The AngloGold Ashanti (AGA) Sunrise Dam Gold Recovery Enhancement Project (REP) was an upgrade project to the existing process plant to increase gold recovery. The project required the existing screened cyclone overflow to be redirected into a new flotation and ultra-fine grinding circuit, producing concentrate up to a rate of 400 000 t/a. Metso Outotec supplied six TC200 TankCell® flotation units, one 14 m High Rate Thickener and one HIGmill® HIG3500/23000. At this point in time the HIGmill is the world’s largest stirred mill supplied into a pyrite concentrate regrind duty.
This paper discusses the HIGmill test work and sizing, the challenges of commissioning and rampup and subsequent design optimisations. The energy efficiency and operational performance is also discussed.