12

The gangue minerals associated with these are hornblende, glassy
quartz, banded milky quartz, and small amounts of calcite, siderite, and
tourmaline. The hornblende greatly exceeds in amount all of the other
gangue minerals. Tourmaline was found in only one or two places and in
quite small amounts.

Two types of ore are found in this mine which differ markedly in
appearance and mineral composition, and which usually occur in different
parts of the mine, though in one or two places the two kinds were found in
contact. The more plentiful of the two types and that which produces the
bulk of the copper may be called the chaleopyrite-hornblende ore, for
these two minerals constitute fully 90 per cent of the vein material. The
chalcopyrite is usually in great excess over the hornblende, and conse-
quently this is an unusually rich copper ore. The other type consists of
large quantities of banded milky quartz with relatively small quantities
of zine blende, tetrahedrite, galena, and chalcopyrite. The silver content
is more valuable than the copper and this ore will, therefore, be referred
to as the silver-lead ore. It is largely confined to No. 2 vein and is best
developed in the 1202 drift to the west of the main tunnel.

Chalcopyrite-hornblende Ore. This ore contains, besides the chal-
copyrite and hornblende, a considerable amount of pyrrhotite, arsenopyrite,
pyrite, magnetite, tetrahedrite, and molybdenite. A fairly large amount
of quartz occurs in some of the ore-shoots, but it is distinguished from the
quartz of the silver-lead ore by having no banding, and by being clean and
glassy instead of milky. The tourmaline is very subordinate in amount
and may be considered only as a rare gangue mineral in this deposit. Cal-
cite and siderite are much more common. ‘The group of minerals as above
enumerated strongly suggests high temperature deposition.

The chalcopyrite presents nothing unusual in its appearance either
in hand specimen or under the microscope, and large masses of it seem to
be quite homogeneous; however, Mr. J. D. Galloway, of the British
Columbia Bureau of Mines, claims that analyses show it to vary consider-
ably from the theoretical composition CuFeS:. It is associated more
closely with hornblende than with any other mineral, and was frequently
seen replacing crystals of hornblende in a manner similar to that shown in
Plate IVA. On the other hand numerous places were observed in the
polished sections where fringes of actinolite followed the contacts of the
chalcopyrite, and feathered out in a manner which clearly shows it to have
been deposited later than the chalcopyrite. This is shown in Plate IVB
and it will be observed that this actinolite is also later than the pyrrhotite
and magnetite. The chaleopyrite was seen to have replaced magnetite,
pyrrhotite, pyrite, arsenopyrite, molybdenite, and quartz. It was found
to be replaced by molybdenite and, in the proximity of the silver-lead
ore, by arsenopyrite, tetrahedrite, and galena. Occasionally tetrahedrite is
veined by chalcopyrite (See Plate VA). The replacement by arsenopyrite
is shown in Plate VB. The chalcopyrite which forms a large shoot in vein
No. 2 is fractured and sheared, the cracks being filled with calcite, and in
the same specimen calcite was observed which was clearly replaced by
chalcopyrite.

Pyrrhotite was found in all the big chalcopyrite ore-shoots, but
seemed to be much more plentiful in vein No. 4 than in No. 2, though it
was observed in the latter in the 1002 stope. It occurs as irregular masses
in the chalcopyrite, and some evidence was found to show that it was