A New or Improved Apparatus for Treatment of Auriferous Sand and other Matters Containing Free Gold.
Year: 1888

page_text: Date of Application, 10th Dec., 1838:
Complete Specification Left, 9th Sept., 1889-Accepted. 30th Nov., 1889
PROVISIONAL SPECIFICATION.
A New or Improved Apparatus for Treatment of Auriferous Sand
and other Matters Containing Free Gold.
I ANTOINE (LÉMENT-CONTI, Engineer of Foletto in the Kingdom of Italy do
hereby declare the nature of this invention to be as follows:-
The object of this invention is a simple, inexpensive and portable apparatus for the
washing of auriferous sand or alluvial deposits or other mixtures or matters containing
loose free gold for the recovery of the latter.
On a suitable base is supported a cylinder having an inverted shallow conical floor
with a central orifice therein usually closed in this cylinder is an inverted conical
chamber open below and in communication above through a pipe with a tank or
chamber in which the gold and sand etc. falls through suitable sieves, of gratings or
perforated plates arranged in the base or floor of an inclined channel along which the
sand or matters containing the gold are washed by a current of water. The gold and
finer sand falls into the aforesaid tank through the meshes or orifices preferably of
3" size of the sieves or the like together with some of the water, the remainder of the
water, washing the stones and larger parts out at the end of the channel. At a certain
height in the chamber is a water overflow so that the height of the water in the
chamber is substantially the same at all times during the period the apparatus is
in use.
The chamber is adjustable in height above the cylinder so that the force of
water issuing into the cylinder may be varied according to the weight of the matters
mixed with the gold. The water falling through the tube carries the sand and gold
into the inner inverted conical chamber which throws the same down on to the
inverted conical bottom of the cylinder whence it passes upward between the wall of
the inner conical chamber and the wall of the cylinder to suitable outfalls or overflow
pipes arranged in the wall of the cylinder. The gold is left on the bottom of the
cylinder, but the force of the water is sufficient to carry the sand etc. out of the
overflows or outfalls into an annular trough whence it may be suitably removed.
After sufficient gold has become collected in the cylinder, the orifice in the conical
bottom is opened and the gold is washed out by water.
The various parts may with convenience be made of sheet copper with tin soldering
when necessary.
Dated this 10th day of Deconshar 1000
HERBERT & Co.,
Agents to Applicant.
COMPLETE SPECIFICATION.
A New or Improved Apparatus for Treatment of Auriferous Sand
and other Matters Containing Free Gold.
I ANTOINE CLÉMENT-CONTI, Engineer of Folletto in the Kingdom of Italy 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 object of this invention is a simple, inexpensive and portable apparatus for the
washing of auriferous sand or alluvial deposits or other mixtures or matters containing
loose free gold, for the recovery of the latter.
To fully explain my invention I call hydraulic pressure the impact of a fluid in
motion and hydrostatic pressure that which is solely due to the weight of a stationary
fluid. Taking then a vessel A B C D (fig. a) filled previously with water wherein is
immersed a vertical tube, 1. 2. 34 the upper level 1. 2 of which is above the level A B
by a distance 2; 6, and the base 3, 4 of which is above the bottom CD at optional

page_text: distance. It is certain-that in pouring a stream of water through the top of the
tube, 1. 2 3 4, this water will rush down to the bottom of the vessel A B C D at the
speed due to the pressure produced by the height 2, 6, which is the difference between
the two levels, 1, 2 and A B and that the fluid body A B C D will be pushed from
below upwards in proportion to the quantity of water sent in through the
tube 1. 2 3 4.
It is this power which I call hydraulic pressure. Being more powerful than the
weight of a water column A or B D (hydrostatic pressure) it produces an impact
upon the stagnant fluid body A B C D and causes horizontal vibrations which
diminish in intensity and power in proportion as they rise or move away from the
departure point 3, 4.
It is there, where the effect takes place of the hydraulic pressure struggling against
the weaker hydrostatic pressure and governing it in proportion to the height of fall
due to the difference of the two levels 1. 2 and A B.
A different current is thus produced from the one which takes place in a slightly
inclined channel, as for instance the channel of the gold washers or chutes. In these
channels the speed of the current is due to two powers which co-operate for the same
purpose, following the same direction, the hydraulic power due to the inclination of
the channel; the hydrostatic power to the weight of the water jet. These two
pressures increase reciprocally in power and enlarge gradually as they move away
from the point of departure, the outflow speed being uniformly accelerated as far as
the bottom of the inclined plane.
The contrary takes place in the manner of outflow which I have described above.
The current 1, 3 takes place vertically from above downwards and the pressure of the
fluid body contained in the tube 12. 3, 4 is always constant, suffering no variation
whatever.
But this pressure acts upon another fluid body A B C D which opposes its
hydrostatic pressure, a resistance which the hydraulic pressure of the fluid
column 1. 2. 3 4 should overcome in order to compel the body A B C D to run off
in overflow, in proportion to the volume of water which it gives to it and as the
current acts in a direction contrary to the hydrostatic pressure A B C D a shoot is
produced at the meeting of the two fluid bodies which creating permanent vibrations,
occasions horizontal undulations following each other successively from below
upwards and which loose their intensity and power in proportion as they distance
the point of departure C D to die away at the furthest point A B where the fluid runs
off in overflow.
These shoots, the vibrations and the undulations, due to the impact of two fluid
columns exercising their pressure in contrary direction have a considerable importance
for the subject which I have in view, in fact if the fluid body injected through the
tube, 1, 2, 3, 4 keeps in suspension solid bodies, such as gravel, powdered iron or gold
it will occur that the solid particles weighing more than the volume of water displaced
by them sink to the bottom of the vessel A B C D and they will accumulate there if
the shoots produced by the impact of the two contrary pressures do not keep them in
motion and in suspension to be successively raised from below, upwards by the power
of the up-vibrations of which I bave spoken.
But these vibrations diminish in intensity and power instead of increasing (as is the
case in the gold washer channel or in the chute) in proportion as they rise and
approach the upper edge B, the following also takes place, the body, the weight of
which in the water is superior to the weight of the gravel or of the iron which are
immersed therein at the same time as the platina the gold, the lead etc. can only be
raised very slightly and are compelled to remain at the bottom of the vessel A B D
the upward vibrations not having the power to carry them away. It is not the same with
the sand, the weight of which especially in water is by far inferior to the weight of these
metals. Being lighter at equal volume the swell has sufficient power to raise it above
the point 3, 4, the base of the injection tube and there the vibrations of the fluid push
it successively as far as the level A B where it flows off with the water which
overflows.

page_text: On the other hand the gora in dust is easier retained by this manner of treatment
as by only showing two surfaces to the pressure of the fluid agitated by the swell it is
absolutely impossible for it to escape or to be carried away by the upward vibrations.
In fact the gold spangles flutter about in the fluid in ebullition and hurry to the
bottom of the vessel, where resting flat upon one of their two surfaces they are held
down in a measure by the hydrostatic pressure.
The apparatus is represented in the accompanying drawing. Fig. 1 in vertical
section and Fig. 2 in horizontal section on line A B.
All the parts which compose it fit into one another so as to make the erection or
dismounting quick and easy.
The water and the sand are introduced by an optional wooden or metallic channel
and fall into a lower channel A' intended for separating the pebbles as well as the
gravel from the sand which contains the gold.
This separation is naturally obtained by means of the dividing plate which is at the
lower part of this channel, and which is composed of four transverse notches a a a a
distributed over the whole length of the channel A' and being slightly over 3 millimeters
at the opening, further of three sheets of galvanized metal or copper 6 6 6 having three
holes of three millimeters diameter.
The holes a aa a are made for the case which happens sometimes when the sand
contains gold spangles of a larger diameter than three millimeters. Being flatly
carried along in the channel A' these spangles bend down to meet these slits and fall
into the inferior channel which takes them into the apparatus from where they
cannot escape.
Below the channel A' is a second channel K conjointly with the one which is
superposed to it and intended to receive the water, the fine sand and the gold which
pass through the openings a aa a and the perforated metallic sheets bbb so that
the separation of the coarse from the fine takes place rapidly without mechanical
means and by the sole effect of the current which carries along the whole on the
first separator K.
The pebbles, the gravel and the coarse sand pass over the openings and the
perforated metal sheets and continue to be carried along by the upper current
which discharges them either into a waggon or into a relieve channel A
The proportion of the water the fine sand and the gold which have been thrown
into the lower channel are poured into a funnel B₁ as is shown in Fig. 1 by the
arrows showing the direction of the various currents which take place within the
apparatus.
This funnel possesses two overflows h so that the top level of the fluid is always the
same (this point is essential to avoid the intermittances which might take place in
the hydraulic pressure as well as to avoid the ram shocks which would give a too
violent impulsion to the swell and the vibrations of the fluid in the apparatus) and
a tube K which I call the injector tube.
This funnel which is adapted to the apparatus by the tube K' can be raised and
lowered at option by several centimeters in order to regulate thoroughly the hydraulic
pressure in proportion to the weight of the immersed sands as these latter may vary
in density.
The important part is the cylinder Q. The force of the swell which is produced
at the bottom of the apparatus by the hydraulic pressure of the poured in fluid
being mitigated by the height OP the sand and the light bodies which should
evacuate the apparatus after the stirring only being able to be raised to a height
of 6 to 7 centimeters I use in this case the siphons D D¹ D² D³ at the mouths of the
overflows.
The addition of an upper ring shaped vessel () covering the cylinder within which
the concentration of the gold in spangles takes place has for its purpose to introduce
clear water into the apparatus at weak pressure in order to produce a counter swell
at the contact with the inner sides of the vessel.
This cistern is fed by means of an india-rubber tube which continually pours in
It is perforated being slightly conical at its base and in contact with
clear water.

page_text: the inner wall of the cylinder by 8 holes t³ ³ etc. to which are adjustod
8 tubes uu³ ³ etc. (Figs. 1 and 2) of an inner diameter of 5 to 6 millimeters.
These tubes are inserted into the apparatus as far as fivi centimeters from the
.bottom.
The volume of water to be introduced into the apparatus being larger than the one
which can escape by the siphons D D D D³ I place in the interior of the large
cylinder and in contact with the vertical side, four overflow tubes M. M1 M² M³ which,
starting from a level N leave the apparatus by a bend at R and pour the surplus into
the ring shaped cistern B which receives the sterile sand cast away by the
siphons D D D D³ and retains the gold which the sterile sand might carry away.
The apparatus should work in a continual manner and without stoppage in order to
avoid shocks for these shocks exercise a three times larger pressure than one of a
continual current and if not careful a quantity of gold may be driven away.
The operation takes place with the greatest case within one or two minutes. It
suffices for this purpose to take off the stopper which closes the orifice S in order that
the whole contents of the cylinder Q and of the cistern G fall into the receiver which
is placed underneath the apparatus.
The cistern B is intended to receive the gold spangles which enter the apparatus.
Before the operation a loose stopper is placed in the opening of this cistern.
In addition and in order to collect the invisible gold I place in this cistern a
layer of mercury mm of 5 to 6 millimeters thickness more than sufficient to
amalgamate the impalpable and invisible gold which the sand carries along from the
apparatus.
The whole apparatus rests upon a pedestal of flat iron as indicated in the
accompanying drawing by numbers I II III IV.
The method of washing auriferous sand which I have adopted as being the most
efficient, the most practical and the most economical consists of going on with this
washing by successive concentrations. Thus the apparatus of which the annexed
drawings represent the arrangements and the dimensions, can, notwithstanding its
small size (36 centimeters diameter) treat per minute 18 liters of sand passed through
the sieve of 3 millimeters that is 10800 liters per working day of 10 hours representing
to of fine sand, 108 cubic meters of rough soil.
These 10800 liters of sand are reduced to 10 liters of enriched sand in two loads
the working of the apparatus never being allowed to be interrupted without taking
the precaution to empty it, which is a matter of two or three minutes.
The 10 liters of enriched sand are allowed to pass into another similar but much
smaller apparatus where they are reduced to or of a liter which is then transferred
into a third still smaller apparatus where it is reduced to 50 cubic centimeters of iron
and gold with a few grains of sand. The grains of sand are removed by a careful
washing during the treatment, but only as far as the iron, the evacuation of the iron
by the beater causing always a considerable loss.
Then it is dried in the sun or on a heated copper sheet and spread carefully
over a sheet of paper the iron is removed by means of a magnet covered with a
piece of silk or paper in order to avoid the adherence of the iron to the magnet.
This operation completed, there remains nothing but the gold in spangles and a very
firm impalpable dust which is almost as heavy as the gold and which consists of
miseroscopical gems and invisible gold.
I have likewise introduced in my method the treating of auriferous sands by
my apparatus, whether the amalgamation of gold is partly or entirely treated, partly
by placing mercury into the ring shaped cistern AB as mentioned above, entirely by
making the large concentration cylinder of cast iron and by putting therein several
kilogrammes of mercury.
This amalgamation can take place quicker and without loss of mercury or gold
as the pressure of 2 grammes per square centimeter does not allow the gold to
escape as it has been shown above, nor the mercury to oscillate and adopt the
globular state. It is easily understood that by means of this apparatus the beating
becomes useless until the gold is forcibly compelled to remain in the apparatus or

page_text: gradually it mixes with the mercury by this combination under a pressure of
4 to 5 grammes per square centimeter and allows the washing of a large number
of liters of sand per minute and a quicker evacuation of the steriles the weight
of the immersed mercury being about 12.6 grammes per cubic centimeter and the
pressure only 4 to 5 grammes it is quite impossible that this pressure of
4 to 5 grammes per square centimeter could move the mercury.
Having now particulary described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
The new or improved apparatus consisting of the various devices and parts as
illustrated and described for the treatment of auriferous sand or matters containing
free gold.
Dated this 9th day of September 1889
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.