Sep. 29, 2009 (PR Newswire) -- TSX-V: RES
VANCOUVER, Sept. 29 /PRNewswire-FirstCall/ - Rare Element Resources Ltd. (TSX-V: RES) is pleased to announce further progress in rare-earth-element (REE) metallurgical test results on oxide samples from the Company's 100%-owned Bear Lodge property, Wyoming, USA. The favorable metallurgical test results on the near-surface oxide material allow the following interpretations:
1. With vigorous attrition scrubbing, a recovery potential of 90% was
achieved in 32 wt-% of the original sample weight while still
retaining a grade of 13% rare-earth oxide (REO); the REO resides in
the finest fraction (minus 500-mesh) pre-concentrate.
2. Further upgrading of the minus 500-mesh (25(micro)) pre-concentrate
by flotation may be able to achieve concentrate grades of 40-50% REO.
3. Hydrochloric acid leaching in an agitation leach system is predicted
to recover up to about 85% of the total REO from the original
mineralized material.
4. Additional testing is likely to provide further improvements to the
processing methods.
Metallurgical testwork is continuing at Mountain States R&D International of Vail, Arizona. Dr. Roshan Bhappu of MSRDI states that "Since the results of the preliminary metallurgical tests on the REO oxide samples are quite encouraging, MSRDI recommends a more detailed test program to determine the best operating and design parameters for developing a conceptual flowsheet... In addition a flotation step would be ideal for the minus 500-mesh Bear Lodge REE mineralization since it would be technically feasible to obtain a relatively high grade (40 to 50% REO) concentrate in about 12 to 15 wt-% with a recovery of plus 70% of the REO values. Accordingly, additional flotation testing of the fine pre-concentrate is planned."
The metallurgical testing is being conducted on oxide samples from an NI 43-101-compliant inferred resource of oxide mineralization consisting of 4.5 million tons averaging 4.3% REO. The oxide resource is part of a larger inferred resource estimated at 9.8 million tons averaging 4.07% REO using a 1.5% REO cutoff grade. The oxide zone of mineralization extends from surface to depths of 300 to 500 feet. Excellent exploration potential for expansion of the oxide zone is being tested by a current program of step-out drilling.
The test program on this oxide mineralization was specifically designed to take advantage of the mode of mineral occurrence of the REE mineralization unique to this mineralized material type. This uniqueness is characterized by the occurrence of fine-grained REE minerals that variably adhere to the surfaces of the coarser gangue minerals. The REE minerals in oxide mineralization from the resource area are nearly all from the bastnasite-group-listed in decreasing order of abundance: synchysite, parisite, and bastnasite. Initially the REE minerals were readily liberated by gentle scrubbing of the oxide mineralized samples that had been crushed to minus 1/4 inch (6 mm). The scrubbed pre-concentrate product consisting of the fine particles less than 500 mesh contained more than 70% of the REO in about 20 wt-% pre-concentrate product of the original sample material and assayed 14% REO.
Most of this news release is derived directly from an MSRDI progress report received in late August, 2009.
Summary
In general, the MSRDI tests have shown that the following conclusions
apply:
1. The oxidized REE-mineralized material should be initially crushed to
minus 1/4".
2. Beneficiation is best accomplished by scrubbing the material with
vigorous agitation for an extended period of time.
3. Screened or cycloned minus 500-mesh particles contain up to 90% of
the REE values.
4. Sulfuric acid leaching would require extended times and/or the use of
an acid roasting circuit to be viable.
5.
