Focusing on cleaner, greener operations is no longer an alternative for mining companies, it is crucial to business success. According to the PwC Mine 2021 report, “Companies with higher ESG ratings outperformed the broader market during the peak of the COVID-19 crisis. These companies also demonstrated stronger performance in the longer term.”  

However, the unique challenges that the mining industry will face over its 30-year path to decarbonization are still being unpacked as it decides how to utilize enabling technologies and solutions. The journey to net-zero requires flexibility, and we need to incorporate that flexibility from the very beginning.

This has seen an increased focus on collaborative solutions across the mining value chain, including the re-emergence of a 70-year-old technology: in-pit crushing and conveying (IPCC).

IPCC works by crushing ore and waste material in an open-pit and using conveyors to transport the material to the process plant or to the waste dump. It is a system that miners often associate with a rigid, inflexible mine. However, an IPCC system no longer needs to be just a fixed asset. One of the new ways that IPCC can be implemented is by using a combination of relocatable and mobile conveyors in tandem with a mobile, truckless system, where a shovel dumps material into a moveable sizing rig that loads the automated conveyor fleet.

Much like irrigation sprinkler machines, the system operates in parallel, or pivot, and a combination of different length hoses and pipes connect it back to a fixed point, which in this case is the process plant. By increasing the reach of the system, multiple combinations of bench level, mine direction and pass widths can be considered and optimized. 

At one site in Queensland, Australia, an overburden truck fleet that moved material from the mine face to the top of the in-pit dump was replaced with an IPCC system. Introduction of the IPCC system reduced energy usage by 63 per cent and displaced 58,000 barrels of diesel each year.  

As the mine face moves, a relocatable IPCC system can move with it. Alternatively, trucks powered by renewables can complete small distances to a crusher that is moved periodically, with conveyors used for the rest of the journey to the plant. While both options give the flexibility to change mining locations, this hybrid option provides the energy efficiency and cost-effectiveness of conveyors while benefitting from the relative flexibility of a truck system over much shorter distances.

Related: Energy efficiency, reliability and condition monitoring are key components driving improvements in conveyor performance

Flexibility is especially useful for miners establishing sites with minimum viable capital or starter-case options. Miners can start with a conveyor, a small truck fleet and minimum fixed plant, relocating the crusher and extending the conveyor as and when required. This is a key advantage because it helps achieve project specific goals through different mine sequences (i.e., the order in which benches are mined and equipment is relocated) to enhance an operation’s sustainability.

Powered by electricity “from the grid,” or supplemented from alternate renewable options, IPCC is an energy efficient option for miners. Mining companies can develop partnerships for the supply of green energy, such as solar and wind, to power their site, including the energy used for the mass material movement from the mine face to the process plant and waste dump.

IPCC can further improve a mine’s sustainability by adding bulk ore sorting capability to the system.

Sensor-based ore sorting (SBS) technology can be retrofitted to IPCC conveyors to measure everything on the belt. The option also exists to increase grade by removing dilution and very low-grade ore while maintaining throughput on existing systems, maximizing metal recovery through the entire system. The data from the SBS process can also be used to learn more about what is coming out of the ground as it is mined, with assumptions verified in real-time.

By improving sorting efficiency, and processing a better material grade, water and electricity consumption per tonne of ore mined can be reduced.

One of the world’s largest iron ore mines, Vale’s S11D Eliezer Batista Complex in Brazil, is a notable example of how new IPCC technology is enhancing sustainability and protecting people and the environment. This project is a truckless mine – the first of its kind at such a large-scale iron ore mine – that uses mobile crushers and conveyor belts to replace traditional trucks, consequently reducing diesel consumption by approximately 70 per cent.

The system also means the miner can process waste rock in existing industrial areas, moving it away from environmentally sensitive ones and avoid the need to expand the mine site with stockpiles on the pit edge, further reducing the project’s environmental impact.

In designing the project, besides rethinking the mine plan and how the technology could be used on the site, another challenge was re-evaluating the role people play in executing the concept. It is critical to re-educate technicians and engineers to equip them with the skills needed to work with these technologies safely.

Technologies like IPCC will help miners meet their decarbonization commitments. However, sustainable mining is complex – no individual technology can solve the challenge. To focus solely on the benefits of the equipment and disregard the need for flexible operations to accommodate changing grades and rock types, and revisions to sorting and blending for example, is a short-term solution to a long-term challenge.

If miners are to meet sustainability goals, they need flexibility, collaboration with technology and energy partners, and a holistic approach to implementing new technology that starts at the mine planning stage.

Nicholas Russell is a senior mechanical and mining engineer at Worley, a global company that provides professional project and asset services to the energy, chemicals and resources sectors.