Geology of the Culebrilla-Alalaj area


Geology of the Culebrilla property


Silica-tourmaline stockwork veining, Alalaj Zone


Tourmaline breccia dyke, Alalaj Zone


Sampling at Letra Rumi North Cu-Ag+/-Au vein

Culebrilla

Summary

Strait Gold holds a 100% interest (subject to a 3% NSR) on the Culebrilla precious metals property in north-central Peru.

Eleven zones of mineralization with accompanying historical mining are known on the Culebrilla property. Scattered shallow adits and small pits attest to the widespread mineralization found throughout the property. Drilling on three zones in 2007, the first drilling ever conducted on the property, returned anomalous to low-grade gold-silver mineralization.

Detailed mapping and sampling of the veins at Letra Rumi North, one of the known zones at Culebrilla, is planned as well as regional prospecting on the western half of the property in the vicinity of a molybdenum stream sediment anomaly.

Property Description

The Culebrilla Property consists of nine contiguous concessions totalling 6800 ha in the Cordillera Negra of north-central Peru, approximately 325 km north-northwest of Lima, and approximately 14 km northwest from the town of Caraz. The property occurs within the districts of Mato, Huaylas, and Caceres del Peru, in the provinces of Huaylas and Santa, of the department of Ancash.

Strait Gold holds a 100% interest in the Culebrilla property subject to a 3% NSR up to 2% of which can be purchased by Strait Gold for cash payments totalling US$2 million.

Travel to the property is via a 4x4 accessible dirt road beginning 12 km north of the city of Caraz, and heading west up into the Cordillera Negra mountains to the small town of Ancoraca, a travel time of roughly 1 hour from Caraz. From Ancoraca a well established foot path heads north to the centre of the property to the exploration camp, where recent exploration has focused on the Culebrilla-Alalaj areas. Travel time from Ancoraca to the camp is roughly 2-3 hours.

Geology, Alteration and Mineralization

The geology of the Culebrilla property is largely underlain by shallowly dipping intermediate to felsic volcanic tuffs and flows of the Lower Calipuy Group, with flat lying Upper Calipuy Group intermediate tuffs occuring within the southwestern portion of the property, exposed at higher elevations in the Western Ranges. The entire central portion of the propery is intruded by a ~9 km long by ~5 km wide northwest trending Neogene granodiorite intrusion known as the Ancoraca stock.

Precious metal and polymetallic mineralization within Calipuy Group volcanics occurs within a broad arc ~11 km in length around the northern perimeter of this intrusion. A general sense of metal zonation can be observed in this arc, consisting of polymetallic (Pb-Zn) along the northeast margin, precious metal rich (Au-Ag) along the northern margin, polymetallic (Pb-Zn-Ag; Cu-Ag-Au) along the northwest margin, and base metal rich (Cu+/-Mo) with subordinate precious metal (Ag-Au) values along the southwest margin.

Eleven zones of mineralization with accompanying historical mining are known on the Culebrilla property, including: Culebrilla, Caballo, Alalaj, Q.Ancush, Las Pampas, El Plano, Metal Punta, Coyllorcocha, Pistana, Letra Rumi North, and Letra Rumi South. Mineralization in all of these zones, except for Letra Rumi South, tends to be hosted by narrow veins and fracture swarms with vein-hosted sulphide+/-oxide mineralization. Host rocks are predominantly intermediate to felsic volcanic tuffs with only a few showings hosted within granodiorite of the Ancoraca stock. Wallrock alteration is dominated by a propylitic assemblage of silica-chlorite-epidote+/-tourmaline while mineralization is hosted by pyrite-magnetite-hematite with local arsenopyrite and base-metal sulphides. Scattered shallow adits and small pits outside of these principal zones attest to the widespread mineralization found throughout the property.

Culebrilla-Alalaj Area

Exploration on the property between 2004-2005 identified the Culebrilla-Alalaj area (consisting of the Culebrilla, Caballo, Alalaj and Q.Ancush zones), located along the northern margin of the Ancoraca stock, as having the greatest potential for hosting precious metal mineralization. The area is underlain by Lower Calipuy Group volcanics consisting of a basal porphyritic andesite flow unit, overlain by interbedded intermediate to felsic ash and crystal tuffs, volcanic silstones and local quartzite-pebble conglomerates (derived from basement lithologies). Mineralization in the area is characterized by extensive historic workings, wide spread silica+/-clay-chlorite-tourmaline alteration, silicified and/or mineralized structures and well defined gold-soil anomalies.

In 2006 detailed soil sampling, bedrock mapping and ground magnetic geophysics were executed in the Culebrilla-Alalaj area and identifed numerous targets for drilling.

In early 2007, drill permitting, access and camp improvements were initiated in anticipation of a 2000 m diamond drill program which began in late 2007. The drill program was cut short after ~1300 m, due to the onset of the rainy season and unexpected delays in drilling.

Results of the drilling returned weakly anomalous to low grade Au-Ag mineralization associated with widespread propylitic and locally intense porphyry-style phyllic alteration. It was concluded that surface veins were generally discontinuous or poorly mineralized in the subsurface environment in this area. Details of the drill results can be found in the technical report.

Other Showings

Further prospects on the Culebrilla property remain to be fully investigated and warrant further exploration, including:

• Letra Rumi South project (Cu+/-Mo-Ag)
• Letra Rumi North prospect (Cu-Ag+/-Au): consists of two prominent vein sets (northern and southern veins) transecting the contact between intermediate volcanics and granodiorite of the Ancoraca stock. Past sampling on the southern vein has returned up to 8.4% Cu with 304 g/t Ag and 0.8 g/t Au (single grab sample) and 1.3% Cu with 73 g/t Ag and 0.8 g/t Au over 1.3 m (chip sample). The strike of the southern vein has been traced continuously for 1 km on surface.
• Regional anomalies: a >1.2 km long Mo stream sediment anomaly identified in an unnamed valley draining the southern portion of the Rosa Mistica 40 concession, located on the western half of the property.
• Reports of the 2007 Drill Program in the Culebrilla-Alalaj Area, Sampling and Geophyics in the Letra Rumi South Area, Culebrila, Property, Ancash, Peru - March 2008
• Geological Report on Exploration at the Culebrilla Project, Department of Ancash, Peru - September 2005

Malachite stain at Letra Rumi North