With a growing global emphasis on tackling climate change by reducing emissions, many in the mining industry are looking at new ways of doing this. As part of its FutureSmart Mining scheme, which aims to cut greenhouse gas emissions by 30% by 2030, Anglo American has teamed up with First Mode (as the system integrator), Ballard and Williams Advanced Engineering (WAE) to develop a fuel cell haul truck.
Based on an existing diesel/electric model with the diesel engine removed, the fuel cell system will be integrated into the motor/inverter set up. It is made up of 8 FCveloCity-HD 100kW modules feeding power into a battery system to be developed by WAE at its Grove, Oxfordshire base.
The Fuel Cell Haul Truck Test
The test site will be at the Mogalakwena platinum operation in South Africa, where a solar photovoltaic array will be used to run an electrolyser to generate the hydrogen for the fuel cells.
James Hoxey at WAE says, “In the initial concept creation, we went through a detailed study to agree the best sizing for the battery pack and fuel cell; this approach has enabled us to optimise the vehicle for the application, balancing the total cost of ownership (TCO) model for the whole mine strategy, from solar PV through to truck.”
WAE has gained considerable knowledge of battery design through its involvement with Formula-E and the upcoming Extreme-E racing programme, which begins in 2021. The requirements here are similar but not identical, as Hoxey explains, “For the concept programme we have utilised nickel manganese cobalt (NMC) chemistry, commonly used in EVs on the road today. As we look towards the future of this project we are considering different system approaches to deliver optimum performance and cost solutions. Unlike many of the automotive projects we work on, for this kind of vehicle and application, we expect cycle life, as opposed to calendrical ageing, to be the factor that will inform the cost model as these machines are in operation every day.
“We have of course designed for robustness; selecting materials that are more appropriate for the cost and purpose of the vehicle – so more aluminium and less carbon composite. The most significant shock to the vehicle will be the ~300 tonne load being dropped into the haul bed; so we have run a number of simulations to ratify material and design approach.”
Thermal management is always an issue when designing new battery systems, and Hoxey is open-minded here. “For the prototype battery system, we do not require liquid cooling; however looking at other usage cases we have designed for this on future iterations. The battery technology we have selected was in fact developed for an air-cooled EV. Flexibility is key in the design as Anglo American operates in a number of different environments and the systems need to have the flexibility to optimise for this in a modular fashion.”
For regeneration, the capability of the battery system (2MW of peak power, and 1MWh of stored energy) does mean that the pack is capable of storing enough energy. Mogalakwena has a journey from the top of the open pit to the bottom that generates in the region of 90KWh of energy, which is around the same as a fully charged Tesla Model S or Jaguar I-Pace battery. Testing will begin at the mine later this year.
Electric Haul Trucks
The result of nearly two years testing conducted with four 795F AC trucks using 700m of electric trolley line at Boliden’s Aitik mine in Sweden, Caterpillar’s trolley assist system is now available for retrofit. It also fits on the 794 AC, 796 AC and 798 AC.
The idea is a simple one: when the vehicle is in the most demanding part of its route it’s electrified via the pantograph. In this application, there is a 10% gradient on the ramp out of the pit, and when on the trolley the truck saves up to 40 litres of diesel fuel per kilometre of trolley line. Fuel costs are cut by 90% when it’s hooked up.
It’s faster too – Cat reports speed-on-grade increases as much as 100% versus the diesel-only mode, so up to 28kph fully loaded. When not needed, the pantograph has a quick-drop feature to allow the vehicle’s normal height to be restored.
Jonas Ranggård, a programme manager at Boliden says, “Availability has been high despite the arctic conditions, and we’ve had good support from Caterpillar and all other partners involved. There are few projects that can show both environmental and productivity improvements of this magnitude. This is why Boliden has decided to expand the trolley infrastructure in Aitik and equip its entire 795F AC truck fleet with trolley assist systems.”
Changes To The 457
JCB has made several updates to its 457 wheeled loading shovel. As well as becoming Stage V-compliant, the changes have improved fuel economy by a claimed 10%.
The largest change to the machine is a new engine – the old 192kW (258hp) MTU unit has been replaced by a Cummins model that offers a dual power option, so 210kW (282hp) is available for heavy duty work with a switch in the cab to reduce this to 167kW (224hp) for lighter duties. The aftertreatment is housed in a single module, featuring a diesel oxidation catalyst, selective catalytic reduction (SCR), a diesel particulate filter (DPF) and an ammonia slip catalyst (ASC). There’s also a new auto engine shut-down feature which the operator can fine tune.
The old four-speed box has been replaced with a five-speed Powershift transmission designed to offer better spacing for the ratios.
Other enhancements include better mudguards, a new engine canopy and better seating.
Expanded Training Capabilities
Anything that can accelerate training is good. CM Labs Simulations has expanded its training capability with a new exercise designed around earth moving equipment.
It allows an excavator operator to work while a colleague learns how to operate the truck, interact with the excavator, and drive on various types of terrain.
CM’s Julien Richer-Lanciault says, “We believe this crew training capability is unique to the industry, in that it is the only training solution that simulates critical machine reactions, such as the precise motion of the truck when dirt hits the trailer or when it is struck by the bucket. This allows operators to develop the sense of feel that is so critical to efficient operations.”
In addition to those two tasks, another operative can simultaneously offer guidance from CM Labs’ Signalperson Training Station while a fourth can work from an Instructor Operating Station. The simulation then merges the various parameters to give a score for the team.
The company also offers a similar package for training mobile and crawler crane drivers. So, as Stage V comes into force across Europe, the efficiency drive continues.
Volvo & Hitachi’s Advancements
In other news from this sector, Volvo’s latest EC300E Hybrid crawler excavator uses energy generated by the downward motion of the boom to charge 20 litre hydraulic accumulators that feed into hydraulic assist motors that help power the hydraulic pump. The company reckons the fuel saving payback can be in two years when used in high production dig and dump applications – especially those within a 90° swing, with up to 15% lower fuel consumption and 12% less CO₂ emissions than a conventional machine.
Finally, Hitachi’s latest offering is the 35 tonne ZX345USLC-6. It’s the largest in the firm’s reduced-tail-swing excavator line. It uses a three pump system designed to improve economy.
Two pumps operate under normal loads and the third lends a hand when required providing additional hydraulic oil to the swing circuit without robbing oil or speed from other functions.