8.3.2 Rough Grade Backfill
Rough grading will be required for the random fill and rock material. Rough grading is based on
Appendix E of WDEQ/LQD Guideline 12. The equipment selected is D9T Dozer. The surface is
assumed to be flat. A maximum pushing distance of 50 ft. was assumed.
8.3.3 Fine Grade Backfill
Topsoil will require fine grading to spread the material properly. Fine grading is based on
Appendix G of WDEQ/LQD Guideline 12. The equipment selected is a caterpillar 16M Motor
Grader.
8.3.4 Native Topsoil Removal
The removal of topsoil will be completed as part of operations and site construction. There is no
closure cost associated with the removal of topsoil. Topsoil redistribution costs are discussed
below.
8.3.5 Native Overburden Removal
The removal of overburden will be completed as part of operations and site construction. There
is no closure cost associated with the removal of overburden.
8.3.6 Overburden Redistribution
Closure activities associated with overburden redistribution are discussed in Section 8.3.1.
8.3.7 Demolition and Disposal
Demolition unit rates were calculated using WDEQ/LQD Guideline 12. Items to be demolished
include the plant site buildings and equipment, fences, power line from the substation to the
plant, gas line tie-in, and transformers.
Fence removal is based on Appendix H of WDEQ/LQD Guideline 12.
Disposal of hazardous waste is based on a vendor quote from the Deer Trail Landfill Facility in
Deer Trail, Colorado. Items to be disposed of at the hazardous waste facility include Underdrain
Pond sludge, spills from the plant site, and the transformers.
8.3.8 Removal of Monitoring Structures
Removal unit rates of monitoring structures are calculated using WDEQ/LQD Guideline 12.
Monitoring stations to be removed include both groundwater wells and surface water sites (if
there are structures built at the sampling locations).
Groundwater well removal unit rates are calculated using Appendix L of WDEQ/LQD Guideline
12. The monitoring wells are first located and the top few feet of casing is removed using a
backhoe and cutting torch. The wells are then sealed using a high-solids bentonite grout.
8.3.9 Ripping or Scarification
Ripping activities are based on WDEQ/LQD Guideline 12. Areas to be ripped include the roads,
plant site, and the TSF embankment slope. The selected equipment is a Caterpillar D10T with
single shank ripper.
8.3.10 Topsoil Redistribution
The topsoil material excavation, loading and hauling is based on Appendix C of the LQD closure
guideline. The equipment selected is a fleet of scrapers. The average grade is level ground over
a distance of 4,000 ft.
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