Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
13-2
produces a higher grade product with much improved economics compared to the
2012 PFS.
13.3 Summary of Process Design Criteria
13.3.1 Process Description
The flow sheet that was used in this PFS evaluation is described stage-wise as
follows:
13.3.2 Crushing and Screening
In years 1-9 of mine life, mined ore will be crushed and screened for direct processing
at Upton without application of gravity and magnetic separators (PUG Plant). The ore
will be stage-crushed and screened at a cut-off size of 3 inches. Approximately 20%
of mined feed ore will be stockpiled as low-grade coarse material (+ 3 inch) while the
undersize (- 3 inch) fraction will be transported to the leach plant at Upton.
A set of cone and roll crushers will be installed at Upton to reduce the ore from minus
3 inch to 100% passing - 48 mesh mineral pre-concentrate.
On the basis of crusher work index (kW-hr/ mt), Phillips Enterprises determined the
crusher power requirements for Whitetail ore. This ore was classified as soft, CWI =
6.0 kWh/mt or 5.4 kWh/st) and abrasive AI = 0.237g). For Bull Hill composite ore, the
crusher work indices was determined by Hazen Research as 10.98 -13.11 kWh/mt.
13.3.3 PUG Plant
In years 10-45, the crushing plant will be modified by adding beneficiation units to
upgrade the ore by gravity and magnetic separation. Mine production will be ramped
up to process mid-grade ore at a feed rate of 1346 tpd in order to off-set the
decrease in REO grade and high gangue content of the ore.
Bull Hill ores (mid- and low grade oxides and carbonatite) plus White Tail ores
responded well to pilot-scale gravity and magnetic separation techniques. The mass
pull was equivalent to 40-77% of feed mass.
13.3.4 Acid Digestion, Rare Earths and Base Metal Separation
The PUG process produces a mineral concentrate rich in rare earth (RE) minerals.
Subsequently, at the hydromet plant the mineral concentrates are leached in hot
chloride solution to extract rare earths, thorium, uranium and significant amounts of
base metals.
