2025-06-30_PERMIT FILE - C1981019 ‎(5)‎

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 6/30/2025
• Doc Name: Volume 1 Rule 4
• Section_Exhibit Name: Rule 4 Performance Standards
• Media Type: D
• Archive: No

RULE 4 PERFORMANCE STANDARDS

Rule 4 Performance Standards 4-24 Revision Date: 4/9/25
Revision No.: MR-261
4.07 SEALING OF DRILLED HOLES AND UNDERGROUND OPENINGS

4.07.1 General Requirement

Each exploration hole, or other bore hole well or other exposed underground opening encountered
during surface mining, will be cased, sealed,. plugged, or otherwise managed to meet the
requirements of this Section and described more fully in Section 2.05.4.

Holes used for surface blasting will not be included under the requirements of this Section.

4.07.2 Temporary Sealing

Each exploration hole or other drill or bore hole described in this Section will be protected,
inspected and maintained according to this Section. This performance is described more fully in
Section 2.02 and 2.05.4 of this application.

4.07.3 Permanent Sealing

Drilled holes no longer needed for monitoring or other approved uses will be backfilled and sealed
as described in this Section. This performance is described more fully in Sections 2.02 and 2.05.4
of this application.

4.07.4 Abandonment in Designated Groundwater Basins

This subsection is not applicable to the Colowyo mining plan.

Exploration taking place inside and outside of the permit area will be handled through the Notice
of Intent (NOI) procedures. See the appropriate NOI for details for each program.

4.08 USE OF EXPLOSIVES

4.08.1 General Requirements

Colowyo will comply with all applicable State and Federal laws in the use of explosives.

Colowyo will conduct all blasts that use more than five pounds of explosives or blasting agent
according to the schedule required by Section 4.08.3.

All surface blasting operations at the Colowyo operation will be conducted by experienced,
certified, trained and competent persons who understand the hazards involved. Persons responsible
for blasting operations at a blasting site shall be familiar with the blasting plan and any site-specific
performance standards. The blaster and at least one other person must be present at the firing of a
blast. Each person responsible for blasting operations will possess a valid certification in
accordance with the appropriate federal and state law.