Approaching circularity in mining

The role of sensor-based sorting in future green mining

By Mathilde Robben

Every year we create more than 2 billion tons of waste

worldwide. In 2019, the United States’ total primary energy consumption approached 100.2 quadrillion Btu. Both are expected to continue to increase at a sobering rate. These figures reflect the key trends we are facing and need to address urgently, such as climate change, urbanization, population growth, the fourth industrial revolution, rising per capita consumption, and decreasing resource availability. The mining industry is among the first links of the supply chain, while also being a large consumer of water, chemicals and energy (up to 11% of global use). For this reason, it has a key role to play in the pursuit of better resource management, a low-carbon future and increasing circularity of the economy. A circular economy is one that is restorative and regenerative by design. It looks beyond the take-make-waste extractive industrial model, and aims to redefine growth, focusing on positive societywide benefits. It is based on three principles: design out waste and pollution; keep products and materials in use; and generate natural systems.

The time when mining could be labeled as a dirty industry is over. Mining companies focusing on green mining practices, which include the use of renewable energy and implementing a minimum waste philosophy, are responding to the energy transition and the shift from a linear to a circular economy. They are under pressure to operate more sustainably by increasing legislation and regulations aimed at reducing the industry’s environmental impact, as well as growing resource scarcity. In addition, they need to adapt, as their customers move towards a circular economy approach. The demand for sustainably mined products and their price is expected to rise, as companies in all industries aim to reduce their emissions footprint. A growing number of operations are turning away from fossil fuels and moving to renewable energy sources. This is driving the requirement from

mining and mineral processing equipment suppliers to develop innovative and sustainable equipment.

Sensor-based sorting The mining industry must be part of the solution to the challenges of the future, because primary resources will continue to be needed. While the circular economy approach fosters sustainable processes along the entire life cycle of products, so that the resources remain in use for as long as possible, complete circularity cannot be achieved. The Sustainable Development Goals that all 192 member states of the United Nations have set out to achieve by 2030 are driving the development of green technologies, which use a variety of minerals. For example, solar panels, wind turbines and batteries cannot be manufactured without primary resources or critical minerals. The role of the mining industry is to ensure that whenever these raw materials are needed, their footprint is as small as possible. It is necessary to find ways to maximize the efficiency of mining and processing operations and to minimize the use of energy, water and chemicals, while reducing waste as much as possible.

This is precisely what the innovative and disruptive field of sensor-based sorting technology is aiming to achieve, so that the unavoidable extraction of resources has as little environmental impact as possible.

It is well known that mining generates considerable volumes of waste rock, tailings, mine water and chemicals. Effective waste management based on a circular economy approach, combined with practices that turn waste into value, can be a solution to address the limited metal supply, for example. This can be achieved with sensor-based ore sorting. It can be used as a separation process for coarser grain sizes before the application of fine comminution and separation technologies. It can be applied at various points in the process flow and can be used to eliminate or differentiate waste, separate materials into different process lines, produce pre- and final concentrates, reprocessing coarse-grained waste dumps and other applications.

Sensor-based sorting is an umbrella for all applications where particles are singularly detected by a sensor technique and then ejected by a mechanical, hydraulic or pneumatic process. Sensorbased ore sorting systems detect single particles using a sensor technique. Contactless and real-time measurements provide the location of the particle, which the system will then use for the ejection process, and material properties.

Sensor-based sorting technology can also significantly increase efficiency in terms of the input resources, such as energy, water and process reagents per ton of product, consequently reducing the environmental footprint of the operation. Also, in an environment where competition for resources with other stakeholders such as communities and agriculture is increasingly fierce, this can become a driver to obtain the social licence to operate. Grinding is the most energy-intensive part of the production process, and sensor-based sorting has been proven to reduce energy consumption by about half, with a consequent cut in CO2 emissions.

Mining companies are rethinking their operating and business models to address the challenges of climate change and to meet the demands of their customers as they shift to circular economy models. Contributing to an economy that is efficient in how it extracts, produces, consumes, recovers and recycles resources will be an increasing priority in the 21st century. However, it is vital that the mining industry achieves this move towards sustainable practices without losing sight of profitability. Sensor-based sorting technologies support the participation in the circular economy through green mining practices, while providing a highly cost-effective solution. At TOMRA Sorting Mining, the world leading supplier in sensor-based sorting, we are proving the worth of this technology in the field. TOMRA’s solutions, which range from industrial mineral processes to sorting gemstones, ferrous and non-ferrous metals, other fuels and slag metal, are in operation across the world, each contributing to extending the lifetime of mining operations, increasing the value derived from deposits, increasing productivity and decreasing the footprint of operations.

The mining industry has a key role to play in achieving more circularity in the economy. As both a supplier of vital resources and a consumer of resources, it is under pressure to embrace sustainability. The innovative and disruptive sensor-based sorting technology is tackling this challenge by turning waste into value and by saving chemicals, water and energy. With it, the resource revolution is more than a vision: it can soon be a reality for the mining industry.

– Mathilde Robben is a key account manager with TOMRA Sorting Mining.