The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1899-12-20
Costly Mistakes in the Early Er-
ploration Of Mines.
runssl,No. the M,NEas' FAD.
1lisleaains EviAence Gathered From
A Outerop 81 Mineral-Ressona
why tAe ore sAsuIa BE Followed
Fron Discovery, and Tunneling
NOT Attenptea Until the condi-
tions Are TAorosshly Understood.

The practical miner Is apt to know his
own particular mine very well, and this
Hnowiedre gives him Z certain contempt
Tor eeologists or other trained observers.
who bring . wider knowledge and more
unbiased Judgment to the work IN hand.
Perhaps the conservatism Of the average
miner and prospector Ii most evident In
his cnnging to the idea that the beet way
% nnd out what there z h the vein he
has located Is to prove II with depth" by
cross-cut tunnel.
A. matter Of fact, when a miner has
etaked out his claim the first and most
essential thing ID for him to determine the
/ direction of the vein. Thus he win know
whether his location really covers the vein,
thereby very likely saving himself heart
breahing lawsuit should the vein prove
+ valuable. In case the surface debris is
not deep, say ten feet or less, it will not
take him very long to dig surface cross
outs or trenches the whole width OF the
VEIN He VIII md out also whether the
ORC that he located ID really in place, or
whether II u slide or noat-rock from high
u up the hillside. Having determined the
general direction Of the ledge, and opened
& n. II the surface IL not too deep. in at
least four places on q claim $500 feet long,
\ the next thing to do Ii to sink on the ledge
far enough to determine accurately its dip
OF the inclination at which It slopes into
the ground. II the vein has been opened
up at four points several hundred feet
apart careful analysis Of the rock from
the bottom Of the different pits Of cross
cuts will show whether the vein grows
richer In one direction than In another. or
carries fairly uniform values. Having
ascertained this much, the prospector h in
position to SO to work systematically.
Ne can decide whether he shall sink his
+ zn1< <<rs R1rvr a q M
also tell where ID the best point to locate
his shaft or tunnel 30 that It will show up
the vein TO the best advantage.
Advantages Of Following Ore.
Tho Mining and Engineering Journal
very correctly maintains that the best adj
vice to b given. in opening any mineral
deposit. II: Follow the ORE" There IL
shown UP 30 thoroughly, and the ore taken
out will 60 often = long way toward pay
ing expenses. Even II the ore is not rich
enough to pay for shipment, 1t Is always
evidence Of the value Of the rock IN the
vein, and Is a5tangible, self-evident thing
no show prospective investor. Again.
shafts. vertical or Inclined, that follow
the vein. will show up any chahges M the
ore and give large amount In sight.
Thus. four shafts fifty feet down In
ledge four feet wide would expose 1850
square feet OF the vein. A tunnel driven
100 feet through rock to cut the vein
would expose but the section the height
and width Of the tunnel say 100 square
feet To expose larger area, drifting
must be done and such drifts can be run
with better discrimination at the foot Of
shaft that has followed the ore.
In the great majority Of cases the miner.
working by rule-of-thumb methods and
disdaining to 90 at a thing in scientific
way, proceeds in an altogether different
thot ,t.t1t horto IJo
staked on his claim. often located on the
strength Of an apparent outcrop of ore. or
on the showing OF a single shallow shaft,
he proceeds to run a tunnel. The miner
or prospector with limited resources wastes
only his own time and money by such
work: i = when the practical miner un-
dertakes to open up a claim for some
company hoated with $1000.000 capital, or
some other attractive figure, that great
mischief ID DONE tunnel is started to
open the ledge, say at 200 feet Now, as
Stunning that the ledge dips into the ground
vertically, that the slope of the hill is As
degrees, and that the tunnel is driven at
right angles to the course Of the vein, a
tunnel 200 feet long will cut the vein at q
depth Of 200 feet. 1t Is easier to tunnel
than to sink this distance. The dirt and
rock removed can be trammed much
easier than 1t can be hoisted, the tunnel
will drain itself. and II the ground Is at
u
a pumping outfit.
Evidence That Ii Misleading.
So much for the advantages. As a mat
ter Of fact the different factors are sell
dom as cited above. The evidence that
can be gained from an apparent outcrop
or one shaft is very misleading. A COM
mon error Is to mistake the slope of the
hill. Any ordinary hillside Is very much
more likely to be a slope OF % or 20 de-
grees than As. and the tunnel to open
ground at 200 feet may have to be driven
200 feet. In a tunnel Of this length the
chances are that the ventilation will be-
come bad at the heading, long waits will
be necessary after each blast. work will
proceed slowly, and finally some sort
Of ventilatlng plant will be necessary.
Again, the dip OF the vein may be UNI
known, as the apparent outcrop may be
slide-rock. If ore has been found in place,
and the dip of the vein determined by one
shaft, still the pay value may be confined
to a chute or chimney the limits and In
clination Of which, In the plane OF the
vein, are altogether unknown. In such
case the tunnel expected to strike vein
in 200 feet, approaching from the footwali
side, may fail to reach 1t In 500 feet
When finally cut, the vein may be abso-
lutely barren. The section exposed is just
the size OF the tunnel; whether there is
rich ore to right. to left or below 1t is
absolutely impossible to say except by
doing what might have been done In the
first place. that Is, by following the vein.
In the case OF mining company that has
gone into such q venture on nonassess-
ment plan. the end comes quickly and
certainly The funds raised. from selling
stock are used up In driving the tunnel
200 feet or more Failure to find the vein