The extreme conditions present in mining and tunnel construction place extra burdens on automation solutions.
Noise, dust, dirt, heat, strong vibrations and shock stress are all part of the usual working conditions in mining and tunnelling. Under such conditions, the soundproofed and airconditioned driver’s cab in the boom type road-header Alpine Miner ATM 105-IC seem like a comfortable place to be. The machines, developed by Zeltweg-based Sandvik Mining and Construction, achieve a considerable increase in efficiency thanks to the automation provided by B&R control systems.
Before automation of the boom type road-header, the driver had to manually control the hydraulic cylinders and motors, as well as the electrical drives, using handles and switches. Due to the high levels of dust, the driver also had an extremely limited view of the working area. Today, he controls the machine from a fully airconditioned driver’s cab using joysticks and is guided by a graphic realtime display of the wall that is being mined. Pieces that have broken off the wall are highlighted in colour on the display, which helps the driver with orientation. The pre-programmed limits for tunnelling are automatically monitored by the controller. This guarantees that the intended excavation cross-section is kept within considerably tighter limits than before. This is a significant factor for the efficiency of the tunnelling process because the volume of excavation is reduced. Much more important, however, is the substantial savings on reinforced concrete.
Sandvik Mining and Construction automation director, Alfred Marek, says: “The increased level of automation has resulted in significant value add for the user.”
In addition to the automated drives and motion procedures, the machines today also include an integrated direction guide and navigation. Data archiving makes it possible to reproduce procedures and to collect and develop profiles. When necessary, the machine operator can access these and other necessary support from the comfort of the cab. In special working situations, the machine can also be driven remotely from outside the driver’s cab.
Resistance to shock and temperature
During the tough evaluation tests performed in a tunnel in the Styrian town of Erzberg, the B&R control system proved its worth. Resistance to vibration was a crucial criterion for design decision, the automation components were therefore subjected to rigorous vibration tests that lasted for days. The functional capability of the B&R components such as the industrial PC APC 620 with its compact flash memory could not be shaken even by forces up to 25 g over six milliseconds. According to B&R, units from other suppliers were broken by the high stresses.
Global acceptance
An industrial PC and PLC combination, housed in a pressure resistant casing, form the platform of the automation system. Depending on the machine, the PLC is supplemented with modules such as bus controllers, analogue interfaces, temperature inputs and digital I/O. The machine is equipped with POWERLINK for all data communication as well as POWERLINK Safety for the incorporation of functionality pertaining to machine safety.
Marek points out a series of other positive criteria: for example the complete, compact and clearly-organised system architecture as well as the modular design. This enables the same automation concept to be used in all of the company’s machines. Also the contact with expert counterparts at B&R has proved invaluable from the development phase right up to field implementation. “The machines from Zeltweg are used all over the world, from Australia to Chile and South Africa to Svalbard,” he says. “And as a partner, B&R offers a matching presence for support world-wide.”
For more information contact Chris Simpson, Klare Technologies, +27 (0)41 503 9900, [email protected], www.klaretech.com
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