Location
Santa Rosa is located some 100km north of Lima, Peru, just 4 hours drive from the capital at an altitude of 4,000-4,500m above sea level. Geologically, the property lies within the prolific Central Peru Polymetallic Belt.
Several world class silver, lead and zinc mines owned by major operators such as Panamerican Silver, Buenaventura, Glencore and Volcan lie within 50km radius of the Santa Rosa property. Volcan, the world's fourth largest silver and zinc producer, operates the Shalca Ag-Pb-Zn Mine which borders the Santa Rosa property on its northern end.
History
Santa Rosa is currently owned by a private Peruvian company who staked the 551 hectare property in the 1970's. The property has undergone some small scale production during the last 30 years where it is estimated that approximately 20,000 - 30,000 tonnes of ore were mined. The last recorded production was in 2008, when ore grading around 6 oz/t Ag, 9% Zn and 7.8% Pb was mined exclusively from the Santa Rosa and Milagros zones and sold to a local mining company. The property has never been explored or drilled.
Geology and Mineralization
Host rocks are a steeply dipping sequence of folded quartzites and minor coal seams belonging to the Cretaceous Chimu Formation, and younger overlying andesites belonging to the Tertiary aged Calipuy Formation.
Mineralization occurs within a N-S to NNW-trending corridor along the steep limb of a fold closure and the setting is very similar to the Iscaycruz deposit (the World's highest grade zinc deposit). Iscaycruz lies along strike around 40km north along a parallel structure with the same fault zone as the Santa Rosa property.
Mapping and sampling along 1.5km of underground tunnels in two mines, Santa Rosa and Milagros-Sally, have identified wide intervals of silver, lead and zinc mineralization as massive sulphide veins, breccias and stockworks associated with a system of northeast/southwest to east-west trending splay faults.
Underground samples taken perpendicular to the trend of the structures returned the following results:
Total Length |
Zn % |
Ag g/t |
Pb % |
|
|---|---|---|---|---|
Santa Rosa Level |
53.6 |
4.0 |
32 |
1.0 |
Santa Rosa Level |
27.6 |
3.6 |
43 |
1.8 |
Milagros-Sally Level |
11.3 |
14.6 |
76 |
3.2 |
Milagros-Sally Level |
15.1 |
7.8 |
43 |
2.6 |
The Santa Rosa workings are located some 100m north and at an elevation difference of approximately 60m below the Milagros-Sally workings.
The high-grade mineralization observed in the underground workings, despite being only 50m below the surface at Milagros-Sally, does not outcrop at surface. However, strongly anomalous rock chip sampling of silicified and stockworked volcanic rocks at the Santa Rosa Sur target, 500m south, is believed to represent the surface expression of the extension of the mineralized trend observed in underground. Here, rock chip sampling averaged 0.17 % combined Pb and Zn, with individual assays from trace to 1.7% Pb and 0.7% Zn. Silver values ranged from trace to 1,170 g/t, and averaged 18 g/t. Other targets include Huallay and Huallay Norte approximately 300m to the west of the underground workings, and Zona Oxidos, located some 400m NW respectively, where anomalous rock chip geochemistry in Ag, Pb, Zn and Mn is believed to be a good indicator of the upper parts of the mineralized system.
In the south of the property, the veins are more fissure-type, with local bonanza silver grades, for example at Yanapata where sampling in underground workings gave 160 g/t Ag, 2.8% Pb and 5.4% Zn over 4.75m, including 0.5m @ 619 g/t Ag and 1.0m @ 321 g/t Ag.
Santa Rosa Mine
Underground development has taken place over an area of approximately 140m x 40m on 2 levels. Mapping showed the zone of mineralization to be up to 50m wide (apparent width) in the lower 4267 level and composed of at least 3 massive sulphide veins within broader zones of stockwork mineralization and hosted mainly in andesitic volcanics. Massive sulphide mineralization is composed of mainly sphalerite and galena with minor chalcopyrite. Epithermal vein textures include crustiform quartz and ginguro banding, typical of an intermediate sulphidation vein system. Higher grade intervals included 9.8% Zn, 50 g/t Ag and 0.2% Pb over 4.3m, and 9% Zn, 94 g/t Ag and 5.4% Pb over 4.7m, with individual samples assaying up to 14.1% Zn associated with stockwork sphalerite and galena mineralization in pyritized sandstones.
Milagros-Sally Mine
The underground workings at Milagros-Sally cover an area of approximately 120m x 80m and are less accessible than at Santa Rosa. In the upper 4380 level, 11 samples taken across a zone consisting of several massive sulphide veins and stockworks cutting andesite lavas gave a composite grade of 76 g/t Ag, 3.2% Pb and 14.6% Zn over 11.3m. Individual samples assayed up to 248 g/t Ag, 15.3% Pb and 29.9% Zn over 1m. This structure was observed to form a single vein further into the adit with notable higher quantities of galena.
In the lower level 4340 workings a zone of at least six northeast trending veins with surrounding stockwork mineralization hosted in quartzites were mapped and sampled over a length of 31m with a higher grade portion averaging 43g/t Ag, 2.6% Pb and 7.8% Zn over 15.1m
Drill Results
Five drill holes have been drilled to date by Focus. Drilling has demonstrated silver, zinc and lead mineralization hosted in a quartzite that is blind to surface due to overlying Tertiary-age andesites. Intercepts include high grade, massive sulphide intervals (best intercept DDH-11-03 - 10.8m of 169g/t Ag + 7.8% Zn + 8.3% Pb) and low grade disseminated/fracture-controlled mineralization (DDH-11-02 - 59m of 1.2% Zn from 63m -- 122m). The low-grade, bulk-style mineralization is open to the south and represents a type of mineralization previously unknown to the district and requires further exploration to understand the controls and magnitude. The drill program has been concluded and the Company is currently compiling and assessing the results.
The Agreement
Focus can earn 100% in the property by making cash payments totaling US$9 million over 4 years. For resources defined in Measured and Indicated categories in excess of 5 million tonnes, a royalty of US$1.19 per tonne will be payable.
