NI43-101Pre-Feasibility Study Report - page 133

Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
, 2014
10135-200-46 – Rev. 0
north-easterly direction, reflecting the overall orientation of a relatively persistent
swarm of steeply dipping, northwest-striking dikes and veins of FMR and carbonatite
(Figure 8.2). Individual dikes display traceable strike lengths of 300 to 800 feet (91 to
244 meters), down dip extensions of 300 feet (91 meters) to more than 800 feet (91
meters), and thicknesses of less than 10 feet (3 meters) to more than 80 feet (24.4m).
Individual dikes can pinch, swell, and bifurcate along strike and down dip. These
generally follow the interdigitating contact between the Bull Hill diatreme and adjacent
trachyte and phonolite.
Drilling shows that the southern two thirds of the dike swarm east of the Whitetail
Creek drainage include a persistent northwest-striking zone of dikes, veins, and
stockwork. Within this zone is a relatively continuous dike, locally more than 80 feet
(24.4m) thick and steeply dipping to vertical, and multiple subparallel dikes and
stockwork zones. In general, the main dike zone appears to follow the interfingering
contact between diatreme breccia and the host trachyte-phonolite unit in the southern
portion of the Bull Hill deposit. Increased density of drilling through 2013, as well as
limited surface mapping and trenching, define a more complex distribution of
mineralization in the northern third of the deposit. The NW-trending zone described
above contains northerly-striking splays at either end. At the northern end of the NW-
trending zone, the main dike splits at an inflection point into a horsetail that consists
of a more WNW-trending set of dikes and stockwork, and another set of smaller
NNW-trending dikes and stockwork zones (Figure 8.2). Zones of moderate to strong
stockwork are observed between the dike splays.
Drilling through 2013 indicates that FMR and carbonatite dikes, veins, and stockwork
extend west of the drainage that borders the west flank of Bull Hill and are variably
hosted by diatreme, trachyte, and phonolite (Bull Hill West). To the south of Bull Hill,
mineralization may be offset along an easterly-trending fault, or feather out close to
the boundary with Section 20, which is withdrawn currently from mineral entry and
drilling. Structural orientation, the diatreme contact, and host rock lithology exhibit a
complex interplay of controls on the localization of mineralization in the Bull Hill
resource area.
REE mineralization in the Bull Hill Northwest resource area is contained within dikes,
veins, and minor stockwork of FMR and carbonatite/silicocarbonatite that intrude
trachyte and phonolite. Less well-understood, owing to decreased drilling densities
compared with the Bull Hill resource area, the dikes, veins, and stockwork zones are
northerly trending, steeply dipping to vertical, and relatively narrow and broadly
spaced. Individual dikes appear to have strike lengths of less than 100 feet (30
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