April 2018

Developments in metallurgy

  • By AusIMM Metallurgical Society

In this special series of articles, we asked some of our AusIMM professional societies and networks for their industry insights.
The following is a collection of thoughts from our professionals on how practices have developed over the past 125 years.

Is there a single event that defined the beginning of this technical discipline in Australasia?

In Australasia, modern metallurgy as a discipline arguably began with the development of the flotation process for lead and zinc ores that started at Broken Hill mine in the very early 1900s. This dramatically improved the economics of the processing of sulphidic ores and was subsequently adapted to large-scale applications in gold and base metals processing.

What industry issues or problems has this discipline helped to address?

To a large extent the discipline of metallurgy is about how much of the valuable mineral in an orebody we can recover. This is done through physical separation, hydrometallurgy or pyrometallurgy, to produce saleable products from ores and concentrates.

The biggest advances in metallurgy have been related to various processes, such as the flotation process for sulphide ores. Flotation technology has evolved to more effectively recover coarser and finer particles and applying numerous advances in equipment and techniques to optimise the process.

Additionally, the widespread adaptation of the carbon-in-pulp process for recovery of gold has made processing low-grade ores more cost-effective. Similarly, advanced hydrometallurgical techniques such as pressure oxidation, bacterial oxidation, alternative lixiviants and solvent extraction have reduced the processing costs of refractory gold ores and base metal ores.

Technological advances such as high pressure grinding rolls (HPGR) and stirred mills have made the comminution of mineral ores more energy efficient, and adapting bulk centrifugal concentration and intensive cyanidation has increased the efficiency of gravity gold extraction.

How has this discipline changed and how might it look in the future?

Mining processes 125 years ago used very basic manual techniques. Reporting took the form of printed hard copies for the operator to decipher trends, etc. This evolved to use analogue measurement and control systems such as programmable logic controllers and distributed control systems which are costly to install and maintain. Instruments were stand-alone and not easily integrated into the control platform.

Now, online measurements are available, which are easier to install and integrate with the plant; data is real-time and easily accessible online in the cloud and we can implement process variables into advanced control strategies.

The future of metallurgy will involve using sophisticated data collection and analytical techniques to understand, communicate and optimise digital control and advanced online measurement. The McKinsey Global Institute stated that the Internet of Things will be soon be used by the mining industry for data collection, monitoring processes, decision-making and optimising workflows. Artificial intelligence will be the future of integrated exploration, mining, minerals processing, recovery and rehabilitation. The collection of mass data will enable us to create large information and feedback loops to truly optimise the entire recovery process. The boundaries between our conventional disciplines of mining, metallurgy, geology, manufacturing and environmental science, as well as human resources and maintenance, will be even more blurred in future.

What are the big challenges or opportunities facing this discipline?

Challenges include the difficulty of measuring minerals, competition in the market increasing pressure on pricing variations, varying demand on different minerals, shorter mine life and tightening of environmental and social permitting expectations.

One of the main challenges we have found is getting the mining industry to fully embrace advanced measurement and control. Technology has significant proven benefits for process optimisation with grinding throughput, flotation recovery and gold plant efficiency.

The AusIMM will continue to play a leading role in fostering partnerships to drive innovation in the digital transformation of mining. To put together a place to upskill, support and deliver miners of the future will have a positive impact to the Australasian mining industry, which in turn will contribute significantly to the global economy.

What has AusIMM’s role been in advancing professional practice in this discipline?

The AusIMM Metallurgical Society has played a leading role in supporting and promoting major global standard conferences such as the AusIMM Mill Operators’ Conference and the MetPlant conference, and landmark publications such as the Mawby volumes and the recent compilation of industry best practices in We are Metallurgists, not Magicians.

The AusIMM has helped give suppliers and consultants a platform to present, engage and collaborate with industry stakeholders through events, journals etc. The Mill Operators’ Conference is a key event that helps open dialogue to help mining operations become more streamlined, with less costs involved. There is, however, a gap for the AusIMM to address in terms of student engagement at conferences to help expose them to the latest technology and provide an opportunity for them to present papers themselves.

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