The gold plant of the future
Following his keynote presentation at AusIMM’s recent Gold Plant of the Future Symposium, the AusIMM Bulletin caught up with Kenneth deGraaf, FLSmidth’s Global Product Line Manager, Downstream Gold Recovery Products, to discuss the latest technologies and approaches in gold plant processing.
Kenneth paints a picture of highly sophisticated gold plants that can provide improved sampling and ESG outcomes, thereby helping to meet the ongoing demand for gold that is processed safely, efficiently and sustainably.
Why is now the right time to be talking about harnessing technology to get the most out of gold processing plants?
Kenneth deGraaf (KD): Gold processing plants are operating in an increasingly challenging environment with regards to energy, labour and environmental, social and governance (ESG) considerations. We are also seeing average grades of new deposits continuing to decline.
Optimising operations over a range of sometimes competing objectives requires the best available technology and trained personnel to operate and maintain plants. None of this has a simple answer, and the challenges are often site-specific. But harnessing the most advanced yet acceptable technology should always be a component of getting the most out of any mineral processing plant.
In your presentation at Gold Plant, you talked about the importance of correct sampling practice – can you please explain why this is critical for plant operators to get right? What sort of value can proper sampling provide?
KD: In a gold processing plant, if you don’t have accurate information on how much gold is entering and leaving the plant through various process streams then you will not know whether your plant is operating efficiently or if it is optimised.
What’s more, it is not enough to know how efficiently the plant is recovering the gold product – it is often important to know what deleterious elements the plant may also be processing and releasing into the tailings. It can also be very important for the tailings management team to know if desliming of tailings is meeting particle size specifications for the tailings storage facility. All of these require accurate sample collection and analyses.
How can laboratory automation improve plant optimisation and productivity?
KD: It is often overlooked that the largest errors in analysing any process stream containing solids (dry or slurry) occur in the initial collection of a sample and the subsequent sample preparation steps (crushing/splitting/pulverizing), not the actual analysis of the sample (fire assay or ICP analysis).
Properly selected and installed automated sampling systems that adhere to the Theory of Sampling are imperatives for unbiased accurate sample collection; it is physically impossible for a human to consistently collect unbiased samples from the usually large process flow streams in modern gold processing plants.
Once the samples are collected, consistent proper sample preparation is essential for maintaining the representativeness of any sample collected from a process stream. Automated sample collection and automated sample preparation laboratories deliver consistently more reliable samples and dependable sample preparation, which in turn provides reliable data for assessing plant performance and optimisation strategies.
Can you provide a real world example/case study of such a laboratory?
KD: FLSmidth has been involved in more than 90 per cent of the global robotic mining laboratories representing over 250 installations, so there are multiple examples/case studies to show the benefits of automated sampling and laboratories. Automated laboratories have been shown to reduce operational costs, enhance quality of analyses, deliver quicker turnaround of analytical results, and also deliver benefits regarding ergonomics, health and safety for plant personnel.
How do resources professionals fit into automated plants – what skills do they need and how will they continue to help deliver business improvements?
KD: For metallurgists and plant engineers, an automated plant would allow for more sophisticated and prompt analyses of operational parameters and the optimisation of process parameters and production. These would likely lead to improved recoveries, reduced reagent consumption/wastage, and lower energy and water consumption.
How might the resource plant of the future improve overall ESG outcomes?
KD: The resource plant of the future should improve overall ESG outcomes by reducing water wastage, reducing energy consumption and reducing emissions – both from fossil fuel usage and from reduced reagent usage. FLSmidth has its ‘Mission Zero’ initiative with the goal to deliver solutions in mining processes to manage zero-emissions by 2030. It’s an ambitious goal that we have proudly committed to that requires a paradigm shift in collaboration, innovation and adoption of new technologies in the mining industry.