Overview
Status | Temporary Suspension |
Mine Type | Open Pit / Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Longhole stoping
|
Processing |
- Heap leach
- Carbon in leach (CIL)
- AARL elution
- Merrill–Crowe
- Cyanide (reagent)
|
Mine Life | 15 years (as of Jan 1, 2015) |
Latest News | AngloGold Ashanti Provides Update on Argentina Operations November 10, 2020 |
Source:
Cerro Vanguardia, in which AngloGold Ashanti has a 92.5% stake, is the company’s sole operation in Argentina. Fomicruz(Fomento Minero de Santa Cruz S.E.), a state company operating in the province of Santa Cruz, owns the remaining 7.5%.
Deposit Type
- Epithermal
- Vein / narrow vein
Summary:
Cerro Vanguardia is located in the core of the 60,000km2 Deseado Massif, one of the most extensive volcanic complexes in southern Patagonia, Argentina. The Deseado Massif is an extensive rhyolite province of Middle to Upper Jurassic age deposited over Paleozoic low-grade metamorphic basement rocks. These rocks are exposed in erosional windows through overlying Cretaceous sediments and Tertiary to Quaternary basalts. The orebodies comprise a series of epithermal vein deposits (low-sulphidation deposit) containing gold and large quantities of silver, produced as a by-product.
The mineralisation is concentrated in steeply dipping quartz veins that cut the flat-lying ignimbrites and volcaniclastic rocks. The Cerro Vanguardia district contains around 100 gold and silver-bearing epithermal veins for a cumulative exposed vein strike extension of more than 240km. Fifty-seven veins are currently known to contain economic gold and silver mineralisation.
All veins at Cerro Vanguardia consist mainly of quartz and adularia containing minor electrum, native gold, silver sulphides and native silver as fine-grained disseminations. Vein textures are mainly characterised by colloform-crustiform banding, pseudomorphic quartzlattice textures, massive-to-vuggy quartz veins and vein breccias. 40Ar/39Ar dating on adularia from the Osvaldo Diez vein yielded ages of 153.4 ±1.46Ma, 152.9 ±2.75Ma and 155.1 ±3.0Ma, while the age of the thick sequence of ignimbrites hosting the veins has been dated between 166 to 150Ma.
The Middle to Upper Jurassic ignimbrites and volcanic rocks from Chon Aike formation hosts a low-sulphidation epithermal type gold and silver deposit. The thickness of the ignimbrite sequence is estimated to have exceeded 1,000m, but some lateral variations have been identified across the district. Epithermal Au-Ag bearing structures cut across all Jurassic rocks in the stratigraphy. The two main ignimbrite units, Masiva-Lajosa and Granosa, host the majority of mineralised veins. The Masiva-Lajosa ignimbrite occurs at the top of the sequence whilst the Granosa ignimbrite occurs towards the bottom. These two ignimbrites are separated by two thinner, polymictic ignimbrite units (Brechosa and Brechosa Base) and a sequence of stratified crystal to ash-rich tuffs (Estratificada unit). The base of the sequence is a mixed unit of stratified ignimbrite intercalated with fine-grained tuffs (Estratificada Inferior ignimbrite).
Mining Methods
- Truck & Shovel / Loader
- Longhole stoping
Summary:
Cerro Vanguardia uses conventional open pit mining with a doubled bench height of 20m and in the underground, longhole stoping. Open pit mining is distributed between multiple operating pits, typically three to five at any one time, depending on the plant feed requirements. Currently, there are four underground mines which are operated at same time, located at Fortuna, Osvaldo 8, Verónica and Zorro veins. Two more are in development (Liliana and Serena). The underground workings, which began production in 2010, account for around 30% of total production, a percentage that will increase in the next few years. Low-grade material is stockpiled and processed as heap-leaching.
Processing
- Heap leach
- Carbon in leach (CIL)
- AARL elution
- Merrill–Crowe
- Cyanide (reagent)
Source:
Summary:
The Cerro Vanguardia mineral processing plant has a capacity of 3129 tonnes per day. The process involves the following steps:
- Three stages of crushing;
- Stockpiling and blending;
- Grinding in a ball mill, with cyanide addition;
- Cyanide leaching;
- Washing and thickening;
- Leach solution clarification and precipitation or gold and silver using zinc powder (Merill Crowe process);
- Smelting to form metal doré;
- Carbon in leach (CIL);
- Heap leaching;
- Elution using the Anglo American system;
- Cyanide recovery using volatilization;
- SO2 cyanide destruction to around 30 ppm CN (WAD);
- Deposition of tailings in a tailings dam.
Recoveries & Grades:
Commodity | Parameter | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Gold
|
Head Grade, g/t
| 4.77 | 6.49 | 7.5 | 7.45 | 6.88 | 6.08 |
Reserves at December 31, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven & Probable
|
12.16 Mt
|
Gold
|
1.97 g/t
|
0.77 M oz
|
Proven & Probable
|
12.16 Mt
|
Silver
|
47.99 g/t
|
18.76 M oz
|
Total Resource
|
34.13 Mt
|
Gold
|
2.56 g/t
|
2.81 M oz
|
Total Resource
|
34.13 Mt
|
Silver
|
69.15 g/t
|
75.89 M oz
|
Commodity Production Costs:
| Commodity | Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Total cash costs
|
Gold
|
USD
|
......
|
......
|
522 / oz
|
563 / oz
|
625 / oz
|
692 / oz
|
All-in sustaining costs (sold)
|
Gold
|
USD
|
......
|
......
|
772 / oz
|
773 / oz
|
873 / oz
|
938 / oz
|
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Financials:
| Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Capital expenditures
|
M USD
| ......  | ......  | ......  | ......  |
67
|
58.3
|
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