Thyssenkrupp cuts crushing challenges down to size

The eccentric roll crusher at Bauma.

The minerals processing company has debuted the eccentric roll crusher (ERC), an innovation for the primary reduction of hard rock and ore ideal for underground and surface mines.

A decade of research and development led to the global launch of thyssenkrupp’s eccentric roll crusher (ERC) at Bauma in Munich this year.

While the core vision for a revolutionary underground crushing system has remained intact over this time, the company premiered the ERC with a broader market in mind.

thyssenkrupp initially targeted the underground hard rock minerals processing sector with the design of the ERC.

It planned to develop a robust and compact machine that overcame long-standing disadvantages that traditional hard rock crushers faced, particularly their large height.

The company has, however, realised that surface mines and quarries with mobile equipment join underground operations as applications where the machine can add significant value.

Detlef Papajewski, head of mineral processing at thyssenkrupp, says the potential for the ERC has expanded since the early focus on underground mining.

“Our customers wanted a hard rock crusher for underground mining that did not have the same height as the gyratory crusher,” Papajewski tells Australian Mining on the sidelines at Bauma.

“We started by developing a hard rock sizer. We soon realised that it was physically not possible to bring all of this energy into the small hold. A hard rock sizer was not an appropriate solution.”

The company researched ways to overcome this limitation and identified a new technology that could combine the advantages of crushers and screeners in one machine.

“We designed a crusher with a totally new operating principle and an integrated screen,” Papajewski continues. “If you look at a normal plant, screening and crushing both need a big height – not only for underground but also for open pit sites. The combination of an all-in-one machine will lead to less capital investment for the customer.”

The ERC design includes a roll mounted eccentrically between the crushing and screening chambers. The large, constant stroke of the crusher allows for a high degree of reduction.

An integrated screen increases the efficiency of the machine. Fines are not guided through the crushing chamber, but instead discharged directly to reduce energy consumption and minimise wear to the crusher elements.

thyssenkrupp has succeeded in its goal to develop a machine with a much lower height than conventional crushers while incorporating each of these elements.

The design of the ERC is 20 to 55 per cent lower in height than most primary crushers for hard rock. The reduced height greatly simplifies transportation, installation and maintenance (including underground), and saves costs.

Despite the low height, testing of the ERC has proven the machine also achieves significantly higher throughputs than conventional crushers.

thyssenkrupp currently has four ERC models with throughput capacities of between 600 and 8000 tonnes per hour. The largest of these machines is the most ideally suited to the massive mining operations of Australia.

The crusher during testing.

Papajewski says there are plans to expand the range to up to six models. He believes collaboration with mining companies, which has included copper and iron ore miners in Australia, has and will continue to be critical as the range evolves.

“We wanted to cooperate with partners from the production side to move in the right direction and I think that was very healthy,” Papajewski says. “There was a lot of discussion about our general ideas and how to use the machine in an underground mine.

“It also turned out that thanks to its unique design the crusher is fully balanced. Thus, the ERC has great advantages also in mobile applications compared to incompletely balanced crusher types like gyratory or jaw crushers. The next step was very quick to go into open pit mines with this machine as well.”

Falk Silbermann, head of research and development mineral processing, says the trials confirmed the benefits of having a crusher height that is significantly lower than conventional machines.

“The trials we’ve done have not only been for the performance of the machine itself, but also for the costs of the machine,” Silbermann says.

“For that machine and that type of installation you could save a lot of capital investment on the underground cavity. You could decrease the cavity height by 20 to 30 per cent – that is really the big cost driver.”

With its unique kinematics and screening/crushing chamber design, the ERC economically crushes hard rock and ore in underground operations, while also helping improve cost efficiency in open pit mines or quarries.

thyssenkrupp found during trials that the symmetrical arrangement of the roll provides superior balance and lowers machine vibrations and the loads on surrounding structures compared with other primary crushers. This factor makes the ERC useful as a mobile and semi-mobile crushing system.

The testing also provided a clearer view of how maintenance would be performed on the machines and what could be done to simplify this process, according to Silbermann.

“The beauty of having a collaboration for the development was to not just focus on the throughput and the performance of the machine itself, but to also discuss the maintenance issues,” Silbermann says.

“Our customers attach great importance to being able to maintain their machines quickly, safely and as easily as possible. We have found good ways that allow to quickly exchange crushing tools without safety issues.”

The ERC on display at Bauma was set to be commissioned at a German quarry during May. The company expects the first machine will provide guidance on how the ERC will be rolled out into other markets.

Australia is targeted as one of the major markets for the ERC, but Papajewski believes it could be until at least next year before mines in the country start to introduce the machine.

This article also appears in the June edition of Australian Mining.

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