IMPROVE- MENTS IN EXTRACTING GOLD AND SILVER FROM THEIR MATRICES AND FROM OTHER SUBSTANCES OR MATERIALS WITH WHICH THEY ARE COMBINED, MIXED, OR ASSOCIATED
Year: 1857

page_text: PROVISIONAL SPECIFICATION left by Joseph Gibbs, at the Office of
the Commissioners of Patents, with his Petition, on the 9th January
1857.
I, JOSEPH GIBBS, of Abingdon Street, in the City of Westminster, Civil
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN EXTRACTING GOLD AND SILVER FROM THEIR MATRICES AND FROM OTHER
SUBSTANCES OR MATERIALS WITH WHICH THEY ARE COMBINED, MIXED, OR ASSOCIATED,"
to be as follows:-
Before describing the nature of my Invention, and in order that it may be
more clearly understood, and also to define that part of the process of extract-
ing gold and silver from their matrix or matrices and from the materials with
which they are commonly found combined, it is necessary to state what has
heretofore been the usual mode of extracting gold and silver when such silver
has been combined with gold in a common matrix.
The usual course of proceeding has been, when the object has been to extract
these metals from rock, to crush such rock, quicksilver being in contact with
the rock so crushed and whilst being crushed, or to crush the rock and wash
the crushed rock, so that the metallic portions of the rock may be separated,

page_text: and then to run this separated part over a surface of quicksilver in and through
machines called Tyrolean mills, or otherwise to work the materials through
revolving barrels with adequate charges of quicksilver; and in the case of gold
and silver being in combination with primitive gravel or diluvial sand of the
geologists, nothing but simple washing has been commonly resorted to, except
in some cases the run of water from the washing apparatus has had placed in
or under it a surface of quicksilver, over which the water glides, and on which
surface of quicksilver some of the smaller particles of clean gold are caught,
and which would otherwise be lost.
From great research and numerous experiments in endeavouring to ascer-
tain the best method of extracting gold and silver, I have found that none of
these methods are adequate to the purpose of obtaining all or nearly all the
gold and silver contained in either the rock, or in the sand, or diluvial gravels.
Now, my Invention for extracting gold and silver consists in the following
improved process; which is performed, first, in washing the diluvial sands and
gravels so as to obtain about 3 th part of the original bulk, which I call
concentrating; and, secondly, by re-grinding or re-crushing this material so
concentrated, the crushing machine being at the same time charged with quick-
silver, and I cause the concentrated material to be ground so fine, that it shall,
while passing and repassing over the surface of either, resemble mud; and for
the more perfect grinding and to carry off the muddy substance when so
formed I cause water to flow through the crushing machine: and, thirdly, I
sometimes smelt this concentrated material instead of grinding, as described in
the second part of my Invention.
And for the more perfect operation of some of the processes described, and
for maintaining the quicksilver in a state of greater fluidity, I cause a small
quantity of nitre from time to time to be put into the crushing machine whilst
the process is being carried on.
I have not described the several machines and apparatus alluded to for
washing, crushing, and re-grinding or smelting, all those being well understood,
and forming no part of my Invention; but what I intend to claim as my
Invention is, the combined process of washing and concentrating the materials
containing gold and silver and then re-grinding the same into mud, or in smelt-
ing the same; and what I mean by concentrating the materials is, separating
by washing, or by washing and sifting combined, as already described, the par-
ticles of greatest specific gravity left by such washing, or washing and sifting
combined, either of crushed rock or diluvium. And further, I do not confine.
myself to the concentration of these materials to 3 th of the original bulk ;

page_text: sometimes I vary this degree of concentration; but I find from experience
that generally that degree of concentration or thereabouts is best, though I
have found materials which are more conveniently and may be more profitably
worked where concentrated to a less degree sometimes when concentrated to
1th orth of the original bulk only.