Ann: High Grade Koolan Island Ore Reserves Increase, page-41

BHP commenced open-pit mining operations on Koolan and neighbouring Cockatoo Island in the late 1940s and by 1963 had established substantial mining operations there. The Koolan Island mine closed in 1994 after BHP had extracted 68 million tonnes of high-grade haematite ore averaging 67% iron.

Major rehabilitation of the island was undertaken since the mine closure, with buildings and exotic vegetation removed. The state government authorised the breaching of the sea wall as an alternative to stabilising the pits high wall. That was a crime in that it threatened to sterilise remaining ore that belongs to the crown (the people).

MGX's issues with the seawall are rooted in that decision: a naturally, in situ rock was always likely to be stronger than any man made (earth) wall. In my humble view, the state govt should have come to the party in paying for the wall's repair: they are happy enough to take the royalties from something they had condemned after all!