some of them containing abundant native silver, occur in a
steep, fractured, and sheared zone in massive granodiorite.
The ore contained a little pitchblende. About 10,080
tons of ore were milled and 348,250 ounces of silver and
6,933 pounds of pitchblende were recovered. When
Operations ceased, only a small amount of known ore was
left in the mine. During 1945, the property was diamond
drilled by International Uranium Co., Ltd., and results
were reported to be promising.

In 1935, gold-was discovered by a Geological Survey
party along the west shore of Yellowknife Bay, and, as a
result, many claims were staked in the immediate vicinity.
It was at this time that the property of Giant Yellowknife
Gold Mines Ltd. was staked. The year 1936 saw a
great influx of prospectors into the area: during 1937 and
1938, many exploration syndicates, financed in Eastern
Canada, entered the field, and prospecting activities spread
far and wide. During 1938 and 1939, three mines—the
Con, Rycon, and Negus—were brought into production,
and these were followed in 1941 by Thompson-Lundmark
and Ptarmigan. Interest in the Yellowknife area waned
during the early years of the war, but revived in 1943
following spectacular results of diamond drilling on the
property of Giant Yellowknife Gold Mines, Ltd.

Most of the known gold-bearing quartz deposits of
the Yellowknife area occur within early Precambrian
volcanic and sedimentary rocks. The quartz veins contain
a great variety of metallic minerals, of which pyrite is the
most plentiful, but these minerals are sparsely disseminated.
The area has at one time been subjected to great disturbance
and the rocks are broken by faults which strike north and

along which the rocks on the east side are displaced to the
north.

The Con and Rycon mines are on the west side of
Yellowknife Bay. The Con mine is owned by Consolidated
Mining and Smelting Company, which controls the adjoining
Rycon mine and operates both properties from one mining
and milling plant. Many faults and shear zones occur
on the properties and the main fault in the area, the West
Bay fault, lies in Yellowknife Bay about 4,000 feet east of
the Con shaft. The gold occurs in quartz and carbonate
shear zones that cross the strike of pillowed and massive
andesite lavas. Milling began in July 1938, and 286,251
tons of ore were treated for a recovery of $6,957,331 up to
August 1943, when production was suspended owing to a
shortage of labour. Milling operations were resumed on
August 20, 1946. Ore reserves in December 1944,
at the Con mine, were estimated at 251,970 tons of probable
ore averaging 0-52 ounce of gold per ton, and 92,500 tons
of indicated ore averaging 0-36 ounce of gold per ton.

Adjoining the Con and Rycon mines to the east is
the property of Negus Mines, Ltd. The gold-bearing
veins at Negus mine are tabular and lenticular quartz bodies
within shear zones in altered andesite, gabbro, and diabase.
The rock in the shear zones, which range up to 27 feet wide

3681—3

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a

and average about 5 feet, is a chlorite-carbonate schist.
The quartz in the shear zones varies from a few inches wide
up to 12 feet. Production began in February, 1939, and
was suspended in October, 1944, during which period
129,546 tons were milled for a recovery of $4,398,251.
Ore reserves in December, 1945, were estimated at 36,300
tons at 0-61 ounce of gold per ton, plus 11,000 tons of
possible ore averaging 0-57 ounce of gold per ton. Milling
was resumed on July 16, 1945.

The property of Thompson-Lundmark Gold Mines, Ltd.
is on Thompson Lake, about 30 miles east-northeast of
Yellowknife. The property is crossed by a number of
gold-bearing quartz veins, which in most cases are parallel
to the bedding of the quartz-biotite schists in which they
occur. The walls are, for the most part, sharp and not
sheared, and no greater fault displacement than two feet
has been’ observed. Mineralization is not widely dis-
seminated and consists of tourmaline, muscovite, biotite,
pyrite, arsenopyrite, pyrrhotite, chalcopyrite, galena, and
sphalerite. Milling started in August, 1941, and continued
until September, 1943, when Operations were suspended
due to a shortage in labour. Total gold production
from 73,215 tons of ore had a value of $1,765,000. Reserves
in December, 1942, were 57,894 tons, containing 0-44

ounce of gold per ton. During 1946, plans were made for
the resumption of Operations in 1947.

Ptarmigan Mines, Ltd. is situated about 4 miles east of
the head of Yellowknife Bay. Only one vein on the
property is known to contain ore shoots. The-width of
this vein down to 300 feet varies from 1 foot to 45 feet, and
averages about 12 feet. The wall rock is mostly quartz-
mica schist, and mineralization, which is sparse, includes
pytite, sphalerite, galena, arsenopyrite, chalcopyrite, pyr-
thotite, and tourmaline. A 125-ton mill Was operated
from November, 1941, to September, 1942, and treated a
total of 34,249 tons averaging 0-35 ounce of gold per ton.
Operations were suspended because of shortage of labour

and not exhaustion of ore reserves, on which there is no
teport available.

The International Tungsten Mines, Ltd. holds a
tungsten gold property on Outpost Island, Great Slave Lake,
55 miles southwest of Yellowknife. The property formerly
belonged to Slave Lake Gold Mines, Ltd. The ore occurs
in sheared and silicified zones of quartz-mica schist and
gneiss. Some of the sheared and fractured rock is cut by
quartz veinlets and is cemented and partly replaced by
quartz, chalcopyrite, and pyrite, with which are associated
small amounts of other iron and copper minerals and the
tungsten mineral ferberite. A 50-ton mill was operated
on the property from February, 1941, to July, 1942. Pro
duction in bullion and tungsten concentrate, which latter
amounted to 55 tons, was valued at $427,660. In 1943, the
property was optioned to Consolidated Mining and Smelting
Company, but results of work were not encouraging and
the option was dropped.

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