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Azteca Guerra al Tirano Silver / Gold Project
(The following text has been extracted from the 43-101 technical reports) Summary: The Guerra al Tirano (GAT) Silver/Gold Project property consists of three mining concessions in the Tèmoris district in the Sierra Madre Occidental, located in southwestern Chihuahua State, Mexico. In aggregate the three concessions cover 94.5 hectares. Azteca Gold has executed an option agreement to purchase the property and now owns 100% of the Project. Prior to Azteca’s involvement, no systematic geologic mapping, sampling, or exploration work has been done on this property. There are, however, shallow historical mine workings to a depth of 120 meters dating from the early 1900’s on the property. Historical production is unknown. Azteca Gold has recently undertaken a 5,000 meters drilling campaign where five core drill holes and 30 reverse circulation drill holes were completed. Analytical results of this drilling program are pending. Location: The GAT Project area is located in the southwestern corner of the state of Chihuahua (Click here to view location map). The nearest town is Tèmoris which has a population of about 5,000. Tèmoris is about 9 hours by road southwest of the city of Chihuahua. The property consists of three mining concessions in the Tèmoris district in the Sierra Madre Occidental. In aggregate the three concessions cover 94.5 hectares. These concessions are “exploitation claims” as defined by the Mexican Mining Law. The Guerra al Tirano, Reyna de Oro, and Tres de Mayo concessions are current with respect to both tax and "comprobaciones de obra" (annual work expenditures required under Mexican Mining Law). The Guerra al Tirano Ejido holds surface ownership in the area of proposed exploration. Ejidos are communal farms where individuals have title to specific plots of land, but most land-use decisions must be made by the community as a whole. Azteca has obtained written permission from the Ejido for exploration and exploitation of the Guerra al Tirano Silver/Gold Project. History: The representative and partial owner of the Guerra al Tirano property, Jesus Quintana, reports that the property has had intermittent production of “high-grade” silver-gold ore since the early 1900’s. Based on the extent of underground workings which show 150 meters of development along strike, 185 meters down-dip, and an average stope width of 2 meters it is likely that the mine has produced between 75,000 and 125,000 metric tons of ore. Although there is currently no production, the inclined “Main Shaft” reaches to a depth of 125 meters. The hoist is operational and the workings are still accessible. Geology: The Guerra al Tirano Silver/Gold Project lies near the western edge of the Sierra Madre Occidental, a north-northwest-trending volcanic plateau that separates the southward extension of the Basin and Range Province of the southwestern United States into two parts. The property is located near the boundary between the Sierra Madre Occidental and western Mexican Basin and Range Province. Basement rocks in the Sierra Madre Occidental are obscured by Cenozoic volcanic flows, tuffs, and related intrusions but are inferred to include Proterozoic basement rocks, overlying Paleozoic shelf and eugeosynclinal sedimentary rocks, possibly scattered Triassic-Jurassic clastic rocks, and Mesozoic intrusions (*). The project area lies southwest of the west-northwest to northwest-trending Mojave-Sonora Megashear, along which an estimated 700-800 km of left-lateral slip is thought to have occurred during the Jurassic (*). Cenozoic magmatic rocks in northern Mexico, including the Sierra Madre Occidental, are generally thought to reflect subduction-related continental arc magmatism that slowly migrated eastward during the early Tertiary and then retreated westward more quickly, reaching the western margin of the continent by the end of the Oligocene (*). The eastward migration is represented in the Sierra Madre Occidental by the Late Cretaceous-Paleogene “lower volcanic series” or Nacozari Group, of calc-alkaline composition. Over 2,000 meters of predominantly andesitic volcanic rocks, with some interlayered ash flows and associated intrusions, comprise the lower volcanic series. Rhyolitic ignimbrites and flows, with subordinate andesite, dacite, and basalt, formed during Eocene and Oligocene caldera eruptions. These volcanic rocks form a one kilometer thick unit that unconformably overlies the lower volcanic series andesitic rocks and constitutes the “upper volcanic supergroup” of the Sierra Madre Occidental (*). The upper volcanic supergroup is also commonly referred to as the upper volcanic series, or Yecora Group. The ignimbrites are gently dipping to flat lying. As the magmatic arc retreated to the western edge of the continent, becoming inactive by the end of middle Miocene time, late Oligocene to Miocene (24-17 Ma) basaltic andesites were erupted in a backarc basin in the Sierra Madre Occidental. Still younger alkali basalts related to Basin and Range extension are found in and east of the range. Although there appears to have been little late Cenozoic extension in the Sierra Madre Occidental itself, extensional Basin and Range-type structures and ranges formed to the east and west. A gold-silver metallogenic province that hosts low-sulfidation epithermal polymetallic gold-silver deposits lies along the western margin of the Sierra Madre Occidental. This province appears to exhibit a regional zonation of silver-rich deposits (Au:Ag ratios of 1:150) to the west and gold-rich deposits (Au:Ag of 1:40) to the east (*). Guerra al Tirano, a silver-rich deposit, lies in the western part of this province. In the Tèmoris mining district, the lowest exposed unit of the lower volcanic series consists of rhyolitic flows and volcaniclastic units and related shallow intrusions. These are overlain by andesitic flows and epiclastic rocks with related andesitic porphyry intrusions. Local pillow lavas and limestone within the andesitic sequence attest to their deposition in a subaqueous environment. These rocks are probably part of the upper Cretaceous Tarahumara Formation. Mineralization in the Tèmoris/Guerra al Tirano district, which is hosted in andesites of the lower volcanic series, may be synchronous with nearby dacite and rhyolite intrusions, which form prominent cliffs to the north of the mine area. The lower volcanic series exhibits regional propylitic alteration. Structural extension in the district takes the form of what are interpreted to be listric normal faults striking north-south to north-northwest, with west-northwest-trending flexures, as well as dilation of west-northwest-trending fractures, caused by strike-slip faulting. Mineralization in the Guerra al Tirano Silver/Gold Project area, including prospects outside of Guerra al Tirano, consists of epithermal, low sulfidation, silver-gold vein/breccia deposits occurring in north-northwest-striking and west-northwest-striking structures. This deposit type is common within the silver-gold metallogenic province of the Sierra Madre Occidental, and accounts for much of the historic gold and silver production from the province. The vein/breccia/stockwork bodies are characterized by pervasive silicification, quartz-fill expansion breccias, and sheeted veins. Silicification and quartz stockwork veining extend 2 to 4 meters into the footwall and 2 to 6 meters into the hangingwall of the vein. Sulfides are generally less than 1% to 3% in unoxidized rocks and iron oxide staining is weak to moderate at the surface. Argillic alteration consists of 30% to 60% clay with 2% to 10% limonite/goethite and occasional patches of manganese oxide staining. Structure: The quartz vein at Guerra al Tirano lies along a major north-northwest trending normal fault. The fault dips 50 to 75 degrees to the east. It has a strike length on the property of at least 1.4 km and extends to the northwest a distance of 11 km to the Palmarejo Silver/Gold Project operated by Coeur D’Alene Mining Corp (CDE). In outcrop and underground workings the Guerra al Tirano fault zone is mineralized over a width of 2 to 17 meters with banded quartz vein, quartz vein stockwork breccia, and silicification. A parallel post-mineral fault lies about 10 meters into the hangingwall. This fault has 0.5 meters of clay-gouge, uncemented breccia, and strong manganese staining. The mineralization has a down-dip extent of at least 185 meters from the surface to the deepest mine accessible working. Mineralogy: Guerra al Tirano is a classic low-sulfidation silver-gold epithermal system. Banded milky quartz veins host trace amounts to 3% combined of argentite, acanthite, chalcopyrite, pyrite, and galena. High-grade silver mineralization contains visible black bands of argentite/acanthite within the banded quartz veins. The main quartz vein generally is 0.5 to 2 meters wide. The adjacent footwall and hangingwall quartz stockwork/silicified zones extend up to 7 meters away from the vein. The maximum total width is about 17 meters. Although the quartz vein/stockwork zone on the property has a continuous strike length of at least 1,250 meters, the higher grade mineralization is not evenly distributed along the strike of the mineralized zone. This is normal in epithermal vein systems. Economic mineralization of higher grade and greater width occurs at fault intersections and at bends in the mineralized structure. The main mine workings lie in a zone of greater structural complexity where the vein/fault intersects minor N25W striking fractures. The general strike of the vein changes here from due north to N20W. Exploration: Azteca Gold began its initial investigation of the Guerra al Tirano Silver/Gold Project in 2004. A prominent quartz vein with at least 1.4 kilometers of strike length on the Guerra al Tirano, Reyna de Oro and Tres de Mayo concessions was recognized. Based on surface observations of vein textures, widely-spaced secondary quartz veins, multiple stages of brecciation and silicification, and wall rock alteration, Azteca management concluded that the property has potential for both a high-grade underground silver - gold resource and, possibly, a bulk-minable low-grade open pit resource with high-grade zones. In addition to the many favorable geologic characteristics of the Guerra al Tirano Silver/Gold Project target area, the lack of any modern exploration or drilling of the vein system suggested that the target area is essentially untested in all directions. Adjacent Properties: As shown on Figure 3, the Guerra al Tirano Mayo project area falls near the middle of an historically productive silver-gold belt characterized by faults filled by quartz veins, silicified breccias, and, in some instances, manto-like precious metal replacement of limestones. In just the past few years this historic silver-gold belt has become the focus of modern exploration activity. This re-emergence of exploration activity has lead to some major gold-silver discoveries, including the El Sauzal deposit acquired by Glamis Gold, the Palmarejo discovery by Bolnisi Gold NL, the Monterde discovery by Kimber Resources, the Ocampo discovery by Gammon Lake Resources, and the Mulatos discovery by Alamos Gold. Many other historic gold-silver districts in this region are also being investigated by a number of companies. The El Sauzal deposit, 30 miles southeast of Guerra al Tirano (Figure 3), is the most advanced of the near-by projects. Glamis Gold began mining and milling at El Sauzal in late 2004. Glamis announced that El Sauzal produced 191,586 oz gold in 2005 (*). Production at El Sauzal is estimated to average 190,000 oz gold per year over a 10-year mine life and at an average cost of about $110/oz gold (*). The Palmarejo Silver/Gold deposit is 12 km northwest of Guerra al Tirano (Figure 3) and lies on strike and along the same regional shear zone that hosts the mineralization at Guerra al Tirano (*)Bolnisi Gold NL began exploring the district and has been drilling since 2003 (*). Mine Development Associates of Reno, Nevada released a 43-101 report in December of 2004 on behalf of Bolnisi Gold NL (*). Coeur d’Alene Mines Corporation announced in July, 2007 that it has completed due diligence on its planned $1.1 billion purchase of Bolnisi Gold NL and Palmarejo Silver and Gold Corporation and expects to close the deal in the fourth quarter of 2007.
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