2016-05-04_PERMIT FILE - C1982056 ‎(7)‎

• Permit No: C1982056
• IBM Index Class Name: Permit File
• Doc Date: 5/4/2016
• Section_Exhibit Name: 2.06 Special Categories of Mining
• Media Type: D
• Archive: No

The area that TCC proposes to undermine (NMD) in the Fish Creek drainage is located in parts of Sections 10
and 11 of TSN, R86W, and is identical to the area that P&M Coal Company was planning on undermining and
subsiding in its proposed Fish Creek Mine. P&M contracted with the consulting firm of Kaman Tempo to
prepare a report responding to the requirements of Rule 2.06.8(4)". This report has been incorporated into
Exhibit 7e-2. The soils information presented in the Kaman Tempo report was updated with the work
performed by Habitat Management, Inc., and a copy of their report is presented in Exhibit 7e-4. Additionally,
chemical and physical properties of the Binco Silty/Clay Loam are presented in Table 73. None of the data
presented indicates a problem with this soil, for example the low SAR's indicate that leaching will not be
problematic, downstream of the mined area. The original data presented on this table was taken from Table 72
of Permit C 81-071. The conclusions presented in the report agree with TCC's contention that subsidence of the
AVF will not materially damage the existing ranches. It should be noted that the Kaman Tempo report was
prepared in 1982. Since that time, land management practices for the affected areas have not changed, i.e. large
acreage ranches to meet the economic requirements of the marketplace. This ownership pattern continues in the
Twentymile Park basin. The ownership patterns are reflected on Map 1, Surface Ownership.
TCC contracted with SubTerra, Inc. to expand the subsidence predictions, to further evaluate impacts to Fish
Creek and its AVF for mining disturbance in the NMD. This report is presented in Exhibit 7e-6, Twentymile
Coal Company, AVF Subsidence Report, Final Report. The report provides a numerical analysis of
approximately 200 cross-sections through the subsided area, and also used a 3D Geologic Modeling software
program (GEMCOM) to compare against the mathematical model. The results of the mathematical model show
that of the 25.5 acres in the AVF area, approximately 7.3 acres will be impacted by subsidence during normal
flow periods, and 12.3 acres during high flow periods. In reference to a change in the gradient of Fish Creek,
SubTerra analyzed the creek from Stations 0+00 to 100+00. The analysis included evaluating the gradient both
before and after mining. The result of this analysis is presented on Tables 2 and 3 in the report. The narrative
also includes a discussion of change in gradient of the creek. The gradient change in this segment of Fish Creek
is approximately 0.6 percent.
More recently, a supplemental subsidence evaluation was completed by SubTerra Inc. for mining of Panels 12 -
through 16 -Left (WMD) under Fish Creek and its associated AVF. The results of this evaluation are presented
in Exhibit 25Z, Western Mining District Subsidence Review (PR09-08). This evaluation indicated similar
subsidence effects to those experienced for the SWMD, EMD, and NMD, with temporary flooding of
approximately 39.9 acres under normal flow conditions, and a total of 66.9 acres under high-flow (spring runoff)
conditions. Based on subsidence modeling, the maximum change in stream gradient would be 0.7 percent (0.7
feet or 8.4 inches in 100 feet).
Three landowners would potentially be affected by undermining and subsidence of Fish Creek and its associated
AVF; Camilletti and Sons, the State of Colorado, and Cross -Mountain Ranch, LLC. Camilletti and Sons own
property within the Permit Area that will be affected by mining of Panels 15- through 24 -Right (TSN, R86W,
Sections 2, 3, 10, and 15). Fish Creek and its associated AVF will be affected within their property boundaries
by mining of Panels 14- through 19 -Right. Personal communications with Mr. Frank Camilletti, of Camilletti &
Sons, indicate that this acreage is not critical to the continued operation of the ranch, and will not materially
damage it. This area is not cropped and is treated as unimproved rangeland. TCC conducted a vegetation study
of the adjacent upland area and the bottomlands to evaluate the productivity of the respective areas. The study is
presented in Exhibit 7j-1, Northern Mining District, Fish Creek Vegetation Study. The data presented in the
study verifies TCC's assumption that measured productivities for the two areas do not vary significantly,
supporting the contention that any subsidence -related impacts would be minimal.
The State of Colorado is the surface owner of lands within the permit boundary to be undermined and subsided
during mining of the 13- though 24 -Right Panels and the 14- through 17 -Left Panels. Fish Creek and its
associated AVF will be affected by mining in the 17 -Right Panel. As presented in Exhibit 7e-6, a total of 4.4
acres will be flooded by mining of this panel. As is the case for all the lands along Fish Creek to be undermined
• and subsided, no flood irrigation system has been established to increase the productivity of the land, nor are
management practices established for haying this area. The land is treated as unimproved rangeland utilized for
grazing by the lessee.
PR09-08 2.06-25.5 09/29/09