Report on Sustainable Minerals ‘22

Sustainability is such a crucial issue that MEI's Sustainable Minerals conferences are annual events for the foreseeable future. Following on last year's Sustainability '21, this year's event, also online held from July 11-13, will be followed next year by Sustainable Minerals '23, face to face in Falmouth.

This week's conference was our 7th International Symposium on Sustainable Minerals and was organised in consultation with Prof Markus Reuter and sponsored by ZEISS, Metso Outotec, Hudbay Minerals, Weir Minerals, Capstone Mining and Promet101. Our Media Partner was International Mining, and our Industry Advocates the Coalition for Eco-Efficient Comminution, the Cornwall Mining Alliance and the Critical Minerals Association.

Amanda and Jon Wills opened the conference, Amanda saying that the rapid growth of the world economy is straining the sustainable use of the Earth’s natural resources due to modern society’s extensive use of metals, materials and products. An astute and conscious application and use of metals, materials and products supported by the reuse and recycling of these materials and end-of-life products is imperative to the preservation of the Earth’s resources. 

Following is a brief report on each of the day’s presentations.

Monday July 11th

Over the three days of the conference specialists from around the world presented 28 papers, commencing on the first day with presentations highlighting the need to mine responsibly in the light of strict Environmental and Social Governance restrictions and the requirements for mine closure, mitigation of acid mine drainage and reduction of water and energy consumption.

The day commenced with a very brief keynote address from Sheri Meyerhoffer, the Canadian Ombudsperson for Responsible Enterprise for the Government of Canada.

Sherri provided information on responsible business conduct and how mining companies can prevent and remedy human rights issues that may result from their operations, and opened the first session of the conference on ESG, mine closure, tailings and effluents. Ten presentations from Australia, Canada, Singapore, Sweden, The Netherlands, UK and USA covered mine planning and closure, reducing liquid discharge and handling of effluents, geochemical characterisation of tailings, and management of acid mine drainage.

The afternoon session on Water and Energy was shortened at the last minute due to a no-show from Morocco, and the four presentations from Australia, Canada and The Netherlands highlighted the importance of reducing water dependency and of reducing energy consumption. 

Last week we announced a new book on dry processing, which is likely to increase in importance as water reduction becomes more important, and a presentation by conference sponsor Weir Minerals showed how the use of HPGRs in a processing circuit allows for more efficient dry comminution and the specific ways that operating a HPGR can favourably impact the water balance of a processing plant.

Tuesday July 12th

Primary mining alone will not be enough to satisfy future mineral supplies and major research efforts are being made around the world to develop methods of recycling minerals from end-of-life commodities. The second day of the conference focused solely on recycling and the quest for the circular economy.

It began with a keynote lecture from Prof. Nabil Nasr, Director of Golisano Institute for Sustainability at Rochester Institute of Technology, USA and the founding Chief Executive Officer of the REMADE Institute, formed in 2017.  Prof. Nasr currently serves as a member of the International Resource Panel of the United Nations Environment Programme (UNEP). In addition, he has been an expert delegate with the U.S. Government in several international forums.

Prof. Nasr's presentation provided an overview of REMADE and the international technology strategies which seek to enable early stage applied research and development of key industrial platform technologies. These could dramatically reduce the embodied energy, emissions, and waste and increase material availability associated with industrial-scale materials production and processing, by eliminating and/or mitigating technical and economic barriers that prevent greater material recycling, recovery, remanufacturing and reuse.

The seven presentations which followed, from Brazil, Japan, Spain, South Africa, The Netherlands and Turkey, covered a wide range of topics. 

The demand for lithium for batteries, particularly for electric vehicles, is soaring, and two presentations dealt with the recovery of lithium from spent Li-ion batteries. 

There were also two presentations on the design and disassembly strategies to improve the recycling of metals in automobiles, as well as a presentation on industrial and urban waste recycling.

The presentation from Turkey looked at the production of precipitated calcium carbonate from marble waste and one of the presentations from South Africa's Stellenbosch University showed that recycling of gold mine tailings is a promising avenue to address the current challenges confronting a maturing gold mining industry characterised by increasingly deeper mine shafts and refractory ore bodies.

A short, but very interesting day with some fine presentations.

Wednesday July 13th

The final day was devoted to critical minerals, those that are essential to the green revolution, but whose future supply cannot be guaranteed due to scarcity and geopolitical factors. 

Sehliselo (Selo) Ndlovu is a Professor in the School of Chemical and Metallurgical Engineering at the University of the Witwatersrand in Johannesburg, South Africa and a former President of the Southern African Institute of Mining and Metallurgy (SAIMM).

This morning she presented a keynote lecture showing how the gradual exhaustion of free milling resources of gold ores has made the gold industry increasingly reliant on complex, refractory gold ores and other non-traditional sources such as leaching of tailings and electronic waste. However, the extraction of gold from these sources has been associated with significant challenges due to the inability of traditional methods to deal with the complex mineralogical characteristics of such feed material and she stressed the value of mineralogical characterisation, which will be featured at MEI's next conference. 

While traditional pretreatment methods such as roasting, pressure oxidation, bio-leaching, etc. and the integration and combination of such techniques in alternative flow sheets have remained key, consideration is, however, now also being given to non-conventional techniques such as mechano-activation, cavitation and ultrasound pre-treatment processes prior to cyanidation. At the same time, the extraction of metals has also come under severe scrutiny from both regulators and the public leading to the establishment of stringent environmental laws that have also had a significant impact on the approach to gold processing. 

These, together with an increasing focus on the circular economy and the drive for responsibility in mining, have forced mining companies and researchers to look at alternative and environmental friendly reagents and to consider cleaner production and process re-engineering for sustainability in gold extraction. 

Selo's keynote was followed by three presentations from Australia, Spain and Sweden, two of these highlighting critical minerals in mine waste and tailings. Yousef Ghorbani, of Luleå University of Technology, Sweden, discussed climate gains and minerals supply sustainability in the automotive battery industry, a useful prelude to the main event of the week, a 2-hour live panel discussion "Will the production of critical minerals be sufficient to satisfy the green revolution?".

This was chaired by Jeff Townsend, the founder of the UK's Critical Minerals Association. The four panelists, from divergent backgrounds, were Dr. Anita Parbhakar-Fox, Prof. Markus Reuter, Lucy Crane and Yousef Ghorbani (see posting of 23 June for full details). A great discussion on a wide range of topics.

As with all the recent online conferences the recordings of the presentations and the panel discussion are now available on demand, so it is not too late to register and view these at your leisure.

We now look forward to seeing you face to face next year in Falmouth for Sustainable Minerals ’23, details of which will be announced shortly. Thanks again to our sponsors, and to all who took part in the conference.

@barrywills