The Sepon copper project came into production in 2005 at an estimated capital cost of US$235M. The adjacent gold mine, also owned by MMG (formerly Oz Minerals), was commissioned in 2002 and is considered separately in the Wood Mackenzie Gold Mine Cost Study.
Sepon is an open pit copper mining operation approximately 550km southeast of Vientiane in Savannakhet Province, Laos. The mine began production in 2005 and produces copper cathode by ore leaching, solvent extraction and electrowinning. The adjacent gold mine, also owned by MMG, was placed on care and maintenance at the end of 2013, due to low gold prices and high operating costs.
In 2015, mining began transitioning away from the depleting high grade Khanong deposit to the Thengkam deposit, approximately 12km from the current mine. The mining fleet was expanded at the end of 2015 to manage expected declining head grades and longer haulage distances.