LONDON, UNITED KINGDOM--(Marketwire - July 21, 2010) - Orsu Metals Corporation (TSX:OSU)(AIM:OSU) ("Orsu", or the "Company") provides an update of on-going work at the Talas and Tokhtazan exploration licence areas of north west Kyrgyzstan.
Talas Update
A metallurgical study was conducted at the Dawson Metallurgical Laboratories (which is independent of Orsu), Salt Lake City, Utah, United States. The works were performed on ten (10) initial composites and four (4) additional composites made from 2 metre interval core samples from the Taldybulak prospect.
The initial ten (10) composites consisted of two (2) oxide and eight (8) sulphide samples. The composites also represented different copper ore types with high or low grades of gold or molybdenum. Characterization test work on each of the ten (10) initial composites was conducted at a target primary grind of 80% passing 75 microns and included the following procedures:
In the ten (10) initial composites copper grade averaged 0.256% Cu, the average gold grade was 1.1 g/t Au and the average molybdenum grade was 0.013% Mo. Liberated gold grains were observed in seven (7) of the ten (10) composites at a grind size of P80=75 microns. The predominant oxide copper mineral was malachite; the predominant sulphide copper mineral was chalcopyrite with some bornite. Fine (<34 microns) sulphide locking with gangue was observed in most composites. The ten initial composites were low in platinum (0.041 g/t Pt) and low in arsenic (0.003% As).
Four (4) additional composites were made up of sulphide (primary) material and graded 0.19% Cu, 0.465 g/t Au and 0.015% Mo. Sulphide copper mineral was primarily chalcopyrite with some bornite and some fine (<34 microns) grained copper minerals locked in the silica gangue. The four (4) additional composites were also low in platinum (0.004 g/t Pt) and low in arsenic (<0.002% As).
The test results from the fourteen (14) composite samples are as follows:
1. BM Work Index
Closing size 100% passing 106 microns and product average 80% passing 72 microns.
Two (2) Oxides averaged 17 kWh/t
Twelve (12) Sulphides averaged 20 kWh/t
2. Whole Ore Acid Leach
Oxides – copper extraction average 66% and was directly proportional to the amount of oxide copper in composite, with average heads 0.32% Cu(t) & 0.21% Cu(as).
Sulphides – copper extraction average 4% and was not proportional to oxide Cu in composite, with average heads 0.24% Cu(t) & 0.02% Cu(as).
3. Whole Ore NaCN Leach
Oxides – gold extraction averaged 98% and copper extraction averaged 44%, with average heads 0.54g/t Au & 0.33% Cu(t).
Sulphides – gold extraction averaged 94% and copper extraction averaged 14%, with average heads 1.12g/t Au & 0.23% Cu(t).
4. Bulk Rougher Flotation
Oxides – sulphide + oxide flotation recoveries at 60% Cu, 70% Au and 73% Mo, with average heads 0.32% Cu, 0.74g/t Au & 0.004% Mo.
Sulphides – sulphide rougher flotation recoveries averaged 92% Cu, 85% Au & 90% Mo, with average heads 0.24% Cu, 0.98g/t Au & 0.015% Mo.
5. Locked Cycle Testing
A master composite was made from five (5) selected composites. The head grade of the master composite was 0.19% Cu, 0.013% Mo and 0.93 g/t Au. Initial locked cycle test work at high collector dosages provided bulk concentrate recoveries of 88% Cu, 89% Mo and 85% Au, but Cu/Mo separation testing could not make a selective high grade Mo concentrate. Collector dosages were reduced and a second locked cycle test was conducted. Bulk concentrate recoveries were 86% Cu, 87% Mo and 81% Au and Cu/Mo separation test work was more selective. Copper, molybdenum and gold recoveries for the 3rd cleaner concentrate were 88%, 89% and 85%, respectively at grades of 19% Cu, 1.30% Mo and 102 g/t Au.
The Company believes the results of the tests indicate that a potentially sellable copper-gold-molybdenum concentrate grading 19%Cu, 1.30% Mo and 102g/t Au with respective recoveries of 88%, 89% and 85% can be produced from the Taldybulak sulphide ore material. Additional optimisation work on leaching of the floatation tailings fraction and floatation of oxidised material is planned for Q3&4 2010.
Additional information relating to the Talas project is contained in the technical report of Wardell Armstrong International Ltd. entitled "Updated Technical Report on the Taldybulak property held by Orsu Metals Corporation, Kyrgyzstan" dated March 22, 2010 and prepared by Mr J C Osmond and Mr M L Owen.
Tohktazan Update
Orsu conducted metallurgical testwork at the Stewart Assayers Laboratory (which is independent of Orsu) in Kyrgyzstan. Two samples, representing the Northern (TH-1; 344.5 kg) and Southern (TH-2; 333.3 kg) mineralised areas of the Tokhtazan deposit were analyzed using the cyanide bottle roll leaching and percolation column tests. The average grade of ТÐ-1 was 2.35 g/t Au, whereas the average grade of ТÐ-2 was 3.17 g/t Au. Samples were made up of primarily oxidized material collected from drill road cuts at surface.
The NaCN bottle roll test resulted in an 83.7% recovery from -2mm fraction over 72 hours.
The column test of TH-1 (-25 mm fraction) revealed 89.5 to 90% recovery during 32 days. The NaCN consumption was 0.381 kg/t to 0.334 kg/t of ore. Lime consumption was 2.10 kg/t of ore.
The column test of TH-2 (-25 mm fraction) revealed 85.2% to 86.4% recovery during 32 days. The NaCN consumption was 0.331 kg/t to 0.348 kg/t of ore. Lime consumption was 2.02 kg/t of ore.
The Company believes that these results confirm principal amenability of the Tokhtazan ores to heap leaching extraction of gold.
Notes to editor:
FORWARD-LOOKING INFORMATION
This press release contains forward-looking information which is not comprised of historical facts. Forward-looking information involves risks, uncertainties and other factors that could cause actual events, results, performance and opportunities to differ materially from those expressed or implied by such forward-looking information. Forward-looking information contained in this press release includes, but may not be limited to, the Company's expectations and beliefs relating to: the continuation of work at the Talas and Tokhtazan exploration licence areas; the potential for production of sellable copper-gold-molybdenum concentrate (having the grading and recovery estimates set out above) from the Taldybulak sulphide ore materials; and the expected additional optimization work on leaching of the floatation tailings fraction and floatation of oxidized material at the Talas property and the anticipated timing of same.
Factors that could cause actual results to differ materially from those described in such forward-looking information include, but are not limited to, risks normally incidental to exploration and development of mineral properties, uncertainties in the interpretation of results from metallurgical testing and drilling, the possibility that future exploration, development or mining results will not be consistent with expectations, uncertainty of mineral resources estimates, the Company's inability to obtain, maintain, renew and/or extend required licences and related rights, permits, authorizations and/or approvals from the appropriate regulatory authorities and other risks relating to the political environment and regulatory and/or legal framework in Kyrgyzstan, adverse changes in commodity prices or the Talas joint venture, as well as certain other risks set out in the Company's public documents, including its annual information form dated March 24, 2010, filed under the Company's profile on SEDAR at www.sedar.com.
The forward-looking information in this press release reflects the current expectations, assumptions and/or beliefs of the Company based on information currently available to the Company. In connection with the forward-looking information contained in this press release, the Company has made certain assumptions about the Company's business, the economy and the mineral exploration industry in general, the Company's continued exploration at the Talas project, the regulatory framework in Kyrgyzstan with respect to, among other things, the Company's ability to obtain, maintain, renew and/or extend required permits and related rights, licences, authorizations and/or approvals from the appropriate regulatory authorities, the political environment in Kyrgyzstan, no material adverse change in the price of gold occurs, the Company's ability to continue to obtain qualified staff and equipment in a timely and cost-efficient manner to meet the Company's demand, and has also assumed that no unusual geological or technical problems occur, plant and equipment work as anticipated and no significant events occur outside of the Company's normal course of business. Although the Company believes that the assumptions inherent in the forward-looking information are reasonable, forward-looking information is not a guarantee of future performance and accordingly undue reliance should not be put on such information due to the inherent uncertainty therein.
Any forward-looking information speaks only as of the date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking information, whether as a result of new information, future events or results or otherwise.