Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
The Port Kembla Copper stack is expected to separate into three pieces as it falls following demolition on February 20.
In a detailed briefing with PKC general manager Ian Wilson, it was explained the stack would not fall to the ground in a single piece.
Because of different rates of velocity acting on the stack as it falls, it is expected to break into three.
The stack is made up of three layers with the outer two being load bearing.
A total of 934 holes have been drilled in the outer two layers and, in the days before the demolition, they will be filled with a charge 150 millimetres long and 40millimetres in diameter.
The bulk of those holes are around the base on the north-western side, the direction in which the stack will fall. Before the charges are detonated, they will be wrapped in chain wire and geo-fabric material to manage fly material.
The detonation will blow out a wedge at the base of the stack on the north-western side. The charges are designed to blow backwards into the stack. Charges at the front will be blown first, followed by the others in a decreasing ring around the base.
As the structure begins to fall, a final ‘‘cracking charge’’ on the side opposite to the direction of the fall will be detonated.
For at least an hour before detonation, water cannons will be spraying the area, creating a water curtain where the stack will fall.
After the stack hits the ground, the spraying will continue to minimise dust.
The land the stack will fall on is not flat but broken up into three tiers, part of which have been coated in road base and bitumen.
Unused buildings surrounding the fall line will offer further shielding. A representative from Precision Demolition will check all the charges have gone off before giving the all-clear.
