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section on the other side called the "duct end". The tap end of
the cell room is an area where molten metal is tapped, excess
bath and wasted anodes are placed after removal from the cells,
and front-end loading machines operate. The tap ends vary in
size from 7,000 to 8,500 square feet.
Originally, each cell room had a concrete subfloor
strengthened with iron rebar overlaid with bricks. The brick
layer acted as insulation to prevent electrocution by contact
with the rebar in the subfloor. ALCOA used this type of floor
for over 40 years and employed a full-time brick replacement crew
to maintain the integrity of the brick insulation.
However, in part because of the introduction of mechanical
equipment and in part because of direct contact with wasted
anodes and with molten aluminum and bath, the brick layer became
so worn that it was hazardous. In some places the brick layer
was worn down to expose the concrete and rebar subfloor, which
created a risk of electrocution. Furthermore, the surface of the
floor was very irregular because of the replacement of many
bricks over many years. As a result of the uneven surface,
Vanalco reported 21 accidents due to falls in the first half of
1992.
Vanalco repaired the floor by replacing bricks and also
tried patching areas with Portland cement. Portland cement did
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Last modified: May 25, 2011