AngloGold Ashanti avoids potential delays and costs
through RCM based maintenance strategies
By determining RCM based maintenance strategies before production kicked off, AngloGold Ashanti avoided potential delays and costs down the track.
AngloGold Ashanti is one of the world's leading gold mining companies, with operations spread across 10 countries. When AngloGold Ashanti began work on the Tropicana Gold Project near Kalgoorlie, Western Australia, Tropicana's gold deposits stretch across 300km of an ancient collision zone, and the area promised fertile ground for the mining giant.
Slated to produce 3.45 million ounces of gold over a 10 year mine life at a cash cost of between A$710-A$730/oz. In the first three years of its operation, gold production targets were set between 470,000- 490,000 ounces per annum at a cash cost of A$580-A$600/oz.
To cope with the expected in-flux of raw materials, Tropicana's processing plant aimed to process 5.8 million tonnes of fresh ore per annum. It's comminution circuit comprises of two-stage crushing, high pressure grinding rolls and ball milling, followed by a carbon in-leach circuit for gold recovery.
Tropicana boasts a gold-standard setup that needs a premium maintenance plan. The team developed maintenance strategies for more than 300 assets, with full RCM studies and a live RCM model implemented for each to enable ongoing updates and continuous improvement.
Challenge
Drawing on almost 70 years in the mining industry, AngloGold Ashanti is a leader when it comes to best practice procedures and methodologies for setting up new mines. When the Tropicana opportunity arose, it sought to set the mine and processing plant up in the most efficient and reliable way possible.
As part of this, AngloGold Ashanti project team saw the need for the creation of maintenance strategies for all of the processing plant equipment before the mine commenced operation.
"We sought to develop maintenance strategies using a reliability based mode, for the Tropicana Gold Mine, prior to commissioning," said Hugh Beveridge, Engineering manager, AngloGold Ashanti.
By completing the RCM analysis prior to operation, the maintenance and production team can focus on the day-to-day operation of the plant once commissioning is complete. With the RCM study and maintenance strategies completed up-front, AngloGold Ashanti will avoid costly delays once the plant is in operation.
Solution
Our team developed maintenance strategies for more than 300 pieces of equipment in the processing plant - such as conveyors, vibrating screens, crushers, high-pressure grinding rolls, ball mill and more.
The team spent 12 months performing detailed RCM Study on each asset. For the critical equipment, the studies were performed in teams comprising ARMS Reliability, AngloGold Ashanti subject matter experts and engineers from the original equipment manufacturers (OEMs). The remainder of plant equipment still received full RCM studies, but these studies were completed in smaller teams. This separation of equipment ensured that the right amount of resources and time were devoted to the most important assets; and that people's time was not unnecessarily spent on lower critical items.
The live and updatable models are designed to:
- Identify all Functions, Functional failures, Failure Modes, Effects and Criticalities
- Identify recommended maintenance tasks (corrective, preventative and/or inspections) that will mitigate or eliminate failure modes
- Assign resources to complete the recommended tasks (labour, parts and special equipment)
- Optimize the maintenance tasks to ensure maximum long-term performance with least risk
- Group tasks by discipline, interval and system status
- Construct Reliability Block Model as per flow sheets to simulate results of recommended maintenance strategy
- Compare alternative shutdown intervals and durations to perform recommended offline tasks
- Determine spare part usage which will assist in recommended spares lists and holding levels for critical equipment (insurance spares)
- Produce online and shutdown labour predictions to aid in personnel hiring and shutdown resource requirements
- The maintenance strategies and preventive maintenance documents were then uploaded into SAP.
Benefits
- Detailed reports on each asset in the processing plant. The RCM strategies include predicted plant performance, identification of high impact failure modes/equipment, predictions for spare parts, resourcing requirements, shutdown strategies and optimized maintenance plans.
- Live and updatable RCM strategies. A RAMS model of the Tropicana Process Plant has been built in the RCM and system availability modelling software. This live and updatable format will support ongoing, continuous improvement.
- Clear cost predictions. AngloGold Ashanti will use the RCM strategies to more accurately forecast the cost of maintenance labor for the operating life of the processing plant.
Besides the tangible benefits listed above, additional fringe benefits arose as a result of involving the operation and maintenance teams early in the process. The personnel gained an early understanding of the equipment and processes they would eventually be in control of. In addition to this, it also gave them the opportunity to meet and become familiar with some of the equipment suppliers and representatives, helping to build the relationships that are essential to reliable plant operation.