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Mines - Molly B
The Molly B
Crown-granted claim (Lot 4498) is on the east side of
the Bear River directly
in line with the main street and opposite
the airport. It was staked by D. J. Rainey, of Stewart, who first sampled the mineralization in 1915.
In 1917 the Molly B group was
worked by the owners, J. W. Stewart and associates, who opened several cuts
and
prepared a tunnel site. The tunnel was continued in 1918 and molybdenite
samples
were shipped for assay. As part of the group encompassed about a quarter
of
the Skamakounst Indian Reserve 19, negotiations with the band chief were necessary.
In 1937 the area
was prospected in conjunction with surface work on the
adjoining Oral M group by the Premier Gold Mining Co. Ltd. In 1942, J.
Haahti, of Stewart, sent three samples of tungsten-molybdenite mineralization
from
the main adit vein to the Prince Rupert sampling plant, and in 1946 Stewart
Canal
Gold Mines Ltd. extended the adit and sampled the mineralization.
No further work on the property has been reported, but Haahti is known
to have continued driving
the adit. A sketch of the main adit on the east bank of the Bear River at
elevation
30 feet is shown on Figure 32. The geology and other pertinent sample information which was included in Bulletin 10 (revised), pp. 54-56, as
reported by
W. H. Mathews, has been quoted in the following:-
The workings consist of four
open-cuts and one short adit on the steep hillside above
the Bear River. The lowermost open-cut, at elevation 10 feet, has been driven south-easterly for 10 feet, the adit, at elevation 30 feet and 12 feet
easterly from the last open-cut, has been driven south-easterly for 10 feet. An upper open-cut,
at elevation 50 feet and 40 feet easterly from the lower open-cut, has been
driven easterly 6
feet, another open-cut, at elevation 90 feet and 60 feet easterly from the middle one,
has been driven easterly for 6 feet.
The uppermost open-cut, at
elevation 105 feet and 12 feet easterly from the last, has been driven easterly for
5
feet. They have all been driven on the same mineralized bed.
The scheelite and molybdenite
are found in a band of lime-silicate rock formed by
high-temperature replacement of a bed of limestone. This bed, which
strikes south
60 degrees east and dips from 65 to 75 degrees southwestward, is 8 feet
in width
in the lowest open-cut, but decreases gradually to a thickness of 2 feet
up the hill,
then, where next exposed, in the open-cut at elevation 50 feet, it is 4
feet in thickness, and
finally, in the uppermost open-cut at elevation 105 feet, it abruptly narrows from 4
feet to less than an inch. The bed can be traced for only
a few feet beyond this cut.
The rock, originally an impure limestone, has been metamorphosed to a
mixture of diopside, garnet, and epidote. Calcite, which may or may
not be part of the original limestone, is found in places. This bed, evidently
favourable
for replacement, has been mineralized with scheelite, moiybdenite, and pyrite.
The adjacent beds, both above and below the mineralized bed, consist of hard, relatively thin-bedded tuff or impure quartzite, often containing
significant amounts
of lime-silicate minerals, but no excess caicite, and probably for this
reason they were unfavourable for mineralization.
The grade of the molybdenite and
scheelite is not high. A 360-pound shipment sent to the Government Sampling Plant at Prince Rupert of hand-sorted
material taken from the lowest open-cut assayed: Molybdenum, 4.2 per cent, and
tungstic oxide (WO3), 1.5 per cent. Impurities included:-
Per Cent Per Cent
Iron --------------- 11.0 Copper
--------------------- Trace
Sulphur ---------- 3.5
Arsenic --------------------- Trace
Silica ------------ - 40.4
Manganese ---------------0.9
Zinc ---------------- 0.4 Tin
------------------------------Trace
Phosphorus ---- 0.24
Antimony --------------------Nit
Lead -------------- Trace
Bismuth --------------------Nil
A channel sample, taken across
the face of the adit, a length of 5V2 feet, assayed:
Tungstic oxide (WO3), 0.37 per cent; molybdenum (Mo), 0.17 per cent.
A second channel, taken across 4
feet on the cut 90 feet above the river level, assayed:
Tungstic oxide (WO3), 0.22 per cent; molybdenum (Mo), 0.02 per
cent.
A 148-pound sample blasted from
the lowest cut and from the face of the adit assayed:
Tungstic oxide (WO3), 0.15 per cent; molybdenum (Mo), 0.2 per
cent.
Examination with an ultra-violet
lamp shows that scheelite is present throughout the
exposures, with somewhat lower grade in the constricted parts of the bed
than elsewhere.
Occasionally high-grade streaks or patches of scheelite-bearing material
are found, but these are not sufficiently large to form shipping ore.
Elsewhere scheelite
is too fine-grained or too uniformly distributed to permit any appreciable
concentration
by hand-sorting. It is doubtful whether the molybdenite shows the same
uniformity of grade throughout the deposit as does the scheelite; in general,
it
appears to be concentrated in the lower exposures.
The mineralization, consisting
of quartz-sulphide vein breccia and scattered tactite,
is confined to a narrow, northwesterly trending shear zone opposite Stewart.
Sulphides recognized in the narrow lenses include pyrite, pyrrhotite,
chalcopyrite, sphalerite, and molybdenite. These are also found as disseminations in
cataclastic rocks near joint planes.
Scheelite appears to be confined to lenses
of tactite which are composed of epidote and garnet and are best exposed in
the
open cuts.
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