2014-07-31_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 7/31/2014
• Section_Exhibit Name: Rule 4 Performance Standards -ST
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
1. MW -95 -01 — Located in the Wilson Creek alluvium, this site represents the upstream,
undisturbed background conditions of the alluvial aquifer.
2. MW -05 -03 — Located in the Wilson Creek and unnamed drainage alluvium, this site represents
alluvial groundwater quality immediately downgradient from Lower Wilson.
3. MW -95 -02 — Located in the Wilson Creek alluvium, this site represents the downgradient
conditions below Lower Wilson and the proposed haul road.
It is reasonable to expect potential future monitoring activities for the Lower Wilson locations to mirror those
for the existing operation as it pertains to frequency and specific parameters.
Groundwater, Fill Piezometers - The Streeter Draw piezometer and the Section 16 Fill piezometer will be
monitored annually for water levels. The West Pit Fill piezometer will be monitored quarterly for water
levels. After mining, two additional piezometers will be installed into East Taylor Fill and West Taylor Fill
as described in Exhibit 21 Item 1. These piezometers will be added to the monitoring program.
4.05.14 — 4.05.18 Various Topics
These sections are addressed in the original permit and will not change with addition of the South
Taylor /Lower Wilson permit revision.
4.06 TOPSOIL
The topsoil removal, storage, and redistribution plan for the proposed disturbed area associated with the Lower
Wilson and South Taylor mining areas will follow the procedures described in Section 4.06 of the original permit
and as described in Section 2.05.3 (5) and 2.05.4 (2) (d) of this South Taylor /Lower Wilson Permit Revision
document.
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
previously- approved permit document.
4.08 USE OF EXPLOSIVES
Explosives will be used for blasting in accordance with the procedures and specifications presented in the
previously- approved permit document. Map 26A presents distances to various structures of possible concern
surrounding the mining area. Only Section 4.08.2 has changed from the original permit; see the original
permit for Sections 4.08.1 and 4.08.3 through 4.08.6.
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 in valley fill area as shown on Map 23A and Map
45. Colowyo expects a 20% swell of excavated materials; therefore, part of the material stockpiled in the East
South Taylor /Lower Wilson — Rule 4, Page 13 Revision Date: 10/31/13
Revision No.: MR -129