Cerro Vanguardia

Overview

AngloGold Ashanti has a 92.5% interest in Cerro Vanguardia with Fomicruz (the province of Santa Cruz) owning the remaining 7.5%.

Located to the northwest of Puerto San Julian in the province of Santa Cruz, Cerro Vanguardia consists of multiple small open pits with high stripping ratios. The orebodies comprise a series of hydrothermal vein deposits containing gold and large quantities of silver, which is mined as a by-product.

Ore is processed at the metallurgical plant which has a capacity of 3,000t per day and includes a cyanide recovery facility. Technology at the plant is based on a conventional leaching process in tanks and carbon-in-leach with a tailings dam incorporated in a closed circuit. The final recovery of gold and silver is achieved through a Merryl Crowe method with metallic zinc. 

Location

Located to the northwest of Puerto San Julian in the province of Santa Cruz, Argentina.

Geology and Mineralization

Gold and silver mineralisation occurs within a vertical range of about 150 to 200 metres in a series of narrow, banded quartz veins that occupy structures within the Chon Aike ignimbrites. These veins form a typical structural pattern related to major north-south (Concepcion) and east-west (Vanguardia) shears. Two sets of veins have formed in response to this shearing; one set strikes about N40W and generally dips 65 to 90° to the east; the other set strikes about N75W and the veins dip 60 to 80° to the south.

They are typical of epithermal low-temperature.

Mining & Operation

Consists of multiple small open-pits with high stripping ratios. The orebodies comprise a series of hydrothermal vein deposits containing vast quantities of silver, which is produced as a by-product.

Attributable gold production of 194,000oz was marginally up on the previous year. The mine’s production strategy focused on ensuring 100% supply of plant feed.

Cerro Vanguardia was the group’s lowest cost producer in 2010. Cash costs of $366/oz were 3% higher than the $355/oz in 2009, chiefly reflecting increased labour costs and the impact of local inflationary pressures. Higher spot prices and increased royalties also contributed to the higher costs but were partially offset by higher silver credits. The stockpile movement was favourable as a consequence of higher ore tonnes mined compared with last year.

Processing

Ore is processed at the metallurgical plant which has a capacity of 3,000t per day and includes a cyanide recovery facility.

Technology at the plant is based on a conventional leaching process in tanks and carbon-in-leach with a tailings dam incorporated in a closed circuit.

The final recovery of gold and silver is achieved through a Merryl Crowe method with metallic zinc. 

Environment & Community

The Development Agency is one of the major programmes the mine shares with the local community of Puerto San Julian. This year it was agreed that the funds to sponsor these activities will be revised in line with the mine’s profitability. The application of these funds will be agreed between the Development Agency representatives, the mayor and a representative from the mine.