32

( Zinc blende
Freibergite
Metallics-Second| Tennantite About same time
mineralization {Chalcopyrite
Galena
Jamesonite
Minor crushing
Calcite
Marcasite
’ Covellite
Limonite

Discussion. The Silver Standard ore is very similar to the silver-lead
ore of the Rocher De Boule mine, but it also contains jamesonite, a con-
siderable amount of pyrrhotite, and a higher proportion of arsenopyrite.
The order of deposition of the two latter minerals is interchangeable, and
the veins of each cut the other in the same polished section.

The amount of zine blende and tetrahedrite is much greater, and of
galena somewhat greater than in the Rocher De Boule occurrence, thus
giving a higher grade silver-lead-zine ore. Plate [XA shows the average
high grade ore. Free gold was observed in the arsenopyrite of the Silver
Standard veins and jamesonite is commonly associated with the galena,
in places in considerable amount.

Of the gangue minerals, calcite is abundant and is only slightly
exceeded in amount by the quartz; the calcite is later than the quartz
but preceded the metallic minerals as a rule, although small veins of calcite
occur as the last phase of the mineralization.

There is very little chalcopyrite present and the values in copper are
negligible.

The deposits may be classified as true fissure replacement veins.
Galena, zinc blende, and freibergite are the most important minerals,
but the arsenopyrite is important since it apparently acted as the
precipitant for the gold.

Although two periods of mineralization are noted, there does not
seem to have been any decided time-break between them and the depo-
sition was more or less progressive with a cooling of the mineralizing
solutions. It would thus be expected that in depth the minerals of the
first group would tend to become relatively more abundant than the
lower temperature group. Variations in dip and in width of vein are
noted and these seem to be due in part at least to the different layers of
sediment through which the veins pass.

The only factor so far shown to be associated with the location of the
ore-shoots is the occurrence of small fissures which join the main vein at
a small angle and which are themselves mineralized for a short distance
from the intersection; these fissures are observed to be quite numerous
near the more valuable shoots and were probably more or less concerned
in localizing the main ore-bodies.

Properties on Ninenule Mountain.

West Side.

AMERICAN BOY PROPERTY. General Statement. This property is
situated on the southwest slope of Ninemile mountain, about 6 miles from
New Hazelton, and is reached from that place by a good wagon road which