8
tons per day in order to maintain a nearly consistent production of final rare earth oxide (REO)
product. Stockpiled low and mid-grade ores will also be PUG processed along with fresh mined
ore until mining Year 25 when the mineable pit ores will be depleted. Stockpiled ores will
continue to be PUG processed up through Year 43 when they are estimated to be depleted.
Reclamation of mining facilities will begin as soon as the mineable ores are depleted.
The pre-concentrate produced at the PUG Plant will be transported to the Hydromet Plant near
Upton via covered trucks. The Hydromet Plant will process the pre-concentrate through acid
leaching followed by additional chemical processing to remove impurities and finally
precipitation to produce the final total rare earth oxide (TREO) product. The tailings produced
from the process will be stored in a double lined tailings storage facility (TSF) adjacent to the
Hydromet Plant.
A detailed project description of the Bull Hill Mine is provided in Section 4.5. Details of the Upton
Plant are provided in Appendix A.
4.2
PROJECT HISTORY
The Bear Lodge Mountains were initially prospected for gold during the late nineteenth and
early twentieth centuries. Thorium and rare earth mineralization were first discovered in 1949 as
a result of uranium exploration activity by prospectors, and the mineralization and some
carbonatite occurrences were documented. The U.S. Bureau of Mines completed a limited
radiometric survey and a ten-hole drilling program in the area in the early 1950s.
In 1972, Duval Corporation acquired the exploration rights and initiated an exploration program
focused on copper-molybdenum mineralization that continued through 1977. Duval recognized
that the Bear Lodge property had potential to host an economically significant REE deposit and
brought Molycorp Inc. (Molycorp) into the project as a partner in 1978. Molycorp also owned and
operated the Mountain Pass rare earth mine in California. Molycorp completed 12 diamond drill
holes and conducted other surveys and analyzed for REE abundances within the Bear Lodge
Project Area.
The United States (U.S.) Geological Survey conducted field and laboratory studies on the
property between 1975 and 1979. Results were documented in a professional paper which
concluded that the Bear Lodge disseminated deposits have one of the largest resources of both
total rare earths and thorium in the United States.
Phelps Dodge Corporation acquired a large part of the area in 1994 and focused on gold
exploration, but ceased exploration after 3 years. Paso (USA), Inc. (now known as RER) began
looking at the Bear Lodge property in 1998-99, staked some claims, and negotiated a lease and
option agreement on adjacent claims held by Phelps Dodge Corporation in March 2000. Phelps
Dodge Corporation/Freeport has no further interests in the property.
On June 1, 2006, RER, through its subsidiary, Paso Rico, and Newmont North American
Exploration signed an agreement to establish a gold exploration venture. This agreement was
terminated in May 2010, with RER becoming the sole participant in the project. RER owns the
Bear Lodge property claims in Wyoming.
In 2009, the Forest Service completed an Environmental Assessment (EA) for the Newmont
Mining Corporation Sundance Exploration Project (Forest Service, 2009). The project included
phased mineral exploration over a 4 year period with up to 200 acres of surface disturbance.
RER began exploration of the Bear Lodge Project properties for REE in August 2004, following
the Company’s merger in 2003 with Paso Rico Resources Ltd., including the wholly owned
subsidiary, Paso Rico (USA), Inc. Paso Rico had accomplished some geological and
