2014-10-10_PERMIT FILE - C1996083A ‎(24)‎

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 10/10/2014
• Doc Name: pages 2.05-84 to 2.05-165
• Section_Exhibit Name: Volume I 2.05 Operation and Reclamation Plans Part 2
• Media Type: D
• Archive: Yes

2.05.6(6)
(b)(i)(B) A description of the subsidence related phenomena predicted to occur within
the permit and adjacent area is presented in Volume IIIA, Exhibits 15,17 and
21.
(b)(i)(C)
The aerial extent of predicted subsidence related phenomena within the
permit and adjacent area is shown on Map 27 Subsidence. Traditional
subsidence and predicted rock roll out areas are both shown on the Map.
The aerial extent for the traditional subsidence is calculated based on a 25
degree angle of draw over areas where subsidence is expected to occur.
The rock roll out areas are predicted using the Colorado Rockfall Simulation
Program, version 4.0, developed by the Colorado Department of
Transportation, the Colorado School of Mines and the Colorado Geological
Survey. The results of the rock roll out predictions are presented in Volume
VII, Geotechnical Studies, Tab 11.
The Bruce Park Main Dam and Saddle Dam should not be affected by
subsidence since they lie entirely outside the limits of mining and are more
than 2,000 feet above the coal seam to be mined. The location of the mine
and its configuration are specifically designed to avoid subsidence or seismic
damage to the Bruce Park Dams.
GEI Consultants Inc. studied the stability of the main dam and saddle dam
during 2001 and 2002. See Volume X, Geotechnical Studies, Bruce Park
Dam. The study first determined the strength parameters, foundation and
soil types of the dams. The study then evaluated mine induced seismicity on
Bruce Park main dam and saddle dam. The basis for the analysis was that
mining in the area of the dams would occur over a period of 2 years and
would be within 1300 feet of the dam. Permanent deformations were
calculated considering a single magnitude 4.2 event and a combination of
100 magnitude 1.75 events, 20 magnitude 2.0 events, and 5 magnitude 2.5
events. The study concluded the main dam and saddle dam would be stable
under the assumed seismic loadings. The Applicant has determined the
events used in the GEI Consultants study are conservative. See Volume
IIIA, Exhibit 18 Seismic Monitoring, Summary Statement.
PR -14 2.05-151- 03/14