PERMFILE45875

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 5/21/2004
• Section_Exhibit Name: 2.06 Special Categories of Mining
• Media Type: D
• Archive: Yes

Table 72 B, NMD Recharge Time Estimate, provides the number of days it would take to fill in the additional
fracture volume resulting from subsiding the bedrock. Again, it should be recognized that this is a very
conservative estimate due to the character of the stream. The data presented assumes that sandstone bedrock can
be found for the entire length of Fish Creek overlying the panels and this is not the case. The section in which the
sandstone unit is exposed is the approximate 1260 feet of channel in section 10, TSN, R86W. The remainder of
the channel is alluvial material overlying the Lewis Shale. Given the nature of the shale it will swell to fill in any
cracks that may occur. The amount of time necessary to fill in the additional fracture volume varies from 0.6 days
to 17.4 days for panel 13 Right, depending upon the time of year mining and subsequent subsidence occurs. For
panel 14 Right the amount of time required to fill the fracture volume varies from 0.3 to 7.9 days, panel 15 Right
varies from 0.2 to 6.2 days, panel 16 Right varies from 0.2 to 6.8 days.
Twentymile is the immediate downstream user of irrigation water and does not foresee any impacts to its
agricultural operations due to the potential loss of water form the system. In the event that significant losses
occurred during the irrigation season Twentymile has sufficient water rights to augment and loss.
In reference to water quality impacts, the ongoing downstream monitoring at station 900 on Foidel Creek does not
show any changes that can be attributed to subsidence over panels 8 and 9 Right. The reader is referred to TCC's
1996, 1997, and 1998 Annual Hydrology Reports to review this data.
Table 37A, Foidel Creek Flow Analysis after Subsidence in the EMD, shows that water is not being lost to
segments of the Foidel Creek that have been undermined and subsided in the EMD. This is based on comparing
site 800 plus ponds to site 900. The site 8 data is not being used in the comparison due the discrepancy in the data
for site 800 and Ponds B, D, E, F, and G. The total flow from site 800 plus the ponds should approximate the flow
recorded at site 8. TCC is investigating the discrepancy and will make changes to site 8 as needed.
in order to validate that no impacts will be realized to the AVF located downstream of its operation, TCC will
continue to utilize its current downstream surface and alluvial water monitoring stations. These stations are
presented on Map 13A, Hydrologic Monitoring Program. The stations will be monitored as per the existing
monitoring schedule. These stations are located along Fish Creek in Section 5, TSN, R86W. In addition to the
current hydrologic monitoring program, TCC will initiate a program directed at the segment of Fish Creek to be
impacted by mining in [he NMD. This environmental program is presented in Exhibit 4e-7, NMD- Fish Creek
AVF Monitoring Program. The program includes the following components: hydrologic monitoring, vegetation
monitoring, and subsidence surveying.
NMD (17 Right through 21 Right) (PR03-06)
TCC's mining operation will result in subsiding Fish Creek and its alluvial valley floor. The impact to the ranches
is discussed in the following paragraphs. The ranches are shown on Map 1B. Given the fact that the valley floor
will subside parts of the area will be flooded. TCC is not proposing any reclamation activities for the flooded areas.
The extent of flooding and loss of acreage is described in the following paragraphs. The extent of flooding is
controlled by the elevation overlying the gateroads and bank height immediately upstream from that point.
In reference to Fish Creek, Twentymile is of the opinion that its mining operation will not impact enough of the
valley floor to be significant to the Camilletti and Sons or State of Colorado ranching operations. The valley floor
is used as rangeland and not flood irrigated.
Presently, there are no irrigation ditches established along Fish Creek, which irrigate a designated alluvial floor
within the limits of longwall panels 17 Right and 18 Right. This is due to the fact that it is not economically
feasible to establish an irrigation system on the limited acres formed by the meandering Fish Creek. Given the
PR 03-06 2.06-25.4 03/02/04