Where are your constraints? Pushing the limits of your plant

In this article, learn how identifying the best optimization pathway is key to turning around underperforming mining operations.

Mining operational challenges come in various forms of complexity. Often in underperforming operations, the challenge is to identify the issue quickly and address it with a systematic approach through the optimisation methodology. Identifying where to start the optimisation process is often the first and most challenging hurdle. This is particularly true for a large-complex operation - or any organization - that may not have a complete understanding of the entire value chain, i.e. mine to processing to metal production. 

 

Understand the impact of the optimisation process across the entire system

 

The value chain, as defined in Figure 1, aims to minimise the dollar per tonne of ore processed or metal produced. Therefore, the efficiency of the operating mine can be increased by:

  • Optimising the resource definition to suit the plant and metal pricing
  • Increasing productivity by maximising utilisation of the assets in the flowsheet; operating with the optimal conditions to maximise metal recovery
  • Reducing operating costs and managing risk through optimised asset management
  • Understanding the constraints by pushing the limits of assets and upgrading only to suit the production outcome.

Typically, the focus areas for the optimisation scope are bespoke to each discipline (eg., mining, process, asset) or equipment type. Without an integrated understanding of the interdependencies of the mining and processing value chain, the optimisation solution can lead to the wrong outcome, thus diminishing the value of the optimisation process of the entire operation.  Fully understanding the impact of an optimisation-driven process on the full mine system is the key to successful implementation. 

Figure 1 – Focusing on the value through an integrated approach

 

Finding the optimal path to success

In a complex processing plant, identifying the key problem areas requires a collaborative effort with the site team. Site engagement processes are required between mining, process, and asset disciplines to understand the issues and necessary steps to resolve them (Figure 2). 

As an example, during the cross-collaborative engagement process, the following focusing questions should be addressed:

  • What is the baseline capacity? (E.g., throughput, grind size, recovery, and availability)
  • What is the impact of ore variability on the baseline based on the mine plan schedule? (E.g., ore competency and hardness)
  • What does success look like for the site team? (I.e. short and long term strategy)
  • What are the risks and opportunities for the proposed improvements? (I.e. SWOT analysis)

Figure 2 – What is the optimal path to success?

Key metrics such as cost, schedule and risk should be incorporated into the strategy and prioritised for the identified issues, thus navigating a clear path to a successful outcome. Each implementation strategy needs to be ranked based on the best optimisation pathway; for example:

 

Start with the basics

Pushing the limits of the process plant does not require complicated optimisation strategies. Sometimes some of the most basic and practical site initiatives can uplift throughput and deconstrain circuits. This includes: Get the basics right – maintain good operational practices: e.g. consistent ball charge addition; maintain crusher gap; monitor cyclone wear parts; conduct instrumentation calibration and checks.

We recommend that you:

  • Focus on stability – For high ore variability, the focus should be to achieve plant stability through optimised process control
  • Push the limits of the assets – Assets such as mills and tailings discharge line pumping should be de-constrained and should be pushed to the operating limit for increasing feedrates
  • Understand the constraints – Use benchmarking and mass & metal balances to track the performance of the asset and instrumentation

Any questions? Please contact Rajiv Chandramohan. 

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