2016-11-23_PERMIT FILE - C1981008A ‎(2)‎

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 11/23/2016
• Doc Name: Backfilling and Grading
• Section_Exhibit Name: Section 2.05.4‎(2)‎‎(c)‎ Backfilling and Grading
• Media Type: D
• Archive: Yes

The lands owned by WFC -Lloyd, WFC -Benson West, and Morgan will all be returned to
approximate contour, with a similar drainage pattern to the pre -mine conditions. In areas of
minor topographic change, the land has been improved by having a more consistent slope over
broad areas, which will facilitate irrigation of fields.
The WFC -Johnson parcel has a modified topography with the following properties (determined
using Carlson CAD software):
Table 2.05.4(2)(c)-1: WFC Property Topography Properties
The new surface drainage patterns for the WFC property are shown on Map 2.05.3(3)-1-2.
The backfilling sequence for west of 27.00 Road is shown on both Map 2.05.3(4)-1-2 and
Attachment 2.05.4(2)(c)-7. The mining cuts from Attachment 2.05.4(2)(c)-7 correlate to the
numbered cuts on Map 2.05.3(4)-l-2.
The backfilling sequence has been designed to minimize the need for stockpiling of overburden
and material re -handling. For most of the mine sequence this is done with cast blasting of the
initial overburden into the previously mined out open cut. The remaining overburden material is
then hauled from the new mining cut into the mined out cut. In most cases this leads to each cut
backfilling the one that precedes it (ex: Cut -92 material backfills Cut -91). However, as the shape
of the mining area changes (Cut -94 and Cut -95), not enough material is generated from new
excavation to backfill the previous cut.
In order to mitigate this problem, and ensure that post -mine topography is achieved, two things
are done. Firstly, the mining cut that needs more backfill than the next cut can generate will
remain "open" until enough material is generated by mining to successfully backfill. Secondly,
backfill will be hauled from a variety of cuts ahead of the "open" cut and used to fill the "open"
cut. The source cuts for backfill material can be seen in the Backfill Source column of
Attachment 2.05.4(2)(c)-7.
Revised January 2016 (TR -70) 2.05.4(2)(c)-3
Pre -Mine Topography
Post -Mine Topography
Average Elevation
5,624'
5,610'
Maximum Elevation
5,673'
5,660'
Minimum Elevation
5,550'
5,560'
Average Land Slope
2.7%
4.0%
Steepest Slope
37.7%
38.5%
The new surface drainage patterns for the WFC property are shown on Map 2.05.3(3)-1-2.
The backfilling sequence for west of 27.00 Road is shown on both Map 2.05.3(4)-1-2 and
Attachment 2.05.4(2)(c)-7. The mining cuts from Attachment 2.05.4(2)(c)-7 correlate to the
numbered cuts on Map 2.05.3(4)-l-2.
The backfilling sequence has been designed to minimize the need for stockpiling of overburden
and material re -handling. For most of the mine sequence this is done with cast blasting of the
initial overburden into the previously mined out open cut. The remaining overburden material is
then hauled from the new mining cut into the mined out cut. In most cases this leads to each cut
backfilling the one that precedes it (ex: Cut -92 material backfills Cut -91). However, as the shape
of the mining area changes (Cut -94 and Cut -95), not enough material is generated from new
excavation to backfill the previous cut.
In order to mitigate this problem, and ensure that post -mine topography is achieved, two things
are done. Firstly, the mining cut that needs more backfill than the next cut can generate will
remain "open" until enough material is generated by mining to successfully backfill. Secondly,
backfill will be hauled from a variety of cuts ahead of the "open" cut and used to fill the "open"
cut. The source cuts for backfill material can be seen in the Backfill Source column of
Attachment 2.05.4(2)(c)-7.
Revised January 2016 (TR -70) 2.05.4(2)(c)-3