Overview
Alumbrera is the biggest mine in Argentina. It is an open pit copper and gold mine in the northwestern province of Catamarca in the foothills of the Andes.
Alumbrera operations consist of five facilities in three provinces: the open cut mine and processing facilities at Alumbrera, Catamarca; a 317 kilometer concentrate slurry pipeline through Catamarca and Tucumán provinces; a 202 kilometre 220kV powerline from El Bracho, Tucumán; the filter plant and rail loading facilities at Cruz del Norte, Tucumán; and the port and handling facilities at San Martín near Rosario, Santa Fe.
The mine facilities are the open cut mine, processing facilities and central administration offices at Alumbrera, Catamarca province; a 316 km concentrate slurry pipeline through Catamarca and Tucuman provinces; a 202 km, 220 kv power line from the project's substation at El Bracho, Tucuman; a filter plant and rail loading facilities at Cruz del Norte, Tucuman province; a port, handling facilities and train maintenance facilities at San Martin near Rosario, in Santa Fe province. Port facilities include a rail car unloading building and 50,000 t storage shed. Alumbrera is the biggest mine in Argentina.
The pipeline from the mine crosses the Nevados del Aconquija mountains to the province of Tucuman where the copper/gold slurry is dewatered and shipped 830 km in trains owned by the company to the port at San Martin.
There are approximately 1,800 people working directly at the mine, either as mine employees or contractors. Mine site infrastructure includes offices, a warehouse, laboratory, medical center, a permanent camp, and workshops.
Location
The Alumbrera mine is in the northwest of the province of Catamarca, Argentina, in the eastern foothills of the Andes Mountains at an elevation of 2,600 m. It is about 1,100 km northwest of Buenos Aires and six hours travel time by paved and dirt roads from the airport at San Miguel de Tucuman. The nearest towns are Belen, 95 km northeast and Andalgala 50 km by road from the mine.
The mine, processing facilities and central administration offices are located at Alumbrera, Catamarca province. There is a 316 km concentrate slurry pipeline through Catamarca and Tucuman provinces and a 202 km, 220kv power line from the project's substation at El Bracho, Tucuman province. The port, handling facilities and train maintenance facilities are located at San Martin near Rosario, Santa Fe province.
The mine has good road and air service from Tucuman, Catamarca, and the mine site. The (paved) Pan American Highway, Route 60 from Chile, runs diagonally across Argentina to Buenos Aires, the end of the main highway. The company has scheduled flights between the minesite and Tucuman and bus transport between the mine and Tucuman and Catamarca. A company bus service carries personnel to and from job sites, and accommodation and recreation facilities within the mine site.
Geology & Mineralization
The Bajo de la Alumbrera alkalic porphyry and comagmatic Farallon Negro volcanic complex is mineralized by hydrothermal circulation which developed concentrically zoned alteration, from central potassic to phyllic to outer propalitic. Chalcopyrite and gold with pyrite and lesser bornite, molybdenite and magnetite are contained in fracture fill veins and disseminations in the potassic, and in particular within silica-magnetite, alteration.
Operation
Alumbrera is one of the world's largest and lowest cost copper and gold operations. Mining uses standard trucks and shovels on 17 meter benches, with 2-metre sub-drill, and ore is hauled to processing facilities nearby.
Operation of the mine is on an elevated grade. The current strip ratio is 3.3:1 waste to ore. The average milled grade is 0.56% copper and 0.67 Au g/t. Some ore is stockpiled for later processing. Haul trucks move both ore and waste. Mining is carried out on 17- metre benches.
The major equipment used is four electric 42 cubic meter rope shovels, Bucyrus-Erie BE495; 44 Cat 793 220 tonne haul trucks; four blast hole drills; two L1800 loaders and one Cat 994 loader; five D10 dozers and one D11 dozer; five 16H motograders; and three 777 water carts.
Process
In 2007, a USD15.5 million expansion of the concentrator and an extension of more than 10% in ore reserves at the mine was completed. The concentrator expansion increased mill throughputs by 8%, from 37 million tonnes per annum to 40 million tonnes per annum, with a corresponding increase in concentrate production levels.
A Falcon SB5200SE, the largest centrifugal concentrator in the world was commissioned in 2003 at Alumbrera's third grinding line to treat 392t/h of solids.
Most of Alumbrera's gold is free gold. About 5% of it is recovered by gravitational methods. The rest remains in the copper concentrate and is separated using centrifugal pumps. It is then transferred to the Gold Room and dore bars are produced. No reagents are used. The concentrate contains 27% copper, 25 g/t gold and small quantities of sulphur, iron and silicates.
From Tucuman, concentrate is sent by rail (Nuevo Central Argentino railway) on MAA owned trains to the company's port facility in Puerto General San Martin, province of Santa Fe. The railway rolling stock consists of four locomotives and 182 railcars. Concentrate is shipped by sea to international markets.
Environment & Community
Local communities have the benefit of the company's power line and fiber optic lines which greatly improved telephone and internet access. Water supplies have become more reliable due to improved electric pumping.
National Highway 40 has been upgraded at the company's expense as well as bridges and access roads.
Alumbrera is involved in 18 community improvement programs. These programs focus on education in general, technology transfer, and supporting local agriculture. The company helps to support 80 local clinics and 16 local and regional hospitals.
The mine buys from local suppliers as much as possible. Currently about 80 local suppliers sell their products to the mine and every effort is made through meetings and site visits to make locals businesses aware of opportunities to sell their products and services.
