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Rare Element Reports on Gold Metallurgical Test Results

Posted on: Thursday, 29 May 2008, 09:00 CDT

VANCOUVER, May 29 /PRNewswire-FirstCall/ -- Rare Element Resources Ltd. (TSX V: RES) (the "Company") is pleased to announce that initial successful metallurgical leach tests have been completed for the Sundance Gold Project located in Wyoming. The purpose of these bottle-roll and column leach tests, which were conducted at Newmont Metallurgical Services (NMS) laboratory, was to determine initial leach characteristics and recoveries at various crush and grind sizes of the low-grade near-surface gold mineralized material.

The initial column leach test results, which are more indicative of potential production, have yielded 78.4 percent recovery at -3/4 inch crush size, 80.5 percent at -10 mesh (sand size), and 87.9 percent at -200 mesh (fine powder). These tests successfully provide the first indication of how the Sundance gold mineralization might respond to leaching processes. They also provide a basis for fine tuning the leach methodology to optimize the economic extraction of gold.

Don Ranta, President of Rare Element Resources, commented that "We are very pleased to see the high recoveries of gold from the initial metallurgical testwork. These results suggest that reasonable recoveries may be achieved in an open pit mine and run-of-mine heap leach operation that has the potential to be relatively low in both capital costs and operating costs."

Bottle-roll Leach Tests

NMS completed a preliminary bottle-roll leach study to determine grind size versus gold extraction relationship for eight composites of cuttings samples from the Sundance Project during June 2007. This study included compositing, chemical and mineralogical analysis and bottle-roll cyanidation tests at -10 mesh (sand size particles) and 80% passing -200 mesh (fine powder) grind sizes. The composites were made from assay sample rejects from five separate reverse circulation (RC) drill holes drilled at the Carbon and Taylor gold targets in 2006. Head assays ranged from 0.79 to 2.21 g/t Au and <0.1 to 3.7 g/t Ag. All eight composites have mineralogy consisting of K-feldspar (47-95%), albite (15-41%), goethite (3-11%) and biotite (1-11%) with minor amounts of fluorite, alunite, beudantite (or jarosite) and pyrite identified in some samples. Bottle roll tests on -10 mesh samples reported gold extractions of 64 to 86 percent for 96-hour leach periods. Similarly, gold extractions for 80% passing -200 mesh pulverized composites, based on calculated head and residue assays, varied from 76 to 92 percent. In both cases, cyanide consumptions were low and lime addition to control pH was in the range of 2.2 and 2.6 kg/t, which is also relatively low. One of the conclusions from the 2007 bottle-roll tests was that these composites have characteristics that indicate the presence of coarse gold particles which may result in slow leach kinetics; consideration of longer leach times and/or a gravity recovery circuit will be considered.

Similar results were also reported in a historical study in 1991 by McClelland Labs of Reno, Nevada, for Coca Mines. In the McClelland study, 204 kilograms of Sundance bulk mineralized material excavated from the Smith target show that the bulk sample was more readily amenable to heap-leach treatment than indicated by preliminary bottle-roll test data (various feed sizes at 96 hours of agitated leach). For the Smith target mineralized material, bottle-roll tests showed gold recoveries of 65 to 79 percent with low reagent usage. McClelland's column leach test results were significantly better with gold recovery of 86 percent achieved from the 100 percent -1 1/2 inch material in 73 days of leaching. Gold extraction was fairly rapid and extraction was substantially complete in 30 days. Studies by FMC Gold, Coca Mines and Hecla have all indicated a potential coarse gold "nugget effect" in the Smith target mineralization.

Column Leach Tests

Preliminary column leach tests were performed by NMS to determine crush size versus gold extraction for four composites from the Sundance project. The study included column cyanidation tests at -3/4 inch, -10 mesh, and 80% passing -200 mesh grind size. The composites were made from core drilled in hole SUN-011c at the Carbon target (Composites C & D), and from core drilled in hole SUN-013c at the Taylor target (Composites A & B). Assay results show that the composites contained 0.46 to 0.73 g/t Au and 1.6 to 5.0 g/t Ag.

Mineralogical analysis indicates that the Taylor Composites (A and B) are fairly similar with K-feldspar (75-77%), muscovite (10-11%), biotite (5-8%), iron oxide (3-6%), and fluorite (1-3%). Kaolin is the dominant alteration in Composites C and D from the Carbon target, and samples contain K-feldspar (67-77%), kaolin (16-26%), iron oxide (4-5%), and butlerite (2%). Microscopic examination of the gravity (hand-panning) concentrates indicated coarse gold.

Results show that the column leach tests yielded gold extraction averaging in excess of 78.4 percent. As the mineralized material was crushed to finer sizes, the average gold extraction increased to 80.5 percent for -10 mesh and 87.9 percent for 80% passing -200 mesh. The addition of a gravity step to recover potential coarse gold further increased the average gold recovery at 80% -200 mesh from 87.9 to 89.9 percent, so coarse gold is not an important factor in this material. Table 1 below presents the column leach test results along with bottle-roll leach test results of the finer material.

Although free native gold particles were present, the average column-leach (-3/4 inch crush) gold extraction was only about 10 percent lower than the milling scenario with a gravity circuit. Run-of-mine heap leaching would require less capital and have lower operating costs.

Rare Element Resources Ltd (TSX-V:RES) is a publicly traded mineral-resource company focused on gold and strategic metals such as the rare-earth elements. Rare Element and Newmont have entered into the Sundance gold exploration project on the Company's Wyoming property. Newmont has the right to earn a 65% working interest in Rare Element Resources' property, excluding any rights to the rare-earth elements and uranium, but including rights to gold and other metals, by performing US$5 million in property work expenditures over a five-year period. Newmont also has the right to earn an additional 15% working interest by completing a positive project feasibility study.

Rare Element Resources' Bear Lodge, Wyoming property also encompasses one of the largest disseminated rare-earth occurrences in North America (M.H. Staatz, 1983, US Geological Survey Professional Paper 1049-D). In parallel with the Sundance gold-focused exploration project, Rare Element Resources has completed drilling of eight holes to independently advance the rare-earth potential of its property and is currently conducting a rare-earth metallurgical testing program.

ON BEHALF OF THE BOARD Donald E Ranta, PhD, PGeo, President & CEO

Donald E. Ranta, PhD, PGeo, serves the Board of Directors of the Company as an internal, technically Qualified Person. Technical information in this news release has been reviewed by Dr. Ranta and has been prepared in accordance with Canadian regulatory requirements that are set out in National Instrument 43-101. This news release was prepared by Company management, who take full responsibility for content. The TSX Venture Exchange has not reviewed, and does not accept responsibility for the adequacy or accuracy of this release.

Table 1 Metallurgical results for Sundance Composite gold samples from Taylor core hole SUN-013c (Composites A & B) and Carbon core hole SUN-011c (Composites C & D); (1ppm = 1 g/t). ------------------------------------------------------------------------- Reagent Consumption, Calculated kg/t Residue Head Extraction, --------------- Composite ID Test ID Au, ppm Au, ppm % NaCN Ca(OH)(2) ------------------------------------------------------------------------- ------------------------------------------------------------------------- Composite A Column 0.06 0.34 81.3 0.00 0.0 ------------------------------------------------------------ -10 Mesh 0.07 0.30 77.3 0.11 1.8 ------------------------------------------------------------ 80% -200 Mesh 0.04 0.30 88.4 0.04 1.4 ------------------------------------------------------------ Gravity+ Tails Cy 0.03 0.53 94.3 0.02 1.6 ------------------------------------------------------------------------- ------------------------------------------------------------------------- Composite B Column 0.19 0.50 63.3 0.00 0.0 ------------------------------------------------------------ -10 Mesh 0.15 0.58 74.6 0.13 2.0 ------------------------------------------------------------ 80% -200 Mesh 0.08 0.60 86.9 0.04 2.1 ------------------------------------------------------------ Gravity+ Tails Cy 0.07 0.60 88.2 0.01 1.7 ------------------------------------------------------------------------- ------------------------------------------------------------------------- Composite C Column 0.04 0.45 91.0 0.00 0.0 ------------------------------------------------------------ -10 Mesh 0.06 0.58 89.9 0.18 3.7 ------------------------------------------------------------ 80% -200 Mesh 0.03 0.57 95.1 0.11 4.5 ------------------------------------------------------------ Gravity+ Tails Cy 0.04 0.62 92.9 0.10 4.6 ------------------------------------------------------------------------- ------------------------------------------------------------------------- Composite D Column 0.09 0.38 78.1 0.00 0.0 ------------------------------------------------------------ -10 Mesh 0.07 0.37 80.0 0.19 3.4 ------------------------------------------------------------ 80% -200 Mesh 0.07 0.38 81.1 0.10 4.0 ------------------------------------------------------------ Gravity+ Tails Cy 0.07 0.43 84.2 0.08 3.5 -------------------------------------------------------------------------

CONTACT: refer to the Company's website at http://www.rareelementresources.com/ or contact: Donald E Ranta, President & CEO, (604) 687-3520, don@rareelementresources.com; Mark T. Brown, CFO, (604) 687-3520 ext 242, mtbrown@pacificopportunity.com

Rare Element Resources Ltd.

CONTACT: refer to the Company's website at http://www.rareelementresources.com/or contact: Donald E Ranta, President & CEO, (604) 687-3520,don@rareelementresources.com; Mark T. Brown, CFO, (604) 687-3520 ext 242,mtbrown@pacificopportunity.com

Source: PRNewswire-FirstCall

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