Sa eee

REPORT OF THE MINISTER OF MINES, 1929.

The weather was too rough to make the trip outside to Collison bay, but the following
information was given to me by the Mining Recorder :—

No work has been done on the Thunder group at Collison bay recently; refer to the report
by Geo, A. Clothier in the 1918 Annual Report.

The Violet claim joins the Thunder group on the north-east and is owned by I. Thompson,
Jedway. The property has a yein-dyke of diabase slightly amygdaloidal, carrying copper in
small stringers and bunches. A crosscut tunnel 25 feet below the showing cuts it, giving a width
to the vein of 714 feet, averaging 2% per cent. copper as chalcopyrite and showing a lime
hanging-wall and a diorite foot-wall. ‘The vein has been stripped for 200 feet. There is another
vein of quartz farther up the hill, carrying 214 per cent. copper as bornite; little work has been
done on this.

BLack-SAND DEposits oF GRAHAM ISLAND.

The Queen Charlotte group of islands lies in the Pacific ocean, the southern point being 140
miles north-west of Vancouver island and the north-eastern point is 60 miles west of Prince
Rupert. Graham is the largest northerly island and Moresby, the southern. The east and north
shore of Graham island is low-lying and has beaches which extend for miles. The western shore
is bold, with few beaches, and the southern islands are practically devoid of the low-level shores
seen on Graham island.

Numerous reports have been received by the Department of Mines of gold- and platinum-
bearing black sands on Queen Charlotte islands, and recently a machine was mentioned as
haying been more successful in the recovery of the precious metals than some of the former
appliances. I started my examination of these deposits with a considerable amount of scepticism
as to a favourable report, as I had previously been over the black sands of Vancouver island
and had investigated a number of black-sand gold-saving machines. The machines were often in
the hands of persons who had only a yague knowledge of what the machines were supposed to do
and were occasionally mere toys; in other cases they were no doubt designed to extract gold
from an unsophisticated public.

When I investigated the Graham Island deposits I was forced to change my views both as
to.the deposits and the machine used for saving the gold. The black-sand deposits are much
more extensive than any I have seen on Vancouver island. It is probable that they cover all
that part of Graham island on which glacial drift has been deposited to any extent; this
approximates an area of 800 square miles.

It is unlikely that all this area will contain black sands that will pay to work, but there may
be places where the sands might be so concentrated that they will pay, depending on the size of
the undertaking and the area of sands that will be remunerative for such undertaking. There
are places where the sands have been so concentrated by present-day streams that they haye paid
fairly good wages with a line of sluice-boxes and the most primitive method of moving the sand
with shovels. Such areas are of limited extent and number. There are other less concentrated
areas, but of much greater extent, which would probably support a larger undertaking in which
the gravel would be entirely handled by mechanical power; this will be referred to later. The
black sands carry both gold and the platinum group of metals. This has been proved by many
assays made on samples from widely separated districts.

The origin of this gold and platinum is still a matter for speculation; it has been suggested
that it came from quartz veins that existed on Graham island and that had been eroded. It
seems, however, much more likely that the precious metals were carried by glaciers from
farther north and deposited with glacial drift which forms the major portion of the eastern
side of Graham island. South-eastern Alaska is known to contain many quartz veins carrying
values in both platinum and gold, and it is more than likely that these were eroded by gl
action and millions of tons carried down and deposited on Graham island and the
coast.

acial
surrounding

It is probable that these black sands have become concentrated by three different methods.
First, by the action of glacial rivers when the sands were first laid down: the tendency of these
rivers would be for a moderate concentration over a considerable aren. Secondly, by wave-
action; there is evidence that this has extended for a considerable distance beyond the present
shore-line, probably by the elevation of the shore above the present high-water level. his is
evidenced in test-pits which haye been sunk 100 feet or more back from the beach at Masset
inlet. The level of the ground where these pits-have been dug is 15 to 20 feet above present