CHAPTER IV.—ECONOMIC GEOLOGY.
QUARTZ VEINS.

GENERAL CHARACTERISTICS OF THE VEINS.

In the Stanley area, as in many other parts of the belt occupied by the Cariboo
series, quartz veins are of fairly frequent occurrence. For the most part, the veins are
short and narrow, their average width being less than 12 inches.

In the Barkerville area it has been shown that quartz veins fall into two groups.
“A” veins are those that are parallel to the strike of the rocks. They include forma-
tional veins, those that are parallel to the dip, and strike-fault veins that cut across the
dip of the rocks. ‘B” veins include all veins that cut across the strike of the rocks.
Most “ B ” veins there are either north-easterly trending, called transverse or horsetail
veins, or easterly trending, called diagonal veins.

Quartz veins in the Stanley area fall into the two major groups, but the “B” veins
do not have the same directional groupings represented by the transverse and diagonal
veins of the Barkerville Gold Belt.

“A”’ Veins.

Formational quartz veins are of common occurrence. Most of them are only a few
inches in width or at the most about 2 feet; they are characteristically lensy and only
a few tens of feet long. The quartz frequently contains ankerite or siderite as a narrow
selvage along the walls and rarely is seen to contain pyrite or any other sulphide
mineral. No formational veins carrying gold values are known in the area. Commonly,
the formational vein quartz is fractured and consequently may be older than the quartz
of the “B” veins.

No strike-fault ‘A’ veins were seen.

“B” Veins.

The prominent regional fracturing of the area strikes north 10 to 30 degrees east
and dips steeply to the west. In many places fractures of this system are occupied by
vein-quartz. These quartz veins are the most frequently observed of the “B” veins.
The veins may be but a fraction of an inch in width and serve only to silicify the
adjoining rock or may be a few inches to several feet in width and be sufficiently well
mineralized to induce exploration and some development. Veins of this type include the
Perkins veins on Burns Mountain, the Foster Ledges and other veins on Oregon Gulch,
the veins on the Acme group north of Stanley, and numerous others.

The widest veins of this type are those exposed near the summit of Burns Mountain
on Lots 62 and 63, where maximum widths of 4 to 5 feet are reached. Most of the
veins are less than 2 feet in width, and many of them range from 1 to 6 inches in
width. The vein-quartz generally is unfractured, though this is not universally true.
The quartz may be mineralized with ankerite, which generally appears as a narrow
selvage along the walls, with pyrite either as sparsely disseminated grains or small
irregular masses, and with galena, sphalerite, and free gold. Not all veins contain
sulphide mineralization, and the mineralization where present is generally sparse. Of
the many veins sampled, assays of more than a few hundredths of an ounce of gold per
ton were obtained mainly from “ B” veins of this type.

A group of westerly striking veins on the Acme group and a group of north-easterly
striking veins on Burns Mountain are associated in both places with north-north-
easterly trending “B” veins. These are the only two sets of vein fractures that might
correspond to the transverse and diagonal veins of the Barkerville Gold Belt.

Other “B” veins, with attitudes different from those of the regional type, are to
be seen at the north-east corner of Lot 1684c, in the Ketch pit, in Spruce Canyon, in
the Cariboo Ledge workings, and elsewhere. These veins show no regularity of strike

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