Gilpin observer., 1899-04-20
DEVELOPING NEW MINES.
Suggestions as TO Their Equipment an,
DeyolOpment


Development
When new mine is to be equipped
ana developed, 1t is desirable to place
on the property machinery suitable for
the purpose of development and to
Dlock out the ground as expeditiously
ana cheaply as possible. There Is
MUCH diversity of opinion among mine
superintendents as to what comprises
proper equipment, and also as to
what lines of development should be
followed. AS II matter of course, the
plan adopted will be Influenced by the
conditions under which the mine will
operate. As all undeveloped mines are
most uncertain as to size of ore depOs-
Its. value of ore, amount of water that
may be encountered and character of
ground, 1t Is wise to anticipate difficult
tles. even in n mine which at or near
the surface seems more favored than
some of its neighbors. As the quantity
or ore that may be found Is unknown
when development commences, ex-
periece has shown that it is
unwise to put up an expensive hoist
ing plant until it has been determined
mat such plant would be necessary.
VEINS large at the surface may not con-
tinue large in depth. and even should
they do so, the value of the ore may be
W
case no hoist would be required at all.
On the other hand. some mines. small
and low grade at and near the surface.
in depth develop large ore bodies of
great value.
In such cases the small prospecting
plant may be replaced by such a one
as the development of the mine may
Justify. For n relatively small sum of
money good hoisting plant may be
set up which will hoist at moderate
speed 1000 pounds of rock at a load,
with which large shaft may be sunk
many hundreds of feet.
Abundant power should always be
provided, however, whether steam,
water or electricity be. employed. for
the reason that many shafts compara-
lively dry near the surface become
very wet in depth. When n large in
hux of water occurs. whether it prove to
be permanent and constantly increas-
ing quantity as depth is attained. or
whether, after sudden rush of water.
1t is found to steadily decrease as
pumping or baling is continued,
abundant facility for handling larg-
er quantity of water than has ever
been encountered should always he at
hand. Large valve buckets are very
useful as auxiliary to pumps when
working in levels. but valve bucket
Is useless when sinking. 81
When the shaft has reached depth
of 500 to LOCO feet and levels run along
the ore body or vein crosscuts made
and raises put through, the manager
has definite idea of the quantity of
material exposed possessing n net val
lie, ana can then put in hoisting
plant suited to the requirements of the
Il I.a
hoist capable of raising 1000 or 5000
tons OF ore in twenty-fOur hours at
great velocities, when 1t would be
found difficult to supply forty-stamp
mill with 100 tons of ore daily from II
small vein. Very large ore bodies may
be extracted hurriedly, the chambers
timbered and filled as the work pro-
crosses. A mine capable of supply
ing 1000 tons of ore or twice that
amount should he equipped with en-
gines capable of raising that amount
and doing 1t easily.
What applies to hoisting engines ap-
plies with equal force to metallurgical
plants. The character and capacity of
plants for the beneficiation of ores can
not be determined upon with safety
until the development of the mine has
demonstrated its capacity and the char
i'NIi vi tic Oie. hlStNheS III tlllS Ill
rection are probably of less frequent
occurrences than formerly, but 1t is not
many years since 1t was not uncommon
to see smelter erected to treat dry
ores and wet-crushing stamp mills
built to treat lead carbonates and ga-
lena. There are very few ores indeed
that cannot now be successfully treat
ed by some one of the many processes
In practical operation in every corner
of the world. All that now remains to
do Is to ascertain the one best adapted
to the ore in question. all things being
taken into consideration, us cost of
transportation. chemicals. fuel. labor.
etc. improvements and lower cost in
the processes of to-day may be antici-
pated and new processes which will
treat some ores successfully may be
expected to supercede processes Eow in
use.
In shaft sinking 1t Is cheaper to cut
out the stations when the various
points at which levels are to he run are
reached, and the levels should also be
started at such time. sinking only
enough to afford sump below the
level. In mines where 1t is evident n
large amount OF ore IL to be handled,
where skips or buckets are used for
hoisting. 1t is very good practice to cut
out under the floor OF the level II
space for an ore bin or pocket into
which ore or waste may he dumped
from cars trnmmed to the shaft from
the faces OF the drifts or from the
shoots. This provides an economical
means of loading skips and hoIsting
may be carried on independent of stop
Ing and tramming. The first level In
the mine should he run from the shaft
Mt Il point above which little or no
stopping will be done, at least not for
long time. Having run this level work
in 1t may he discontinued for the time
and the shaft carried on down to the
next level. except while cutting out the