Dampier Salt has three salt operations located at Dampier, Port Hedland and Lake MacLeod and is headquartered in Perth, Western Australia. The Dampier operation was the first DSL site established and is currently the largest producer of the three sites whilst the Port Hedland operation was acquired in 2001. The Lake MacLeod site has the greatest potential for expansion of the three sites, with a current production capacity of 2.9 million tonnes per annum.
Primero was engaged by Dampier Salt in 2019 to undertake the Lake Macleod radial stacker deconstruction, installation and commissioning.
The Lake Macleod Radial Stacker Replacement Project was to be completed during a shutdown of salt harvesting activity with a five-week window of opportunity to undertake the change out. The replacement stacker was supplied by an international OEM with DSL / Primero jointly providing QA support. The stacker was supplied in prefabricated sections transported to the site in six 12m sea containers comprising approximately 100t of loose material and mechanical equipment.
Primero partially removed the existing foundation and stacker runway, replacing the long travel and end-stop buffer foundation to allow preassembly of the inbound stacker to commence while production ensued, reducing turnaround impact.
Safe and controlled deconstruction of the highly corroded in situ stacker was the most critical risk present. Planning, detailed deconstruction procedures, modelling and contingencies were all developed to mitigate the risk of the fragile structure behaving unpredictably on the way down. The superstructure was strategically weakened at several points to bring further certainly to predictable removal.
The machine was removed by attaching 80t mooring rope to designated points on the A-frame and towing with a D11 dozer. Upon removal of the existing stacker, the balance of long travel and storm lock foundations were placed.
Primero implemented a precast concrete solution for the long travel radial foundations, installing thirteen 12.3m segments each weighing 18t. This reduced onsite manning and ensured that concrete processing could occur concurrently to production only further reducing the impact to production. A new slew pivot foundation was placed and included a precast centre block with accurately set hold-down bolts for the centre slew pivot assembly mount.
With foundations in place critical lifts during erection included:
- Two bogie assemblies at 18T ea.
- Lower boom section approx. 40m long weighing 36T.
- Upper boom section approx. 40m long weighing 27T.
- Six sets of pendant stays comprising multiple articulated / pinned tubular sections.
Once erected scope included completion of mechanical alignments of conveyor idlers and pulleys, installation of the conveyor belt (via subcontractor), installation of guards and complete safe access along the structures.