The Eureka sentinel. [volume] (Eureka, Nev.) 1902-current, 1904-10-22

sulphide, as on the Comst0ck and ae
Eureka. This has, with other evil
dences, given ground for calling the
great basin q geological province, dis
tinct in structure 40 we'll ~ topography
from the regions east and west Of it.
The discovery Of Tonopah. with its sill
yer deposits. was only another instance
confirming this. But the free gold de.
posits Of Goldfeld. % miles south Of
Tonopah, are a decided exception.
The Country Described.
The physiography of the country
about Goldfield appears as follows: At
the eastern horizon lies q long mesa
table land). rising gradually and near
the middle of the view. giving place to
a series Of irregular hills. Next to
these hills stand . group of Jagged
peaks closely resembling eroded vol.
canic pipes. These pipe.like hills slope
down to gulch and just above the
gulch. on that slope, lie the mines. In
the gulch itself lies the camp. Turn.
ing now to the west. the side Of the
camp gulch rises suddenly in q per.
pendicuiar scarp-like cliff, 200 feet or
more high. Its sides show exposed
strata of lava and at its top is layer
that causes the surface to continue
westward in q mesa, dipping slightly
in that direction to the foot Of another
scarp. like the first, rising out Of it.
and topped by another mesa. This is
repeated westward to the hills at the
horizon, so that in looking westward
from the camp, it seems like series Of
broad steps, entirely different from the
pipes and jagged hills to the east. The
general appearance Of the mesas
suggests series Of faults. This appear
ance is supported by the repeating in
the scarps Of the layers Of lava exposed
on the cliff that bounds the gulch.
That the lava beds lie also under the
gulch and that the gulch is merely the
surface Of another mesa abutting on
the hills to the east is suggested by its
form. like the long side Of distorted
V. Of which the west scarp is the
abrupt short side, more Of V trough
than rounded ont gulch and, also,
by the fact that water is struck in wells
within 80 feet anywhere in the camp.
indicating an impervious lava bed near
the surface. The mines occur where
this series OF step-like mesas abut upon
the pipe hills.
1t is suggested that the scarp of each
mesa represents a fault line. and that
the mines occur in faulted region. at
the contact of this mesa field with
the pipe field; that the mesas represent
an extensive westward lava flow from
these pipes. divided by step faulting.
Mining Methods Employed.
The methods Of mining employed
both at Tonopah and Goldfield are
simple. At the start the richest claims
were divided usually into 100 feet
lengths and leased. The lessees each
sank vertical shaft reaching some
time 800 feet deep. but usually less. and
crosseut to the vein if it was not itself
vertical then drifted and stopped. Many |
Of the lessees became rich in this way,
and although the leases expired long
ago at Tonopah, they are now much in
demand at Goldfield. The country |
rock being volcanic lava (at Tonopah E.
J. Spur says it is mostly andesite) is
hard and compact. and stands almost
everywhere without timbering. In the
Valley View mine at Tonopah stulls
have been put in the slopes from side to
side Of the empty spaces, and found
sufficient for thousands of square feet
of slopes. The shaft stations are usu-
ally timbered. Ventilation is usually
supplied by small blowers in the Miz-
pah mine they have put large pipe
down an old prospect shaft which then
was filed in. leaving horn on the
surface, like funnel for furnace draft
on steamer. The ore taken out in the
drifts and slopes. aud waste from the
crosscuts, Is loaded into buckets on
trucks, which are then sent along rails
to the shaft. where the cable is hooked
to the bucket. A cross.head above the
bucket keeps the bucket steady.
The shafts are vertical. usually two
compartment. though the New Mizpah
is three accompaniment. They are
usually Jagged all the way, and. though
the mines carry no water. there is Is
to 20.foot sump to facilitate sinking. At
the surface the bucket is dumped by
hand mot automatically into cars and
thrown upon mounds, one for waste and
one for ore. BY this time all the Tono-
pah mines Of consequence have con-
siderable ore on the dumps. waiting for
the railroad to take it to the smelter.
| -