Great Plains Metals Corp. press release
Sienna Gold Inc. - Igor geological update
TSXV - TSX Venture Exchange · Gold · Copper · Molybdenum · Rare Earth Elements · Uranium · Canada
CALGARY, Sept. 25 /CNW/ - Sienna Gold Inc. (SGP.V TSX Venture Exchange) ("Sienna" or the "Company") is pleased to present an update on the IGOR project as reported by Dr. Warren Pratt.
The company today makes available a detailed geological report on the IGOR concession by Dr. Pratt, the Company's principal geological consultant.
The report is not a 43-101 report and contains no new information on the company's gold resources at Igor, which were the subject of an earlier 43-101 compliant report and news release.
This report summarizes exploration at Igor, controlled by the Company. Igor is a gold and copper target in the Libertad province of northern Perú. Of about 3000 geochemical surface samples gathered at Igor, over 45% contains 1 gram/tonne gold or more.
The report is based on field visits by the author to Igor, first as an independent consultant and later as a Director. These visits emphasized the potential for a porphyry system at Igor, responsible for driving the polymetallic and gold (Au) mineralization of the whole district.
The report discusses 4 styles of mineralization at Igor. They comprise: 1) polymetallic, gold-rich mantos, which are best developed in the Domo Zone; 2) fault and breccia-related gold and polymetallics in the Tesoros zone; 3) oxidised gold in sandstone and porphyry at Callanquitas; and 4) a deeper copper-gold porphyry, underlying the Igor Anticline. The porphyry was intersected in drill holes that are over 2 km apart, giving the Igor porphyry great size potential .
Drilling prior to November 2006 focused on the vein and manto gold potential of Igor. Metallurgical work, comprising cyanide leach tests, was carried out and 43-101 compliant resources were published in early 2008. Subsequent drilling targeted near-surface oxidised gold and deep copper porphyry targets, successfully identifying both. All drilling at Igor has been with HQ and NQ diameter diamond drill core. A rigorous QC/QA procedure was also put in place for work after November 2006, with blanks, standards and check assays of both drill core and surface samples.
In his report, Dr. Pratt interprets the mantos in the anticline hinge and the Tesoros Zone as mineralized structures on the periphery of, and above, a porphyry copper-gold deposit. The high zinc/lead/silver/arsenic/antimony values in the mantos are consistent with such a setting. Also, the strong sericite, quartz and pyrite alteration of porphyritic dacites is interpreted as hydrothermal alteration on the flanks of, or above, a porphyry system. This interpretation is supported by the occurrence of pebble dykes.
The author draws attention to the similarities between Igor and the Cerro Corona copper-gold porphyry mine (Gold Fields) and the El Galeno copper/molybdenum/gold porphyry, recently sold to China Minmetals Non-Ferrous Metals Co and Jiangxi Copper Company Ltd. Both of these projects are located north of Igor, in Cajamarca.
El Galeno has Measured and Indicated Resources of 803 Mt at 0.63% copper-equivalent. It is hosted by sills, dykes and stocks of Miocene porphyry emplaced into Cretaceous sandstones and resembles a laccolith. It is important to emphasize that the pattern of mineralization around complex intrusions, such as El Galeno, differs significantly from the classic porphyry model of a cylindrical stock (Lowell, and Guilbert, 1970). Likewise, Igor is probably controlled by sills and dykes.
An oxidised gold resource of 19.4 Mt at a grade of 0.65 grams per tonne of gold (plus a sulphide resource of 21 Mt at 0.93 grams per tonne of gold) sits on one flank of the El Galeno porphyry and is hosted by Cretaceous sandstones (Hilo Rico). Recent drilling at Igor has identified the potential for a similar oxidised gold resource, hosted by Cretaceous sandstones and porphyry intrusives in the Callanquitas area.
Significant lead/zinc/silver mineralization has been discovered recently in the hanging wall of a thrust fault at Hilo Rico (El Galeno) and is an extension to the oxidised gold resource. The high grade lead/zinc zone at Tesoros, which post datesporphyry mineralization, may reflect a similar mineralized extension at Igor.
The current drill program intends to demonstrate the copper/gold grades, the size of the potential deposit, and how it is spatially located at the Igor property.
To review the entire report please visit our web site at www.siennagold.com. It is also filed on SEDAR.
This press release has been reviewed and approved by Murray Lytle, P.Eng., the Company's Qualified Person.
The TSX Venture Exchange has neither approved nor disapproved of the information contained herein.
Statements in this press release regarding the Company's business which are not historical facts are "forward-looking statements" that involve risks and uncertainties, such as estimates and statements that describe the Company's future plans, objectives or goals, including words to the effect that the Company or management expects a stated condition or result to occur. Since forward-looking statements address future events and conditions, by their very nature, they involve inherent risks and uncertainties. Actual results in each case could differ materially from those currently anticipated in such statements.
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