Nov 17 2010
Elissa Resources reports that extensive surface exploration on its 100% owned Thor REE Project has defined several strongly anomalous REE bearing discovery zones, all of which are large enough and rich enough to constitute targets of significant exploration interest.
Assays of samples from each zone indicate that the REE mineralization is unusually enriched in HREE (Heavy REE), which are typically rarer and much more valuable than the LREE (Light REE).
The Thor REE Project is located in the eastern Mojave Desert Region, 119 km (74 miles) south of Las Vegas, Nevada and 32 km (20 miles) east of Molycorp's Mountain Pass REE Mine, California. The Project consists of 198 contiguous unpatented lode mining claims, totalling approximately 1,481 hectares (3,660 acres). Work carried out by Elissa to date includes surface mapping, a district-scale detailed high-resolution airborne magnetic geophysical survey, extensive ground radiometric surveys, satellite imagery studies, petrographic studies, and sampling programs including channel sampling and the sampling of historical surface workings that are remnants of a 1950s uranium-thorium prospecting rush. This work has identified significant REE ± thorium mineralization in nine widely separate prospect localities within three discovery zones known as the Lopez Trend, the Black Butte area and the NED area. A fourth area of interest is the Santos Trend.
The Thor Project occurs in Precambrian rocks somewhat similar to those at the neighbouring Mountain Pass Mine, site of the world's largest and richest REE mine until closure in the 1990s. The owner of the Mountain Pass Mine, Molycorp (NYSE-MCP), is in the process of reopening the mine due to the recent upsurge in REE prices. Elissa's work indicates that the REE mineralization at Thor may be quite different than that at Mountain Pass, where the REE occur in an igneous carbonate body mainly as a carbonate mineral (bastnasite) that is rich in LREE but contains only scant amounts of the more valuable HREE. At Thor, the REE occur in structurally-controlled zones consisting of phosphate minerals (monazite-apatite-xenotime) which are unusually enriched in HREE.
To date, Elissa has collected 127 total rock samples from the Thor Project, mostly continuous channel samples taken across widths of one to several metres from limited rock exposures throughout the project area. More than half of these samples (70 total) returned assays showing anomalous (>0.1%) to very significant (>0.5%) amounts of REE, with at least 22 samples returning assays of 1.2% to 10.6% (average 2.6%) total REE. These 22 higher-grade samples represent various targets within each of the several separate discovery zones. Significantly, they are unusually enriched in HREE, with the HREE comprising 2.6% to 9.3% of the total REE present in the samples.
The Lopez Trend
The most important discovery zone identified to date in the Thor Project is the Lopez Trend. It consists of a mostly covered, 2.5-km (1.2 mile) long structural zone, 50 to 150 m (230-500 feet) wide, that is intermittently marked by anomalous radioactivity and/or REE±Th bearing samples along its length. Much of the trend is concealed by alluvial cover, which effectively masks bedrock radioactivity from Thorium (Th), a common associate of the REE mineralization. Sampling to date has therefore been largely confined to exposures in old prospect trenches and workings widely scattered along the trend. Elissa's recent high resolution airborne magnetic survey, combined with extensive detailed surface radiometric traverses using a sensitive, multi-channel spectral scintillometer, indicates the trend may be continuous through the covered areas, and this work also suggests the presence of a second sub-parallel trend (the Santos Trend) in a covered alluvial valley west of the Lopez Trend.
Mineralization along the trend occurs mainly as REE±Th bearing phosphate minerals (monazite-apatite-xenotime) in a network of braided veins, stringers and interstitial masses up to 3.0 m (10 feet) wide. At least half of the 57 total channel samples collected to date from exposures in four widely separate sites along the Lopez Trend have returned total REE contents of at least 0.5%, with one-third of the 57 containing 1.0% to 10.6% total REE. Significantly, HREE account for 2.6% to 9.3% of the total REE values.
Elissa believes that the apparent size of the Lopez Trend together with REE mineralization of significant grade, plus enrichment in HREE, make this a very compelling target at this time. Recent separate visits by two independent, respected REE specialists, Dr. James Clark, a geological consultant with extensive background and expertise in REE deposits, and Dr. David Jessey, a Cal Poly professor who is very familiar with the geology and REE mineralization of the Mojave Desert Region, confirm that the apparent size and tenor of the Lopez Trend discovery zone is generally similar to other important REE monazite-apatite vein systems of current economic importance, such as Hoidas Lake in Saskatchewan and Steenkampskraal in South Africa. With high REE grades and enrichment in the valuable HREE, these systems offer attractive, viable exploration targets.
Other REE Target Areas
Other encouraging REE areas identified to date in the Thor Project include the Black Butte and NED areas, both of which deserve further exploration scrutiny.
Black Butte is a distinct circular to arcuate intrusive complex with two zones of structurally controlled REE mineralization. The mineralization is generally similar to that encountered along the Lopez Trend. One zone extends for at least 550m (1,800ft) along strike before disappearing beneath alluvial cover. This zone is perhaps a fault offset portion of the Lopez Trend. Values from samples taken in the Black Butte discovery area range from anomalies to 1.3% total REE; the samples show enrichment in HREE similar to those from the Lopez Trend.
REE mineralization in the NED area occurs in a mostly concealed, small outcrop (16 m x 5 m) located approximately 1.6 km (1 mile) east of the northern end of the Lopez Trend. The outcrop consists of a dark-coloured (biotite-rich) radioactive igneous rock that averages about 1.50% total REE. Petrographic studies indicate that this is an unusual magmatic rock with REE-bearing monazite occurring as disseminated inclusions in biotite. The mineralization is likely of magmatic origin, suggesting that the outcrop could be merely the small part of a much larger, but concealed igneous body. The REE mineralization, like that in the Lopez Trend and Black Butte area, is enriched in HREE.
The Thor REE Project area is readily accessible by road, with climate and terrain favouring year-around exploration activities. Elissa plans to continue exploration this winter, focusing detailed work on the known REE-bearing zones. The company has received the necessary permits to commence with an extensive trenching program and expects to soon submit permit applications for a series of shallow "outcrop holes" to be drilled along strike of the REE-bearing zones. Other planned exploration programs include preliminary mapping and sampling of additional promising areas found during recent reconnaissance; test the viability of biogeochemical sampling to prospect covered bedrock areas; conduct ground geophysical gravity and magnetic surveys to help define character and depth of promising bedrock areas; and, initiate environmental base line studies for permitting a deeper and more extensive core drilling campaign.
The technical information outlined in this news release, has been reviewed and approved by Mel Klohn, PGeo, a Director of Elissa Resources Ltd. and a Qualified Person under National Instrument 43-101.
Source: Elissa Resources