Las Calandrias is 5,600 Ha in area and is located in eastern Santa Cruz, 20 km from a paved highway and serviced by the port of Caleta Olivia, 150 km to the NE.
New discovery, no prior company exploration reported.
A cluster of at least 8 Jurassic rhylolite domes and flow domes over an area of about 4 x 3km emplaced in a pyroclastic sequence includes Calandria Sur, Calandria Norte and El Nido domes and flow-domes. The Calandria Sur and Calandria Norte domes host potentially economic gold and silver mineralisation related to widespread hydrothermal sulphidic breccias at Calandria Sur and sulphidic vein-breccias at Calandria Norte. El Nido consists of several lightly explored coalescent rhyolite domes along a northeast trending 3.5 x 2.5km belt west and northwest of the Calandria Sur and Calandria Norte. Veins and sulphide breccias have been identified in outcrop and drilling at dome margins.
Exploration by Mariana Q3/Q4 2008
Follow up of satellite imagery in 2008 discovered quartz-sulphide vein/breccias over two broad zones 600m apart. Initial rock chips assayed up to 21.7 g/t Au, 62 g/t Ag. In early 2009, geological consultant Dr. Richard Sillitoe, recognized that the rhyolite domes had potential for low sulphidation epithermal mineralization.
Sillitoe Tongoril Report February 2009 (pdf)
Follow up of lag gold anomalies discovered further veins at Calandria Norte and breccias at Calandria Sur. Rock chips at Calandria Sur assayed up to 0.8 m @ 5.7 g/t Au and 241 g/t Ag and at Calandria Norte, up to 0.7m @ 20.2 g/t Au, 25 g/t Ag. Trench assays included 17.5m @ 1.9 g/t Au and 56.3 g/t Ag (Calandria Sur) and 2.7m @ 5.4 g/t Au incl. 0.7m @ 20.2 g/t Au 25.4 g/t Ag (Calandria Norte).
Calandria Sur Discovery Q4 2009
Drilling in late 2009 discovered disseminated style gold mineralization at the eastern brecciated margin of the 750 x 350m Calandria Sur dome in holes CSD 9, 12, 13, 15 and 16. Results included 91.5m @ 1.6 g/t Au and 17 g/t Ag incl. 21m @ 4.5 g/t Au and 39 g/t Ag - CSD15 and 102m @ 1.2 g/t Au and 17 g/t Ag incl.20m @ 2.6 g/t Au and 39 g/t Ag - CSD13.
Dr Sillitoe concluded from a second site visit in late 2009 that Calandria Sur is a low-sulphidation epithermal discovery along the margin of a hydrothermally brecciated rhyolite dome. Mineralization is disseminated with bulk tonnage potential evident. He recommended more drilling, plus an IP survey in view of the association with marcasite-pyrite stockworks.
IP Survey Q4 2009
The discovery was followed up with IP at the Calandria Sur, Calandria Norte and El Nido Norte rhyolite domes. Survey dimensions were 1.4 km x 2.5 km using an Offset Pole-Dipole 3D Array. In addition, a N-S pole-dipole test array and five pole-dipole sections each of 500m were carried out at El Nido. Quantec reported a sizeable 8mv/V IP chargeability anomaly with approximate dimensions 220m east-west x 350m north-south x 150 depth extent at Calandria Sur with disseminated sulphide sources inferred.
Follow Up Drilling Q1/Q2 2010
A 37 hole 4,400m diamond drill programme followed up the Calandria Sur discovery and IP anomalies at Calandria Norte and El Nido Este. The drilling confirmed the discovery of bulk tonnage gold-silver mineralisation with numerous intersections including:
- 69.5m @ 2.1 g/t Au & 39 g/t Ag from 47m - CSD23,
- 102m @ 1.4 g/t Au & 21 g/t Ag from 12.5m - CSD24
- 68m @ 2.4 g/t Au & 24 g/t Ag from 74m - CSD25
- 106m @ 1.6 g/t Au & 27 g/t Ag from 3m - CSD39
A 400 x 200m zone of mineralized breccias greater than 20gm.m gold was outlined, within the 750 x 300m Calanadria Sur flow dome complex. Mineralisation was open along the western margin of the dome.
Calandria Norte Bonanza Discovery
In 2009, 8 holes for 800m tested two epithermal vein zones at the eastern and western ends of a 450m vein trend at the Calandria Norte rhyolite dome, 700m to the north of Calandria Sur, with best intersections of 10m @ 0.6 g/t Au from 54m in CND7 and 4.1m @ 0.9 g/t Au from 47m in CND3. Dr Sillitoe concluded that at least one deeper hole was warranted. The dome was covered by the Q4 2009 3D IP survey. A 3D 8mV/V chargeability anomaly extending 570m east-west x 260m north-south x 180m depth was detected. A +14mV/V core at the centre of 450m vein trend was located away from the 09 drill holes. Two diamond holes 70m apart in Q2 2010 discovered impressive bonanza gold and silver mineralisation in each hole:
- 4.0m @ 76 g/t Au & 70 g/t Ag from 92.5m - CND45
- 4.5m @ 102 g/t Au & 72 g/t Ag from 81.5m - CND46
El Nido Norte Target Q2 2010
Scout holesNND49-53 were drilled at the El Nido Norte target, 2km northwest of Calandria Sur to test outcropping bonanza gold and silver mineralisation with up to 0.5m @ 106 g/t Au and 510 g/t Ag in channel samples. The holes intersected broad sulphide breccia stockworks and silicified zones hosted by rhyolite along the northeast-southwest trend. All holes intersected anomalous gold and silver with up to 2m @ 4.9 g/t Au and 72 g/t Ag in NND50. This initial drilling is restricted to the centre of the 1,500m trend. Follow up drilling, guided by new 3D IP, will fully explore this highly prospective trend.
Work Programme Q3/Q4
Calandria Norte Drilling
Step out drilling at the high priority Calandria Norte bonanza gold-silver vein-breccia discovery with approximately 4,000m planned for Q3/Q4 2010 This will also be guided by detailed IP surveying along the 450m trend.
Calandria Sur Resources Drilling
Infill and extension drilling at the Calandria Sur bulk tonnage gold-silver discovery to preliminary resource standard with approximately 5,000m planned. Mariana has appointed independent geological consultants Mine Development Associates of Reno, Nevada to prepare an initial resource estimate for Q 12011 to a standard compliant with the Canadian National Instrument 43-101.
Preliminary metallurgical test work for Calandria Sur by Metcon Laboratories is underway in Australia under the supervision of consulting metallurgist Peter Lewis.
Intensive exploration of the highly prospective Las Calandrias rhyolite dome field with ground magnetics, lag/trench sampling and 2D/3D Induced Polarisation (IP) is underway for El Nido and Calandria Norte. Scout drilling (2,000m) of emerging targets of El Nido multi dome complex planned for Q4 2010.