43

may be intrusive rocks not exposed at the surface and if so the source
probably was deeper-seated parts of the felsitic rocks in which the deposits
occur, thus accounting for the fact that this type of deposit is confined to the
felsites and does not occur in the neighbouring argillites nor in the rocks
of the Copper Belt. ha

Before the drop in price of silver, deposits of the silver-barite-jasper
type were the most promising deposits of the area. Some are as wide as 75
feet and contain about 15 ounces of silver a ton. Most are smaller than
this yet promise considerable tonnages.

SILVER-LEAD DEPOSITS

The silver-lead deposits occur in the eastern part of Alice Arm district
in Illiance River valley. Although the deposits are mainly of the silver-lead
type some are of mixed sulphide, and one consists chiefly of tetrahedrite.
Most of the silver-lead deposits also contain tetrahedrite and it is this
mineral that contains most of the silver. The deposits occur as gashes and
lenticular veins in sheared and altered tuffs and breccias. The shearing
is confined to a zone some 1,000 feet wide along the bottom of the upper
part of [lliance River valley. The surrounding rocks are unsheared. In
the shear zone the rocks have been extensively altered, chiefly to sericite
and pyrite, and are now soft, white, and fissile. Alteration and shearing
have been so extensive that it is difficult to distinguish different rock types.
The deposits in general contain very little gangue but what is present is
quartz. The deposits are as a rule less than 3 feet wide but many are
several hundred feet long. The ore is in most cases quite fine grained.

The source from which the deposits came is not evident. The mineral-
ization appears to be allied to that of the quartz-sulphide type near the
head of Alice arm rather than to any of the other types in the area and
it is assumed that the source is underlying parts of the Coast Range
intrusives.

When the price of silver was high attempts were made to mine silver-
lead ore in upper Illiance River valley, but these attempts were unprofit-
able. The known ore occurrences either outcropped or lay very close to
the surface and very little development work was done. The sheared area
is well defined. The deposits are restricted to it and lie parallel to the shear
planes. With this knowledge search for further deposits becomes simple,
and development can be planned to the best advantage. If the price of
silver again rises, it can be expected that the area will afford small
tonnages of high-grade ore.

Anyox District

The mineral deposits of Anyox district and of the area between Anyox
and Portland canal are grouped into two types: (1) chalcopyrite replace-
ment deposits; (2) quartz veins.

CHALCOPYRITE REPLACEMENT DEPOSITS

Several deposits of this type occur and lie either in the Anyox
amphibolite or at the contact between the amphibolite and the adjacent
argillites. The Anyox amphibolite and closely allied rocks occupy most