NI43-101Pre-Feasibility Study Report - page 478

Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
, 2014
10135-200-46 - Rev. 0
18.2.7 Tailings Storage Facility
The tailings storage facility (TSF) pre-feasibility level design will operate as a ‘zero
discharge’ facility such that no solution from the waste or contact surface water from
the TSF will be released to surface waters or groundwater in a manner that violates
permit conditions or adversely impacts receiving water quality. Design guidelines and
criteria for the TSF presented in this report are in accordance with the Wyoming
Department of Environmental Quality (WDEQ) Land Quality Division (LQD) Noncoal
Mine Rules and Regulations. Rare Element has applied for an exemption from the
U.S. Nuclear Regulatory Commission (NRC) guidelines for tailings impoundment
design, operation, and closure requirements as radioactive elements in the ore will be
removed from the waste streams to achieve acceptable residual levels prior to exiting
the Hydromet plant for disposal in the TSF.
The tailings produced by the Hydromet plant are considered a non-hazardous waste
based on current test data and understanding of the geochemical characteristics of
the waste material. The tailings solids will be non-acid generating material; however,
the residual moisture in the waste may be slightly acidic due to the rare element
extraction process. Limestone and quick lime will be mixed with the waste streams to
neutralize the material prior to transport to the TSF. In addition, the tailings product
delivered to the TSF will be dewatered to a semi-dry, soil-like material suitable for
truck hauling and deposition using conventional earthwork equipment.
The proposed site for the TSF is within private property boundaries to the west of the
proposed Hydromet plant location. The TSF is situated on a broad, relatively flat,
grass-covered slope that will require a side-hill type of embankment for containment
of the tailings. Surficial soils generally consist of clay primarily derived from in-place
weathering and erosion of the exposed shale formations in the area. The TSF is
located pre-dominately over the Belle Fourche Shale, which contains marine fossils,
limestone concretions, and several thick bentonite beds throughout the formation. A
series of steeply dipping Upper Cretaceous aged shale beds appear in the northwest
to southeast striking slopes that form the valley ridgeline west of the TSF footprint.
These geologic conditions indicate that the TSF site is suitable for construction of the
TSF and containment of the tailings.
The dewatered and neutralized tailings will be transported by truck to the TSF and
placed within a lined facility as a ‘filtered’ tailings product using conventional
earthmoving equipment. The TSF capacity is approximately 15.8 million tons,
including both tailings and neutralization amendments, with an average in-place
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