Lyon County times. [volume] (Silver City, Nev.) 1874-1907, 1879-08-02

ana tue assertion l nave mace l6 True
when applied to the case of bonanzas
which are strictly Independent. They
are not connected by stringers of ore,
nor do they overlap in way that
makes it possible to feel for one from
the known position of another. En-
tirely disconnected, they are sur
rounded on every side by barren
ground, and this often reaches up
ward and downward and ON both
sides for hundreds of feet
In an ordinary fissure vein, where
rich part of the ground is worked
out, there often remains a steady sup
ply Of poorer ore from the main ILL
ing of the vein. But this is not the
case on the Comstock. When the
true bonanza is exhausted, large
quantities of poor ore are often
scraped up from the corners and
sides of the great mass; but in time
this also fails, and tho miner finds
his excavation surrounded by country
rock on all sides in a fashion that
veins do not exhibit. The quartz
once removed, nothing like a vein
remains, and the ground beneath him
resembles perfectly the rock that
stretches for miles ON either side.
In lode of this kind, barrenncss
for five hundred feet no more proves
the exhaustion Of the lode than bar.
renness for one hundred feet of depth.
These bodies of ore lie in q thick
mass Of layers composed of eruptive
rock. At a certain period, an i'm
mense quantity of another eruptive
rock was poured out upon them as
they stood in their inclined position.
1t loaded them with such weight that
they began to slide upon each other,
the upper layers sliding upon the
lower, and the movement must have
been accompanied by crushing and
breaking OF the layers on an extern
sive scale.
Into these crushed portions and
into the opened seams Of the rocks
poured stream of water, bringing
with it quartz, gold and silver; and
these were not only deposited in the
crevices, but the solid rock was itself
dissolved, and metalliferous quartz
was left in its place by the process
known to biologists as substitution.
Ore bodies formed in this way may
be in the near neighborhood of each
other, but they may also be far re-
moved aud have no other relation
than that they occupy the same line
of crushing and movement. Mining
on the Comstock has gradually adj
justed itself to this condition of
things, and it is rare to find an effort
made to follow up what in other
mines would be considered good in
dication of metal. If an ore bear
ing seam is found, its character is
carefully ascertained, however insig-
nifcant it may be; for the bonanzas
always begin in a small way, what
ever proportions they may reach after
ward. But in general exploration,
the system pursued is to cut through
the rock layers at points sufficient
ly near to make sure that no I'M
porrant ore body can escape early
discovery. Irregular as the Com
stock ground is, the work upon it is
more uniform than is common in
metal mines.
l have brought these points before
you to show that the present state OF
things is nothing new on the lode.
At all other times, some of the mines
have been in barren ground, and the
only thing remarkable in the existing
condition is the vertical and linear
extent of this barren ground. 1t
covers nearly the whole length of
the lode for perhaps 800 feet of
depth as a minimum. This is un-
pleasant and not profitable; but l
cannot acknowledge that it is proof
of exhaustion.
From the facts given you will see
that the question is really brought
down to one point. The ore bodies
exist because certain parts Of the
ground were opened and crushed by
weight laid on the surface. The
almost uniform cessation of ore at a
given depth might we'll give rise to
the suspicion that the force mentioned
was exhausted in the work it did
upon the rock at higher levels. The
geological aspect of the question
may, therefore, be expressed by the
question, Was the weight to which
the lode owes its formation sufficient
ly heavy to extend its effects to depths
greater than $500 feet, which we may
assume to be the greatest present
depth of the mines
/ think no observer, who will 60
upon the ground and search out the
boundaries of the vast mass of rock
that composed this weight, will
imagine that its effects can be con-
fined to the shallow depth named.
Indeed, visit to the ground is not
necessary. The condition of the ore
in the great bonanzas gives strong
evidence against the supposition.
All the ore taken from the lode, with
exception of scattered lunches, the
outliers Of the bonanzas, and with
exception of that now mined in the
Ophir, Union, and Sierra Nevada, has
been found above the 1650-level. A