Mining is an essential process that has become even more critical as the world moves towards a greater energy transition. Minerals are a crucial component in clean energy technologies such as electric vehicles, solar panels and batteries, and the demand for these minerals is increasing, Howden’s Livio Salvestro says.*

According to the International Energy Agency, the demand for certain minerals to support the transition is projected to increase more than twentyfold by 2040. Meeting global carbon reduction targets is essential to mitigating the effects of climate change and the mining industry will play a key role in this effort. Mining practices must adapt and evolve to be more environmentally friendly and help decarbonise operations. In line with global efforts to meet the Paris Agreement objective, mining companies are setting targets to reduce their greenhouse gas (GHG) emissions.

A PwC survey of CEOs in 2021 showed 76% of global mining and metals executives were concerned about climate change and environmental damage, up from 57% a year earlier. And 70% of global mining executives said they planned to increase their long-term investments in sustainability and environmental, social and governance (ESG) initiatives.

Challenges in decarbonising the industry

There are several ways mines can reduce their carbon footprint, but moving to a 100% electric mine would represent a transformational shift for underground mine operations where diesel engines have dominated for over 100 years. Underground diesel equipment represents one of the biggest environmental challenges a mine faces. Switching to an electric energy source can significantly impact mines, reducing their ventilation shaft and tunnel sizes; the size of their fans and heating and cooling systems; their carbon footprint; and their capital investment.

Diesel equipment can also represent a significant financial burden within a mine’s ventilation cost footprint, so moving to electric sources while updating ventilation solutions can be highly effective for improving overall environmental credentials. While progress has been made, which will result in future benefits, there are opportunities for the mining industry to reduce energy consumption and emissions through a combination of advanced sustainable technologies, actionable insight into mine operations and automation – solutions that exist today.

Energy efficiency in mining

Digital advancements are enabling the industry to become more efficient, safe and productive by collecting, analysing and implementing data to optimise mine conditions, processes and maintenance decisions. Digital technologies and automation can also be applied to ventilation.

Ventilation is a vital process in a mine’s operation. It is necessary for providing fresher air and, in some instances, cooling the working environment, clearing blast fumes and diluting exhaust fumes and gases generated by mining.

This means it needs to run consistently and reliably, often accounting for substantial operating costs and up to 40-50% of a mine’s total energy consumption. Advanced technology and more efficient ventilation systems can reduce costs and significantly contribute to a mine’s carbon reduction objectives.

The primary goals of ongoing mine ventilation developments are to mitigate environmental impact, as already outlined, by reducing GHG emissions and improving underground air quality. They are also necessary to create efficiency that is sustainable and reliable, so a mine continues to produce energy savings throughout its lifecycle. Optimising overall health and safety models is crucial, which rely on automation for unprecedented operational capabilities.

There are several solutions to support these goals, including electric mine air heating, which provides a simple and safe solution with zero emissions. Through a modular design approach, these systems use industrial grade, Incoloy tubular elements selected for optimal functionality and maintenance.

Optimised ventilation systems are also available to drive energy savings and contribute to net zero commitments. Products like Ventsim™ CONTROL utilise intelligent software that communicates with hardware devices to remotely monitor, control and automate airflow and heating and cooling systems.

Thermal heat recovery can result in operational flexibility and reduced emissions. By employing a system of heat transfer coils, liquid pumping stations and control and automation technology, the mine can generate heat recovery using potential sources like waste heat from mine exhaust air, central boilers, power generators, and compressors or green sources such as geothermal energy.

Ammonia refrigeration systems offer a sustainable solution with no harmful CO2 or HFC emissions. Ammonia is considered the “green refrigerant” and has been used for many years, however, it is now coming into its own with the demands for reducing the footprint of hydrocarbon and HCFC refrigerants that can affect the atmosphere.

Demonstrable ventilation success

Companies like Howden have been successfully supplying these green mine ventilation solutions for years, and the results are clear.

The Oyu Tolgoi mine in Mongolia required a new indirect air heating, ventilation and filtration solution. Howden developed a unique thermal heat recovery solution that included airlock access, pipe work engineering, main and bypass damper, and fan outlet. Howden’s solution can be used as a reference for the remainder of the mine’s development. Each heater house was designed to capture 22 MW of waste heat from the hot water system.

An electric heating system was supplied to a high-grade underground mine in northern British Columbia, Canada. The system included two direct-fired, hybrid M.I.D mine air heaters and enabled the mine’s electric mine air heating system to take advantage of low electricity prices.

Ventilation automation has been a part of several large-scale mine operations for decades and some mines have experienced reductions of more than 50-60% in energy consumption and 11,500 t of CO2 emissions.

The Newmont Éléonore mine in Quebec, Canada, brought in a Ventsim CONTROL system, which included ventilation monitoring stations and the automation of all ventilation equipment. To date, there has been a 43% reduction in mine heating costs, a 56% drop in underground ventilation electricity costs and a 73% decrease in the cost of surface ventilation electricity.

Recognising the proven benefits of Howden’s Ventilation on Demand system, Newmont – Éléonore won the Eureka Prize from Écotech Québec.

As a pioneer, Howden engineered ammonia refrigeration systems in mines during the 1970s. More recently, the company supplied ammonia screw chillers at the Prominent Hill mine in South Australia for OZ Minerals. In partnership with the customer, Howden created solutions that had the highest functionality while supporting their net-zero targets.

As environmental pressure builds, especially on mining companies, now is the time to implement proven solutions to support a cleaner energy future.

*Livio Salvestro is Global Mining Team Leader at Howden