Preliminary Public Dose Evaluation in Support of the Development of
November , 2012
Rare Element Resources, Inc. Bear Lodge Project
1
SECTION 1
INTRODUCTION
Rare Element Resources, Inc. (RER) proposes to build and operate a rare earth element (REE)
mining and separate processing facility in the Bear Lodge Mountains in Crook County and near
Upton in Weston County, Wyoming, respectively. The proposed mining facility consists of an
open pit mine called the Bull Hill Mine (BHM) and a physical upgrade plant (PUG). The
proposed processing facility will consist of a hydrometallurgical plant (Hydromet) and tailings
storage facility (TSF). This report refers to the mining and processing facilities collectively as
the Bear Lodge Project (BLP).
1.1
Project Overview
The BHM site is located in central Crook County, northeastern Wyoming (see Figure 1.1), in the
north-western portion of the Black Hills uplift. The property is situated in the central Bear Lodge
Mountains. The BLP lies about 7 air miles (mi., or 11 kilometers [km]) or 12 road mi. (19 km)
northwest of Sundance, Wyoming. The BHM will operate as a conventional truck and shovel
open pit that will extract near-surface ore containing rare earth oxides (REO). Ore from the BHM
will be hauled to the nearby PUG where a rare earth minerals pre-concentrate will be produced,
using a screening and washing process. The pre-concentrate then will be transported by truck to
the Hydromet facility in Upton.
In addition to REO, the BLP ore contains naturally occurring radioactive material (NORM)
consisting of thorium, uranium, and their associated radioactive decay products. NORM is
ubiquitous and present in rocks and soils in varying concentrations, with U. S. background
concentrations typically on the order of 1 to 10 parts per million (ppm) (United Nations
Scientific Committee on the Effects of Atomic Radiation [UNSCEAR], 2000). Uranium and
thorium concentrations in the BLP ore average approximately 109 and 377 ppm, respectively:
above typical background levels.
The Hydromet is located in north-central Weston County, in northeastern Wyoming. The
property is located 3 road mi. (5 km) northwest of Upton and approximately 30 road mi. (64 km)
southwest of Sundance. The Hydromet design contains two parallel circuits to process the
mineral pre-concentrate from the PUG. The hydrometallurgical process uses a 20 percent
hydrochloric acid solution, heated to 194 degrees Fahrenheit (90 degrees Celsius) to leach the
REEs from the pre-concentrate. Iron then is precipitated from the solution, and calcium and
manganese are extracted by an ion exchange process.
Finally
,
REEs are precipitated as
carbonates through neutralization with sodium carbonate as a product. The final product will be
shipped via truck or rail to other facilities for further processing.
