Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
16-3
Table 16.1 lists the bench face angles (BFA) and inter-ramp angles (IRA) used in the
design of the internal mining phases and ultimate pit. Catch bench intervals are on
20-ft intervals (i.e., single benching) due to generally weak rock mass strengths.
Table 16.1 - Pit Design Inter-Ramp and Bench Face Angles
Sector
Pit Area & Wall Location
IRA
Degrees
BFA
Degrees
1
Bull Hill NW wall
35
64
2
Bull Hill N wall
39
72
3
Bull Hill NE-E wall
39
72
4
Bull Hill S wall
37
68
5
Bull Hill W wall
35
64
6
Whitetail W wall
35
64
7
Whitetail N wall
39
72
8
Whitetail E wall
35
64
9
Whitetail S wall
39
72
10
All areas, 150 ft depth
30
52
(WLRC, 2014)
WLRC modified Sierra Geotechnical’s IRA recommendations in sectors 2, 3, 7 and 9
by flattening 40+° inter-ramp slopes to a maximum of 39°. Additionally, some bench
face angles were adjusted to provide 18- to 19-ft minimum catch bench widths for
worker safety and to reflect typical excavation faces left by mining shovels.
Pit walls were designed to fit selected LG shells, minimizing noses and notches for
slope stability reasons and incorporate internal haulage ramps to allow truck access
to working faces. Ramps were limited to a maximum gradient of 10%. A minimum
pushback (phase) width of 150 ft. was used throughout the design process, with
typical widths ranging from 200 to 250 ft.
16.3 Mineral Reserve Summary By Phase
Seven mining phases were developed and are identified in the order of mining as:
BH1, BH2, WT1, BH3, WT2, BH4, and WT3 (BH signifies Bull Hill phases and WT
refers to Whitetail pushbacks). Phase BH2 is subdivided into two parts: the first,
BH2a, incorporates a temporary ramp on the east wall; and the second, BH2b, mines
