, for
the purpose of lifting and discharging the "tailings," a waste from
the copper mines, into the lake. Its diameter is 54 feet; weight in
active operation, 200 tons. Its extreme dimensions are 54 feet in
diameter. Some idea of its enormous capacity can be formed from the
fact that it receives and elevates sufficient sand every twenty-four
hours to cover an acre of ground a foot deep. It is armed on its outer
edge with 432 teeth, 4.71 inches pitch and 18 inches face. The gear
segments, eighteen in number, are made of gun iron, and the teeth are
machine-cut, epicycloidal in form. It took two of the most perfect
machines in the world 100 days and nights to cut the teeth alone, and
the finish is as smooth as glass. The wheel is driven by a pinion of
gun iron containing 33 teeth of equal pitch and face and runs at a
speed of 6OO feet per minute at the inner edge, where it is equipped
with 448 steel buckets that lift the "tailings" as the machine
revolves and discharges them into launders that carry them into the
lake. The shaft of the wheel is of gun iron, and its journals are 22
inches in diameter by 3 feet 4 inches long. The shaft is made in three
sections and is 30 inches in diameter in the center. At a first glance
the great wheel looks like an exaggerated bicycle wheel, and it is
constructed much on the same principle, with straining rods that run
to centers cast on the outer sections of the shaft. The steel buckets
on either side of the gear are each 4 feet 5-1/2 inches long and 21
inches deep, and the combined lifting capacity of the 448, running at
a speed of 600 feet per minute, will be 3,000,000 gallons of water
and 2,000 tons of sand every twenty-four hours.
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