2010-08-10_REVISION - C1981008 ‎(11)‎

• Permit No: C1981008
• IBM Index Class Name: Revision
• Doc Date: 8/10/2010
• Doc Name: Response 4 Revised Section 2.05.4‎(2)‎‎(e)‎
• From: Western Fuels-Colorado
• To: DRMS
• Type & Sequence: PR6
• Media Type: D
• Archive: No

Table 2.05.4(2)(e) -2
Western Fuels Reclaimed Irrigated Pastureland Reference Area
Western Fuels
Reclaimed Irrigated Pastureland
Reference Area
New Horizon #2 Mine
Weighted
Avera e
Soil Type
Area acres
% of Total
Assigned Facto
15
2.4
35.24%
1.20
0.423
81
1.4
20.56%
1.00
0.206
10
1.35
19.82%
1.00
0.198
77
1.66
24.38%
0.80
0.195
Total
6.81
100.00%
1.022
Base Case
Ref Area
As can be seen from the table above, the weighted average factor for the reference area is 1.022.
Map 2.05.4(2)(e) -1 & 2 shows the NRCS soil types for the entire mine permit area. If an area of
Reclaimed Irrigated Pastureland is submitted for bond release, the weighted average factor of this
area is calculated based on the areas of each soil type multiplied by the associated factor. These
numbers are added and divided by the total area to get the weighted average factor. This
weighted average factor is then divided by the reference area weighted average production factor
(1.022), and the resulting value is multiplied by the reference area production sample mean to
obtain the adjusted reference area sample mean. The production standard for that particular
reclaimed block is [90% of] the adjusted reference area sample mean. For the purpose of
statistical comparisons, the reference area production sample standard deviation must be
multiplied by the same value as the sample mean.
This method has the advantage of truly accounting for the differences in soil type from one area
to another. This may not be necessary in other smaller tracts of Reclaimed Irrigated Pastureland
at other mines, but it is important at the New Horizon #2 Mine, since there is substantial variation
of soil types. Jim Boyd has stated that a few of the types are poor enough that they are simply not
irrigated anywhere else in Montrose County. Others, especially some in the western part of the
mine area, are better than those in the reference area.
PR -06 June 2010 2.06.4(2)(e) - 24