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31

Analyses of Ore from No. 7 Vein.

— Gold Silver Lead Zine
Ozs. per ton|Ozs. per ton| Per cent | Per cent

18 feet below surface, 18 inches wide............... 0-26 183-0 17-1 30-0

5 feet from above sample, 20 inches wide......... 0:08 107-20 13-0 40:0
SOSA OKSION OLOwan ss sre eh LAE ae ee etee optus 0-30 224-3 24-8 27-7
HUISACKS OMOLGU Eis ek mas Sa ee 0-24 229-8 16-3 30:3
28 sacks 18 inches to 2-ft. of zincy ore............... 0-18 135-00 9-5 42-6
Shaft 16 feet deep contains 3-5 per cent of Cu...... 0-20 241-5 17-0 58-0
Average 35 sacks 18 inches to 2-ft.-vein............ 0-20 236-8 32-7 30-8
Arwerage lOO SACKS 8s. cece ations s © ser erties sie settee 0-16 180-1 21-0 28-2

The zine content of this shoot is very exceptional and the high silver
and noticeable copper content suggests that the grey copper, or properly
freibergite, is also abundant.

On the 250-foot level a crosscut has been run from the main shaft to
tap this vein. The vein was found to be of milky quartz with bands 2
inches in width on both hang-wall and foot-wall, and it contained some
pyrite, arsenopyrite, chalcopyrite, and siderite, but no galena, sphalerite,
or grey copper; analyses gave only a trace of lead. The vein at this level
varies in width from 6 inches to 3 feet, and in 170 feet of drifting no ore
was encountered.

No. 8 vein outcrops about 100 feet vertically above and 400 feet
horizontally east of No. 7 vein. Only surface work has been done on this
vein so far, and it has opened an ore-shoot 100 feet in length and 3 feet in
width. A crosseut from the 250-foot level would give 500 feet of backs
on this vein.

There are several other veins east of No. 8 and at higher altitudes,
but so far as is known at present they are of minor importance.

On the east side of the mountain an adit tunnel is driven in on a 15-
inch quartz vein which strikes east and dips 60 degrees to the north. The

» vein has many small stringers branching from it into the sediments, and
at 30 feet from the portal a fault zone filled with gouge and mineralized,
cuts off the vein, apparently offsetting it towards the south. The fault
strikes north 10 degrees east and dips about 80 degrees to the east.

Paragenesis of the Ores. The mineralization of the vein was similar
to that in the veins described above, but pyrite is most abundant and the
other minerals occur only sparingly in the part opened up.

Table of Paragenesis of the Ores from the Silver Standard Mine.

Fissuring of the tuffaceous sediments
Deposition of vein quartz
Siderite replacing vein quartz

Pyrrhotite
Pyrite ‘Positions varying, but all replace siderite and quartz
Metallics—First | Arsenopyrite {
mineralization |) Freibergite? \(Small amount)
Chalcopyrite f

(Gold Position later than arsenopyrite