FLSmidth thickeners for Lihir Island expansion

The two thickeners - each 48m diameter x 7,500m3/h capacity - will be designed and fabricated in Australia and supplied ‘piece large’ to take account of the restricted lay down and site construction area at Lihir island. The fabricated pieces will be barged to site. Each will be equipped with a hydraulically-driven bridge drive, making them among the world’s largest bridge drive thickeners.
As part of the design process FLSmidth and LGL operational personnel combined to conduct an extensive testing regime to investigate underflow capacities within the range of ore blends the thickeners could be processing. These test results provided pointers to the overflow clarity and underflow densities that can be achieved.
In line with LGL’s requirements to maximise underflow capacity, the tanks will be elevated. This design will also mean a minimum suction line below the pumps and significantly reduce the chances of underflow blockage.
Along with improved operational efficiencies, the elevated tanks will also provide for improved safety for site operational and maintenance personnel through unrestricted access to pumps and associated equipment.
The overall design on the thickeners and associated operational equipment has also taken account of the proven high seismic activity around the general area of the mine. The thickeners are designed to tolerate seismic events well in excess of what is considered typical activity. A massive fully-integrated steel network structure will support each tank and safely provide the gravity feed between the tanks as requested by LGL.
Final design is close to completion and construction fabrication is underway. Shipping is expected to start in April and final commissioning is scheduled for late 2010.