Page width Text size

Guanaco Project

  1. Location and Geology
  2. Exploration and Drilling
  3. Production
  4. History
     

1. Location and Geology

Guanaco is located approximately 220km SE of Antofagasta in Northern Chile at an elevation of 2,700m, 45km east of the Pan American Highway and 70km south of El Peñón (Yamana´s successful operation). The trip from Antofagasta takes about three hours. The climate is typical Atacama Desert, with little or no rainfall, and a resulting absence of practically any form of vegetation. The altitude ranges between 2,400 and 2,900 metres, averaging 2,600 metres above sea level.

 

Guanaco Location
   Click to view this map greatly enlarged in a new window

The Chile-Alemania Formation, represented by dacitic and andesitic tuffs and andesitic lavas of Paleocene age, has been intruded in the area by synchronous dacitic and rhyolitic domes. The deposit is located within a 5 kilometre long (E-W) and more than 1 kilometre wide hydrothermally altered zone hosted by the abovementioned formation.

Gold mineralisation at Guanaco is controlled by pervasively silicified, E/NE trending sub-vertical zones with related hydrothermal breccias. Silicification grades outward into advanced argillic alteration and further into zones with propylitic alteration.

Dozens of mineralised veins have been exploited in the district, the most important veins being the Defensa, Perseverancia, Abundancia, and San Lorenzo.

In the Cachinalito vein system, most of the gold mineralisation is concentrated between the 2,500m and 2,650m levels. High grade ore shoots (up to 180 g/t Au), 0.5m to 3.0m wide, have been exploited, but the lower grade halos, below 3 g/t Au, can reach up to 20m in width.

Native gold, forming dendrites, coarse and fine grains, is the most important ore mineral, although it is rarely seen. Disseminated pyrite is actually the most common mineral in the non-weathered ores, while enargite, luzonite and minor chalcopyrite are present in the deeper horizons. Chalcocite and covellite, together with copper carbonates, silicates and a number of rare copper arsenates (chenevixite, ceruleite, etc.), have been found in secondary enrichment zones.  Important gangue minerals are quartz, tabular barite, as well as pink alunite and kaolinite (in substitution of feldspars in zones affected by advanced argillic alteration), hematite, chlorite, epidote, etc.

The alteration pattern and the mineralogical composition of the Guanaco ores have lead to the classification as a high-sulfidation epithermal deposit.

 

2. Exploration and Drilling

This diagram shows the principal vein systems at Guanaco. These systems all strike east north east/west south west and dip steeply to the north.

Map of the Guanaco Area Exploration
Click to enlarge


3. Production

Guanaco recommenced mining operations in August 2010 and poured its first doré bars in October 2010. Production to December 2015 is set out in the table below.

 

  Year end
December 2012
Year end
December 2013


Year end
December 2014

Year end
December 2015

Gold (Au) 28,902 oz 50,226 oz 50,375 oz 46,254 oz
Silver (Ag) 74,807 oz 74,031 oz 46,458 oz
41,233 oz


4. Operations


March Quarter
2013 

March Quarter  2014
March Quarter  2015
March Quarter  2016
Total Ore processed (t)
174,219 
 87,776  93,734   135,236 
Ore from underground (t)
39,122 
87,776  93,734  123,313 
Underground grade (g/t Au)
6.01 
 6.38   3.53   3.57 
Weighted average recovery (%)
73 
 80  77   
Gold produced (oz)
8,772 
 12,222  11,425  8,801 
Silver produced (oz)
18,215 
 15,410  9,486  13,548 
Cash operating cost (US$/oz)
 956 
 612  597   917 

 

5. History

  • Intense gold mining activities between 1886 and 1939 with some interruptions.
  • Copper was exploited between 1928 and 1930
  • It is estimated that Guanaco produced in excess of a million ounces of gold until the mid 80's and 500k oz Au between 1993 and 1997.
  • In 1991, Amax Gold optioned the property from Minera Guanaco and within 1 year developed a reserve of 11,5mm tonnes containing 1,77 grams per tonne gold.
  • In 1992, Amax Gold leased additional properties from ENAMI. Mining began in 1993, and in 1997 was shut down mainly due to the low gold price.
  • In 1999, Kinross Gold acquired Amax Gold, and the property was taken over by its local subsidiary Kinam Guanaco.
  • After the acquisition, Kinam performed several exploration programs and technical reviews.
  • In September 2002, Gold Rose International, a subsidiary of Austral Gold, executed an option purchase agreement to acquire the property.
  • In March 2003, Guanaco Capital Holding acquired a 51% direct interest.
  • In May 2007 Guanaco Capital Holding transferred its 51% interest to Austral Gold Limited
  • In May 2008 Austral Gold Limited acquired the remaining 49% to now hold 100% interest in the Guanaco Project.  

Competent Persons Statement

Dr Robert Trzebski is a Director of Austral Gold Limited. He has a degree in Geology, PhD in Geophysics, Masters in Project Management and has over 20 years professional experience in mineral exploration, project management and mining services. Dr Robert Trzebski is a fellow of the Australian Institute of Mining and Metallurgy (AUSIMM) and qualifies as a Competent Person as defined in the 2004 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves.’ Dr Robert Trzebski consents to the inclusion of the resource figures identified in the context it has been provided here. 

Guanaco Project Photographs