Double award winner

By Lindsay Gale18 November 2014

Rio Tinto's High Intensity Smelting plant at Kwinana, Western Australia before work commenced on its

Rio Tinto's High Intensity Smelting plant at Kwinana, Western Australia before work commenced on its deconstruction

Liberty Industrial carried out the deconstruction of Rio Tinto's High Intensity Smelting facility in Kwinana, Western Australia. The project involved the dismantling and relocation to China of almost half of the Hismelt plant, which was sold to Chinese company Molong. Never before has a dismantling project of this scale and complexity been attempted in Australia.

Deconstruction works commenced in January 2013 with the dismantling phase of the project. In total, more than 7,000 tonnes of industrial plant and equipment, including four bulk shipments of over 18,000 m3 (635,500 ft3) and 280 shipping containers of plant and equipment was salvaged and shipped to Shandong Province in China. Over 2,000 bulk units were methodically dismantled, cleaned to export standard, match marked, labelled, recorded and packed, with each item given clear instructions on how to be reassembled in China.

The salvaged items included the 65 m (214 ft) high, 1,200 tonne coal drying and grinding structure, the flue gas desulphurisation plant, hot metal handling equipment, including an 80 tonne induction furnace, the hot metal desulphurisation plant, off gas scrubbing and cooling infrastructure, and a 25 megawatt power station. Carrying out lifts of up to 108 tonne, the dismantling process relied heavily on complex engineering lifts using large crawler and mobile cranes.

Throughout the project Liberty Industrial managed multiple crews across multiple workfronts within a small footprint. The project workforce hit its peak in the dismantling phase of the project at 60 personnel including significant senior management and a supervisory team of two project managers, three safety managers, five supervisors, and three leading hands, supported by a team of five project engineers.

Once the dismantling phase of the project had been successfully completed, Liberty Industrial commenced demolition of the major structures, utilising engineered induced collapse methods to demolish the larger structures, including the 75 m (246 ft) tall, 1,700 tonne preheater structure. This structure, due to risks associated with its proximity to adjoining operating industrial facilities was modelled using the company’s proprietary ASI Extreme Loading software.

Liberty Industrial implemented its Demolition Risk Assessment Workshop (DRAW) system on the project. The DRAW system forms part of its third party certified AS4801:2001 Safety Management System and is the foundation for the company’s approach to hazard and risk management. The resulting DRAW then feeds down to the development of task specific Risk Assessments and Job Hazard Analyses.

The Extreme Loading software was used to 3D simulate the induced collapse methods to ensure that the company was satisfied with the mode of failure, pre-failure structural stability and the effects of wind on the weakened structure. Modelling the structure and simulating the proposed demolition methodology allowed Liberty to refine its methodology and demonstrate a successful, safe and controlled outcome to risk averse client Rio Tinto well in advance of executing the task. Through this simulation Liberty was able to test its proposed demolition scenario involving initial weakening followed by pulling using cables and to determine the pulling force required to collapse the structure. The application of this innovative technology was a key factor in mitigating and managing the potential risks associated with the task, ensuring the structure was demolished in a safe and controlled manner.

Once the higher structures were at ground level the demolition of the plant and infrastructure was undertaken by Liberty’s heavy duty customised 230 tonne Liebherr 994 (Australia’s largest demolition excavator). This machine was assisted by a 120 tonne Hitachi, two 46 tonne and five 36 tonne Volvo excavators, two semi tippers, two telehandlers, a 40 tonne dump truck, water truck, service truck and various sized boom lifts.

Various structures including the off gas hood, smelt reduction vessel and the lock hopper were collapsed using controlled cut and pull demolition techniques whereby engineered pre-cutting and inertia is utilised to bring taller structures to ground level. Working in combination with a smaller fleet of excavators equipped with shear attachments, the 230 and 120 tonne excavators pulled the structures apart. The remaining structures were systematically demolished and the materials processed. Excavators with various demolition attachments downsized and processed the scrap materials to export size for shipment to Asia to be recycled.

Liberty Industrial’s resourceful and innovative approach to waste management and environmental stewardship significantly minimised the amount of waste disposed in landfill. 108,000 tonnes (97%) of the site’s 111,000 tonnes of waste was recycled with only 3,000 tonnes of all waste going to landfill.

In addition to the 7,000 tonnes of plant and equipment items salvaged and 12,000 tonnes of scrap metal recycled, Liberty Industrial found resourceful solutions to dispose of 25,000 tonnes of concrete and waste products from the Hismelt process, including 50,000 tonnes of slag waste, 7,500 tonnes of dolomite and 5,000 tonnes of large irons skulls, sourcing buyers and processing materials to their specifications and consulting geotechnical engineers and blending fill materials;

Liberty sourced a local buyer for the 25,000 tonnes of concrete who was looking for a supply of road base over a four month period. The concrete was pulverised to remove 1,500 tonnes of reinforcing so that crushing could be done quickly and efficiently. In addition, 50,000 tonne of slag waste from the HIsmelt process was crushed into 14 mm road base and stone, and sold it for reuse. A buyer was also sourced for the 5000 tonnes of large iron skulls that contained upwards of 70% Iron and the material was processed down to 4 to 5 tonne blocks so that it could be loaded onto a bulk scrap ship and shipped to Vietnam for recycling.

In lieu of disposing of the 7,500 tonne of dolomite offsite, Liberty consulted geotechnical engineers about its suitability as fill material. Once a suitable blend of fill materials had been determined, the dolomite was incorporated and reused across the site as backfill.

Balancing the conflicting interests of key stakeholders who come to the project with different expectations and interests was critical to the success of the Hismelt project. With two clients to satisfy, Liberty Industrial managed the key objectives of the two on the project; Molong’s key driver was the timely execution of the project while Rio Tinto’s key priority was compliance with stringent safety and environmental standards.

Liberty achieved a high level of client satisfaction through value adding and high standards of service and delivered this project in accordance with Rio Tinto’s world class standards and compliance requirements for the management of health, safety, environment and quality performance.

Liberty Industrial was able to realise maximum value from a number of reusable plant, process equipment and scrap materials and deliver a cash positive project outcome for Rio Tinto through efficient demolition, and innovative asset recovery and resources recovery solutions. The plant closure project delivered for Rio Tinto was cash positive by approximately $3.5 (€2.8) million. In addition, Liberty Industrial also delivered optimal project outcomes for Molong. The ground-breaking dismantling and salvage operation was a complete success; delivered within budget, on schedule, without incident and in accordance with their exacting specifications.

The specialist expertise and experience of Liberty Industrial’s personnel together with state of the art demolition simulation technology ensured a safe and sustainable outcome; Liberty Industrial successfully completed 115,000 man hours of work on the project without a single lost time injury, recycling over 108,000 tonnes of material.

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