PERMFILE107193

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 10/14/2007
• Section_Exhibit Name: 2.05.5 Postmining Land Uses
• Media Type: D
• Archive: Yes

Union Pacific Railroad (formerly Southern Pacific)
• Due to the change in the mine plan, no further subsidence will be experienced by the mining of the 6 Right
longwall panel.
Powerlines
Twentymile successfully undermined and subsided the powerlines during the mining of panel 9 Right. The
powerlines were monitored per the approved plan; this data was presented in the semi-annual subsidence report.
The results of the monitoring show that the lines subsided, but the did not fail or experience foundation failure.
This verified the contention that no impacts will be realized due to undermining and subsiding the lines.
The subsidence prediction for powerlines is presented in Exhibit 7E, Prediction of Subsidence, Eastern Expansion
of Foidel Creek Mine, prepared by Sub Tetra, Inc. in March 1993. As is shown, the subsidence will vary from 0 to
73 inches over the various panels. For panels 4 Right through 6 Right, maximum subsidence is 67 inches, while
maximum subsidence for panels 2 Right and 3 Right is 73 inches.
The powerlines will be monitored, as described in the subsidence control plan, on the basis of distance from the
active longwall mining face to the powerlines. The monitoring will allow for rerouting power in the event the
Hayden-Gore Pass (metal structure) is impacted temporarily. Once the line is stabilized, power would be returned
to the line. A copy of the subsidence agreement, which includes rerouting power and ground-fault interruption
processes, has been forwarded to the Division.
The wooden stmctures supporting the other three powerlines should react the same as the wooden stmctures
undermined and subsided in the Southwest Mining District. The line experienced up to 3.1 feet of subsidence
• without failure to the line or the pole(s). This line has been visited by the DMG inspector during prior inspections
conducted at the mine. The subsidence data for this line is presented in Exhibit 7G, Subsidence Report for YVEA
Power Poles.
The gang switch for the Wolcott Tap-Wolcott 230 KV transmission line was relocated during 1996 to an area
outside the mine area. No problems were encountered when the line was subsided by the 9 Right panel. It is
anticipated the line will continue to respond to future subsidence.
As of November 1999, TCC has undermined the powerline located over the 6 and 5 Right panels. The results of
the monitoring has been included in the semi-annual subsidence reports, and the results have not changed, i.e. no
significant impacts to the line or support towers/poles.
Telephone Lines
The buried telephone lines are not expected to be impacted by the mining operation. Twentymile has undermined
and subsided a section of buried line in the Southwest Mining district. In the event there is a dismption in service
(i.e. line severed), Twentymile would become aware of it immediately as the mine is served by that line. [f service
were dismpted, a repair crew would be called out to service the line.
The line was subsided by mining conducted in the 6 and 5 Right panels without dismption to service.
Aquifers
The Twentymile Sandstone is the only large regional aquifer that is above the coal seam. It is not anticipated that
• any wells will be impacted from the undermining of the Twentymile Sandstone. The present hydrologic monitoring
program conducted by Twentymile Coal Company does not show any impact to this formation outside of the
mining area. Therefore, it would be prudent to predict no off-site impacts to this unit.
pppROVED APR 2 4 2000
Perini[ Renewal No. 3 .2.05-184.1 t 1/1/99