9

miles by way of the Nine Mile Mountain road to the lower end of the Silver
Cup Basin at elevation 3,400 feet. The mine workings are on the steep
southwest rim of the basin between elevations of 4,600 and 5,000 feet (See
Plate I). The mill, now dismantled, is below the basin in the timber at
an elevation of 3,000 feet.

The claims were staked in 1909 by Messrs. Harris and Trainer. Silver
Cup Mines, Limited, was organized, and in 1910 a 200-foot adit was driven
on the main vein at elevation 4,800 feet, a 90-foot adit at elevation 4,700
feet, and a 100-foot adit at elevation 4,575 feet. The latter is now the
main adit level. Two other adits were started in the slide rock, but never
got far enough to strike the vein and soon caved in. Two short adits were
also driven on the Duchess claim at elevations of 3,750 feet and 4,135 feet,
respectively. On the Duke claim to the west, an adit drift 150 feet in
length was driven, and other small veins farther up the ridge were pros-
pected by open-cuts and a 20-foot adit. In 1914 the mine was leased by
Clothier Brothers who shipped 23 tons of selected ore that year and 70
tons in 1915. Work was recommenced in 1925 by W.S. Harris and a little
further ore was shipped. In 1927, Duke Mining Company, Limited, built
a 3,200-foot aerial tram from the main mine level and started construction
of a 50-ton daily capacity mill employing Macintosh flotation cells.
Development work was pushed in 1928 and 256 tons of hand-sorted ore was
shipped during the year. The mill was completed and put into operation
in May 1929 by Silver Cup (Hazelton) Mining Company, Limited.
Difficulties were encountered in treating the ore, but finally a flow sheet
was worked out that recovered a single concentrate containing 92 per cent
of the silver, 90 per cent of the lead, and from 40 to 45 per cent of the
zinc content of the ore. The capacity of the mill was found to be in excess
of the productive power of the mine and it soon became evident that no
profit could be earned under the existing conditions. Mining operations
ceased in November and the mill shut down on December 7, 1929. Approxi-
mately 5,710 tons of ore were treated and 571 tons of concentrates were
made.

The Minister of Mines, British Columbia, report for 1929 gives the
average grade of concentrates shipped for the months of September and
October of that year as: silver, 126-40 ounces a ton; lead, 25-60 per cent;
zinc, 16-90 per cent; and for the month of November and part of December,
as: silver, 152-60 ounces a ton; lead, 27-60 per cent; zinc, 16-00 per cent.
As a check on the precious metals and antimony content of the concentrates
shipped, the writer collected two samples in 1937 from a small amount of
concentrates still remaining in the bins at the mill. These samples gave
an average assay as follows: gold, 0-013 ounce a ton; silver, 79-07 ounces
a ton; platinum, nil; lead, 21-56 per cent; zinc, 18-21 per cent; arsenic,
5°22 per cent; antimony, 6-16 per cent; sulphur, 19-81 per cent; bismuth
a trace; tin, none; cobalt, 0-06 per cent; copper (not tested).

The Silver Cup quartz vein is exposed on the precipitous rim of the
basin between elevations of 4,600 feet and 5,000 feet. It strikes north 30
degrees east and dips 75 degrees southeast. The vein occurs along a fault
marked by horizontal slickensides in bedded sediments.

The quartz gangue carries abundant sphalerite, galena, jamesonite,
tetrahedrite, and pyrite. In some places two or more parallel fractures