EXMIN Restarts Metallurgical Testing on High-Grade Gold Bearing Rock From the Reyna De Oro Mine, Chihuahua, Mexico
EXMIN Resources Inc. (EXMIN) (TSX VENTURE: EXM) is pleased to announce the restart of metallurgical test work on gold-rich mineralized rock from the historic Reyna de Oro mine as part of the ongoing evaluation of the Reyna de Oro project. EXMIN has also been approached by private investors potentially interested in producing from small, at or near surface, high grade gold occurrences, via earn-in joint venture or outright purchase.
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 for complete assay data).
The cyanide leach characteristics of the bulk samples will be determined by bottle roll and column leach tests to determine the viability of producing gold from the mineralization exposed at and near the surface. EXMIN had preliminary tests completed in 2006, at the facilities of the Servicio Geologico Mexicano (the Mexican Geological Survey), in Chihuahua. The tests consisted of bottle rolls of two composites from reverse circulation drill cuttings obtained from EXMIN’s previous drill programs. These two samples responded well to cyanide leaching, yielding recoveries of 87.81% and 90.06% over 72 and 48 hours, respectively (see Table 1 below).
Karl Boltz, Co-founding President, CEO and Director for EXMIN, stated, “The Reyna de Oro project was one of our first projects as a private company and later as a newly public company. Drill programs we conducted in 2004 and 2005 were successful in identifying mineralization on the property. EXMIN drilled the mineralization that is exposed in the historic mine area and that is contained within a 20 hectare concession block. We developed a high confidence level in the deposit, where the mineralization was drilled, although we have not yet completed the work required to qualify an NI 43-101 compliant resource at the former mine.”
Since 2004, EXMIN’s ongoing regional exploration has identified large-scale targets on the surrounding 14,800 hectare project land package, including a potentially significant eastern extension of the mine mineralization. The metallurgical testing of bulk samples being taken will help EXMIN qualify an NI 43-101 compliant resource for the Reyna de Oro project. Initial metallurgical testing in the form of bottle rolls on pulverized drill cuttings indicates that the material tested is amenable to cyanide leaching.”
Reyna De Oro Project
The Reyna de Oro project, located in the prolific Sierra Madre Precious Metal Belt in southwestern Chihuahua State, was one of the first acquired by EXMIN. The project land package consists of 7 concessions, covering 14,800 hectares, in a well mineralized region adjacent to the land packages of several producing mines or development and exploration projects, including the El Sauzal mine (Goldcorp), the Bolivar property (Dia Bras), Bahuerachi (Jinchuan, formerly Tyler Resources), and Urique (EXMIN-Yale joint venture).
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.
The Reyna de Oro project covers multiple mineralized areas and hosts high quality exploration targets of several types, including bulk tonnage gold targets such as at the Reyna de Oro mine and the Reyna east extension, intrusion-related copper and polymetallic mineralization in veins surrounding a granodiorite stock east of the Reyna de Oro mine, as well as structural zones that host epithermal gold-silver mineralization at Balojaque, south of the Reyna de Oro mine and La Currita, to the north.
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.
Reyna De Oro Mine
Many small mine workings and several old rustic mills attest to the mining history at Reyna de Oro. Gold-bearing mineralization, consisting of moderate to strong quartz veins and stockworks as well as silicification, exhibits both stratigraphic and structural controls and is largely hosted by a relatively flat-lying sequence of clastic and volcaniclastic rocks. 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.
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 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.
Table 1. Data for metallurgical samples from the Reyna de Oro mine ————————————————————————— Sample Weight (kg) Au (g/t) Comments ————————————————————————— ————————————————————————— Present Study ————- RDO-MET 1 216.45 2.16 From Vicente adit area 2.33 —- Average 2.25 RDO-MET 2 222.91 7.37 From Cuse adit 6.93 —- Average 7.15 Previous work ————- RDO MEX 1 28.3 4.20 Mixed composite-RC drill cuttings; gold recovery of 87.81% over 72 hours RDO MEX 2 27.0 8.76(i) Oxide composite-RC drill cuttings; gold recovery of 90.06% over 48 hours ————————————————————————— (i) Average of three analyses, 8.69, 9.2 and 8.5 g/t Au. Table 2. Selected intercepts from 2004 and 2005 drilling, Reyna de Oro mine(i) ————————————————————- Drill Hole Intercept (m) Au (g/t) Ag (g/t) Cu (%) ————————————————————- RDO-04-R3 25.9 4.02 2.9 0.18 includes 10.7 7.17 3.3 0.09 RDO-04-R4 19.8 1.32 2.9 0.22 RDO-04-R5 32.0 2.17 1.3 0.42 includes 13.7 4.05 2.7 0.66 RDO-04-R6 18.3 6.14 4.1 0.55 RDO-04-R7 18.3 1.37 2.0 0.98 RDO-04-R8 48.8 1.61 0.4 0.07 includes 27.4 2.08 0.8 0.13 RDO-04-R9 9.1 2.08 1.0 0.13 24.4 0.93 0.9 0.14 RDO-04-R10 33.5 2.03 4.4 0.27 includes 7.6 4.80 7.3 0.21 RDO-05-R13 4.6 5.35 2.4 0.22 RDO-05-R15 19.8 1.84 7.4 0.10 22.9 2.94 6.6 0.64 includes 9.1 6.49 8.7 0.78 RDO-05-R16 15.2 1.19 1.0 0.08 13.7 7.85 7.2 0.89 Includes 3.0 25.41 20.3 2.26 RDO-05-R21 29.0 0.93 3.3 0.15 includes 6.1 1.60 4.4 0.49 ————————————————————- (i) Data was previously released and is included here for the purpose of clarity.
Drill samples were prepared and analyzed by ALS Chemex and BSI Inspectorate in their facilities in Mexico and Vancouver, respectively. Gold analyses were performed by 30 gram fire assay with an AA finish; samples with more than 10 g/t gold were analyzed by fire assay and gravimetric methods at Chemex, and samples with more than 3 g/t gold were checked by gravimetric methods at Inspectorate. Silver and the base metals were analyzed as part of a multi-element ICP package using an aqua regia digestion at Inspectorate, and by AA at Chemex; samples with more than 1% base metals were analyzed by AA. EXMIN undertook a quality control program whereby standard pulps and RC blanks were inserted into the sample stream, and duplicate and second-lab check samples were completed.
For the metallurgical samples, gold analyses by the Servicio Geologico Mexicano samples were by fire assay.
Dr. Craig Gibson, PhD., Certified Professional Geologist, and Executive Vice President of Exploration, is the authorized professional geologist for EXMIN Resources Inc. and the direct manager of all technical programs and information on the part of EXMIN.
EXMIN Resources Inc. (EXMIN) is currently focused on the exploration and development of precious metal properties of exceptional merit in the Sierra Madre gold belt of Northwestern Mexico as well as in other highly mineralized areas of Mexico.
Note: EXMIN Resources Inc. (EXMIN) has taken all reasonable care in producing and publishing information contained in this news release. Material in this news release may still contain technical inaccuracies, omissions or typographical errors, for which EXMIN assumes no responsibility. This news release may include certain “forward-looking statements” including but not limited to comments regarding predictions and projections. All statements, other than statements of historical fact, included in this news release, including, without limitation, statements regarding potential mineralization, exploration results, and future plans and objectives of EXMIN, are forward-looking statements that involve various risks and uncertainties. There can be no assurance that such statements will prove to be accurate, and actual results and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from the Company’s expectations are disclosed in documents filed from time to time with the regulatory authorities.
The TSX Venture Exchange has not reviewed this release and does not accept responsibility for the adequacy or accuracy of this news release.
Contacts: EXMIN Resources Inc. Karl J. Boltz Co-Founding President & CEO 1-866-493-9646 or 1-866-49-EXMIN Email: email@example.com Website: www.exmin.com
SOURCE: EXMIN Resources Inc.