Overview
Kinross acquired its original 50% interest and became operator of the mine on June 1, 1998, through the Kinam merger. In February 2007, Kinross acquired the remaining 50% through the acquisition of Bema Gold Corporation.
Commercial production began on October 1, 1996. Five years later, mining activities were suspended and the operation was placed on care and maintenance due to low gold prices. In late 2002, a multi-phase exploration program commenced and in 2003 it was determined that the mine would be recommissioned.
The mine went into commercial production in the fourth quarter of 2005 and achieved its average targeted production rate of 40,000 tonnes per day in November 2005.
The Maricunga mine is a three-stage crushing and heap leach operation with a name plate capacity of 40,000 tonnes of ore per day, or 11 million tonnes per year.
Facilities include a permanent camp with access to the site from Copiapó provided by road. Power is supplied by the main power grid.
Location
The Maricunga open pit mine is located in the Maricunga mining district in central-east Chile. The property is approximately 120 kilometres east of Copiapó and is between 4,200 metres and 4,500 metres above sea level.
Geology
The Verde and Pancho gold deposits at Maricunga occur in the Maricunga Gold Belt of the high Andes in northern Chile. Since 1980, a total of 40 million ounces of gold have been defined in the belt, (Muntean and Einaudi, 2000). Gold mineralization at Maricunga has been interpreted as porphyry style gold systems and is hosted in the Maricunga volcanicintrusive complex of Early Miocene age. The porphyries occur within a sequence of intermediate tuffs, porphyries and breccias that are the host rocks to the gold mineralization.
Mineralization
Gold mineralization at Verde is interpreted to be the result of the fracturing and concentration of fluids in the carapace of an intrusive plug or stock. Gold is closely associated with quartz, magnetite, calcite, and garnet stockworks. Gold mineralization at Pancho is characterized asporphyry hosted stockwork and sheeted veins. The veins are subvertical and have a strong, preferred north-westerly strike. The northwest structural control is evident not only at outcrop scale but is also reflected in the northwest alignment of intrusives and the three centers of mineralization in the district, Verde, Pancho and Guanaco.
Mining & Operation
Maricunga production re-opened in October 2005 and achieved its targeted production rate of 14 million tonnes per year (40,000 tonnes per day) in late 2005. The mine operates two 12-hour shifts per day for 352 days annually allowing for inclement weather interruptions. Final pit design for Verde and Pancho assumed 10 meter bench heights, bench face angles of 65° to 70°, berm widths of 8 to 11 meters, berm interval of 20 meters, inter-ramp angles of 38° to 52.5° and haul road gradient at 10% with a 25 meter road width.
Processing
The Maricunga gold recovery process consists of a single line primary crushing, fines crushing (secondary and tertiary), heap leach and adsorption and regeneration ("ADR") plant operation. The process treats 45,000 tonnes per day of dry Maricunga ore using primary crushing followed by a secondary and tertiary crushing plant. The crushing plant product is approximately 80% passing 10.5 millimetres. A pad type heap leach and an ADR plant are used for gold recovery.
