Modern Mining May 2021

GOLD

and mine infrastructure, the extensive refurbishment of existing surface and underground infrastructure and the construction of new facilities. This will see Obuasi transformed into a modern, mechanised mine that will produce an average of 350 000 oz to 400 000 oz of gold a year. Phase 1 of the project, which set up the plant to achieve a daily processing rate of 2 000 t of ore per day, mainly involved mine rehabilitation, as well as the demolition and refurbishment of parts of the pro- cessing plant. “Phase 1 was all about getting some cashflow to get the project going, and entailed the refurbishment of some elements of underground infrastructure and then we started mining via a decline access. We reached first gold at the end of December 2019, and this was quite a milestone,” says Ehm. Phase 2, which aims to further expand plant capacity to 4 000 t of ore a day, continues unabated. It involves refurbishment of the underground materi- als handling system, shafts, ventilation system and the upgrade of the processing plant to double its capacity. The processing plant expansion includes a new primary crusher, a semi-autonomous grind- ing (SAG) and ball mill circuit, a carbon regeneration facility, a new tailings facility and a new gold room. “The Obuasi Redevelopment Project is on track with Phase 2 ramping up to mine 4 000 tonnes of gold ore a day that will be processed through the biox plant, the biggest of its nature in the world” says Ehm. “Mine production in the first 10 years will focus on the upper orebodies and is expected to average 350 000 oz to 450 000 oz annually at

The redevelopment project, says Graham Ehm, executive VP Group Planning and Technical at AngloGold Ashanti (AGA), has progressed well to reach 97% completion by the end of March this year, and remains on schedule and within budget. An investment of US$545-million, the project will develop 6-million ounces (oz) of high-grade gold reserves, adding another 20+ years to the lifetime of an iconic operation which ran for about 125 years before the suspension of operations in 2014. The operation history of Obuasi mine dates back to 1897. AngloGold became the owner and opera- tor after acquiring Ghana’s Ashanti Goldfields in a US$1-billion deal back in 2004. When gold prices took a big slide towards the end of 2014, the mine was placed on limited operation for the processing and clean-up of tailings. In the meantime, AngloGold Ashanti initiated an optimised feasibility study which was completed in 2016. The operation was placed on care and main- tenance the same year and the company started negotiations with the government for the redevelop- ment of the mine in 2017. “After a fairly long period of negotiations, it was clear that both parties shared a strong will to see Obuasi rise again. The agreements were subse- quently signed in 2018, before the redevelopment project was officially launched in January 2019,” says Ehm. Scope of project Implemented in two phases, the project basically entails the demolition of old and redundant plant

Construction at the Obuasi Redevelopment Project achieved 97% completion by the end of March this year.

May 2021  MODERN MINING  15