IMPROVEMENTS IN OPERATING UPON AURI- *FEROUS QUARTZ, CLAYS, AND OTHER MINERALS, PREPARATORY TO AND IN ORDER TO ACCOMPLISH THE SEPARATION OF THE GOLD AND OTHER METALS; ALSO IN MACHINERY OR APPARATUS FOR EFFECTING SUCH IMPROVEMENTS
Year: 1853

page_text: LETTERS PATENT to George Henry Bursill, of Offord Road, Barns-
bury Park, Islington, in the County of Middlesex, Engineer,
for the Invention of "IMPROVEMENTS IN OPERATING UPON AURI-
*FEROUS QUARTZ, CLAYS, AND OTHER MINERALS, PREPARATORY TO AND IN
ORDER TO ACCOMPLISH THE SEPARATION OF THE GOLD AND OTHER
METALS; ALSO IN MACHINERY OR APPARATUS FOR EFFECTING SUCH
IMPROVEMENTS."
Sealed the 22nd July 1853, and dated the 12th February 1853.
PROVISIONAL SPECIFICATION left by the said George Henry
Bursill at the Office of the Commissioners of Patents, with his
Petition, on the 12th February 1853.
I, GEORGE H BURSILL, of Offord Road, Barnsbury Park, Islington,
in the County of Middlesex, Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN OPERATING UPON AURI-
FEROUS QUARTZ, CLAY, AND OTHER MINERALS, PREPARATORY TO AND IN ORDER
TO ACCOMPLISH THE SEPARATION OF THE GOLD AND OTHER METALS; ALSO IN
MACHINERY OR APPARATUS FOR EFFECTING SUCH IMPROVEMENTS," to be as
follows:-

page_text: Firstly, as relates to hard minerals, I cause the quartz and other
ores, more especially when they owe their hardness to the presence
of silica, to be brought in contact with, or precipitated when red
hot into, a caustic ley, prepared as in the manufacture of soap in the
large way; and by which means the minerals become so disinte-
grated or altered in structure, that they may be readily reduced to
any required size.
After this I cause such portions of the mineral as are very rich
in gold to be boiled in a separate portion of the caustic ley, in
order to loosen still farther any adherent pieces of silica; and either
one or both of these operations I repeat if required, before
subjecting the mineral to any further kind of treatment whatever.
SECTION B..
As relates to the softer minerals, in which the gold is mixed up
with alumina chiefly, or with alumina and silica in small particles
only, such as the clays, or as relates to minerals that may have been
disintegrated by operations described in Section A, but in which
alumina nevertheless forms a chief ingredient. Then, in order to
concentrate any gold that may be present, I cause the mineral to be
washed in a particular way, and to be afterwards treated with an
acid, such as diluted-sulphuric acid, my object being to dissolve
any alumina in which small particles of gold may continue to be
enveloped; after which it becomes more easy to get at the auriferous
residuum either by filtration or otherwise.
My particular manner of washing is to cause the water employed
for that purpose to be admitted beneath the contents of the vessel
employed for the washing, and in such manner as to have a tendency
to flow upward, and so get away by running gently over the edge of
the vessel; and which is readily accomplished by aid of a pipe and
stop-cock attached to the bottom of any neighbouring tank filled
with water and placed at a higher level.
The vessel in which acid is used may be a separate vessel, and

page_text: quartz or from the aluminous or other sands or deposits; and after
having caused the minerals to be broken up, and their contained
metals to be concentrated, either by operations described, or by any
such convenient means as are now in use, with the additional pre-
caution, in some cases, of rendering them thoroughly dry, I employ
a readily fusible compound or alloy of lead and bismuth, or of lead,
bismuth and tin, either with or without the aid of mercury, and
kept just above the melting point by any suitable means; the object
being to secure only, and not to smelt, the nobler metals (whenever
it can be avoided), and by aid of an alloy of such low specific gravity
that the native alloys of gold and of silver (some of which are of a
specific gravity considerably less than that of pure mercury) may the
more readily sink to the bottom.
When mercury is occasionally added in small quantity to the
fusible compound or alloy of lead, bismuth & tin, it enables me to
work at a lower temperature than otherwise; so much so, that the
entrapped metals may afterwards be freed from any adhering par-
ticles of the readily fusible alloy (if we except only a little portion
of the sometimes adhering mercury), even by the aid of boiling
water alone; the mercury also, when at a temperature requisite to
keep the readily inelting compound in a state of fusion, licks up the
gold very greedily, when there is any; but when silver or copper
only are to be obtained, I prefer to dispense with mercury alto-
gether.
SECTION D.
I will now proceed to describe my improvements in machinery or
conetuo, and which onnlu to the ordinary systern of amalgamation.

page_text: the.operations described in Section C, my object being in every case
to cause the auriferous meal or ore to be brought into forcible con-
tact either with the mercury or readily fusible compound employed
instead of it (as the case may be), and also to be kept in such for-
cible contact for a time amply sufficient to deprive it of any con-
tained treasure.
For this purpose I cause the pulverized ore to descend into an
upright cylinder through a hole made. in its side, in the centre of
which cylinder is a vertical spindle working in bearings, and having
arms or fans attached, and set at such an angle that when the
spindle is made to rotate, the meal or ore is, by the motion of such
arms, continuously forced downwards through a gradually dimin-
ishing tube attached to the bottom of the cylinder. At the lower ex-
tremity of the tube or nozzle is an enlarged opening resembling an
inverted funnel, and which funnel is made to dip beneath the
surface of the mercury employed for amalgamation.
The auriferous ore then being forced downwards until it arrives
at the upper or small end of the funnel-shaped opening, comes in
contact with the mercury, through which it is gradually obliged
to descend, owing to the pressure exerted by the ore continually
thrust from above.
The contact between the ore and the mercury may be still farther
increased, when desirable, by aid of a small agitator made to rotate
within the funnel; the vertical spindle of which agitator should pass
through the bottom of the iron bowl that contains the mercury by
aid of a stuffing box.
The result of these arrangements is, that the denser and more
valuable metals are either taken up by or sink to the bottom of the
mercury, and the impoverished meal or ore ultimately escaping
from under the funnel-shaped opening, floats upon the surface.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said George Henry Bursill in the Great
Seal Patent Office on the 12th August 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
GEORGE HENRY BURSILL, of Offord Road, Barnsbury Park, Islington,
in the County of Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of February, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said George Henry Bursill, Her special
licence that I, the said George Henry Bursill, my executors, admi-
nistrators, and assigns, or such others as I, the said George Henry
Bursill, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an In-
vention for "IMPROVEMENTS IN OPERATING UPON AURIFEROUS QUARTZ, CLAYS,
AND OTHER MINERALS, PREPARATORY TO AND IN ORDER TO ACCOMPLISH THE
SEPARATION OF THE GOLD AND OTHER METALS; ALSO IN MACHINERY OR APPA-
RATUS FOR EFFECTING SUCH IMPROVEMENTS," upon the condition (amongst
others) that I, the said George Henry Bursill, by an instrument in
writing under my hand and seal, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the
Great Seal Patent Office, within six calendar months next and im-
mediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Henry Bursill, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained.
in and by the following statement thereof (that is to say):

page_text: butable to the presence of silica in compact form, or to that of any
substance in large proportion, having when hot a marked affinity
for caustic soda or potash, I cause the quartz or other matrix to
be brought in contact with, or precipitated when red hot into, a
caustic ley, prepared as is usual for the manufacture of soap in the
large way; and after allowing it to cool and to remain in the ley
for a short time, I find that the mixture or gangue is in general so
altered as to be disintegrated, or so readily reducible to any required
size, that the gold may not unfrequently be pressed out, even by
aid of the fingers only.
The strength of the ley employed for the disintegrating process
must depend upon the nature of the matrix, and the extent to
which it is desired to act upon any metallic oxides or other sub-
stances contained in such matrix, or with which the gold or silver
may be associated, and which metallic oxides or other substances it
is in some cases possible and very desirable to dissolve, either
wholly or in part, as well as the silica, by a subsequent boiling in
the ley, and particularly if in small quantity and of little value,
while at other times it is desirable to avoid such contingency; but
in general a ley of the specific gravity of about 1.200, is what I
employ, though a much weaker ley may be used.
When the ley has become so nearly saturated with silica, or with
other impurities, as to be unfitted for further use, I cause it to be
purified, either by the use of carbonic acid gas, and the subsequent
addition of lime that has only been recently slacked, or by any other
Secondly, as relates to the softer minerals, in which gold is mixed up
with alumina chiefly, or with alumina and silica in separate particles
only, such as the clays, or as relates to minerals that have been
disintegrated by the operation described in section A, or crushed by
other or additional means, but in which either alumina or lime forms
a chief ingredient. Then in order to concentrate any gold that
may be present, I cause the mineral to be washed in a particular

page_text: way, and to be afterwards treated with an acid, such as dilute sul-
phuric, or dilute hydrochloric acid, my object being to dissolve
either the alumina or the lime, as the case may be, in which small
particles of gold may still continue to be enveloped; after which
it becomes easy to get at the auriferous residuum by filtration.
My particular mode of washing is to cause the water to be
admitted beneath the contents of the vessel employed for such
purpose, and in such manner as to have a tendency to flow upwards,
and so get away by running gently over the edge of the vessel, and
which is easily accomplished by aid of a pipe (in which pipe should
be a stop-cock), one end of which is inserted into the bottom of the
washing vessel, while the other is connected with the bottom of any
neighbouring tank filled with water, and placed at a higher level.
An agitator should be fitted to and made to work inside the
vessel used for washing; but when any violent agitation is required
to break up the clods of mineral (and which if not practicable to
have it previously crushed and screened, should be at least free from
all large pieces or boulders), care must be taken to cut off for a
time the supply of water from the tank; at all other times the
agitation should be very gentle, and should be rendered particularly
so towards the latter stages of concentration, in order that the finer
grains of gold may not be forced upwards over the edge of the
vessel, along with the diffused clay or other matter.
Before using the acid, the supply of water from the tank must
not merely be cut off, but the contents of the washing vessel allowed
to subside, and the surplus water drawn off to any convenient depth
by aid of a tap placed at side, or the acid, which should always be
of a strength calculated to act upon the matrix, and render it
soluble, will be rendered too dilute for such purpose. After adding
the acid the mixture should be well agitated, and after sufficient
time has been allowed for the acid to have dissolved as great a
portion of the matrix as it will take up, the solution may be drawn
off, if adapted for any useful purpose, and the process of washing
allowed to proceed as before, until it becomes necessary to add a
fresh portion of acid, small quantities of which may from time to

page_text: time be introduced in the manner described, until the required.
amount of concentration is obtained.
The vessel in which the acid is used may be a separate vessel,
but in every case should be lined with lead.
Imiraty,
separation
precious metals, whether from
pulverized quartz, or from aluminous or other sands, or after
having caused the mineral to be broken up, and its contained metals
to be concentrated by any convenient means, I employ a readily
fusible alloy of bismuth and lead, or of bismuth, lead, and tin,
mostly with the addition of a little mercury; in which case,
properly speaking, it is an amalgam, and kept just above the
melting point by any suitable means, the object being to entrap and
secure the nobler metals but not to smelt them (whenever it is
avoidable); and this by aid of a medium of such low specific gravity,
that the native alloys of gold and of silver, some of which are of a
specific gravity considerably less than that of pure mercury, may
the more readily sink to the bottom...
The proportions that I prefer to employ are bismuth, sixteen
parts by weight; tin, six parts; lead, ten parts; and mercury, five
parts; by the aid of which I am enabled to work at a temperature
even below that of boiling water, while the entrapped gold may
afterwards be freed from any adhering particles of the amalgam,
(that is, if I except only a little of the sometimes adhering mer
cury), often by boiling water alone.
As the operation proceeds, mercury should be added occasionally
in small quantity, and which, at the temperature requisite to keep
the amalgam in a state of fusion, licks up the gold very greedily.
The pulverized ore, before it is brought in contact with the
amalgam, should be brought to the same temperature; for which
purpose I cause it to be passed through a hot chamber; and when
mercury is dispensed with, or whenever the alloy. employed is not
fusible under 212' Fahrenheit, I first render the meal perfectly dry.

page_text: My improvements in machinery or apparatus have reference to
an apparatus for extracting gold, either by process of amalgamation,
or by aid of the readily fusible alloy or amalgam described.in
Section C; in which latter case some slight modification is obviously
necessary; but the object of the apparatus is in every case to bring
the auriferous ore or meal into more forcible contact with the
mercury than has been customary heretofore, and that such intimate
and forcible contact shall be kept up by pressure for a time amply
sufficient to deprive the mineral of its treasure.
For this purpose I cause the pulverized ore (which I prefer to
work moist, and to have previously ground up very fine by the aid
of edge rolls) to descend into an upright cylinder through a hole
made in its side, and in the centre of which cylinder is a vertical
spindle working in bearings, and having arms or fans attached; but
in such manner, or set at such an angle, that when the spindle is
made to rotate, the meal or ore is by the motion of the arms
continuously forced downwards, through the gradually diminishing
aperture of a vertical tube that is attached to the bottom of the
cylinder; at the lower extremity of which tube, however, is an
enlarged opening resembling an inverted funnel, and which is made
to dip to any required extent beneath the surface of the mercury
employed for amalgamation.
The auriferous ore, then, being forced downwards until it arrives
at the small end of the inverted funnel, is at length brought in
contact with the mercury, against which it is forcibly thrust, and
through which it is gradually and forcibly obliged to descend,
owing to the pressure exerted by the ore continuously arriving from
above, or the supply of which can be easily regulated.
The certainty of contact between the mercury and every particle
of the pulverized ore is still further ensured, when desirable, by
trituration, or by aid of a small agitator made to rotate within the
funnel-shaped opening, the vertical spindle of which agitator passes
by aid of a stuffing box through the bottom of the iron bowl con

page_text: taining the mercury; and the result of which arrangement is, that
the denser and more valuable metals are either taken up by or
otherwise sink to the bottom of the mercury, while the impoverished
mineral ultimately escaping from under the funnel-shaped opening,
floats upon the surface, from whence it is carried away in any con-
venient manner.
Having now described the nature of my Invention, and the
manner in which it is to be performed, I wish it to be understood
that I do not confine myself to the particulars herein laid down, as
the manner of operating may to a considerable extent be varied
without departing from the general character of my Invention; but
what I claim to be of my Invention, and am desirous to secure by
Letters Patent, is as follows, -
.
Firstly (or as relates to Section A), I claim the employment of a
caustic ley for suddenly cooling, and so causing to be disintegrated
the auriferous quartz or other metal-bearing inineral, the hardness
of which is traceable to the existence of silica, or to any substance
having when hot a known affinity for caustic, soda, or potash, and
which ley I am by its subsequent purification enabled to employ
over and over again for disintegrating purposes, as described.
Secondly (or in Section B), I claim as my improvements in
operating upon metal-bearing minerals, the means whereby the
water employed for the purpose of washing, or in order to effect the
concentration of the gold or other contained metals, is admitted
beneath the contents of the vessel containing the ore to be washed,
and made to flow upward, combined with the use of an acid for
effecting the solution of the matrix either wholly or in part..
Thirdly (Section C), I claim the employment of a readily fusible
alloy of bismuth, lead, and tin, or a readily fusible amalgam of
bismuth, lead, tin, and mercury, for entrapping and securing the
nobler metals, without the immediate necessity of smelting, properly
so called (that is to say), without involving any immediate necessity
of fluxing the matrix, or production of a slag.
Fourthly, as relates to my improvements in machinery or
apparatus (Section D), I claim the means whereby the ore, when

page_text: properly prepared, is brought into contact with the mercury or
medium employed for extracting its contained metal with a force
the amount of which can be regulated agreeably to the height or
pressure of a column of mercury surrounding the mouth of the
apparatus through which it is supplied, or as in manner described.
In witness whereof, I, the said George Henry Bursill, have
hereunto set my hand and seal, this Twelfth day of August, in
the year of our Lord One thousand eight hundred and
fifty-three.
Witness,
JNO. COOK.
GEORGE HENRY BURSILL. (L.S.)