Improvements in Means for Effecting the Separation of Particles of Different Specific Gravities, more Especially Intended for the Separation of Gold and other Metals from Crushed or Divided Ores.
Year: 1889

page_text: Date of Application, 27th May, 1889
Complete Specification Left, 21st Jan., 1890-Accepted, 22nd Feb., 1890
PROVISIONAL SPECIFICATION.
Improvements in Means for Effecting the Separation of Particles of
Different Specific Gravities, more Especially Intended for the
Separation of Gold and other Metals from Crushed or Divided
Ores.
I, MIDDLETON CRAWFORD of 3 Oxford Street, Liverpool in the County of
Lancaster Engineer do hereby declare the nature of this Invention to be as
follows:-
My Invention has for its object to provide means whereby the separation of
particles of different specific gravities is effected in a very ready complete and
efficient manner and by means of apparatus which is inexpensive in first cost and
easily worked.
The invention is more especially intended for use in the separation of
gold and other metals from crushed ores containing them without necessitating the
amalgamating or chlorinating processes hitherto resorted to in many instances.
According to my Invention I take the ore or material from which the gold or other
metal is to be separated and if it be not already in a finely divided condition I reduce
it to that condition in any suitable apparatus adapted for the purpose. I then place
the divided ore or material in a receptacle (preferably arranged as hereinafter
described) in which I subject it to a sideway vibratory to and fro, or jogging
movement the bottom of the receptacle being inclined downwards in one direction and
water being admitted so that it passes in a direction the reverse of the direction of the
downward inclination of the bottom of the receptacle. I prefer to arrange these
receptacles in the shape of troughs placed side by side in a container to which
container I impart a sideway vibratory, to and fro, or jogging movement by
excentrics or other suitable means. Each trough may have one only or there may
be two or more such inclined surfaces at bottom following each other in the direction
of the length of the trough there being an outlet at the higher end of the inclined
surface or the last of the two or more such surfaces. There may be two or more
superposed or otherwise relatively placed series of such troughs each series being held
in a container to which the sideway movement is imparted as aforesaid so that the
water and material which passes off from one series of troughs falls into the next
series of troughs and so on if more than two be used.
I believe that the best effect will be obtained if the extent of the sideway movement
is about one third the width of the troughs. About six inches is a very advantageous
width for the troughs.
When the crushed ore or material is placed in the troughs and the water is
admitted the downward inclination of the bottoms of the troughs and the passage of
the water in the other direction combined with the sideway movement cause the
heavier particles consisting of or containing the metallic portions to descend and pass
back towards the lower ends of the inclined surfaces which constitute wells or
receivers therefor from which the deposit can be removed either by removing the
troughs or tipping them up or by causing the bottoms of the troughs to move forward
towards the outlet end of the said troughs.
In some cases especially in working alluvial deposits when stones and other debris
are present I may place on the sideway moving container or the uppermost of them
when two or more are used a moving sieve or sieves of various degrees of mesh so
that the stones or debris are prevented from entering the troughs. The sieve or sieves
may be provided with shoots or hoppers which catch and direct the portions of the
material to be treated according to the grades into the troughs in any suitable
proportions as desired.
Dated thin auth
2000
J. H. JOHNSON & Co..
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Means for Effecting the Separation of Particles of
Different Specific Gravities, more especially Intended for the
Separation of Gold and other Metals from Crushed or Divided
Ores.
I, MIDDLETON CRAWFORD of 3 Oxford Street, Liverpool in the County of
Lancaster, 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:-
My Invention has for its object to provide means whereby the separation of
particles of different specific gravities is effected in a very ready complete and
efficient manner and by the employment of apparatus which is inexpensive in first
cost while it may be successfully and easily worked.
My said Invention is more especially intended for use in the separation of gold and
other metals from crushed ores containing them without necessitating the
amalgamating or chlorinating of the mass in the manner hitherto employed.
I will describe my Invention with reference to the accompanying drawings
which represent an apparatus constructed according to my Invention.
Figure 1 is a side elevation, Figure 2 a plan and Figure 3 an end view of the
said apparatus and Figure 4 is a longitudinal section thereof on the line 1-2, Figure 2.
In these Figures I have shewn two tiers of four troughs each but I wish it to be
understood that I do not limit myself to any particular number of either tiers or
troughs.
1 take the ore or material from which the gold or other metal is to be separated
and if it be not already in a finely divided condition I reduce it to that condition
in stamps or any suitable apparatus adapted for the purpose I then place the divided
ore or material in receptacles A A the bottoms of which are inclined as shewn
at a the said receptacles being in the from of troughs with sides and with ends A² A³
or ends only at A². These troughs are placed side by side in a container B.
The containers have imparted to them a sideway movement which can conveniently
be effected by supporting the said containers by "spring hangers" b b and connecting
them by rods or strips cc with the straps of eccentrics d d on a shaft D to
which motion is imparted from any convenient prime mover or by hand so that by
rotating the said shaft the eccentrics impart a to and fro sideway movement to
the containers and the troughs which they carry. Water is supplied at the ends of
the troughs nearest to or towards the lower parts of the inclines. The top series
of troughs having openings at a² a discharging into the lower series of troughs
which have in them discharge openings which open into a passage leading to one
common outlet at e. The troughs are preferably made so that they can be readily
withdrawn from the containers for removal of the deposited matter. In order to
keep the said troughs in position I may employ a rod or bar entering recesses
in the trough sides and provided with lugs 2 which embrace the sides so as to keep
the troughs in position both sideways and vertically. The inclination of the troughs
can be regulated by means of the cams g on the shafts g² so that by partially
rotating the shafts the cams raise or lower the ends of the troughs to alter their
inclination and to allow of this movement the rods are carried by arms / led
to the ends of the troughs opposited to those at which the cams are situated the said
arms being centred at h² to allow of the said adjustment of the troughs.
When the crusbed ore or material is placed in the troughs and the water is admitted
the downward inclination of the bottoms of the troughs and the passage of the
water in the direction the reverse of the incline combined with the regulated move.
ment of the contents of the trough by the sideway motion aforesaid effect the
required washing and separation of the matters under treatment the particles
consisting of or containing the heavier or metallic portions descending and passing
back towards the lower ends of the inclined surfaces which lower ends constitute wells

page_text: or receivers for the said portions from which the deposit can be emptied either by
removing the troughs or by tipping them up or by causing the bottoms of the troughs
to move forwards towards the outlet ends of the said troughs.
In some cases especially in working alluvial deposits when stones or other debris
are present I find it advantageous to place on the sideway moving container or on the
uppermost of them when two or more are used a moving sieve or sieves of various
degrees of mesh so that the stones or debris are prevented from entering the troughs.
The sieves when several are used should be provided with passages for directing the
ore or material from sieve to sieve and with shoots or hoppers (one for each sieve)
which catch and direct the ore or material passing through the sieves into the
troughs in any suitable proportions and according to the grades as desired.
My improved troughs may be used singly or in any suitable number preferably
placed side by side and either in one plane or in two or more planes or tiers the series
above discharging into the series beneath and the troughs may have one or more
inclines at bottom
I have found that in order to obtain the best results certain proportions are requisite
and that the best effect is obtained if the troughs have imparted to them a sideway
movement of about one third of the width of the troughs. About 6 inches is a very
convenient width for the troughs and their sides should be of, or about, the same
height. The inclines at the bottoms of the troughs are preferably about one in twelve
and the length of each incline is preferably about 12 inches but some variation is
permissible in the dimensions for instance although the best effects are obtained by
the aforesaid dimensions good effects are obtainable if the trough be as low as three
or as high as nine inches in depth and width and the inclines may vary from 1 in 12
to 1 in 48 or three in sixteen and the length of the inclines may be as low as four
or six inches or they may be longer than twelve inches up to say about twenty four
inches. The sideway movement of the troughs should not vary in extent beyond
inch greater or lesser than a third of the width of the troughs although results
superior to those hitherto obtained may be attained if the said sideway movement
be as low as one twelfth or as high as two thirds the width of the trough.
When the machine is at work the agitation effected by the sideway movement of
the troughs causes a thorough washing and separation of the refuse from the particles
which are to be retained which latter owing to the inclination of the bottoms of the
troughs settle in the pockets formed by the lower ends of the inclines.
Moreover the sides of the troughs cause the water to splash back over the surface of
the contents of the troughs so causing the carrying down of any floating particles
which it is desired to recover but which would otherwise pass off with the water. In
order to facilitate the precipitation of the particles I find it advantageous to use a
dipping board or baffle as at i in the drawings which enters the water but leaves a
space between itself and the bottom of the trough. In cases where it is difficult or
impracticable to obtain a supply of water for working my arrangement of troughs
they may be used without water.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what I
claim is -
First. In machines or apparatus for separating materials of different specific
gravities the employment of a trough or troughs of or about the dimensions herein-
before named and with an incline or inclines at bottom and having in combination
therewith means for imparting sideway movement thereto to an extent of or
about one third of the width of the trough or troughs substantially as herein before
described.
Second. In machines or apparatus for separating materials of different specific
gravities a trough or troughs with sides and an end or ends and with an incline or
inclines at bottom in combination with means for causing a flow of water in a direction

page_text: the reverse of that of the downward inclination of the incline or inclines and with
means for imparting a sideway movement to the said troughs substantially as herein-
before described.
Third. The combination of parts constituting the machine or apparatus substantially
as herein before described and illustrated in the accompanying drawings.
Dated this 23rd day of December 1889.
MIDDLETON CRAWFORD.