Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
16-1
16 Mining Methods
16.1 Introduction
The exploitation plan for the Bear Lodge Project utilizes conventional truck and
excavator open pit mining methods, focusing on the near-surface, oxidized portions of
the deposit. Excavators and/or front-end loaders with bucket sizes ranging from 9-11
cubic yards would load off-highway haul trucks with payload capacities of about 60
tons. Operating bench faces would be 20 ft. high for the proposed scale of
operations.
The mine design was created using Mintec’s MineSight® software package, which
includes a three-dimensional Lerchs-Grossmann (LG) algorithm for pit optimization
and extraction sequence analyses. The deposit block model was originally developed
by O.R.E. using CAE’s Studio 3 software and transferred to WLR Consulting, Inc.
(WLRC) in the form of ASCII CSV files containing block grades, tonnage factors,
geologic codes, ore types, resource classifications and other data. The model and
topographic surface were then loaded into MineSight and the accuracy of the model
transfer validated.
The open pit development sequence was evaluated using the economic and overall
slope angle parameters and mining restrictions described in Section 15.2. The REO
prices were progressively discounted to lower levels in order to target the mineralized
zones with the highest grades for initial development. Only oxide and OxCa
measured and indicated mineral resources were considered to be potentially
economic in these analyses; transition, sulfide materials are not being mined, and all
inferred mineral resources were treated as waste. A series of LG pit shells were
generated for use in guiding the design of internal mining phases.
16.2 Mining Phase Designs
Marc Orman of Sierra Geotechnical, based in Chicago Park, California, performed
geotechnical data collection and slope stability analyses for the Bear Lodge Project
with the purpose of providing pit slope design recommendations.
