BATTERY AND ELECTRIC MACHINES
branch in Elko , Nevada , for additional testing . This testing will include the development of a brand-new method of introducing accelerating chemical to the shotcrete , creating increased savings in material use that will be passed on directly to the mines , MacLean says .
The unit in question will also be fitted with a new chiller package to cool the battery .
Set to be released commercially in the next few months , this chiller is intended to ensure battery-electric vehicles can operate in environments that exceed 35 ° C .
Keeping up the electrification developments and building on its experiences of helping convert ( in partnership with MEDATech Engineering ) a Cat 12M diesel-powered dozer to electric power for the Borden gold mine in Ontario , MacLean is also working on a purposebuilt battery-powered grader for underground mines , as Maarten van Koppen , Product Manager – Mine Operations at MacLean , revealed .
He explained the product development rationale : “ First and foremost , any mine with a ramp or roadway benefits from having good ramps / roadways . That message might have got lost at some mines with diesel equipment , but when you look at the top performing ramp haulage mines , that ramp is always in immaculate condition .”
This maintenance effort allows trucks to tram faster , while lowering the maintenance costs of the machines that travel up and down it , van Koppen said . MacLean has conducted tests that demonstrate battery-electric vehicles regenerate more energy while tramming downhill on a wellmaintained ramp , too .
He continued on the grader ’ s development : “ It will be one of the heavier-class road graders on the underground market , in the same category as the Cat 12M . In terms of drawbar pull , weight , blade-down pressure , operator comfort and visibility etc , it will be very competitive .
“ It will also be purpose built for the underground mining industry , which is different to some machines being used at underground mines that have been adapted from typical civil road construction configurations . This means that some functions seldom used underground were eliminated while making maintenance-intensive components more robust .”
The company is also lining up a Tier 3 diesel engine version of this grader , with both diesel and battery-powered machines able to operate in drifts as small as 4-4.5 m wide by 4.5 m high . van Koppen says the company is looking into equipping the machine , which leverages one of the company ’ s own frames , with other attachments that could be used outside of road grading while the machine is operating at low speeds .
More details could follow closer to the machine being launched , expected in the September quarter .
Further down the project pipeline is a battery-electric , heavyduty forklift for underground mining that could feature attachments such as a tyre handler .
The company is also considering developing new products for South Africa ’ s narrow-reef miners , a market it knows well with a longstanding MacLean branch and manufacturing facility in Parys , as well as a service and support footprint in Phalaborwa .
More widely , the company is setting itself up to provide a comprehensive battery offering to clients that considers the specifics of the applications at hand .
“ I would say our current battery offering is in the middle of the battery capacity range and will suit most applications ,” van Koppen said . “ But , if you design a product that fits the majority of applications , it means you are not providing an optimised option for most of them .”
He expanded on this : “ On the SS5 , for instance , operators could have applications where they plug into the grid more and can , therefore , get away with a lower-capacity battery . Whereas , on the TM3 transmixer , you can have a lot of uphill tramming over a longer distance , so we could afford to expand the capacity of our current batteries a bit .”
Right now , the company ’ s batteries have a capacity of 93 kWh , but , in the future , it will present miners with options from 78-155 kWh .
“ We have realised not every application is the same ,” van Koppen said . “ It is unfair to have one product servicing all types of different mines – such as block caves and truck haulage mines with significantly different duty cycles . We wanted to ultimately provide better value to our customers .
“ It is eventually going to be a battery option similar to the way customers select a Tier 3 or Tier 4 Final diesel engine , or a compressor on board a machine .”
Customers will not be stuck with these selections for life . There is the potential to swap out the batteries should a machine move to a different mine or application requiring more or less power .
SmartDrive shifts gears
It has been a year of progress for Normet and its SmartDrive series of battery-electric machines .
Having refined the platform during testing at
The Normet Charmec MC 605 VE SD trial at the Carrapateena copper-gold mine in South Australia involved the charging of 30 faces with tramming times of 5-15 minutes and tramming distances of 1-3.5 km
First Quantum Minerals ’ Pyhäsalmi mine , in Finland , with its Charmec MC 605 VE SD , the company has since rolled out several machines to the international market .
Soon , a Multimec MF 100 SD cassette-type vehicle will be put to operation at a mine site in Canada , while an Utimec MF 500 Transmixer SD concrete transport vehicle is in transit to an underground mine site in Chile , according to the company .
The latter machine was also put through its paces at Pyhäsalmi , with the initial findings from one month ’ s worth of testing proving to be positive .
Carrying a 7.5 t load ( for a gross weight of 23.5 t ) from surface to level 990 at Pyhäsalmi – a distance of 7.6 km – the vehicle ’ s battery regeneration capacity stood out .
Driving down a decline with an average slope of 14 %, the battery went from 14 % state of charge at surface to 55 % at level 990 . This regeneration was possible even when rotating the concrete drum , which Normet said only consumes 2-5 kW of power .
Extrapolating out these results , Normet estimated that regeneration charges the battery by around 4 % per vertical 100 m with a 23.5 t truck weight and 5 kW of auxiliary consumption . The tests confirmed that , as planned , the control system starts to automatically reduce vehicle speed when the battery state of charge reaches 80 % to ensure safe operation and machine controllability even when the battery is approaching its capacity .
The results were equally impressive on the incline with an empty drum , no auxiliary consumption and a gross weight of 16 t .
Driving from level 660 to surface over a 5 km distance on the 14 % grade ( average ) incline , the battery state of charge went from 91 % to 24 % at
14 International Mining | MARCH 2021