2011-08-09_REVISION - M1981185 ‎(52)‎

• Permit No: M1981185
• IBM Index Class Name: REVISION
• Doc Date: 8/9/2011
• Doc Name: CN-01 112d permit application Exhibit U Attachemnt U-5 thru Exhibit X
• From: Wildcat Mining Corporation
• To: DRMS
• Type & Sequence: CN1
• Email Name: WHE
• Media Type: D
• Archive: No

Footing
y
cohesion
o
BC Factors
Bearing (psf)
F.S.
width
(ft)
depth
(ft)
Pcf
Kpa
psi
psf
deg.
Nc
Nq
N7
Qu
Qw
1.5
120
100
14.50
2088
15
12.9
4.4
2.5
27,958
16,000
1.75
1.5
1.5
120
200
29.01
4177
20
17.7
7.4
5
75,714
16,000
4.73
1.5
1.5
120
100
14.50
2088
20
17.7
7.4
5
38,748
16,000
2.42
1.5
1.5
120
200
29.01
4177
15
12.9
4.4
2.5
54,900
16,000
3.43
Geotechnical Stability Exhibit
Exhibit 6.5
The steel set footings will bear on rock. The geotechnical engineer will observe footing
excavations during construction to confirm rock is exposed in footing excavations. To estimate
the factor of safety for bearing pressures of 16,000 psf of footings bearing on rock, we used the
rock strength range obtained from the Portal Support Calculations Table (Attachment 6.5 -2, page
3), and Terzaghi's bearing capacity factors and equation. The results are presented on the
following table.
As shown, factors of safety across the range of conservatively obtained strength values range
from 1.75 to over 4.7. The intent is to support all mill - related structures in cut.
The May Day No. 1 portal repair plan is presented in Attachment D -2.
The Chief manway and ventilation geotechnical drill program for the stability work plan for the
Inca's road and Chief Portal is illustrated on Figure 6.5 -2 where Attachment D -4 summarizes the
Chief Drainage and Portal Work Plan.
New Access Road, road stability including cut slope
The following information was used to prepare the New Access road design:
• Geotechnical reconnaissance report submitted to DRMS on May 29, 2010 prepared by
Erich Rauber P.E. # 26647);
• New Access Road Stability Report (Attachment 6.5 -3 and Attachment 6.5 -4) prepared by
Erich Rauber P.E. # 26647); and
• Mine Plan New Access Road design (Attachment D -1) Prepared by CLC Associates.
The construction work plan, including erosion and sedimentation Best Management Practices
(BMPs), is presented in Attachment D -1. The New Access Road (CLC, 2011) has been designed
to carry loads up to 25 tons.
In Wildcat's November 4, 2008 Report, Trautner Geotech LLC ( "Trautner ") obtains a factor of
safety of slightly over 1.3 for the road cut. Trautner's analysis illustrates the lowest factor of
safety is associated with a modeled failure on the outboard side of the road that is entirely in fill;
at no point does the failure surface pass through rock nor does it pass though the road bed. Thus,
a surcharge load, such as vehicle or equipment load, would not affect this factor of safety
Wildcat Mining Corporation
May Day Idaho Mine Complex - 112d Permit Application
Revised August 2011
Geotechnical Stability Exhibit 6.5
Page 4 of 11