Open Cut » Overburden Removal
This project was for the trial of the link chain concept at Mount Thorley Operations. At the conclusion of the initial engineering difficulties were encountered with the MTO dragline in establishing the trial in an acceptable timeframe. An approach was made to ACARP to reduce the scope and budget to conduct a second stage of modeling to further refine the system. A commitment was received by Central Queensland Mining Supplies Pty Ltd to commercialise the results if supported by Internal Rate of Return (IROR) calculations.
The link chain connects the dump block and dump equaliser. When the bucket disengages in the zone where the link chain plays a role, (which should be the majority of the time), the load will pass through the drag and hoist ropes, and the link chain. If the dump rope and link chain are set to short lengths the rope sockets will be dragged closer to each other which effectively pulls the whole system closer to the tight-line of the machine.
It is considered unlikely that any mine will embrace this technology due to the interactions between the link chains and other rigging components.
The link chain will not be able to connect to the dump block assembly due to the high loads passing through the dump block to the tri-link. There is no practical way to connect a single chain/rope to the tri-link, therefore two chains/ropes will be required. Due to the weight of two chains a dual system of pre-socketed 50mm ropes was recommended for the first trial.
While a likely productivity increase in the range 3% to 9% has been measured, this is probably insufficient to justify the significant extra effort (and probable extra downtime) which will be required to make this technology work efficiently.