IMPROVEMENTS IN MACHINERY FOR CRUSHING AND PULVERIZING ORES, AND IN APPARATUS FOR SAVING GOLD AND SULPHURETS IN SLUICES AND FLUMES
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
"
County of Middlesex, Patent Agent, for an Invention of IMPROVEMENTS
IN MACHINERY FOR CRUSHING AND PULVERIZING ORES, AND IN APPARATUS
FOR SAVING GOLD AND SULPHURETS IN SLUICES AND FLUMES." A commu-
nication from abroad by William Henry Howland, of San Francisco, in the
County of San Francisco and State of California, United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 26th May 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN MACHINERY FOR CRUSHING AND PULVERIZING
ORES, AND IN APPARATUS FOR SAVING GOLD AND SULPHURETS IN SLUICES AND
FLUMES." [A communication from abroad by William Henry Howland, of San
Francisco, in the County of San Francisco and State of California, United States
of America.]
The first part of this Invention relates to machinery for crushing and pulverizing
ores, and it consists in a pan which is provided with a peripheral die and a driving
muller, and in which a continuous circuit of short cylinders or rollers are placed,
so that the rotation of the muller will cause them to revolve and travel against the
die. The ore is fed into the centre of the pan, and is thrown outward by the
centrifugal action against and between the crushing and grinding rollers, by which
it is reduced to a powder. The pan is provided with a screen for discharging the
pulp, and when water is used it is fed into the pan underneath the muller, all as
hereinafter more fully described.
The pan is shallow, and has an external flange at top, upon which is fixed a
conical cover having an internal flange at top, and covering only the outer portion
of the pan, leaving the centre open. On the inside of the rim of the pan horizontal
and vertical lugs are cast at intervals, said lugs forming rectangular bearings, on which
is fixed an annular die of L section, so that the lower rim of the die will rest on
ED '

page_text: the horizontal lugs, while its outside bears against the vertical lugs. This die is
made of chilled iron or steel, and extends around the inside of the pan, forming ก
stationary track for the rollers. The muller is fixed on a vertical spindle rising
through the bottom of the pan. The muller bottom is a plane annular plate
carried by a driver made adjustable on the spindle, so that it can be raised clear of
the bottom of the pan. The muller bottom revolves within and on a level with
the upper face of the horizontal rim of the annular die. Upon the muller a number
of short rollers are placed on end, so that when the muller is rotated these cylinders
will assume position one behind the other in a circuit around the pan. A sufficient
number of cylinders to form two concentric circles are usually employed, those in
the outside circle being larger than those of the inside circle, but usually a single
circle will answer every purpose. Each cylinder in the outer circle will then rest
partly upon the horizontal rim of the stationary die, and partly upon the travelling
muller, so that the rotation of the muller will cause them to simultaneously rotate
and move around the inside of the pan one behind another, while the centrifugal
force will carry them outward against the vertical face of the die.
A water pipe leads up through the bottom of the pan, the water being intro-
duced underneath the muller, so as to lubricate and buoy it up and prevent the
pulp or particles of ore from getting underneath the muller.
Screens are fixed in openings in the conical cover, so that the splash against
them will discharge the pulp as fast as it is ground fine enough to pass through
the screens; or, if preferred, an upward current discharge could be provided
between the annular die and the rim of the pan. Amalgamated plates are placed
in the space between the annular die and rim of the pan, one plate being usually
placed on each side of the space, so that the pulp as it moves upward or downward
between the die and rim will be brought in contact with the plates.
The great feature of the Invention is the rollers placed loosely in a pan provided
with a circumferential die, said rollers being caused to rotate on vertical axes, and
follow each other in a circle around the track of the die by the rotation of the
muller in combination with a suitable screening device. The rollers thus operated
present a large amount of grinding surface, as their rotation causes their lower
ends to grind against the die and muller, while their sides serve as crushers to
crush the ore which is caught between them and against the die.
When two circles of rollers are used the inner circle impinges and grinds against
the outer circle, and the whole travel together.
The ore is introduced into the pan through the central opening in the cover, and
is instantly hurled by centrifugal force outward, into, and among the rotating and
moving rollers, by which it is crushed and ground to a powder. The water is also
carried to the periphery by the same force, so that as fast as the ore is ground
sufficiently fine it passes through the screens or other discharge. A large portion
of the pulp will pass between the die and rim of the pan, where any free particles
of gold contained in it will be arrested and caught by the amalgamated surfaces,
and as a free circulation is kept up from the interior of the pan through the space
behind and under the dic, all large particles that fail to pass through the screens
and get into the space behind the die will settle downward and be drawn up under
the rollers by the action of the water and rollers, thus providing for complete
pulverization of every particle. The action of the rollers or cylinders upon the
ore is positive and instantaneous, and as the screens are placed above the crushing-
rollers nothing can escape the action of the rolls until it has been ground fine enough
to pass through the screens, because the particles must always fall back into the
rolls if they are too large to pass through the screens, and the same result will
happen if the upward current discharge is used.
.
The second part of the Invention relates to an improved device for saving gold
and sulphurets in sluices and flumes in place of the riffile-bars and other obstructions
heretofore in use for that purpose.
It consists of a peculiar cast iron-grating, which is made in sections, so that it
can be taken up in pieces when desired. Each section is made in the form of a

page_text: ridge-roof, and its inclines are slotted or perforated from top to bottom. The slots
are parallel, and those on one side of the ridge alternate with those on the opposite
side. The intervening bars are grooved, so that the slots on one side will be in
line with grooves on the opposite side of the ridge. This construction is preferred,
although the arrangement of the slots and grooves might be varied in a number of
ways, all of which would be effective in a greater or less degree. At the bottom
of each incline is a transverse shallow box, in which quicksilver is contained, and
on which the end of the sections rest. The channels or grooves lead directly into
these boxes. A vertical partition extends downward from the underside of the
ridge or apex to the floor of the sluice, and may also be made hollow like a box,
and contain quicksilver, thus forming a riffle-bar or obstruction for arresting the
heavy particles and supporting the middle of the section.
The sections are placed in longitudinal rows on the bottom of the sluice or
flume, so that their ends abut against each, two or more rows being used. The
sections in one row overlap the sections in the adjoining row, so that the ends of
the sections in one row come opposite the middle partition of the adjoining row.
The sections can be made of any desired size, and their width should be gauged so
ns to cover the entire width of the sluice. The current of water carrying auriferous
material will then strike the upper incline as it moves down the sluice, and a large
portion will pass through the slots into the chamber underneath, while the large
particles and a portion of the fine particles will follow the grooves up over the
quicksilver in the hollow partition, and thence across and through the slots on the
opposite side or over onto the next section. The portion that passes through
the slots into the first chamber underneath the section will be arrested by the
partition or obstruction, and an eddy will be formed, in which the heavy particles
will settle, while the water and lighter portions pass out through the open side of
the chamber, and diagonally across upon the first incline of the following section
in the adjoining row, where the operation is repeated. The current is thus
separated, broken, and directed from one section to the other, and from one row of
sections to the other row throughout the entire length of the covered floor of the
sluice. This produces a slow upper current and quick moving and broken under
current. The effect of alternating the sections in the adjoining rows is to produce
cross-currents, which prevents the sand and clay from packing, and washes the
sulphurets and heavy particles, so as to keep them in a clean condition.
The ridge shape of the sections and the sharp corners of the grooved bars present
a roughened surface to any large or heavy lumps that may be passing with the
current, and serve to disintegrate and pulverize them, and thus liberate any
particles of gold or sulphurets that may be carried by or in them. This feature
renders this rifle especially valuable in hydraulic mining. The free particles of
gold are brought in contact with the mercury in the boxes, over which they are
compelled to pass, and are thus amalgamated and saved, and in case any quick-
silver or amalgam should escape from any of the boxes they will be caught in
some of the succeeding sections with the sulphurets and other heavy particles.
This riffle can be used below batteries for catching the free gold, quicksilver, and
amalgam, in which case it would be of small size.
In some instances the quicksilver troughs and the grooves in the intermediate
bars might be dispensed with.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
26th November 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN MACHINERY FOR CRUSHING AND PULVERIZING
ORES, AND IN APPARATUS FOR SAVING GOLD AND SULPHURETS IN SLUICES AND
FLUMES." A communication from abroad by William Henry Howland, of San
Francisco, in the County of San Francisco and State of California, United States of
America.
The first part of this Invention relates to machinery for crushing and pulverising
ores, and it consists in a pan which is provided with a peripheral die and a driving
muller, and in which a continuous circuit of short cylinders or rollers are placed
so that the rotation of the muller will cause them to revolve and travel against the
die. The ore is fed into the centre of the pan and is thrown outward by the
centrifugal action against and between the crushing and grinding rollers, by which
it is reduced to a powder. The pan is provided with a screen for discharging the
pulp, and when water is used it is fed into the pan underneath the muller, all
as hereinafter more fully described.
In the accompanying Drawings, Figure 1 is an elevation in vertical section;
Figure 2 is a one half view below line x, x, Figure 1; Figure 3 shows details of
the crushing and grinding cylinder; Figures 4 and 5 are detail sections of the
rotating muller and its ring; Figure 6 shows the pan and the stationary ring in
section.
Let A represent a shallow pan, the rim of which has a flange b projecting
outward around its upper edge so that a sloping top or cover C can be secured
upon it. This sloping top has a narrow horizontal rim d extending from its upper
edge inward toward the centre of the pan, so that the top and flange cover only
the outer portion of the pan, leaving the centre open. D is a vertical spindle by
which a muller G is driven. This spindle passes up through the bottom of the
pan, and is driven by power applied to it underneath the pan in the manner of
operating mullers in amalgamating pans. The rim of the pan is cast with ribs or
lugs e at intervals on its inside, which lugs are extended horizontally a short
distance along the bottom of the pan, thus forming a rectangular bearing, on which
I place an annular die F, so that the lower rim of the die will rest on the horizontal
lugs, while its outside bears against the vertical lugs. This die I make of chilled
iron or steel, and quite heavy so that it will sustain the wear and strain to which
it is subjected. The die is rectangular in cross section and extends entirely around
the pan, forming a stationary track, as hereinafter described. The muller Ğ is made
with a plane bottom portion g which may either be a permanent part of the muller
or simply a plate to which the muller is attached by cross arms E. The muller is
adjustable up or down, like the muller of an amalgamator, by means of the screw h
and hand wheels i, j, so that it can be raised clear of the bottom of the pan; the
upper face of the muller bottom g will then be on a plane with the upper face of
the horizontal portion of the annular die. Upon the bottom of the muller I place
a number of short cylinders K, K, K, upon end, so that when the muller is rotated
these cylinders will assume position one behind the other in a circuit around the
pan, as shown at Figure 1. I usually employ a sufficient number of cylinders to
form two concentric series, the cylinders in the outside circle being larger than those
of the inside circle, but usually a single circle will answer every purpose; each
cylinder in the outer circle will then rest partly upon the horizontal portion of the
stationary die, and partly upon the outer rim of the travelling muller, so that the

page_text: rotation of the muller will cause them to simultaneously rotate and move around
the inside of the pan, one behind another, while the centrifugal force will carry
them outward against the vertical face of the die. The cylinders K may be
tubular and provided with perforations, as shown in Figures 1 and 3, to permit
of the escape of any pulp that may get into them, they however are not necessary
in the operation of the Invention. is a water pipe which passes up through the
bottom of the pan, the water being introduced underneath the muller so as to
lubricate and buoy it up, thus causing it to run much easier than if the water
were introduced above the muller. The water pressure under the muller also
prevents the pulp or particles of ore from getting underneath the muller. Screens L
are fixed in openings in the sloping cover C, so that the splash against them will
discharge the pulp from the pan as fast as it is ground fine enough to pass through
the screens; or if preferred an upward current discharge could be provided between
the die F and rim of the pan, but both of these methods of discharging pulp from
crushing mills are old, and can be applied by any skilful mechanic. In the space
between the die F and rim of the pan I place amalgamated plates, one plate
being usually placed on each side of the space, so that the pulp as it moves
upward or downward between the die and rim will be brought in contact with the
plates.
The great feature of the Invention consists in the cylinders or rollers placed
loosely in a pan which is provided with a die F, said rollers being caused to rotate
and follow each other in a circle around the track of the die by the rotation of the
muller in combination with a suitable screening device. The rollers thus operated
present a large amount of grinding surface, as their rotation causes their lower
ends to grind against the die and muller while their sides serve as crushers to
crush the ore which is caught between them and against the die. Two circles of
rollers would usually be employed, the inner circle impinging and grinding against
the outer circle, and the whole travelling together. The ore is introduced into the
pan through the opening in the cover, and is instantly hurled by centrifugal force
outward, into, and among the rotating and moving cylinders, by which it is crushed
and ground to a powder. The water is also carried to the periphery by the same
force, so that as fast as the ore is ground sufficiently fine it passes through the
screens or other discharge. A large portion of the pulp will pass between the die
and rim of the pan, where any free particles of gold contained in it will be arrested
and caught by the amalgamated surfaces, and as a free circulation is kept up from
the interior of the pan through the space behind and under the die all large
particles that fail to pass through the screens and get into the space behind the
die will settle downward and be drawn up under the rollers by the action of the
water and rollers, thus providing for complete pulverisation of every particle. The
action of the rollers or cylinders upon the ore is positive and instantaneous, and as
the screens are placed above the crushing rollers nothing can escape the action of
the rolls until it has been ground fine enough to pass through the screens, because
the particles must always fall back into the rolls if they are too large to pass
through the screens, and the same result will happen if the upward current discharge
is used.
The second part of the Invention relates to an improved device for saving gold
and sulphurets in sluices and flumes, in place of the rifle bars and other obstructions
heretofore in use for that purpose. It consists of a peculiar cast iron grating
which is made in sections so that it can be taken up in pieces when desired. Each
section is made in the form of a ridge roof, and its inclines are slotted or perforated
throughout their length. The underside of each section is formed with obstructions
for arresting the particles, and a quicksilver chamber is provided at each end of
the section. The sections are placed lengthwise upon the bottom of the sluice or
flume in two or more rows according to the width of the sluice, and the sections in
one row overlap the sections in the next row, so as to form a broken undulating
surface that will break up the current of water and direct it in various directions in

page_text: -such a manner that the heavy particles are caught and retained, all as hereinafter
more fully described.
Figure 7 is a perspective view of a portion of the flume or sluice with the
improved rifles arranged therein; Figure 8 is an elevation of several riffles, one
being shown in section; Figure 9 is a top view; Figure 10 is an end elevation of
one of the riffles.
Let A represent a section of a mining flume or sluice through which auriferous
material is carried by a stream of water. Upon the bottom of this sluice or flume
I place the riffle sections (represented more distinctly at Figures 8 and 9) so that
they will cover the bottom or floor of the sluice or flume to a greater or less extent
of its length, according to the necessity of each case. The sections are placed in
rows lengthwise upon the bottom of the sluice, and the sections in one row overlap
or breakjoint with the sections of the adjoining row, as represented. Each section
is made of cast iron in the form of a ridge roof, and the incline on each side of the
ridge or apex is provided with a number of parallel slots b' extending its entire
length, the slots on one side of the ridge alternating with those on the opposite
side. The portion of metal c' between each two slots is hollowed out on its upper
surface so as to form channels or grooves, so that the slots on one side will be in
line with grooves on the opposite side of the ridge. I prefer this construction
although the arrangement of the slots and grooves might be varied in a number of
ways, all of which would be effective in a greater or less degree. At the bottom of
each incline is a transverse shallow box e in which quicksilver is contained, and
on which the end of the sections rest, the grooves c leading directly into these
boxes. A vertical partition f' extends downward from the underside of the ridge
or apex to the floor of the sluice, and may also be made hollow like a box and
contain quicksilver, thus forming a riffle bar or obstruction for arresting the heavy
particles and supporting the middle of the section. The sections are placed in
longitudinal rows on the bottom of the sluice or flume, so that their ends abut
against each other, two or more rows being used. The sections in one row overlap
the sections in the adjoining row, so that the ends of the sections in one row come
opposite the middle partition f¹ of the adjoining row. The sections can be made
of any desired size, and their width should be gauged so as to cover the entire
width of the sluice. The current of water carrying the auriferous material will
then strike the upper incline as it moves down the sluice, and a large portion will
pass through the slots b¹ into the chamber underneath, while the large particles
and a portion of the fine particles will follow the grooves c¹ up over the quick-
silver in the hollow partition f¹, and thence across and through the slots on the
opposite side or over onto the next section. The portion that passes through the
slots into the first chamber underneath the section will be arrested by the partition
or obstruction f', and an eddy will be formed in which the heavy particles will
settle, while the water and lighter portions pass out through the open side of the
chamber and diagonally across upon the first incline of the following section in the
adjoining row where the operation is repeated. The current is thus separated,
broken, and directed from one section to the other, and from one row of sections to
the other row throughout the entire length of the covered floor of the sluice. This
produces a slow upper current and quick moving and broken under current. The
effect of alternating the sections in the adjoining rows is to produce cross currents
which prevents the sand and clay from packing, and washes the sulphurets and
heavy particles so as to keep them in a clean condition. The ridge shape of the
sections and the sharp corners of the grooved bars c¹ present a roughened surface to
any large or heavy lumps that may be passing with the current, and serve to
disintegrate and pulverize them, and thus liberate any particles of gold or
sulphurets that may be carried by or in them. This feature renders this riffle
especially valuable in hydraulic mining, as with the old style of riffle a large
quantity of precious metals was lost by being thus enclosed in large particles of
clay, and this has been heretofore so common that these large particles were known

page_text: The
as "robbers," and various mechanical devices have been attempted for reducing
them in the flume. This riffle however accomplishes the object by its grating
action upon the lumps as they are moved forward by the force of the current.
free particles of gold are brought in contact with the mercury in the boxes over
which they are compelled to pass, and are thus amalgamated and saved, and in case
any quicksilver or amalgam should escape from any of the boxes they will be
caught in some of the succeeding sections with the. sulphurets and other heavy
particles.
This riffle can be used below batteries for catching the free gold, quicksilver,
and amalgam, in which case they would be of small size. In some instances the
quicksilver troughs and the grooves in the intermediate bars c¹ might be dispensed
with.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is,-
1st. The pan A having the annular die F placed on its bottom inside of its rim,
said die being rectangular in cross section, in combination with the muller G with
its plane bottom and one or more circles of rollers or short cylinders K, K, K,
substantially as described and for the purpose set forth.
2nd. The pan A with its sloping cover C in which screens L are arranged, in
combination with a series of crushing and grinding rollers or cylinders K which are
driven by a muller G inside of said pan, substantially as specified.
3rd. In a machine for pulverising ores, the pan A having the water supply pipe
of an approximate U shape with one arm extending above the pan and the other
arm passing up through the bottom of the pan, substantially as and for the purpose
set forth.
4th. A mining riffle composed of roof shaped sections A¹, each of which is
provided with parallel longitudinal slots 6 and intermediate grooved bars c¹ on
each side of the apex, substantially as described.
5th. The riffle sections A¹ having the alternate longitudinal slots 61 and
intermediate grooved bars c¹ and having the partition fl, said rifle sections being
provided with the transverse quicksilver troughs e¹, substantially as above
described.
6th. A mining riffle composed of a number of roof shaped gridiron sections A¹
placed in longitudinal rows on the bottom of the sluice or flume, so as to be in
contact with each other, the sections in adjoining rows overlapping each other,
substantially as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty fifth day of November, A.D. 1881.