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High-Grade Mineral Resource
High-grade Mineral Resources, which are those resources above a cutoff grade of 3% TREO, are particularly
important, since they are the focus of mining in the first nine years of production. The high-grade Mineral
Resource is summarized below. It occurs predominantly on the flank of Bull Hill which contains 78% of the
Measured and Indicated, high-grade resource.
Summary of High-Grade Measured and Indicated Mineral Resource
(1)
effective October 9, 2014
(2)
Cut-off Grade
(3)
Bull Hill
Whitetail
Total
Resource
Classification
Tonnes (in
millions)
Average
Grade (%
TREO)
Tonnes (in
millions)
Average
Grade (%
TREO)
Tonnes (in
millions)
Average
Grade (%
TREO)
Measured
1.5
5.01
-
-
1.5
5.01
Indicated
4.0
4.43
0.7
3.93
4.7
4.36
Measured & Indicated
5.5
4.59
0.7
3.93
6.2
4.52
(1) Bull Hill Mine includes both the Bull Hill and Whitetail Ridge deposits from NI-43-101 (2014).
(2) Inclusive of previously reported Mineral Reserves under NI 43-101 (2014).
(3) Cut-off grade of 3.0%.
Quality Assurance
The Mineral Resource estimate was completed by Mr. Alan C. Noble, P.E., principal engineer of Ore Reserves
Engineering, and is based on geological interpretations supplied by the Company to Ore Reserves Engineering and
subsequently modified by Ore Reserves Engineering. Mr. Noble is an independent Qualified Person for the purposes
of NI 43-101 and verified the data disclosed here.
Rare Element’s field programs prior to 2014 were carried out under the supervision of Dr. James G. Clark, formerly
the Company’s Vice President of Exploration. Dr. Clark is a senior geologist and previously was exploration
supervisor for Hecla Mining Company during the late 1980s and early 1990s, and was responsible for that
company’s exploration of Bull Hill and the Bear Lodge district, and its initial discovery of the Bull Hill resource
area. In 2014, John T. Ray, the Company’s Chief Geologist and a Qualified Person via SME Registered
Membership, directed our exploration efforts. Mr. Ray was a consultant to Newmont Mining Company during its
operations in the project area from 2004 to 2010 and has continued in that role since 2010. A detailed QA/QC
program was implemented for the 2007 through 2013 drill programs. The QA/QC program was organized by Dr.
Jeffrey Jaacks. Drs. Jaacks and Clark verified the sampling procedures and QA/QC data delivered to Ore Reserves
Engineering. They share the opinion that the data are of good quality and suitable for use in the Mineral Resource
estimate.
Metallurgy and Mineralization
The Mineral Resource size is sensitive to an assumed cut-off grade and to metallurgical operating costs. The
mineable pit includes the known Measured and Indicated (M&I) Mineral Resource as disclosed in the Technical
Report dated October 9, 2014 and is inclusive of the adjacent Whitetail Resource Area that extends towards the
northwest. The current mine plan for the Bull Hill Mine will allow mining for approximately 38 years and
processing for approximately 45 years.
A Physical Upgrade (PUG) Plant, located within the project area, is designed to maximize concentration of the rare
earth minerals and produce a mineral concentrate using a crushing, screening, and gravity separation process
depending on the material type. The PUG process is designed to concentrate the rare earth-bearing fines and reduce
the physical mass. There are areas of the mineable pit that contain variable amounts of weathered oxide material or
oxide-carbonate (OxCa) mineralized material, and that contain variable grades of stockwork mineralization adjacent
to the higher-grade material. Each of these material types will have a different upgrade percentage and mass
reduction in the PUG circuit. The mining plan anticipates exposure to a distinct high-grade zone early in the project
that will allow for preferential mining in the initial years of the mine. Low and mid-grade material will also be
mined and stockpiled for future PUG processing.
