Projects
Sierra Blanca
Sierra Blanca (7,000ha) is located 50km N of AngloGold's 6Moz Vanguardia low-sulphidation epithermal gold deposit. First pass exploration identified a series of low-sulphidation epithermal quartz veins over a 7km strike length with a 6m-thick main vein zone extending for 1.6km. Rock chip assays of up to 1.1 g/t Au and 635 g/t Ag have been reported (Lucilla Vein). Geological mapping, rock chip sampling and prospecting by Mariana in 2006 discovered 14 new quartz veins/vein breccias/quartz stockworks trending for at least 12km with vein widths from <1m up to 4m.
In early 2007 Mariana drilled 22 diamond scout drill holes for 2,995m at the Sierra Blanca and Cañadon Largo properties. A total of 18 holes for 2,523m at Sierra Blanca tested eight veins within 13km of mapped and 29km of inferred veins. The veins are strongly anomalous in gold, silver and pathfinder elements, consistent with high-level epithermal silver-gold systems. Ten holes intersected multi-stage quartz veins but six did not reach the planned target, either due to drilling difficulties or structural off-sets.
Highest gold values of 1.2 g/t Au and 24 g/t Ag in hole SB 2 over 1m from 28m, and 1.15 g/t Au and 17 g/t Ag over 0.8m from 36.5m in hole SB4 were obtained. This hole also contained a silver intercept of 113 g/t Ag over 0.9m from 33m.
Despite these disappointing scout drill results, Mariana persisted with geological mapping and prospecting which utilized high resolution IKONOS satellite images. As a result, new vein zones were discovered at Vetarron and Cero Bola. At Vetarron, anomalous rock chips were returned, eg 1.4m @ 1.6 g/t Au, 91 g/t Ag.
A programme of ground geophysics followed which included 55 line-km of IP/Resistivity and 294 line-km of magnetics. The IP was very encouraging with a large system of prospective silicified structures indicated, many with coincident chargeability responses. Importantly, the geophysics indicated that the quartz vein/breccia zones extend under cover.
Subsequent prospecting discovered another vein system at Veta Chala, in the NE Sierra Blanca area. High grade silver and gold assays have been returned from rock chip channel and diamond saw channel sampling of outcropping vein zones, including 9.4 m @ 2,362 g/t Ag 1.3 g/t Au, 3.4m @ 1,238 g/t Ag, 10 g/t Au and 1m @ 25 g/t Au. The E-W Veta Chala trend extends for 1km.
Drilling commenced in mid-September. Approximately 19 separate targets are to be tested by approximately 3,200m of RC and diamond drilling.
The majority of drilling will test the high grade silver-gold mineralization discovered by trenching and surface channel sampling at Veta Chala.
