102

1 inclusions of . . . limestone occur in places in the porphyrite. The
croppings consist of a few magnetite lenses, the largest seen measuring
| about 100 feet in length. The magnetite contains some pyrite and small
; quantities of chalcopyrite, but is too low grade in copper to be considered
Wy Ea, Wes 5 se 6
The Good Hope fraction . . . . is situated on the south side
of Raven bay about 250 feet from the coast. . . . The country rock
HI is porphyrite cut by a few quartz diorite dykes. A magnetite lens 100
We feet in length and from 5 to 15 feet in width has formed apparently in the
porphyrite, but may replace a lime inclusion. The magnetite contains
some pyrite and a small percentage of chaleopyrite, but is freer from
| impurities than most of the lenses in the vicinity.”
Further details regarding the deposit on the Good Hope claim have
\} been given by Brewer! who states that it has been developed on four
levels. On the surface are two open-cuts each about 100 feet long and
AN separated by a vertical interval of 20 feet. Lower down, a short adit
| was driven into the hill-side to the magnetite body below an exposure
20 feet lower than the lower open-cut. From the end of the adit, the
ore has been stoped down over a length of about 100 feet. A fourth level
was being driven in 1923 at approximately 75 feet below the outcrops on
the surface. The magnetite body is stated to average about 11 feet in
width, with, in places, a considerably greater breadth.

VANCOUVER MINING DIVISION
(25) Iron King, Alta Lake

Source of Information. Camsell, C.: ‘‘Reconnaissance Along the Pacifie Great Eastern Railway
between Squamish and Lillooet’; Geol. Surv., Canada, Sum. Rept. 1917, pt. B, pp. 21-22.
Brewer, W. M.: ‘‘Ann. Rept., Minister of Mines, B.C., 1918, pp.-294-5.

GENERAL DESCRIPTION

Alta lake is on the Pacific Great Eastern railway about 35 miles north
of its terminus at Squamish. In the vicinity of the lake are deposits of
} limonite. The rocks of the country side consist of deformed sediments
and voleanics which form a wide band bordered by granitic rocks of the
Coast Range batholithic area. According to Camsell, ‘A group of about
twenty claims at one time covered an area at the north end of Alta lake
where deposits of bog iron occur on the western slopes of the valley. All
except four (controlled by Dr. Davidson and J. H. Thompson of Van-
couver) . . . . have now been abandoned. The principal exposure
occurs about half a mile west of the north end of Alta lake. Here on a
heavily wooded slope a large number of trenches have been dug. . . .
These trenches show the deposit to have a maximum thickness of about
10 feet, thinning out, however, on all sides. The area covered by the
deposit is about 60,000 square feet, having a length of 450 feet and a greatest
width of 250 feet. The top of the deposit is composed of loose, earthy
material, whereas the bottom is hard and shows stratification. It is
estimated that there are about 12,000 tons of ore in this deposit.
Other small areas of bog iron ore of similar character occur in the neigh-
bourhood, but their extent is unknown. The iron ore seems to be derived
from pyrite-bearing rocks which are exposed on the hill-sides above the

deposits”’.

1 Brewer, W. M.: Ann. Rept., Minister of Mines, B.C., 1923, p. 258.