2009-07-30_REVISION - C1981008

• Permit No: C1981008
• IBM Index Class Name: Revision
• Doc Date: 7/30/2009
• Doc Name: DRMS Request for Permit Revision
• From: DRMS
• To: Western Fuels-Colorado
• Type & Sequence: PR6
• Email Name: MLT
• Media Type: D
• Archive: No

3. Narrative on permit pages 2.05.4(2}?d}-11 through the first half of page
2.05.42}?d}-13, regarding topsoil salvage procedures, appears to correspond to
the Findings Document. However, narrative on page 2.05.42}?d}-13 under
Topsoil Salvage Techniques--Year 2001 and Onward, diverges from the
procedures described in the Findings Document in many respects. This section
describes salvage of Lift "A" only, with this soil material to be spread on f nal
graded spoils, with a minimum goal of approximately one foot of laydown
thickness. Narrative later in this section states that topsoil redistribution will no
longer consist of phased campaigns as in the past, but will be an integral,
ongoing portion of the mining operation. The lift B material will consist of
suitable material selected from the upper bench and is essentially the same as the
uppermost four foot of regraded spoil as described in an earlier section.
Also, the version of Map 2.05.4-4 in the current permit document does not
indicate separate replacement thicknesses for the individual replacement blocks,
as described in the Findings Document. Rather, each of the blocks (A through D}
is designated to receive a 10 inch top lift and a 12 inch lower lift, for an average
soil replacement thickness of 22 inches for each block, regardless of the original
soil resource present in the block or the associated land management category.
For Block A, the proposed average replacement thickness would equate to
approximately % of the replacement thickness originally approved. The dominant
soil unit in this block is the 98E ?Darvey-Bari complex}, deep eolianlalluvial soils
that supported irrigated hayland prior to mining. Based on tables included on the
Soil Baseline Map Map 2.04.9-1 } as well as Table 2.05.4?2)?d)-3, on page
2.05.42}?d}-3 of the application, a total average salvage thickness of 4.4 feet was
projected for the 98E map unit (1.4 foat top lift and 3.0 foot lower lift}.
Replacement of a minimum 1 foot thickness of topsoil over blasted overburden
would almost certainly not be sufficient to restore premining agricultural
productivity levels within the irrigated hayland and irrigated pasture blocks where
deep soils predominated prior to mining Blocks "A" and "B"}. In the RN-4
Findings Document, the Division did determine that salvage of lower portions of
the "B" and "C" horizons, separate from the upper soil horizons, was necessary to
be replaced as subsoil in order to ensure soil productivity consistent with the
approved postmining land use, for those units occurring on irrigated hayland and
irrigated pastureland, pursuant to Rule 4.06.23}. Current permit application
narrative on page 2.05.42}?d}-13, under Topsoil Salvage Techniques, indicates
that only upper lift soil would be salvaged, and replaced directly on regraded
spoils. This conflicts with the determination made by the Division in the RN-4
Findings, that two lift salvage and replacement was necessary.
Two lift salvage and replacement is warranted for these thick agricultural soils, to
avoid dilution of the chemical, physical, and biological characteristics ofthe
upper sub-horizons, which contribute to the productivity of the native soils. The
two lift, 22 inch average replacement thickness for Blocks "A" and "B", presented
on the current version of Map 2.05.4-4, would be an improvement over a single
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