Quarrying & Mining Magazine

Converting a quarry to electric

Volvo Construction Equipment and its customer Skanska have recorded ground-breaking results from their Electric Site research project – including a 40 percent reduction in operator cost.

VOLVO AND SKANSKA tested the viability of the Electric Site research project over 10 weeks at Skanska’s Vikan Kross quarry, near Gothenburg, Sweden.

The results were better than expected and support the potential for a 25 percent reduction in total cost of operations at the quarry. However, at this stage, the reduction in total cost of operations is just a prediction. As the prototype machines are part of a research project and are not commercially available, it is impossible to give a guaranteed figure.

Uwe Muller, chief project manager for the Electric Site at Volvo says the aim is to electrify each transport stage in a quarry – from excavation to primary crushing, and transport to secondary crushing.

“It incorporates electric and autonomous prototype Volvo CE machines, new work methods, and site management systems, which together form a complete site solution,” Uwe says.

“New technology encompasses machine and fleet control systems and logistic solutions for electric machines in quarries.”

“The aim is to electrify each transport stage in a quarry – from excavation to primary crushing, and transport to secondary crushing.”

The Electric Site project involves eight HX2 autonomous, battery-electric load carriers, which transport the material from the primary mobile crusher up to the secondary static crusher.

They use a lithium ion battery to power two electric motors which drive the machine; the hydraulics are driven by an additional electric motor.

The HX2 is fitted with a vision system, which allows it to detect humans and obstacles in its vicinity. It can follow an adjustable, pre-programmed GPS path.

The LX1 prototype electric hybrid wheel loader is said to have delivered more than a 50 percent improvement in fuel efficiency at the quarry, as well as significant reductions in noise pollution, compared to its conventional counterparts.

The LX1 is a series hybrid that incorporates a driveline that consists of electric drive motors mounted at the wheels, electric-driven hydraulics, an energy storage system, a significantly smaller diesel engine and new machine architecture, including a new design of the lifting unit. 

The EX1 70-ton, dual-powered, cable-connected excavator prototype loaded the primary crusher at the quarry.

The base machine for the EX1 is a Volvo EC750 crawler excavator that has been upgraded to incorporate an electric motor in addition to the diesel engine. At the quarry, the machine was plugged into the grid. And when the cable is connected, the EX1 automatically starts in electric mode. If not, it will start in diesel mode. The EX1 is operated in exactly the same way as a conventional Volvo excavator. 

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