Obuasi, Ghana

Obuasi is an underground operation with the main accesses into the mine consisting of shafts and a single access decline with interlevel development of between 15 and 30m. The Obuasi Deeps Decline, which is situated at the southern end of the mine, is designed to extend to a depth of about 1,500m. The Obuasi underground operation employs mostly the long hole open stoping (LHOS) mining method for ore extraction.

Existing infrastructure includes a 2.4Mtpa processing plant with flotation and bacterial oxidation (BIOX), underground development, hoisting shafts and associated infrastructure, power and water reticulation, office complexes, workshops and company housing estates. Power is supplied to the mine by the Volta River Authority and GridCo.

A brief history

• Production at Obuasi started in 1897 and stopped in the last quarter of 2014. Some aspects of the mine continued under limited operational conditions, including the development of the underground decline.
• A favourable feasibility study was completed in 2017 and indicated a strong technical and economical case with an anticipated 20-year LOM
• In 2018, approval was received from the AngloGold Ashanti board to proceed with the project.
• The redevelopment project began in late 2018 and first gold was poured during the fourth quarter of 2019.
• Phase 1 of the redevelopment project was completed by end September 2020 and began commercial production on 1 October 2020.
• Phase 2, construction and mine development, was completed in 2021.
• Phase 3 of the redevelopment project is currently underway to develop the infrastructure necessary to support the planned ramp up in production to 5,000tpd by the end of 2023.
• The operations' ramp up was delayed by the temporary stoppage of underground activities after a fall of ground incident in May 2021. Production remained suspended for several months to allow for reviews and investigations, but slowly resumed in the latter part of 2021.