2023-01-05_PERMIT FILE - C1981019 ‎(13)‎

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 1/5/2023
• Section_Exhibit Name: Rule 4 Performance Standards -ST
• Media Type: D
• Archive: No

RULE 4 PERFORMANCE STANDARDS

South Taylor/Lower Wilson – Rule 4, Page 7 Revision Date: 11/23/21
Revision No.: TR-152

4.05.14 – 4.05.18 Various Topics

These sections are addressed in the Volume 1.

4.06 TOPSOIL

The topsoil removal, storage, and redistribution plan for the disturbed area associated with the Lower Wilson
and South Taylor mining areas will follow the procedures described in Section 4.06 in Volume 1and as
described in Section 2.05.3 (5) and 2.05.4 (2) (d) of this Volume (Volume 12)..

4.07 SEALING OF DRILLED HOLES AND UNDERGROUND OPENINGS

Drill holes and underground openings will be sealed in accordance with the procedures outlined in the Section
4.07 in Volume 1.

4.08 USE OF EXPLOSIVES

Explosives will be used for blasting in accordance with the procedures and specifications presented in
Volume 1, Section 4.08.. Map 26A presents distances to various structures of possible concern surrounding
the mining area. Only Section 4.08.2 has changed from Volume 1; see Sections 4.08.1 and 4.08.3 through
4.08.6, in Volume 1.

4.08.2 Pre-Blast Survey

In accordance with Rule 4.08.2(1), pre-blast surveys have been offered to owners of all structures within one-
half mile of the permit area. Pre-blast surveys were conducted on residential structures located at 6647 and
7072 Moffat County Road 51, various associated groundwater supply wells, and eleven power pole
foundations located along the ridge between Wilson and Taylor Creeks. Copies of the surveys are included in
Exhibit 14, Item 4.

4.09 DISPOSAL OF EXCESS SPOIL

Spoil removed from the South Taylor pit will be stockpiled as shown on Maps 45 and 20B. Colowyo expects
a 20% swell of excavated materials; therefore, part of the material stockpiled in the East and West Taylor Fills
will remain at the conclusion of the project as shown on Map 19. Placement will occur as described in
previous sections of this volume and in Volume 1.

Design of the two (East Taylor and West Taylor) fills associated with the South Taylor Mine plan are
provided in Exhibit 21. The East Taylor Fill will contain approximately 26.6 million yards of temporary out-
of-pit spoil and approximately 7.5 million yards of permanent out-of-pit spoil. The West Taylor Fill will
contain approximately 10.9 million yards of temporary out-of-pit spoil and approximately 22.6 million yards
of permanent out-of-pit spoil. Both fills will be regraded in accordance with the approved post mine
topography shown on Map 19. The final configuration of the fills is designed to minimize erosion. This
takes into account a number of the components of the other fill piles at the mine, which have proven
successful. The final outslope will not exceed 3h:1v.

Fill Name Temporary Volume Permanent Volume
East Taylor Fill 26,663,608 Cubic Yards 7,511,137 Cubic Yards
West Taylor Fill 10,993,667 Cubic Yards 22,609,016 Cubic Yards