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Liner system being installed on slope
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The Gilt Edge Gold Mine is located southeast of Deadwood,
South Dakota, in the Black Hills. The Ruby Gulch Project is
the closure of a waste rock repository. Comanco
Environmental Corporation was contracted to design and
construct the liner cap system. The U.S. Bureau of
Reclamation managed the project.
A series of ten slopes of varying size and shape provide
for water run-off control and slope stability. The slopes
and sediment basin are lined with a new and unique Super
Grip Drain Liner geotextile. The liner presented some
unusual challenges for installation. |
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Engineers described it as “having a
pattern of knobs on the upper surface to provide for
drainage, and a pattern of sharp spikes on the lower surface
to provide for higher friction angles.” They could not use
standard “pull in place” deployment techniques due to
the spikes on the back side of the material unraveling the
finished surface of the subgrade. Slip sheets and “roll
out in place” methods with special deployment equipment
were used to place the geotextile material.
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Field workers fit the liner cap system
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Aerial view of the Black Hills site
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New methods and techniques for welding the
knob-to-knob edges and seams had to be developed. The
research and development department developed new welding
methods and modified equipment to make the butt-seam and
patch-welding possible in the field. Another challenge for
the slope liner was to match the actual slope length to
manufactured panel lengths. An Auto-CAD program was used to
design panel lengths for each panel on the slopes. Field
crews reported a near perfect fit for the panels.
The Comanco crew covered the entire lined
area with the 227 g geotextile. Another contractor placed
the crushed rock. The slope area of the project was fitted
with an electronic leak detection location system for the
entire area. After testing, zero leakage was detected. |
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From an article in “Mining Environmental Management”
magazine, photos from Comanco Environmental Corp. |
