rapidity with which the
ores travel on the table.
The grading box D by which the concentrates are graded and classified as they
come from the ends of the grooves extends across the end of the table and has an
open top divided into compartments by means of strips d, each compartment being
so located as to receive the concentrates from one of the several shelves. Means are
provided for grading the concentrates from each shelf so as to combine like grades
from the several shelves. To do this my correspondent has in the floor of each
compartment several openings 1, 2, 3 through which grades from each shelf are led
through several chutes c c and c to common discharge spouts bb and b. (Figs. 4
and 5). Each of the openings marked is placed opposite the upper grooves of the
shelf from which the finest concentrates come and the opening 3 are placed opposite
the lower grooves as herein shown.
The various grades of concentrates are conducted to the discharge openings by
dividing strips which are pivoted between the openings, their inner ends swinging
adjacent to the end of the table. By moving the ends of the strips one way or the
other the concentrates are guided from any desired group of grooves.
Each of the openings communicates through the chutes c¹ to the discharge
spout 6' so that the finest grades from each shelf are mixed and delivered from a
common spout and the medium and lower grades are treated in the same manner.
The operation of the machine is evident from what has been already said. The
concentrates which are successively taken off from each shelf are delivered over the
end, the finer and heavier from the grooves nearest the upper edge of the shelf, and
the waste and unconcentrated material is delivered from each of the upper shelves to
the next lower shelf to be again acted on until the lower shelf is reached where the
tailings are discharged through the spout F. If any tailings come from the ends of
the grooves it will be from those near the lower edge and they may be run off through
the openings 3.
The machine is capable of great adjustability by regulating the flow of water on
each shelf and raising or lowering the sides or ends of the table laterally or longi-
tudinally. Very fine or very coarse ores may be operated on at will and the capacity
regulated with great facility.
If the first shelf is forced the second and third will immediately take up the surplus
and effective work is still performed.
As little water is used on the first shelf, it follows that less slimes or fine ores is lost
than in the old way of separating and in practice it is found that the first shelf takes
up the finer ores, which is exactly the reverse of tables where the water is all applied
at once.
After the fine particles of ore are removed on the upper shelf and the material
conveyed back to the next lower shelf, and increased flow of water may be used
sufficient to remove the heavy waste as there is then no danger of washing away the
The advantage of having the grooves extend the whole length of the table
consists in the fact that much better protection is given to the fine ores which, owing
to the rapid vibration of the table are kept below the coarser parts and will protect
them from being washed away by the water.
fine ores.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is:-
1. In an ore concentrator, the combination of a laterally inclined and longitudinally
reciprocating shaking table having longitudinal riffles extending to the concentrates
discharge end thereof and a water supply duct extending along the upper side of
said table.
2. In an ore concentrator the combination of a longitudinally reciprocating shaking
able having a series of laterally inclined shelves provided with longitudinal riffles
extending to the concentrates discharge end thereof, a separate water supply for

page_text: each shelf and means for conveying the unconcentrated material from the lower side
of each of the upper shelves to the top of the next shelf in the series.
3. In an ore concentrator the combination of a longitudinally reciprocating shaking
table having a series of laterally inclined shelves provided with longitudinal riffles,
a water supply for each shelf, and a spout having inclined partitions therein extend-
ing along the lower side of each of the upper shelves for delivering the unconcentrated
material to the next shelf below.
4. In an ore concentrator, the combination of a longitudinally reciprocating shaking
table having a series of shelves and provided with longitudinal riffles extending to the
concentrates discharge end thereof, a grading box extending across the end of the
table for receiving the concentrates, said box being divided into several compart-
ments each of which receives the ore from one of the shelves, openings in said
compartments and guide strips for conducting the several grades of concentrates to
said openings, a discharge spout for each grade of concentrates and chutes connecting
one or more openings in each section with a cominon discharge spout.
5. In an ore concentrator, the combination of a shaking table, an eccentric and
eccentric rod for reciprocating said table, a yielding spring or buffer on said rod for
forcing the table forward, a buffer on said rod for returning the table of greater
rigidity than said yielding buffer and an independent adjustable spring for aiding the
forward motion of the table.
Dated this 20th day of Datobar 1808
WM. P. THOMPSON & Co.,
Agents, of London, Liverpool, Manchester, and Birmingham.