_REVISION - M1980244 ‎(31)‎

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Name: Adequacy Response
• From: Cripple Creek & Victor Gold
• To: DMG
• Type & Sequence: AM8
• Media Type: D
• Archive: No

_ -_ - 1?1968; s~=! ,~. -_ - _
t5
pointed;+out by the OMLR in Section V.B.1 of these comments, CC&V is projecting an excess of about
388,9DD cubic yards of growth medium which indicates that an adequate quantity will be available for
reclamation. As a result, CC&V believes that the criteria employed for growth medium salvage is the
most appropriate for the equipment being used and the nature of the soils in the area. CC&V
appreciates the ability to develop temporary soil stockpiles during operations. Growth medium that can
be, easil,'y~removed with available mining equipment will be salvaged.
la •Y 3:ii.
G, hit ~va11 bench design according to the slope designs provided in Yodume III North Cresson Mine area
slopesterbiliryEvaluation, is asfoliows:
Nortk~GYesson A, 1?, and C, and East Cresson Extension Mine, all slopes are to be 60°, triple bench, 105
feet vertical between benches. However, Figure 10 through ll triple bench - "60° slope and 45D1slvpe
with anil without break show what appeared to be benches every 35 feet height, please clarify.
Response: Spbcific slope designs for each of the North Cresson mine areas are summarized on page 35 in
Appendix 5 of Volume III of the Amendment Na. 8 application. Figures l0 and 11 in Appendix 5 of
Volume III show 105 vertical feet between benches. As discussed in the text, the design is a lDS-foot
high face with two-foot setbacks every 35 feet and a 41-foot wide catch bench every 105 feet. CC&V
believes that the benches the OMLR is referring to in this continent are actually the small setbacks
shown.tin the Figures. Please refer to page 52 of the Project Description for this discussion in Volume I
as welllas pages 30 through 33 in the accompanying North Cresson Mine Area Slope Stability Report in
Appendix 5 of Volume Ili.
.... k;
Fi'~uzz;12 does show benches cvcry 35 feet in vertical hcight as an altt:rnativc design for the schist
b`enche6 in the North Cresson "b" Mine Area. This is discussed in the text of the North Cresson Mine
Area- Sjope Stability Report in Appendix 5 on page 31.
H. CC&l(proposes to remediate open or collapsed laterals/ihclines/edits by blasting the crown pillar then
bac~lling the depression ftf any) with Structural Fitl. After which the area wilt be capped with
geagritl.. This method of closure is okay. As an alternative, CCc4V proposes to plug the open lateral via
an injeceian of a flowable fill into the excavation withoutfurther excavation or blasting. CCdrV does
not provide any information about theproposed 'ylowable fill" except that it should be a suitable, low
cgmpressibility, inert fall material. CC&V needs tv obtain DMG approval to use 'Jlawablefill"prior to
using:r7ie material jot closure of open laterals.
„i,
Response:. As_:discussed in the text, the flowable fill is an alternative stabilization construction method to
blasting and filling with sttuettaal fill. At this time CC&V dons not plan to use flowable fill. Ln the
future;if flowable fill is proposed for use CC&V will provide additional information for the fill method
and obtain OMLR approval prior to use.
},
I. CC&Ynvtll commit to: 1) monitor wall deformation, including bench-scale behavior, Z) model re-
dtia/aidiion whenever new information becomes available that afjects the cusrent understanding gjrock
mass~titsperties and structure and.?) back-analysis to calibrate actual rock mass/wall behavior:f
significant wall deformatiaru should occur and provide the data to the Division thirty (3l)) days after
CC&a!recorded the data.
r „ •r..;
Ytaspottse: , CGBcV currently routinely monitors the highwalls. If new information that affects highwall stability
is obtained, highwall stability will he re-evaluated. If significant wall deformations occur which could
adversely affect the highwal] geotechnical stability, then CC&V will complete a "back-analysis" to
calibrate the actual rock mass/wal] behavior and associated stability. CC&V will commit to provide the
iitfortrjapon to the OMLR within 30 days after recording of the data, assuming that the wall deformation