t. In fact there are mines which with a yield
of 1 1/2 to 2 dwt. a ton, and crushing with water power, have actually
yielded large profits. On the other hand, mines which have given
extraordinary trial crushings have not paid working expenses. Everything
depends on favourable local conditions and proper management.

Having decided what class of crushing machinery you will adopt, the
first point is to fix on the best possible site for its erection. This
requires much judgment, as success or failure may largely depend on
the position of your machinery. One good rule is to get your crusher as
reasonably high as possible, as it is cheaper to pump your feed water
a few feet higher so as to get a good clear run for your tailings, and
also to give you room to erect secondary treatment appliances, such
as concentrators and amalgamators below your copper plates and blanket
strakes.

Next, and this is most important, see that your foundations are solid
and strong. A very large number of the failures of quartz milling plants
is due to neglect of this rule.

I once knew a genius who erected a 10-Lead mill in a new district, and
who adopted the novel idea of placing a "bed log" laterally beneath
his stampers. The log was laid in a little cement bed which, when the
battery started, was not quite dry. The effect was comical to every one
but the unfortunate owners. It was certainly the liveliest, but at the
same time one of the most ineffective batteries I have seen.

In a stamp mill the foundations are usually made of hard wood logs about
5 to 6 feet long, set on end, the bottom end resting on rock and set
round with cement concrete. These are bolted together, and the "box" or
mortar is bolted to them. The horizontal logs to carry the "horses" or
supports for the battery frame should also be of good size, and solidly
and securely bolted. The same applies to your engine-bed, but whether it
be of timber, or mason work, above all things provide that the whole of
your work is set out square and true to save after-wear and friction.

Considerable difference of opinion exists as to the most effective
weight for stamps. My experience has been that this largely depends on
the nature of your rock, as does also the height for the drop. I have
usually found that with medium stamps, say 7 to 7 1/2 cwt. with fair
drop and lively action, about 80 falls per minute, the best results were
obtained, but the tendency of modern mill men is towards th