resulted in windrows of overburden material with water between the
windrows.
MATERIALS AND METHODS
Due to removal of the ore body during mining, sufficient
material did not exist in the area to achieve design elevations. Sand
tailings were, therefore, pumped between the overburden spoil piles
over a period of eight months to provide the backfill material necessary
to construct the planned elevations. The backfilling operation was
completed in February, 1981. Earthmoving began in March, 1981, with
bulldozers and scrapers to redistribute the sand tailings as planned.
Overburden was spread over the sand to provide a 30 centimeter thick
cap. As the earthmoving progressed, the excess water displaced by the
sand and overburden was pumped into the mine's water recirculation
system to maintain satisfactory operating conditions for the equipment.
The area was contoured so that all drainage is towards the
east. The levee along the east boundary of the site impounds drainage
from the 148 hectare watershed to form the wetland. Two swale outlets
were constructed in the levee to allow overflow of excess water from
the wetland into the flood plain of Payne Creek. The elevation in the
wetland along the base of the levee is 36 meters MSL. The elevation
rises gradually to an elevation of 36.8 meters MSL along the west
boundary of the wetland and less gradually on westward across the
upland portion of the project to an elevation of 40.8 meters MSL.
Permanent ponds were constructed within the wetland with
bottom elevations of approximately 32.9 meters MSL to maintain open
water areas year round. Two lakes were also constructed in the uplands


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