NI43-101Pre-Feasibility Study Report - page 135

Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
, 2014
10135-200-46 – Rev. 0
Pre-existing fractures in more competent host rock in this area may have influenced
the northerly orientations and size of the dikes and veins. The size and spacing of
veins, elevated original sulfide content, and faults or structural zones may have
enhanced leaching of gangue carbonate during oxidation, leaving little to no oxide-
carbonate zone. In the Bull Hill Northwest resource area, structure appears to be the
dominant control on the localization of mineralization, and there may be additional
mineralized zones to the north.
REE mineralization in the Whitetail Ridge resource area is contained within
discontinuous dikes, veins, and stockwork FMR, and carbonatite/silicocarbonatite
hosted primarily by heterolithic breccia of the Whitetail diatreme. Higher-grade
mineralized zones typically contain narrow, steeply dipping dikes and veins up to 10
feet (3 meters) in thickness. The dikes appear to be emplaced along WNW and NNW
to N-S structures that run through the Whitetail diatreme. Based on the resource in
Chapter 14, this area exhibits an overall HREE enrichment of about 1.89 times that of
the Bull Hill resource area, with variable, and subordinate, quantities of monazite and
cerianite accompanying the bastnasite group minerals. In addition, the bastnasite
group minerals exhibit variable Ce depletion and common enrichment in Nd, Y, and
Th. Monazite shows significant Nd and Th enrichment (relative to Bull Hill), as well.
The oxide to oxide-carbonate boundaries are variable in the area, more similar to
zones observed at the Bull Hill resource area.
Lithology and structure appear to exert significant control on the localization of
mineralization in the Whitetail Ridge resource area. The diatreme appears to have
been relatively permeable and less brittle than host rocks in the other resource areas.
Mineralization is dominantly hosted within discontinuous stockwork veinlets and
hairline fractures (referred to as disseminated deposits by Staatz, 1983).
HREE-enriched FMR veins and stockwork zones were drilled between 2010 and
2012 in two additional target areas – Carbon and East Taylor (Figure 8.1 RER
Technical Reports dated April 13, 2012 and June 26, 2013). They are particularly
enriched in europium, terbium, dysprosium, gadolinium, and yttrium (Eu, Tb, Dy, Gd,
and Y, respectively). Carbon is located approximately 800 feet (244 meters)
northwest of the Whitetail Ridge resource area (Figure 8.1, e.g., drill hole SUN-079).
FMR veins and stockwork at Carbon are locally silicified and hosted by phonolite,
trachyte, and syenite. The East Taylor target is located approximately 2,500 feet (760
meters) west of the main Bull Hill resource area, and 2,500 feet (760 meters)
southwest of the Whitetail Ridge resource area (Figure 8.1). Steeply dipping FMR
veins and stockwork are hosted by trachyte and minor Deadwood Formation
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