IMPROVEMENTS IN PREPARING AND AWDYUSBAND AND ÅRGENTIFEROUS ORES.
Year: 1870

page_text: LETTERS PATENT to George Holcroft, Engineer, and Robert Martin
Roberts, Mining Engineer, both of Manchester, in the County
of Lancaster, for the Invention of "IMPROVEMENTS IN PREPARING AND
AWDYUSBAND AND ÅRGENTIFEROUS ORES.'
m
"
Sealed the 30th August 1870, and dated the 7th March 1870.
PROVISIONAL SPECIFICATION left by the said George Holcroft and
Robert Martin Roberts at the Office of the Commissioners of Patents,
with their Petition, on the 7th March 1870.
We, GEORGE HOLOROFT, Engineer, and ROBERT MARTIN ROBERTS,
Mining Engineer, both of Manchester, in the County of Lancaster,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN PREPARING AND TREATING AURIFEROUS AND ÅRGENTIFEROUS ORES," to be as
follows:-
We first sort the different kinds of auriferous and argentiferous ores
before operating upon them for extracting the precious metals (for this
purpose a practical judgment must be used in determining the different

page_text: classes of the ores previous to calcining and reducing when required).
The nature of the ores varies according to the foreign matters they contain,
such as talurian bismuth, arsenic, calamine, blend, and sulphurets, and
the different kinds of pyrites, which ingredients are contained more or
less in the ores, and having an affinity for the mercury prevent it taking
up the gold and silver.
Having sorted the ores in their respective kinds we calcine each kind
separately according to the length of time required to extract the foreign
matter it may contain, and whilst hot we immerse the ore in a solution
prepared for each kind.
First. For the ore containing talurian bismuth we immerse the ore
for about seven days in a solution of common salt and muriatic acid or its
equivalents.
Second. For the ore containing arsenic we immerse for about 24 hours
in a solution of saltpetre and sulphuric acid or its equivalents.
Third. For calamine we immerse for about 48 hours in a solution
of sulphuric acid alone or its equivalents.
Fourth. For blend we immerse for about 48 hours in a solution of
common salt and sulphuric acid or its equivalents.
1
Fifth. Ores containing sulphur only are calcined in the ordinary 2
manner and immersed while hot in water.
After the ore has passed through either of the processes described
and been reduced the greater portion of the gold or silver can be caught
by the process of washing, and that which passes by and floats in and on
the surface we prefer to wash in a solution of ammonia previous to its 2
being taken up by mercury the light particles being collected in settling
vessels or other suitable receptacles.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Holcroft and Robert Martin Roberts in
the Great Seal Patent Office on the 6th September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
HOLCROFT, Engineer, and ROBERT MARTIN ROBERTS, Mining Engineer,
both of Manchester, in the County of Lancaster, send greeting.
30

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of March, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said George Holcroft and Robert Martin
Roberts, Her special licence, that we, the said George Holcroft and Robert
Martin Roberts, our executors, administrators, and assigns, or such others
as we, the said George Holcroft and Robert Martin Roberts, our executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter 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 Invention for "IMPROVED PROCESSES
FOR PREPARING AND TREATING AURIFEROUS AND ARGENTIFEROUS ORES," upon the
condition (amongst others) that we, the said George Holcroft and
Robert Martin Roberts, our executors or administrators, by an
instrument in writing under our, or their, or one of our or their
hands and seals, 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 immediately after the date of the said
Letters Patent..
NOW KNOW YE, that we, the said George Holcroft and Robert
Martin Roberts, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement (that is to
say) :—
We first sort the different. kinds of auriferous and argentiferous ores
before operating upon them for extracting the precious metals, and for
this purpose a practical judgment must be used in determining the
different classes of the ores previous to calcining and reducing when
required. The nature of the ores varies according to the foreign matters
they contain, such as talurian, bismuth, arsenic, calamine, blend,.antimony,.
and sulphurets, and the different kinds of pyrites, which foreign matters
or ingredients are contained in greater or less proportions in the ores,

page_text: Having sorted the ores in their respective kinds we calcine each sort
separately according to the length of time required to extract the
foreign matter it may contain, and whilst hot we immerse the ore. in
a solution prepared for each kind; these solutions contain the ingre-
dients herein-after named and are prepared in the following manner,
namely:-
First. For the ore containing talurian bismuth we immerse the ore for
about seven days in a solution of common salt and muriatic acid or their
equivalents. In preparing this solution to operate upon a ton of ore we
take four cubic feet of soft water, to which are added two pounds of 1
common salt and one pound of rectified muriatic acid of about twenty-
eight degrees of Twaddle's hydrometer.
Second. For the ore containing arsenic we immerse for about twenty-
four hours in a solution of saltpetre and sulphuric acid or their equi-
valents. In preparing this solution for operating upon a ton of oil we 1
take four cubic feet of soft water, to which are added one pound of salt-
petre and half a pound of rectified sulphuric acid of about twenty-eight
degrees Twaddle.
Third. For ore containing calamine we immerse for about forty-eight
hours in a solution of sulphuric acid alone or its equivalents. In pre- 2
paring this solution for operating upon a ton of ore we take four cubic
feet of soft water, to which is added one pound and a half of rectified
sulphuric acid of about twenty-eight degrees Twaddle.
Fourth. For ore containing blend and antimony we immerse for about
forty-eight hours in a solution of common salt and sulphuric acid or 2
their equivalents. In preparing this solution for operating upon a ton
of ore we take four cubic feet of soft water, to which are added ono
pound of common salt and three pounds of rectified sulphuric acid of
about twenty-eight degrees Twaddle.
Fifth. Ores containing sulphur only are calcined in the ordinary
manner until all the sulphur is driven off and immersed while hot in
soft water to slack.
"
We wish to remark that auriferous and argentiferous ores containing
other foreign matters may also be partially prepared for calcining, and
finally operated upon by the processes now known and in use for extracting
the gold and silver.

page_text: After the ore has passed through either of the processes described and
has been reduced the greater portion of the gold or silver can be caught
by the process of washing, and that which passes by and floats in and on
the surface we prefer to wash in a solution of ammonia previous to its
being taken up by the mercury, the light particles being collected in
settling vessels or suitable receptacles.
During the process of washing the flowring gold or silver is made to
sink for the mercury to catch it by putting it in a solution of ammonia.
A coarse flannel is drawn over the mercury table to more perfectly bring
the gold and silver in contact with the mercury. The flannel should be
made of wool and horsehair or such materials as will scratch the surface
of the mercury to cause the mercury to catch the gold or silver.
Having thus stated the nature of our Invention, and described the
manner of performing the same, we wish it to be understood that we do
not intend to limit ourselves to the details given, as they may be varied
according to the nature and quality of the ores to be operated upon, and
we claim,―
First. Calcining auriferous and argentiferous ores for the purposes of
preparing them for the subsequent operations employed for extracting
the gold and silver.
And, secondly. We claim the various processes and solutions described