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Green Mining: Recovering Value Hidden in Waste Rock

In the face of climate change and its drastic consequences, monumental shifts in our everyday business activities are required. The mining industry, as a very large consumer of energy, is a prime example of an industry where much can be done to reduce its environmental footprint.

10 May 2019

Green iridescence in rock cross section

By investing in new technologies, mining companies can take new approaches to extract natural commodities in an energy-efficient and resource-conserving manner. TOMRA has been a leading pioneer of optical sorting technologies that are not only energy saving but recover valuable ore from rock material -- and even waste rock. This plays well into the established concept of Green Mining, which should not be seen as a short-lived buzzword, but a necessary and holistic approach to mining processes.

The all-encompassing concept of Green Mining

Water, waste, energy, safety and sustainability -- all essential factors in the future of mining. Moving towards a more holistic approach like Green Mining involves advancing technologies, enhanced methodology as well as improved socioeconomic conditions for the impacted region. Methods to improve waste and water management must be developed and implemented. Just as the demand for sustainable energy is on the rise, commodities like copper, lithium and zinc will proportionately grow in the future. Therefore, it is just as paramount for mining companies to invest in sustainable streamlined processes as it is for them to maintain their operating license. Reduced energy consumption and environmentally sound practices will become exponentially more critical in the future.

Turning non-economical ore and minerals into value

For the mining industry, it is vital to move towards sustainable practices without losing sight of profitability. Energy consumption is one aspect that affects both parameters and can be easily optimized. According to a study conducted by the IEA, mining consumes up to 3% of global energy production annually. An estimated 50-75% of the energy used is for the liberation/comminution of ore and minerals only, making grinding the most energy-intensive part of the production cycle.1 Beyond the level of energy consumption, waste material as a result of the extraction of ore or minerals has been increasing steadily for years.

“Decades of processing [ore] have resulted in waste piles consisting of millions of tons of material, 25-40% of which is good ore.2

TOMRA’s Head of Sorting Mining, Tord Svensson, suggests that becoming greener and more profitable requires a shift in focus, starting with placing more value on potentially limited commodities like water and ore. "An environmentally-focused and efficiency-oriented production process is integral to Green Mining. To reduce energy consumption and mitigate the adverse environmental effects of mining operations, it is necessary to implement solutions from the beginning of the mining process. Ore sorting machinery in the early stages of mining reduces waste material and carbon footprint while increasing profitability," says Svensson.

Advanced technology with a small environmental footprint

TOMRA's sophisticated solutions contribute to a more environmentally sustainable approach in mining. Its range of smart technologies includes sorting and separating various valuable substances, such as removing copper and lithium from gangue. The sensor-based sorting technology by TOMRA not only significantly reduces the amount of energy and water need in more traditional methods like grinding and DMS (Dense Media Separation), but also maximizes the efficiency and quality recovery of valuable ores.

XRT is one of TOMRA’s leading solutions, as it uses X-Ray transmission for the dry material separation of various ore and minerals based on their atomic density, irrespective of surface properties and thickness. With XRT technology, it is unnecessary to crush or grind every rock into smaller particles, which results in massive savings of energy, water and their related costs.

Pre-concentration techniques like sensor-based sorting have been proven to reduce energy consumption by about half. It is therefore not only cost effective but also reduces the CO2 footprint considerably.

Seeing Green with our CO2 Counter

To highlight our achievements in sustainability, TOMRA has created a Green Counter. It displays the total amount of CO2 reduced through the utilization of TOMRA’s sorting machines in real time. The Counter is made possible by the smart technology within the machinery, which records the amount of rock sorted and eliminated, as well as throughput and total hours of operation.

The data gathered enables TOMRA and mining companies to calculate the energy in kWh saved by not treating the waste which has been removed by the sorters. The amount of energy saved is converted into CO2 equivalents, which in turn is calculated into CO2 metric tons. Through the use of TOMRA sorting machines, client companies have saved 123,696 metric tons of CO2 in 2018 alone.

TOMRA’s sorting solutions have proven to be more than just technological innovation – they are also considered the benchmark for industry standards in both efficiency and sustainability. TOMRA remains committed to evolving its technology with a clear focus towards preserving our shared natural resources.


1: “The Mining Industry and the Circular Economy” Mines – NREL Joint Workshop September 13, 2018 p. 34

2: “The Mining Industry and the Circular Economy” Mines – NREL Joint Workshop September 13, 2018 p. 41, Harold Cline