IMPROVEMENTS IN MACHINERY AND PROCESS FOR AMALGAMATING AND EXTRACTING GOLD AND SILVER FROM THEIR ORES
Year: 1882

page_text: LETTERS PATENT to Louis Ferguson Gowans, of 80, Cheapside, in the
City of London, for an Invention of "IMPROVEMENTS IN MACHINERY AND
PROCESS FOR AMALGAMATING AND EXTRACTING GOLD AND SILVER FROM
THEIR ORES."
PROVISIONAL SPECIFICATION left by the said Louis Ferguson Gowans
45
at the Office of the Commissioners of Patents on the 19th January 1882.
LOUIS FERGUSON GOWANS, of 80, Cheapside, in the City of London. IMPROVE
MENTS IN MACHINERY AND PROCESS FOR AMALGAMATING AND EXTRACTING
GOLD AND SILVER FROM THEIR ORES."
My Invention relates more especially to machinery used for amalgamating or
extracting by means of metallic mercury the particles of gold contained in
auriferous quartz stamped or otherwise reduced to powder, or silver from silver
ores similarly reduced. It has for its objects novel methods of constructing and
arranging machinery or apparatus by means of which the metal to be extracted is
brought into contact with the mercury, so that every particle in its passage through
the machine is necessarily brought into such contact, and great saving both of gold
and of mercury is effected as compared with machinery or apparatus for such
purpose as heretofore ordinarily constructed and used, in which often a considerable
part of the gold, especially the very minute particles, passes away from the
machine without being detained by the mercury and either escapes and is lost or
has to be recovered by subsequent processes.
I take a vertical hollow shaft of sufficient height revolving in bearings formed
upon or attached to a suitable framing, preferably of wood, and having at its upper
end a hopper into which the auriferous sand, powdered quartz, or other material
is admitted together with a supply of water.
The auriferous sand and water may
be allowed to pass to the hopper directly from stamps or other pulverizing
appliances in which it has been reduced to powder, or it may be supplied gradually
from any other source by means of elevators, endless screws, or other, feeding
mechanism of any of the well known kinds, or it may be fed in by hand.
:

page_text: The vertical hollow shaft and hopper are set in revolution at the desired speed,
which may be varied according to the character of the material being treated, by
steam, water, or other convenient power. I prefer to drive it by means of a
horizontal shaft set in motion by such power and revolving in bearings formed
upon or attached to the framing which carries the vertical hollow shaft, one end
of such horizontal shaft being fitted with a bevilled toothed wheel gearing into
and driving a corresponding bevilled toothed pinion upon the vertical hollow
shaft, and its other end being fitted with a pulley by which it is set in revolution.
The weight of the hollow vertical shaft, and of the appliances hereinafter
described which are attached to its lower end, is supported by a collar arranged
at any convenient part of its length preferably at its upper end, such collar resting
upon a fixed support or bearing in which it revolves, preferably with the
intervention of a sufficient number of steel rings or washers.
At the lower end of the hollow vertical shaft is fixed a block, preferably of
cast iron having a vertical central opening at its upper part which is fitted upon
and attached to the shaft, the lower end of the opening communicating with a
sufficient number, preferably four, of outlets curving down and outward, through
which the sand and water pass out into a circular horizontal pan or dish, preferably
of wrought iron, which is supported upon a frame or foundation immediately
below the hollow shaft..
At the upper part of the hollow casting above described, where it is fitted upon
the hollow shaft, is formed a collar upon which is supported and fixed a horizontal
muller or grinding plate, preferably of cast iron, which is made in four or more
segments bolted or keyed together, so that either of them can at any time be
readily removed or replaced when desired.
The bottom of each of these segments is provided with a flat copper plate,
rivetted or otherwise fixed to it. A circular inclined or vertical flange is preferably
formed upon the outer diameter of the segments, concentric with but of less diameter
than the edge of the lower pan already described, so that an annular space is left
between them.
The action of the apparatus is as follows:-The lower surface of the copper
plates, which are amalgamated with mercury, being adjusted to revolve at a
suitable distance, preferably about one inch and a half, from the bottom of the pan
into which a sufficient quantity of mercury is placed, the vertical shaft, together
with the copper bottomed segments, are set in revolution, a supply of auriferous
sand and water being admitted down the vertical hollow shaft from the hopper
above. By the pressure of the water the sand is pressed, not between the copper-
plated muller and the mercury in the pan, but absolutely through the mercury in
the latter and on the copper plates, and in this way it is impossible for any particle
of gold to escape amalgamation provided the ore be crushed sufficiently fine.
The sand from which the gold has been thus extracted passes from under the
muller and is carried with the water over the edge of the pan in which the latter
revolves. The muller being in segments, either segment can be readily removed
or replaced when necessary.
Where auriferous or argentiferous ores are to be treated in which the metal is
coated or combined with mundic or substance which has no affinity for mercury,
I use the following process. The ore being crushed or reduced to the necessary
degree of fineness either dry, or being thoroughly dried after such crushing, I pass
it in a dry state through the machinery or apparatus already described, to the
mercury in which has been added, in the proportion of about one ouce to every.
four thousand five hundred ounces of mercury, the following composition. I heat
mercury to a temperature of about 300° Fahrenheit and to every hundred ounces I
add seventeen ounces of metallic sodium, in small particles at a time in order to
avoid dangerous combustion, and I mix the alloy in the above named proportions
with the mercury in the pan of the apparatus.
The presence of the sodium in the mercury frees the particles of metal in the
sand from their coating of mundic or other such substance as described, and ensures

page_text: their thorough amalgamation whilst passing under the muller. I do not confine
myself to the precise proportions of the materials named, which may be varied
slightly to suit varying circumstances.
Where the sand is passed dry through the machine or apparatus as described, it
is not necessary that the vertical hollow shaft should be of such height as in the
arrangement first described; and the hopper may be arranged immediately above
the revolving hollow block to which the compound muller is attached, the sand
being made to pass under the copper plates by the revolution of the latter, aided if
necessary by revolving blades or screws by which it is forced down.
The pan may in some cases be surrounded with a casing or jacket, steam or hot
water being admitted into the space between, so that the mercury may be heated
and kept at any desired temperature.
The bottom of the muller inay be provided with ribs or projections, or depressions,
straight or curved, in order that every particle of the sand may more certainly be
brought in contact with the mercury.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Louis Ferguson, Gowans in the Great Seal Patent Office on the
19th July 1882.
"IMPROVE-.
LOUIS FERGUSON GOWANS, of 80 Cheapside in the City of London
MENTS IN MACHINERY AND PROCESS FOR AMALGAMATING AND EXTRACTING GOLD
AND SILVER FROM THEIR ORES."
My invention relates, more especially to machinery used for amalgamating, or
extracting by means of metallic mercury, the particles of gold contained in
auriferous quartz, stamped or otherwise pulverized, or of silver from silver ores
similarly reduced to powder. It has for its objects novel methods of constructing
and arranging machinery or apparatus by means of which the metal to be extracted
is brought into intimate contact with the mercury, so that every particle during
its passage through the machine is necessarily brought into such contact with the
mercury, and great saving of the latter as well as of the gold or silver which is to
be extracted is effected, as compared with machinery or apparatus for such purpose
as heretofore ordinarily constructed and used, in which a considerable part of the
metal, especially the very minute particles, passes away from the machine without
being detained by the mercury, and either escapes and is lost or has to be recovered
by subsequent processes. In order to put my Invention in operation,
I take a vertical hollow shaft of sufficient height, revolving in bearings formed
upon or attached to a suitable framework or support of wood or other material,
and having at its upper end a hopper into which the auriferous sand, powdered
quartz, or other material to be treated, is admitted together with a sufficient
quantity of water.
The auriferous sand and water may be allowed to pass into the hopper directly
from stamps or other pulverizing machinery by which it has been reduced to
powder, or it may be supplied gradually from any source by hand, or by elevators,
endless screws, or other feeding mechanism of any of the ordinary well known
kinds.
The vertical hollow shaft and hopper described are set in revolution at the
desired speed, which may be varied according to the character of the material
being operated upon, by steam, water, or other convenient power. I prefer to
drive them by means or a horizontal bevilled toothed wheel fixed upon the shaft
and driven by a corresponding bevilled toothed pinion upon a horizontal shaft
revolving in bearings formed upon or fixed to the frame, this shaft being provided
with a driving pulley by which it can be set in revolution. The weight of the
hollow vertical shaft, and of the appliances connected to its lower end as herein-
after described, is supported by a collar arranged upon the shaft at any convenient
part of its length, preferably at its upper end, such collar resting upon a fixed
support or bearing in which it revolves, and a sufficient number of loose steel
or other rings or washers being. interposed between the collar and bearing if
required.
At the lower end of the hollow vertical shaft is fixed a block, preferably of cast
iron, having a vertical central opening at its upper part which is fitted upon and
fixed to the lower end of the shaft, the opening communicating below with a
sufficient number, preferably four, of outlets passing down and outward through
which the sand and water from the vertical hollow shaft pass out into a circular
horizontal pan or dish, preferably of wrought iron, which is supported upon a frame
or foundation concentric with and immediately beneath the hollow shaft. At the
upper part of the hollow block described, where it is fitted upon the hollow shaft,

page_text: is formed a collar upon which is carried and fixed a horizontal grinding plate or
muller, preferably of cast iron, which is made in four or more separate segments
bolted or keyed together so that either of them can be readily removed or replaced
at any time when desired.
The bottom of each of these segments is provided with a Hat copper plate
rivetted or otherwise fixed to it. A circular vertical or slightly inclined flange is
preferably formed upon the outer diameter of the segments, concentric with but of
less diameter than the edge of the lower pan already described, so that an annular
space is left between them. The lower surface of the copper plates is amalgamated
with mercury, and is adjusted so as to revolve at a suitable distance, preferably
about one inch and a half, from the bottom of the pan into which a sufficient
quantity of mercury is placed.
The accompanying Drawings are in illustration of my Invention. Figure 1 is a
front view partly in section, and figure 2 a side view of the entire apparatus.
Figure 3 is a side view, half in section, and Figure 4 a plan half from below and
half from above, of the lower revolving apparatus. Figure 5 shows an oil cup
which may be fixed upon the revolving shaft, and Figure 6 is a section of the
lower pan. The same letters of reference indicate the same parts in the several
figures.
a is the wooden framework of the machine, carrying bearings b, 61, in which is
suspended and revolves the vertical hollow shaft c the upper end of which is fitted
with a hopper d. Friction rings are shewn interposed at y. The hollow shaft c
is shewn driven by the bevilled tooth wheel e and the pinion f upon the driving
shaft g which revolves in bearings h, h' and is driven by the pulley i.
Upon the lower end of the hollow shaft c is screwed and fixed the hollow
block k having a vertical central opening communicating with the four
outlets m, m, m, m, which pass down and outward to their inclined mouths
at n, n, m, n, discharging into the fixed pan o, which is supported upon the
foundation p. Upon the block k is a collar r upon which rests the grinding plate s
formed of four segments fitted and bolted together as shewn in Figures 3 and 4,
and having amalgamated copper plates t, fitted and fixed to their lower surface.
These plates have formed upon their lower surface curved inclined grooves v, v,
in continuations of the discharge openings n, by which the distribution and
amalgamation of the escaping metal is more perfectly effected. wis a flange formed
upon the edge of the segments which form the bottom plate 8.
The action of the apparatus is as follows:-The lower surface of the copper
plates t, which are amalgamated with mercury, being adjusted to revolve at a
suitable distance from the bottom of the pan o in which a sufficient quantity of
mercury has been placed, the vertical, shaft c togetlier with the block k and
segments & are set in revolution, a supply of auriferous or other sand and water
being admitted down the shaft c from the hopper d.
By the pressure of the water the sand is pressed-not only between the copper
surface t and the mercury in the pan o-but absolutely through the mercury in the
latter and upon the copper plates, and in this way it is impossible for any particle
of gold to escape amalgamation provided the ore be crushed sufficiently fine.
The sand from which the gold has been thus extracted passes from under the
muller 8 and is carried with the water over the edge of the pan o. The muller or
plates being in separate segments, either segment can be readily removed and
replaced when necessary.
In Figure 5 is shewn a cup keyed upon the revolving hollow shaft c, so as to
receive any oil which may drop from the bearings.
The pan o is provided with an opening fitted with a moveable iron plug, by
which the merury or amalgam can be withdrawn.
Where auriferous or argentiferous ores are to be treated in which the metal is
coated with mundic or other like substances which have no affinity for mercury,
I use the following novel process. The ore being crushed or reduced to the
necessary degree of fineness either dry, or having been thoroughly dried after such

page_text: crushing, I pass it in a dry state through the machinery or apparatus already
described, to the mercury in which has been added, in the proportion of about one
ounce to every four thousand five hundred ounces of mercury, the following
composition. I heat mercury to a temperature of about 300° Fahrenheit and to
every hundred ounces I add seventeen ounces of metallic sodium, in small particles
at a time in order to avoid dangerous combustion, and I mix the alloy thus
produced in about the above named proportions with the mercury in the pan o.
The presence of the sodium in the mercury frees the particles of metal in the sand
from their coating of mundic or other such substance, and ensures their thorough
amalgamation whilst passing under the copper plates t.
I do not confine myself to the precise proportions of the materials named, which
may be varied slightly to suit varying circumstances, such as the character of the
material treated.
Where the sand is passed dry through the machine or apparatus as last described,
it is not necessary that the vertical hollow shaft should be of such height as in the
arrangement first described and shewn, and the hopper may be placed immediately
above the revolving hollow block k to which the compound muller 8 and tis
attached, the sand being made to pass under the amalgamated copper plates by the
revolution of the latter, aided if necessary by revolving blades or screws by which
it is forced down.
The bottom of the revolving muller may be provided with ribs, projections, or
depressions, straight or curved as shewn, in order that every particle of the sand
may more certainly be brought in contact with the mercury.
The lower pan o may in some cases be surrounded with a casing or jacket, steam
or hot water being admitted into the intervening space, so that the mercury may
be heated and kept at any desired temperature.
I do not claim the precise form and arrangement of the several parts of the
apparatus, which may be varied to suit varying circumstances, but having now
described my invention and the manner in which it is to be performed, I claim :-
The combination of the vertical hollow shaft and hopper revolving in bearings, and
the lower hollow block, segments, and amalgamated copper plates, revolving in a
pan containing mercury, substantially as described and shewn in the Drawings.
Also, the combination of the hollow block fixed upon the lower end of the hollow
vertical shaft, and having curved discharge passages through it, the separate
segments bolted together and carried by the hollow block, and the amalgamated
copper plates fixed upon the lower surface of the segments, substantially as
described and shewn in the Drawings,
Also the process of preparing mercury for amalgamating by the addition of
sodium, substantially as and in the manner hereinbefore described.
In witness whereof I, the said Louis Ferguson Gowans, have hereunto set my
hand and seal, this Nineteenth day of July, in the year of our Lord One
thousand eight hundred and eighty two.
LOUIS FERGUSON GOWANS. (L.S.)