Improvements in Ore-concentrators or Amalgamators.
Year: 1896

page_text: Date of Application, 8th Oct., 1896-Accepted, 16th Jan., 1897
COMPLETE SPECIFICATION.
Improvements in Ore-concentrators or Amalgamators.
:
We, MERCHANT STODDARD. and CHARLES HAINES SCOTT, both of
Farmington, in the County of Van Buren, and State of Iowa, United States
of America, Gentlemen, 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:-
This invention relates to an improvement in. ore concentrators. or amalgamators,
and has for its object to simplify and improve the construction of devices of this
nature with a view to obtaining one in which provision is made for saving the
finest float-gold, for scouring particles of quartz and removing the mineral conting
thereform, and for saving and separating the precious metals from the tailings of
the quartz-mill.
To this end the invention contemplates the use, in connection with a vibratory
or shaking concentrator trough or table, of a series of removable riffle-pans of
novel construction, in which the separated ore is conducted to and deposited in a
pocket arranged beneath and connected to the bottom of each riffle-pan.
The invention further consists in certain novel features and details of .con-
struction and arrangement, of parts, as hereinafter fully described, illustrated in
the drawings and finally embodied in. the claims.
In the accompanying drawings,
Fig. 1 is a perspective view of an improved ore-concentrator constructed in
accordance with this invention. Fig. 2 is a vertical longitudinal section through
-the same. Fig. 3 is a plan view thereof.
Fig. 4 is an end elevation showing the manner of imparting, a transverse
reciprocating movement to the concentrating-trough.
Fig. 5 is a transverse vertical section through the machine, showing also the
cross-sectional' shape of the riffle-pans.
Fig. 6 is an enlarged detail perspective view of one, of the riffle-pains or
sections.
Similar numerals of reference designate corresponding. parts in the several
figures of the drawings.
a
In some sections of the world, the gold taken from rivers is almost invariably
coated with iron or other mineral deposits, so that the precious metal cannot be
separated from the particles of earthy matter by bringing them in, contact with,
body of mercury and forming an amalgam. The ordinary sluice-boxes.in, common
use have been found practically useless in handling this ore, for the reason that
the gold would not be taken up by the quicksilver, and for the additional reason
"that said gold was so fine that it would be swept on and away with the water
without gravitating to the bottom of the sluice-boxes. In order to overcome the
"difficulties just referred to, this invention contemplates imparting to the concen-
trating trouglr or table a rapid and short lateral reciprocation and in providing
series of riffle pans or sections of novel construction, which are placed within said
trough and formed in such manner that when such reciprocating motion, is imparted
to the trough the sand, water, and ore deposit will be thoroughly, agitated and
given an approximately circular or rotary motion between adjacent riffles or
cleats, thereby effecting a gravitation of the heavier' particles of the auriferous
&

page_text: earth to the bottom of said pans or sections. The quartz or earthy particles
containing the precious metal are thus subjected to a violent agitation and the
conting or deposit of iron referred to is scoured therefrom in such manner as to
expose the metal to the action of the quicksilver.
Referring now to the accompanying drawings, 1 designates a suitable elongated
supporting-frame forming a guiding-base upon which the ore-concentrating
trough 2 is mounted. This base-frame comprises, essentially, two longitudinal
beams arranged in parallelism and a series of transverse bars connecting said
beams at their upper edges, as shown. Between the end transverse timbers and
the timbers lying next adjacent and parallel thereto are arranged guiding and
anti-friction rollers 3, the spindles of which have their bearings in the transverse
timbers just referred to. These rollers are arranged at the front and rear of the
base-frame or adjacent to the longitudinal timbers thereof, as shown in the cross-
sectional view, and are formed with peripheral grooves which are adapted to
receive depending ribs or rails 3ª, secured to the bottom of the concentrator-
trough 2. The concentrating-trough is thus loosely mounted upon the base-frame
and capable of being reciprocated transversely, and such movement is imparted
thereto by means of a longitudinally-disposed driving shaft 4 having secured
thereto intermediate its ends a driving-pulley 5 adapted to receive a driven belt or
band from any suitable motor, preferably the same motor which drives the
elevator, by means of which the pulverized ore, etc., is lifted and deposited upon
the sieve or screen hereinafter referred to. To the opposite ends of the driving-
shaft 4 are secured grooved eccentrics 6 from which connecting rods 7 extend
inward and attach pivotally to the ends of the concentrator-trough, the outer ends
of said rods having straps 8 which pass around the eccentrics in the grooves
therein. By this means a rapid reciprocation is imparted to the trough 2 for the
purpose of agitating the material contained therein."
The trough 2 is divided into two compartments or gutters by a central longi-
tudinal partition or rib 8, and within said gutters are arranged riffle-pans 9.
These pans may be made of any desired length and correspond in width to the
interior transverse measurement of the trough-gutters, so that they will fit snugly
therein and be properly confined in place during the agitation of the trough, the
number of these pans or sections being limited only by the length of the trough 2.
Each of said pans or sections is in the form of a shallow rectangular tray, which
is preferably formed from sheet metal. The bottom of the pan is depressed
centrally and longitudinally, or made slightly V-shaped, so as to form a longi-
tudinal valley or gutter 10, by means of which the concentrated ore is conveyed
to the lower end of the pan or tray. At such lower end each of the riffle-pans is
provided with an aperture 11 through its bottom through which the ore may drop
into a cup or pocket 12 secured to the underside of said pan. This pocket rests
in an aperture formed therefor in the bottom of the concentrator trough.
13 designates a series of transversely-disposed riffles or cleats which are made
substantially L-shaped in cross-section and arranged at suitable intervals longi-
tudinally of the pan. The particular shape of these riffles affords an overhanging
ledge or flange and materially assists in the proper agitation of the sand, water etc.
contained between the adjacent riffles or cleats. The bottom edges of said riffles
are elevated slightly above the bottom of the tray or pan, as shown so that
sufficient space is left to permit the longitudinal passage of the concentrated ore.
The sections or pans thus constructed may be readily removed from the shaking-
trough and emptied and replaced whenever necessary.
Superposed above one of the projecting ends of the shaking concentrator-
trough and connected therewith is a transversely-inclining sieve or screen 14
formed, preferably, from perforate sheet metal and provided upon three of its
sides with vertically-extending guards or fenders 15, the lower end of said screen
being left unobstructed to permit the escape of water and the larger particles of
quartz therefrom. This screen may be removed when necessary.
In the operation of the device the crushed or pulverized ore is deposited by the

page_text: elevator upon the inclined sieve or screen 14 simultaneously with a stream of
water. The particles of ore of the proper size pass through the screen and fall
between the riffles or cleats of the pans or sections 9 and by reason of the
receiving end of the trough 2 being located at a higher elevation than the
discharge end the material deposited therein gradually works its way toward such
discharge end. Owing to the short and rapid vibration of the concentrator-trough
and the riffle-pans therein a thorough and violent agitation is imparted to the
water etc., thus effecting a corresponding agitation of the pulverized ore and the
consequent gravitation of the heavier particles containing the precious metal to
the bottom of the pans.
During the agitation the iron or other mineral deposit is scoured from the
particles of ore, and upon the descent of such particles to the bottom of the pans
the metal is gathered by the quicksilver, with which such bottom is covered, and
finally finds its way through the longitudinal valleys or gutters 10 into the
receiving pockets 11 from which it may be conveniently removed when desired.
At the same time the greater mass of sand and quartz which is free from the
precious metal by reason of its lighter specific gravity, is retained between the
riffles or cleats 13, from whence it may be removed after the gold has been
separated therefrom and passed into the pockets 11.
From the foregoing description it will be seen that the concentrating-trough
operates in a perfectly level and horizontal plane and such motion, together
with the particular form of the riffles results in imparting the desired agitation
of the contents of the riffle-pans. It will be apparent that more than two
rows of riffle-pans may be employed, according to the capacity which it is
desired to give the concentrator. The apparatus above described has been found
very efficient in use after a long practical test and will effect a saving of the
finest float-gold, and such metal as is found in the tailings from the quartz mill,
which would otherwise be lost. The apparatus is very simple and inexpensive in
construction, may be manufactured at slight cost, and the feature of the removable
riffle pans or sections adds materially to the convenience and portability of the
device as a whole.
Changes in the form, proportion, and minor details of construction may be
resorted to without departing from the spirit or sacrificing any of the advantages
of this invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In an ore-concentrator, a riffle-pan comprising a rectangular tray having an
imperforate bottom which is centrally and longitudinally depressed to form a
V-shaped gutter, a series of transversely-disposed riffles located in the bottom of
the pan, the bottom edges of the riffles being separated from the bottom of the
pan by intervening V-shaped spaces, and a pendent extension of the pan forming
a pocket or receptacle which is arranged centrally of one end of the pan and at
the terminus of the V-shaped gutter, substantially as and for the purpose
described.
Dated thin 9th In" of Ontahan 1000
BOULT & WADE,
Agents for the Applicants.