Arrium Mining is an exporter of hematite iron ore and also supplies iron ore feed to Arrium's integrated steelworks at Whyalla. The business currently exports approximately 9-10 million tonnes per annum of hematite ore, primarily to China.
Iron Knob is located in the Middleback ranges approximately 60 kilometres north west of Whyalla, South Australia. It is said to be the birthplace of Australian steel with commercial mining dating back to the 1890s.
The site is an entire pit to port operation, including mines, crushing and beneficiation facilities, rail, trucking and port facilities.
Arrium engaged Striker Australia to prepare infrastructure to access the ore reserves in the Iron Knob mine. Striker provides quality, reliable and tough crushing, screening and materials handling equipment to the mining and related industries.
The task at hand was to design, supply, assemble, install and commission modular crushing and screening equipment to process hematite iron ore sourced from the Iron Knob Mining Area for rail transport to Arrium’s port facilities with minimum ground works and in a short on-site construction timeframe.
To achieve this, Striker Australia contracted SAGE Automation, a Solution Partner of Rockwell Automation and leading provider of industrial automation and control systems. The company is committed to deliver the highest technical solution and customer service, leading with Rockwell Automation technologies and this project was no exemption.
SAGE Automation was contracted to supply the control system and visualisation together with the complete electrical design, construction and installation works for the new crushing and screening plant.
Keeping it mobile and modular
The Iron Knob crushing and screening plant was designed to have a 10 year life expectancy, making the use of mobile crushing and screening equipment as a more cost-effective solution compared to a fixed infrastructure solution.
“The plant was originally estimated to cost approximately $40 million, but by using mobile equipment, this cost was able to be reduced by half,” said Christopher Poetsch, Senior Electrical Engineer at SAGE Automation.
Poetsch knew that the control and visualisation solution from Rockwell Automation would provide the required flexibility and reliability for this application. As a result of the maintainability and easy integration of the solution into the systems at the site, Rockwell Automation is the control and visualisation vendor of choice for Arrium Mining.
According to Greg Schultz, executive account manager at Rockwell Automation, “By having the crushing in close proximity to the mine, the requirement for transport and materials handling is reduced dramatically.”
The modular design of the plant made integration easy and also delivered the flexibility required to adapt to changes. “The new plant has had a number of design revisions but because it is modular and mobile, it has been easy to adapt to changes,” explained Jonathan Deluao, Principal Control Systems/Maintenance Engineer at Arrium Mining.
Designing a flexible control solution
The overarching control requirements for the entire plant including the conveyors, crushers, feeders and stackers were provided by Allen-Bradley® ControlLogix®. With safety being a vital consideration for the plant, Allen-Bradley GuardLogix® - with local and distributed safe POINT I/O™ modules – provided integrated safety control and the ability to stop either a particular piece of equipment or a section of the plant if required.
Due to the size of plant, over 75 variable speed drives were required. The more complex of these were from the Allen-Bradley PowerFlex® family, used for the synchronisation of the vibrating feeders and for the speed control of the conveyors to optimise flow rates to the crushers. FactoryTalk® View Site Edition (SE) supervisory-level HMI software is used for monitoring and controlling the plant. It provides operational insight into the complete site, including the conveyors, crushers and feeders.