Mobile PlantSafetyTechnical Services

Battery Electric Underground Equipment – constraining factors?

4 Mins read

Main Image Source [ Barminco Youtube]

This week it was announced that IGO has successfully completed a trial with their mining contractor Barminco, testing a Normet Battery Electric Vehicle at their Nova underground project. This would be one of the first publicised trials that has come across my desk in Western Australia and is a great step forward for the industry in reducing the mining sectors reliance on diesel.

The advantages of running a battery electric (BEV) powered underground fleet are numerous: including reducing diesel particulates, decreasing heat at the mining face and therefore reduced ventilation requirements. Early studies also show that the maintenance requirements are reduced, and the lifecycle of BEV drivetrains are improved on their historic diesel counterparts!

With all of this in hand though, what are some of the constraints that mining contractors and operators may experience in transitioning to a BEV fleet?

Alternative Charging Methods:

In deep underground mines a fuel bay for refueling the diesel fleet is not uncommon. Fuel bays drastically reduce downtime for front line machines (Loaders especially) as they would alternatively have to tram to surface for fuel periodically. How would a battery bay look in the underground environment and how would it be managed?

One would think that conceptually it would have to be larger than current fuel bays, as there would have to be a bank of batteries recharging at once. This then poses a further question; would all battery packs have to utilise a similar coupling system? If standardisation wasn’t delivered across the fleet, this could become hard to manage in the tight constraints of an underground mine.

A great idea that I saw at UGOPS was that the Bortana EV can utilise a jumbo box to recharge – this is a very clever idea as these are readily available power sources dotted around the mine. I could imagine that in time mining levels could utilise a designated “charging bay” for machines that are not being utilised or require charging during shift change, this is already common at many underground mines that utilise portable refuge chambers. These could be placed in the access with other auxiliary drives such as sumps and stockpiles.

The Bortana EV (Source: SafeScape)

I would like to think that these points highlight the importance of manufacturers and mine operators working together to establish the recharging process regarding systems, processes and ultimately the mine design, once BEV fleets are implemented. Fire suppression and ventilation considerations are fundamental to the installation of underground fuel bays, what safety considerations would be necessary for the installation of underground battery banks?

Increased Power Demands Underground:

I have a lot of respect for underground electricians (sparkies!) as they are essential to the mining process and often must deal with less-than-ideal working conditions! The labyrinth of cables and substations delivering power to the front line is impressive at any underground mining operation!

With the electrification of the mining fleet, this would place additional emphasis on their work on a project. Would existing infrastructure such as substations, HV bypass cables and surface power stations be able to keep up with the increased demand? If this infrastructure needed upgrading it would be a delicate balance between scheduling essential works and completing project works in tandem.

An example of an underground sub station (Source: JTMEC.com.au)

Increased secondary ventilation requirements (due to more powerful diesel engines) has resulted in the requirement for more powerful secondary fans that has dramatically increased the electrical demand in underground mines. Will a transition away from diesel machinery ,and therefore reduced ventilation requirements, offset the increased electrical demand from a BEV fleet?

New skills for existing workforce:

Heavy Diesel fitters, auto-electricians and electricians would have to learn new systems of work for the new technology and its requirements in the underground environment. This would be delivered by OEMs to the crews on site or via external courses to bring those across the industry up to speed with the requirements for new BEV fleets they will be encountering.

With the strain we are currently seeing to retain and attract skilled professionals to the industry , could adding further tickets and competencies have a negative impact on recruiting? Furthermore would there be sufficient resources available from OEMs to provide the necessary training and technical support required for a new fleet of equipment ? In theory does it create a requirement for a dual trade between heavy diesel and auto-electrician, as both will be involved in BEV mobile plant maintenance?

Sourcing clean generation of electricity:

A clear advantage in removing diesel from the underground environment is reducing exposure for underground workers to diesel particulates. This is reason enough to drive forward with a BEV project. However, the holy grail would have to then be  generating the required electrical power from renewable sources on the surface. This could heavily reduce the overall carbon footprint of the business and allow businesses to drive toward net zero.

It has been great to see Goldfields taking steps toward this with their large power farms at the Granny Smith mine site . Their hybrid system – integrated with an existing gas-fired power station – is powered by more than 20,000 solar panels and supported by a  1 mega watt hour battery system.

“Gold Fields says the reduction in fuel consumption will be the equivalent of taking 2000 cars off the road, while the production of an estimated 18 giga watt hours of energy each year is predicted to reduce carbon emissions at the mine by 9500 tonnes of carbon dioxide equivalent.”

With the often expansive and sterile areas that surround mining operations in Australia, it will be interesting to see if more businesses look to “complete the loop” on reducing emissions by installing similar renewable power generating methods in the near term.

Summary:

There are many advantages to moving toward a BEV underground mining fleet and I will be following this closely on UG Mining Tech in the coming years. However, for the mature & deep mines of Australia some of the above factors may cause headaches beyond simple implementation.

I am extremely excited to observe how the industry develops and rolls out these ideas and I would love to hear your thoughts on any constraints I may have overlooked in this article.


If you like my content and discussions on underground mining, please follow me on LinkedIn or Facebook. I continually strive to offer new and interesting content for those exploring new technologies and ideas for underground mining – so please send me an email if you would like to get involved.

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