2023-06-29_PERMIT FILE - C1981019A ‎(2)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 6/29/2023
• Doc Name: Volume 1 Rule 4
• Section_Exhibit Name: 4.01 Through 4.30
• Media Type: D
• Archive: Yes

RULE 3 PERFORMANCE BOND REQUIREMENTS

Rule 4 Performance Standards 4-54 Revision Date: 6/13/23
Revision No.: MR-247
4.22 CONCURRENT SURFACE AND UNDERGROUND MINING

Colowyo does not currently plan to have concurrent surface or underground mining activities;
therefore, the requirements of this Section are not applicable to this permit application.

4.23 AUGER AND HIGHWALL MINING

4.23.1 Scope

This Section establishes environmental protection performance standards in addition to those
applicable performance standards in Rule 4, to prevent any unnecessary loss of coal reserves and
to prevent adverse environmental effects from auger mining incident to surface mining activities.

4.23.3 Performance Standards

4.23.4 Maximize Recoverability of Mineral Reserves

Colowyo maximize recoverability of the mineral resources through highwall mining in the East,
West, and Section 16 Pits. Please see Map 23 for the historically mined areas. Also please see
Section 4.23.2 in Volume 12 and 15 for additional information pertaining to the South Taylor and
Collom Pit.

4.23.5 Undisturbed Areas of Coal Shall Be Left in Unmined Sections

As for the CDRMS Rules (Rules) requirement for leaving undisturbed areas of coal in unmined
sections, Colowyo contends that this application of the Rules does not apply since the seams to be
highwall mined are being accessed from active surface pits that by this Permit and other applicable
sections of the Rules are required to be backfilled and fully reclaimed. Hence should undisturbed
barrier areas of coal be left for some future access, these potential portal areas would be
inaccessible for future generations because they would be buried under the pit backfill.
Additionally and importantly, as discussed above, due to the many geological reasons, there is not
economical coal to be recovered from “behind” the areas slated to be highwall mined.

4.23.6 Abandoned or Active Underground Mine Workings

To Colowyo’s knowledge, no abandoned or active underground mine workings have ever existed
or currently exist in any of the coal seams in the areas proposed to be highwall mined. No highwall
mining will be allowed to take place within 500 feet of any abandoned or active underground
mining operation.

4.23.7 Surface Mining Activities and Highwall Mining

The highwall mining shall follow the surface coal mining activities in a contemporaneous manner
consistent with the applicable requirements of CDRMS Rule 4. Due to active pit progressions and
sequencing of mining (in addition to meeting the Permit requirements for contemporaneous
reclamation), it is required that highwall mining occurs timely if not immediately following