Hybrid diesel-electric Lokotrack® crusher provides free excess electricity for screening at Tverås Maskin

The surplus of electricity that the Lokotrack® jaw crusher provides is utilized by the mobile scalping screen. Due to this substantial benefit, the company has taken several steps towards a complete, emission-free quarry operation.

In Norway, primary crushing and scalping is typically carried out as its own separate process. Normally, the primary crusher is fed by a dump truck via chute and short conveyor. After the scalping screen, the clean materials are piled for secondary crushing.

This is exactly how Tverås Maskin contracts a crushing and screening operation at Balhald quarry, in the vicinity of Trondheim, Central Norway. Usually, one crushing contract is sized between 50 000 and 100 000 tons.

The main working equipment are Metso Outotec’s Lokotrack® LT120E™ hybrid, diesel-electric crusher and Lokotrack® ST2.8E™ diesel-electric mobile screen.

Within the process, the 0-700 sized blasted granite is first crushed to 0-150 mm in size by the C120 jaw crusher. After that, fines are removed using the ST2.8E scalping screen.

Electric screening saves 10 liters fuel per hour

The core of the hybrid operation is the Lokotrack® jaw crusher, where the on-board diesel motor powers 420 kVA generator and electric motor instead of a normal, direct crusher drive. The jaw is not spending all power capacity created, so the surplus is guided via cable to run the ST2.8E screen.

“By benefitting off the free electricity, we save at least 10 liters of diesel per hour that would normally be used for diesel-driven screening,” Vidar Bjerkås, Operations Manager at Tverås Maskin explains.

“As electric-driven, our screen now requires about 50% less servicing, while all diesel motor related service points are minimized.”

According to Vidar Bjerkås, more savings are achieved at the primary crushing stage, too:

“The diesel motor now runs at a steady and rather low rpm when plugged into a generator instead of directly to the crusher. Steady running is a clear fuel saving aspect.”

“Full Container Load” of wear parts secure availability

Together, Tverås Maskin and Metso Outotec Norway have made an agreement in regards to an economical and environment-friendly way to deliver essential wear parts on-site. This is called Full Container Load.

According to this service agreement, a container full of high-quality Lokotrack crusher and screen wear parts were delivered directly from Metso Outotec foundry to Tverås Maskin’s work site. After using a part, a new one will be automatically delivered to keep the stock full.

“Together with our customer, we selected which wear parts would be most needed within the Lokotrack® crushers and screens. Based on that, a wears selection tailor-made for Tverås Maskin was collected,” says Jan Helge Borgard, Area Sales Manager of Metso Outotec Norway.

“This point-to-point wears delivery saves costs, environment and secures 100% wear parts availability on-site at all times,” Jan adds.

Constant 180-200 tph production

Tverås Maskin is aiming for a constant and steady production to achieve the most cost-efficient result. At Balhald quarry, while processing hard rock, an average of 180-200 tons per hour is crushed and screened, depending on the dump truck travelling distance. A peak production of 500 tph has been reached.

The mobile Lokotrack® fleet is moved 4-5 times per year around Norway. In the future, the company foresees the possibility to utilize the full electric mobile fleet, connected by an external network.

“In fact, without our electric drive option and demand for environment-friendly operations, we would automatically be out of several contract negotiations,” Vidar Bjerkås stresses.

“We have had good co-operation with Metso Outotec since the 1980’s. When meeting any challenge, it’s easy to get connected to the right Metso Outotec experts. Together, all obstacles will be solved.”

“Reliability, cost-effectiveness and advanced technology. Those words describe all Metso Outotec products very well,” he adds.

11 Lokotrack machines, 2 million tons aggregates

Today, Tverås Maskin operates 11 Lokotrack crushers and screens altogether. Their total aggregates production per year exceeds two million tons.

The company is serving several nationwide customers, like the Norwegian road authority and well-known aggregates and recycling company Fransefoss.