of
gold oves. The latest invention is the elephant stamp, a useful
machine, and being portable may be of service, but in its present form
would not be a desirable mill to erect for a large reduction of works.
I am of opinion this stamp may lu greatly improved and rendered very
effective. It may be as well to point out here that a perfect system of
gold reduction and extraction embraces several distinct features or
processes, each one requiring the greatest care and attention, and
especially cleanliness, without which there w'ill be losses, even with
the best appliances. The tailings or waste should also be constantly
examined and carefully tested in order to discover the amount of gold
lost. The importance of this cannot be over-estimated or too strongly
impressed upon those in charge of reduction works. It must, therefore,
be obvious to everyone, considering the minute particles which have to
be collected and the value of the metal obtained, that every detail of
the operation should be carefully watched, and that t he rough and
ready method of treating auriferous quartz, which some people commend,
cannot succeed. In ordinary crushing, the degree of fineness to which
the quartz should be deduced must be determined by the character of the
gold, some portion of which will remain in particles of the quartz
sand, but with proper arrangement the amount lost will not be great.
When the gold is exceptionally fine the treatment must be modified, but
in either case effective arrangements for concentrating the sulphides
from the tailings would save most if not all the free gold. The gold
obtained in each part of the process of separation or extraction will
vary with its character; if the gold is coarse a larger portion remains
in the coffers, if fine the proportion decreases, and that obtained
outside the coffers increases. When the quartz contains gold of average
fineness (without use of mercury in coffers) the coffers may give 60 or
65 per cent mercury or ripple boxes about 23 per cent, blanket tables
about 10 per cent. (Mr, Harvey here explained the construction and mode
of working of the model.) This model has been specially prepared in
order to give you an opportunity of forming your own opinion on what
(in my idea) may be regarded as the most perfect system of stamp in
use, the model is one-quarter size, and with the exception of a few
minor details, represents the general arrangement for the reduction and
treatment of auriferous quartz. l!efore describing the construction of
the mill, use of steel, ecc., and manner of working, let us consider
what are the objects to be obtained by the use of this kind of
stamping-mill. You will say to get out the gold. Well, admitting it is
to take out the gold, but in what way, and in what manner is it to be
obtained ? The object of this machine is to obtain the free gold with
the least possible expense, wear and tear. (Mr. Harvey then described
the machine, which he said was made in three pieces to facilitate the
transport. It was constructed witli a view to economy and stability. A
machine of ten head of stamps would send through three tons per head
per stamp per day, or 30 tons per day in all. It would only require
eight men to attend to it, and where the necessary power could be
obtained the number of stamps could be easily
increased. 1 now propose to describe the process of reduction, and to
make the description complete 1 must draw upon your imagination to
supply what is wanting in the model. And assuming that we have obtained
our auriferous quartz, I will show you how it is possible to extract
the gold to the best advantage. (By means of the model, Mr. Harvey very
clearly explained the system of putting the quartz through the mill,
and extracting the gold ; and mentioned that so large a percentage of
the gold was obtained in the first stage of the process that it was not
necessary to touch the mercury box above once in twelve months.) My
task is ended. It only remains for me to thank you for your kind
attention, and trust lite information I have given will enable you to
form a better idea of the processes employed for the reduction and
treatment of auriferous quartz. (Loud cheers.) If any gentleman would
like to ask any question, or wishes for any information about the
details of the model, I shall be happy to answer them.
