Metallurgical testwork

June 18th, 2019

Dr Mark Cookseyby Mark Cooksey

How falling ore grades and increasing ore complexity are making metallurgical testwork more challenging

When identifying new deposits and planning for plant construction, metallurgical testing is vital to determine mineralogy and process flowsheets, so that extraction and processing can be achieved economically at commercial scale.

These challenges are compounded by the falling ore grades, increased mineralogy complexities and tighter product specifications that have become more common, and which require testing that is more thorough and needs an increased level of expertise.

While larger companies may have the ability to conduct metallurgical testwork in-house, smaller operations or those without a solid background in mineral processing tend to outsource testwork to commercial laboratories.

Although the testwork performed by larger companies and commercial laboratories is generally of high quality, there is an increasing risk of it being insufficient. More complex ores can exhibit greater variability during processing, and there is a greater risk of process performance at commercial scale being different to that at laboratory scale.

Investors are now looking more closely at metallurgical testwork to determine return on investment. Thorough testwork is required to deliver results that will indicate whether an operation will be feasible and profitable.

The correlation between insufficient testing and poor commercial results

With low grade and complex ores, there is a higher likelihood that commercial testing will not be rigorous enough to effectively determine processing outcomes.

There are many statistics illustrating the consequences of insufficient metallurgical testwork:

  • studies have shown that less than 10 percent of all mining projects are completed within budget and schedule
  • less than 20 percent achieve the ROI or NPV projected by their Feasibility Study
  • it is estimated that since the 1990’s, at least 25% of commercial heap leach operations around the world failed to produce a return on capital investment.

Even the best ‘standard’ metallurgical testwork suffers from some limitations:

  1. Testwork will reveal what happens to ore as it is processed (at the laboratory scale), but often not why. This increases the risk that the processing behaviour observed during testwork will not be reproduced at commercial scale. And, if the behaviour at commercial scale is different, it will be an expensive undertaking to develop the understanding to solve the problem, and
  2. Testwork shows the difference between the initial ore and final product, but does not reveal details of the behaviour during processing.

Insufficient metallurgical testwork can lead to inadequate plant design or operating strategy, which can be very costly if the plant does not meet design criteria during the early period of mine life – and if you cannot capture the value of a deposit over the life of the plant.

A thorough understanding stems from thorough testing

While commercial testing is often of high quality, the results sometimes provide insufficient insight to develop appropriate process flowsheets. This is more likely to affect those who:

  • have complex deposits
  • are pursuing novel processes to extract more value
  • have tight product specifications, e.g. for the battery materials market

It is most important to understand the reasons for the behaviour – the ‘why’, not just the ‘what’.

Understanding the properties of complex ores and how they behave during mineral or metal processing at a fundamental level is essential for accurate process design.

The ability to “see” into a dynamic process and understand how it works takes niche expertise and cutting-edge equipment, and can’t be achieved using traditional post-mortem style analyses where samples are analysed before and after processing.

CSIRO testing expertise has proven to deliver results

The expertise and in-house testing capabilities at CSIRO can deliver results and capabilities not available through commercial laboratories.

We have two key capabilities overcoming the limitations of traditional lab-based analyses:

  1. The ability to provide a much deeper characterisation of an ore feedstock and better understand the impact of their properties on processing, using our Advanced Characterisation Facility which assists in selecting the best process
  2. The ability to simulate mineral processes under industrial operating conditions, to provide accurate insights into how material behaves during processing and the impact on the end product

Using advanced techniques (including in-situ XRD, instrumented leaching column and synchrotron), we deliver high quality information to improve understanding of the relationship between ore mineralogy and metallurgical performance.

We can conduct proof of concept testing, process flowsheet development and optimisation, offering:

Our team has significant experience in developing novel minerals processing routes for complex ores. We can help you to understand your materials and understand your process, thanks to our multi-disciplinary capability:

  • ore characterisation
  • flowsheet development and technoeconomics studies
  • lab-scale metallurgical test work
  • pilot scale design and operation, and
  • modelling.

We not only use our hydromet and pyromet end-to-end process expertise to design and conduct tailored metallurgical testwork, but also to analyse the results to provide informed solutions to your processing challenges.

If your existing approaches are inconclusive or you’re facing complexities in developing process flowsheets, CSIRO – through our research, breakthrough science and world class facilities – is uniquely positioned to assist with your operation and add value to your project.

Contact the team on +61 3 9545 8865 or email me,, to discuss how our expertise and experience can help you.

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