PERMFILE60967

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 3/22/2006
• Section_Exhibit Name: 2.05 Operations and Reclamation Plans
• Media Type: D
• Archive: Yes

Overburden Monitorin¢ Pro rg am
Historically, beginning around 1983, Colowyo initiated overburden monitoring in both the pit
(truck/shovel materials) and on regraded overburden. See CDMG Permit Exhibit 6, Item 4 as
described in the associated January 4, 1983 Colowyo memo to Dan Mathews, CDMG, for an
overview of this initial program. Starting in 1990, Colowyo eliminated the in-pit sampling
program. Sufficient data had been collected to indicate that all weathered overburden
material (ie. within ~ 50 feet of the ground surface) was suitable for replacement onto the
reclaimed surface prior to topsoil replacement. Three revisions were submitted to the
Division and approved on January 24, 1983, August 17, 1983, and April 24, 1990
respectively. The following summarizes the requirements of the current regraded overburden
(backfill) sampling program and supersedes all previous commitments. It is based on the
following limitations of the earlier program.
1. placing weathered overburden material onto reclamation areas prior to final regarding,
and
2. sampling regraded overburden at a density of one composite surface sample per 5 acres
of regraded spoil.
The regrading of overburden is an event that takes place sporadically during the year. Once
backfill areas are regraded, but prior to topsoil replacement, the new locations are identified
and sampled. Alife-of--mine sampling grid has been established on 500-feet centers, and
each sample location on the grid corresponds to a letter/number combination as established
on the sampling map. Using this grid interval, each sample location represents an area of
about 5.7 acres in size. A hand shovel is used to take small, representative surface samples of
spoil across the sample area.
Regraded Overburden Suspect Levels:
Parameter Sus ect Level
H Less than 5 or reater than 9 standard units
Electrical Conductive Greater than 12 millimhos/cm
Sodium Adso lion Ratio Greater than 15
Selenium if His reater than 8.4 Greater than 0.8 m
Boron if His reater than 8.4 Greater than 5 m
Lead (if His reater than 10) Greater than 20 m
The laboratory results aze kept at the mine site. Results of the sampling program are
provided in the appropriate Annual Reclamation Report and are periodically checked during
CDMG quarterly complete inspections.
If the results of the sampling indicate that one more of the parameter suspect levels is
reached, the Division will be contacted. At that point, Colowyo will resample the area to
determine the extent of the toxic material. if the problem area is greater than one acre in size,
it will be necessary to cover the area with at least five feet of acceptable material before the
application of topsoil.
2.05-8 Revision Date: 12/15/05
Revision No.: MR-76