Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1910-12-05
GEOLOGY OF NATIONAL.
Veins Strike SortI, and soutl, and Arc
Euultcd.

/ ~
Certain geologic features of mining
camps ARE always q source of discussion
and In relation to the conditions in Ma
tlonal. Nev. the Minirs and Scientific
Press says:
THE geology OF the country both In
thu mine and Its vicinity. is very COM
plicated. The camp Hes near the south
erii edge Of the Idaho lava flow. To
the north and east the mountains are
capped with heavy flows OF basalt and
Tho gold-bearing Tertiary cruptves do
not come to The surface. BesinninE at
EIght Mile creek, about two miles north
OF National the rhyolite and andesite
appear and can he traced for a number
Of miles 10 tho soutn. Buckskin peak.
nearly NIL rhSoitc. Further south, the
more ancient rocks. such as limestone
sschist. slate and granite appear. Scarce.
lease to determine iii. actual geological
conditions with certainty a north-south
break trarerScs the property its entire
miles i'll the adjacent Claims. This break
has every indication or being a faulting
plane-heavy gougc. crushed quartz and
country rock smooth noulders embed
wall. All of the Stall lease workings are
IN this fault plane, and all OF the high
grade ore extracted up 10 me present
time. with the exceptions noted later. has
been IN the form Of smooth boulders
and pebbles or In crushed quartz. The
rocks vary In size fIum pinhcad to
pieces weighing 100 loUIldS
The fault plane, starting with a dip
of 70 degrees at the surface, gradually
straightens until at the i0o-foot level the
break Is highly sllicified f rnyolit" and the
west side, where the ore occurs. Is ande-
site. There Is every Indication that the
far it is impossible NJ present to tell on
account OF the limited amount OF devel-
opmcnt. The andesie belt Is apparently
not more than 800 feet wide, and directly
u,nc ~ to M NOR
10 feet thick Farther west. the rhyolite
appears again lying ov-r the diorite. Ba-
salt dikes cut through both the andesite
and the rirroltc. with a general north
and south trend. but do not believe they
have any relation to the ore deposition.
1t was originally believed that this main
ore was formed and afierward broken
and displaced by u faultinE movement.
ana sun later slightly cemented In places
by n later solution. Development has
tended to disprove this theory and the
present indications are that the ore was
derived from vein IN the andcsitc strik
OF series OF parallel VEINS cut and dis
placed by the fault. All Of these veins
do not carry ore Or commercial value.
although 1t is possible that high grade
ore Will be found in so:ne of the others. |
II this contention OF general fauting |
plane is true. and now It appears to be |
the only reasonable explanation, then all
the ore mined UP to tic present time is |
simply drag from this main vein and the |
fault has broken through and displaced |
the ore from phenomenally rich ore !
shoot. No, ore has been cut by the fault, |
although q drift WAS rim several hundred |
feet south. 1t is quite possible that there |
are parallel veins carrying ore of value |
farther south. and a number of lessees
are working In that vicinity with this
Idea In mind.
Some work was done on this main
vein. and few pounds OF ore or the |
soma phenomenal richness taken out. but |
on account Of the limited hoistlng faciii- |
ties and the appearance of so much high |
grade orc in the fauIting plane lower |
Gown. work was discontinued later. Sew
eral thousand feet of work has been |
done by the National Mining company
on this fault plane north of the Stall
lease, but up to the present no. ore of any
kind has been found beyond a point 30 feet |
north Of the least boundary. quite re-
Gently on the Hyde lease. IN n block Of |
ground l,In feet north of the Stall lease |
some OF the high grade was found in one
of the parallel veins in the andcsite. This |
may lead to another bonanza deposit.