2021-08-09_PERMIT FILE - C1981019A ‎(5)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 8/9/2021
• Doc Name: Volume 1 Rule 4
• Section_Exhibit Name: 4.01 Through 4.30
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS

Rule 4 Performance Standards 4-34 Revision Date: 7/20/21
Revision No.: MR-235
In 2021, approximately 641 acres within Colowyo’s permit boundary, directly adajencet to the east
side of the Collom Pit, was affected by a wild land fire. The location of the wild land fire is shown
on Figure 4.12-8. The area that was burned is mostly comprised of sagebrush. Additional surface
disturbance within the permit boundary of approximately five acres was created to cut in a fire
lines to control and fight the fire. The relatively low intensity nature of the fire does not appear to
warrant or require supplemental seeding; however, the areas impacted by the fire lines will be
roughened, seeded with the approved reclamation seed mix, and reported in the annual reclamation
report.

4.13 CONTEMPORANEOUS RECLAMATION

All reclamation actives, including but not limited to backfilling, grading, topsoil, replacement and
revegetation, will be carried out as contemporaneously as practicable with mining operations.
Implementation of the reclamation plan, as described in Section 2.05.4, will assure that each step
in the reclamation process is completed in a timely manner.

Because of the multi-seam nature of the mining operation described in Section 2.05, backfilling
and grading cannot be completed within 180 days following the coal removal. Backfilling and
grading will be completed in variance of the 180 day requirement in a manner previously approved
and described below, and in Sections 2.05 and 4.14.1. A series of benches will be necessary in the
operation to recover the lower coal seams, and an additional series of benches will be necessary to
dump the shovel/truck overburden material in a configuration that achieves the topography shown
on the post-mining Topography Map (Map 19). When multi-seams are mined, backfilling and
rough grading cannot begin until the lower-most seam is mined. See Spoil Grading Map (Map
29), which shows the time frames in which grading will occur.

Topsoil will be removed prior to the mining disturbance according to the timetable established on
the Topsoil Handling – South Map (Map 28). As can be observed from this map, the initial topsoil
removed at the operation must be stockpiled; however, as the operation progresses, topsoil can be
immediately redistributed rather than stockpiled.

Revegetation will commence as soon as the topsoil has been redistributed and prepared for seeding
as described in Section 2.05.4. The area will be seeded with the seed mixture described in Section
2.05.4 as quickly as possible.

4.14 BACKFILLING AND GRADING

4.14.1 General Requirements

The mining operations of Colowyo will not employ the use of contour mining methods.

The following sample of calculations show that Colowyo does not have thin or thick overburden
as defined in Subsection 4.14.4 or Subsection 4.14.5. These calculations represent the approximate
conditions found in the field and show that there is always more than enough overburden to
reestablish the original elevation. As explained in the 1983 Annual Report, Colowyo currently
uses an average 20% swell factor for planning purposes. Dragline swell is estimated to be 23%,
and truck/shovel swell is estimated to be 17%. Approximately 45% of the overburden is removed