Metso Insights Blog Mining and metals blog The environmental and economic benefits of pre-concentration
Mar 6, 2023

The environmental and economic benefits of pre-concentration in mining operations

Ali Alatrash
Ali Alatrash
Digital and Automation, R&D Director
Rashmi Kasat
Rashmi Kasat
VP, Digital Technologies
In the face of a looming climate disaster - and alongside the current energy crisis - the act of reducing the environmental footprint of your operations has never been so important. Especially when you look at comminution, which plays a major role in the total energy consumption of a mining operation and serves its feed into downstream processing. So, the industry is asking – is pre-concentration the solution?

There are many pre-concentration techniques out there. Ore sorting is the most common and now gaining increasing traction in the mining industry for mines to have and maintain a sustainable minerals processing operation. It is an efficient way to reduce the environmental footprint of your production. Not only in the comminution circuit, but for the entire concentrator plant and beyond.

One of the key benefits of pre-concentration is the reduction of energy and water consumption. In a traditional flowsheet, crushing and milling stages consume a significant amount of energy, equivalent to up to 3-5 percent of the world's GDP. From the milling stage to the beneficiation stage, there are significant volumes of fine material that are processed using water and chemical reagents plus electricity, leading to a large volume of fine tailings produced as an undesirable byproduct.

Processing minerals is energy-intensive as is. With degrading ores that are getting harder as well, significantly more energy is needed to crush and grind these. This creates an imperative to look at efficient technologies in order to maximize grade and recovery.

When you have less waste in the process, you are inevitably processing high-quality material, and that ensures that the resource utilization is at its highest.
Rashmi Kasat, VP - Head of Digital Technologies, Minerals, Metso Outotec

Crushing hard ore requires a substantial amount of energy consumption. As you can see in the animation below, by implementing ore sorting early on in the process, you can reduce the amount of waste that needs to be crushed and moved forward. This leads to minimized energy consumption, water consumption, coarse waste and the amount of fine tailings produced.

Cut waste, cut emissions, cut costs

Along with environmental benefits, there are also massive economic advantages with pre-concentration. In typical mining operations, customers invest a lot in capital equipment and in operating this equipment. The resource utilization of this equipment is a key KPI for operators and is extremely important to keep profitable production up and running. By processing less waste, mining companies can ensure that their capital equipment is being used to its fullest potential, leading to higher resource utilization and lower total operating costs.

Additionally, by sorting the ore early on, mining companies can reduce transportation costs and achieve better grade control. For example, when using pre-concentration with in-pit crushing and conveying underground, the material is sorted into its allocated waste or high-grade pile at the first point of processing in the pit, thus minimizing the need for hauling and/or transportation of the material. You also achieve much better grade control due to the higher-grade material that you are producing.

With pre-concentration, you produce the same or even higher amount of concentrate but with a much lower environmental footprint, so you’re increasing the sustainability of your operations. That is why it is important to utilize a Planet Positive flowsheet.
Rashmi Kasat, VP - Head of Digital Technologies, Metso Outotec

Operating efficiently and responsibly

The world around us is changing, and it is crucial for operations to increase their sustainability whilst keeping their costs low. Therefore, pre-concentration greatly benefits mining operations. Reducing their energy and water consumption, and fine tailings ultimately leads to a more sustainable and environmentally friendly operation. Furthermore, the economic benefits - such as higher resource utilization, increased feed grade and reduced transportation costs - serve as an additional advantage when introducing pre-concentration in a Planet Positive flowsheet. In some cases, there is also the potential to create new revenue streams with dry coarse waste as an aggregate byproduct.

Information from this blog post has been transcribed from the webinar “Ore sorting solutions – Driving sustainability in comminution.”

Webinar: Ore sorting solutions – Driving sustainability in comminution
Information from this blog post has been transcribed from the webinar.
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