OUR TRACK RECORD
ANGLOGOLD ASHANTI - SITE IMPROVEMENT PROJECTS
The Details
TIMEFRAME: 2022 – 2024
CLIENT: AngloGold Ashanti
LOCATION: Western Australia
COMMODITY: Gold
SERVICES: Process Plant Optimisation & Debottlenecking
OPTIONS STUDY FOR NEW CONCENTRATE LEACH CIRCUIT AT SUNRISE DAM
GRAVITY CIRCUIT REVIEW AT SUNRISE DAM
HPGR CIRCUIT REVIEW AT TROPICANA
Project Background
AngloGold Ashanti (Anglo) is the world’s 5th largest gold producer, and their Sunrise Dam and Tropicana operations in Australia produce over 550koz/a. To assist with specific throughput and recovery improvement projects at these sites, Anglo engaged Chemech in 2022 to provide targeted technical support within specific areas of expertise such as HPGR circuit optimisation, leach/CIL modelling and gravity circuit optimisation.
Sunrise Dam Leach/CIL Circuit Upgrade
The Sunrise Dam flowsheet includes flotation of the refractory pyrite, with ultra-fine grinding (UFG) of the concentrate before it is re-combined with flotation tailings in the CIL circuit. Due to relatively high cyanide-recoverable gold losses to tailings, Anglo engaged Chemech in 2022 to analyse concentrate leach testwork and CIL circuit operating data to provide options for improved recovery.
Chemech utilised the expertise of Rick Follis to model different CIL circuit configurations, identifying that separate pre-oxidation and leaching of the UFG concentrate could improve overall gold recovery by 2-3%. Chemech then conducted preliminary design and cost estimation to present upgrade options to Anglo, who chose to proceed with separate pre-oxidation and leaching of the UFG concentrate.
Sunrise Dam Gravity Circuit Upgrade
The Sunrise Dam gravity circuit had been upgraded and modified several times since its installation in 1997. The configuration of the three installed gravity concentrators however was not optimal, with gravity-recoverable gold passing into the CIL circuit and not being fully recovered. Due to their gravity circuit experience, Anglo engaged Chemech to peer review the upgrade proposed by their selected Engineer and propose any alternatives.
Chemech identified several deficiencies with the proposed upgrade, and its potential for gravity recovery improvements. Using their significant database of successful gravity circuits and applying some basic principles, Chemech identified a simpler, cheaper and more effective circuit upgrade.
Tropicana Full Asset Potential (Bain)
Chemech were engaged to provide targeted technical support to Bain and Company, who were conducting Anglo’s Full Asset Potential program at Tropicana. Due to their significant design and operating experience with HPGR circuits such as Boddington, Bain called upon Chemech to analyse the performance of the HPGR and Ball Milling circuit at Tropicana, and recommend options for improvement.
Chemech’s analysis of the operating data showed the potential for a significant increase in the HPGR throughput and specific energy. This presented a significant opportunity for increased plant throughput in Bain’s Full Asset Potential program.