Diesel-powered construction vehicles like excavators, wheel loaders and dozers jointly emit an estimated 400 million t of CO2 annually, accounting for around 1.1% of global carbon emissions. Excavators in the 10 t-plus category represent an enormous 46% of these emissions. The mining industry accounts for up to 7% of all greenhouse gas (GHG) emissions, so controlling emissions relating to transportation is particularly important.
While heavy diesel vehicle emissions pose a risk to worker health in all mining operations, underground environments are riskier. These are typically tight and enclosed spaces where exhaust gases, like CO2 and NOx, can quickly lead to hazardous situations for workers.
Accordingly, mines operating such vehicles require extensive ventilation systems to extract the exhaust fumes and ensure good air quality in workspaces. These electrically powered systems add significantly to the mine’s overall energy consumption and operating costs.
To counter these environmental and health concerns, many industries – including mining – are introducing efforts to reduce vehicle emissions. In mining, the International Council on Mining and Metals (ICMM) has committed to achieving net zero emissions by 2050 or earlier. Electrification will play a significant role in attaining this goal. Underground mining, in particular, is showing great interest in the concept of electric operational vehicles because of the more immediate benefits of reduced emissions, improved ventilation, and lower ambient temperature.
Still, mining vehicles operate at least two shifts daily (around 16 hours) in harsh and challenging conditions. Therefore, the technology in electric powertrains must be highly robust, powerful, and able to withstand these environments.
One of the sternest tests of the technology came at the Kittilä gold mine in northern Finland. Engineers successfully tested three underground electric mine vehicles – the Boomer E2 Battery, Scooptram ST14 Battery and Minetruck MT42 Battery – as part of the European Union’s Sustainable Intelligent Mining Systems (SIMS) project.
The Kittilä mine typically does not face high ambient temperature underground, but specialists measured a reduction of 3°C where the mine used electric vehicles compared to diesel operation. This is a game-changing aspect for mines that have higher ambient temperatures.
Making the energy transition
Electrifying a mine, like mining itself, is a process. Mining operators should seriously consider partnering with OEMs and system integrators to accelerate this process. Such a partnership applies to new vehicles and retrofit projects, like replacing a diesel engine with an electric powertrain.
Nasta AS, a leading distributor of Hitachi heavy construction machinery in Norway, is an example. The company is collaborating with ABB to convert heavy vehicles like excavators for electric operation via battery power or a direct cable connection.
With ABB supplying the electric powertrain components, the conversion procedure involves removing the diesel engine and retrofitting an electric motor and drive. It also includes an energy storage system and charging solution.
A large, 24 t diesel-driven excavator consumes around 18 000 l of fuel annually, the equivalent of almost 48 t of CO2 emissions. An electric upgrade eliminates these and other harmful emissions completely, including noise pollution. But the benefits are not just environmental – the electrified machines are also much more responsive, according to operators who tested them. An electric motor provides instant torque, whereas an internal combustion engine takes longer to reach maximum torque.
Manufacturers of traction powertrains must actively accelerate decarbonisation by improving the components’ energy efficiency and productivity. Such sustainability initiatives can only be credible and effective if the entire powertrain system uses reliable and proven technology. With that in place, electric motors can reach 95% energy efficiency, more than double the efficiency of diesel engines operating in the optimum load range.
Electrically powered vehicles require infrastructure to function, which could either support a direct power supply (such as through overhead catenaries), recharging onboard batteries, or a combination of the two. Specifying the most suitable type of infrastructure for the application is essential.
ABB’s eMine™ Trolley System2
In a pilot project for the Aitik copper mine in Sweden, ABB designed and installed a 700 m catenary line for use by heavy-duty mining trucks. Predictions are that the project will save nearly 830 000 l of diesel annually with a 2200 t reduction in CO2 emissions. Greenhouse gas emissions also dropped almost 80% along the catenary route.
Electrification technology has already proven to reduce emissions in public transport vehicles. The Aitik mine project is one of many recent examples showing that industrial vehicles can and should follow suit. Therefore, mining operators should embrace the benefits of electrification to improve safety, lower costs, and reduce emissions.
To read ABB’s whitepaper on sustainable transportation, visit: https://global.abb/content/dam/abb/global/s/sustainable-transport/ABB_EE_WhitePaper_Sustainable_Transport_en.pdf
By Magnus Nordstrand - Global Product Manager - ABB
Read the article online at: https://www.globalminingreview.com/special-reports/01102022/electrifying-mining-operations/
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