Multiple Gold and Copper Targets in a Well-Mineralized Region
100% EXMIN
New Results
July 16, 2008
Metallurgical Tests
Two bulk samples were taken from the tabular mineralized body that was previously identified by two drilling campaigns conducted by EXMIN and have been delivered to the metallurgical testing facility. Sample RDO-MET 1 consisted of 216.45 kilograms and assayed 2.25 grams per metric ton (g/t) gold and sample RDO-MET 2 consisted of 222.91 kg and assayed 7.15 g/t gold (please see table below).
The metallurgical work being performed on the Reyna de Oro bulk samples for the current study will consist of bottle rolls and column leach tests. The two samples were taken at a surface exposure and in an underground working, about 70 metres from the entrance, in areas selected as representative of the mineralization encountered by drilling. The samples were taken by EXMIN personnel and were delivered to the metallurgical lab in Chihuahua and were subsequently shipped to Reno.
EXMIN previously completed preliminary metallurgical tests in 2006 on two samples of reverse circulation drill cuttings. The two samples were composites from several holes in order to obtain grades and oxidation characteristics believed to be representative of the deposit. One sample was composed of completely oxidized material, while the second sample contained some sulphide minerals, dominantly pyrite or marcasite. The samples did not respond well to gravimetric concentration, probably due to relatively fine gold particles; however, both samples responded well to the cyanide leaching in bottle rolls, with the oxide sample yielding 90.06% gold recoveries in 48 hours, and the mixed oxide-sulphide sample yielding 87.81% recovery over 72 hours. Cyanide consumption for the sulphide bearing sample was higher as might be expected. Both samples were pulverized to about 50-60% minus 200 mesh. The metallurgical work performed to data is preliminary in nature, and leach characteristics for the bulk samples, which can be crushed to different particle sizes to determine optimal crushing parameters, will be more illustrative.
The metallurgical testing of bulk samples being taken will help EXMIN qualify an NI 43-101 compliant resource for the Reyna de Oro project..
Current exploration
EXMIN was recently awarded an additional 140 hectares contiguous to the existing concessions in a lottery that was originally scheduled for January, 2006, but was delayed due to legal
challenges. These concessions cover a portion of a large structural zone with epithermal gold silver mineralization extending from east of the Reyna de Oro mine to La Currita; grab samples taken by EXMIN in the area assayed as much as 5 g/t gold and 1,080 g/t silver.
EXMIN’s regional exploration work has determined that the large granodiorite intrusion east of the Reyna de Oro deposit is the likely source of the mineralization in the area, and the large area of alteration and mineralization in the rock surrounding the intrusion suggests that a large porphyry related mineralized system, similar to that explored by Tyler Resources at Bahuerachi (recently purchased by the Chinese company Jinchuan Group), located 10 km to the southwest, may be present. Please see EXMIN News Release of November 9, 2005, for more information.
Multiple sampling programs over a 15 year period defined a gold mineralized zone measuring approximately 300 metres along strike and about 75-100 metres down-dip. Most exploration and mining activity to date has concentrated on a 250 metre long portion of the mineralized zone because of existing access. Two phases of reverse circulation drilling were successfully carried out by EXMIN, in 2004 and 2005, confirming the previous exploration results in this part of the deposit: most holes intersected 20-30 metre intervals with 1.5-3 g/t gold, and several significant 5-18 metre intercepts yielded as much as 4-7 g/t gold (see table of drill results below).
The deposit is open along strike and down-dip and further exploration has encountered similar mineralization in the volcanic stratigraphy extending several hundred metres to the east of the area drilled (see EXMIN News Release of August 30, 2005). Part of this area is now accessible by road and will be further explored.
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Introduction
The Reyna de Oro project lies within an intensely mineralized region containing several new mines and exploration projects, including El Sauzal (Glamis/Goldcorp), Cieneguita (Sunburst Mining), Piedras Verdes (Dia Bras), and Bahuerachi (Tyler Resources). Past mining at Reyna de Oro is witnessed by numerous small mines and pits, the presence of several old rustic mills (taunas), and the foundation of a small modern mill.
EXMIN completed 2,200 meters of reverse circulation drilling at its Reyna de Oro mine in 2004 and 2005. Average grades encountered in the Phase I and Phase II programs were 2-7 g/t Au over 15-30 meters, with multiple, locally high-grade intercepts of 7-25 g/t Au. A diamond-drilling program is planned to commence during 2007 to bring the known resource up to NI 43-101 standards and to expand the known deposit.
Summary
Geology
Mineralization at the Reyna de Oro mine is hosted by lower Tertiary volcanic rocks, and is controlled by stratigraphic and structural features. Surface and underground sampling by several groups over the last 15 years defined a 300-meter by 50-meter thick body of gold mineralization with grades of 1-30 g/tonne Au, averaging 2-4 g/tonne.
The Luz de Oro property surrounds the Reyna de Oro mine and contains numerous prospects with precious metal and polymetallic mineralization. The Reyna de Oro deposit may be part of a much larger intrusion-related mineralized system. Regional exploration and prospecting of the large land package has been carried out since early 2005, and has identified widespread precious and base metal mineralization and an intrusive that is central to the regional mineralization at El Sauzal (Glamis/Goldcorp), Piedras Verdes (DiaBras), Cieneguita, and Bahuerachi (Tyler Resources), as well as at the Reyna de Oro mine and surrounding region within EXMIN’s 15,000 hectare Reyna project. EXMIN recently announced the discovery of a new area of high-grade gold mineralization in the area of up to 105 g/t Au at Balojaque, and anticipates making more discoveries in the district.
Exploration
In late 2004, EXMIN completed an 11-hole, 771-meter reverse circulation drill program with excellent results; most holes intersected mineralization of 1-4 g/tonne Au over thicknesses of 20-30 meters (Table), while several holes had higher grade intercepts ranging from 6-11 g/tonne Au over 7-18 meters.
In mid-2005, a second phase of drilling commenced, again yielding significant results, including the following holes: 13.7 m grading 7.85 g/t Au (including 3.0 m of 25.41 g/t Au), and 22.9 m of 2.94 g/t Au (including 9.1 m of 6.49 g/t Au). Following the discovery of what EXMIN believes is the source of mineralization in this area, this phase of drilling was postponed to optimize mapping of the area, as well as to enable the building of road access to the next anticipated target area.
EXMIN has delayed completion of the second phase core drilling at Reyna de Oro pending exploration of the surrounding land package in order to identify additional drill targets.
