Miner Mount Gibson Iron has reached agreement on a $64.3 million settlement for business interruption caused by the failure of the Koolan Island main pit seawall in WA.

It says the agreement with 14 insurers represents 92.5% of the cover for business interruption, and negotiations are continuing with another insurer representing the remainder.

The settlement takes combined insurance proceeds for property damage and business interruption at Koolan Island above $150 million, the company says.

The wall failure on November 2014 caused seawater to flood the iron ore pit, halting mining operations.

The company’s broker, Arthur J Gallagher, has described the resulting investigations by Mount Gibson and its insurers as technically challenging and complex, with numerous geotechnical experts involved.

Gallagher’s GM Mining and Construction Colin Todhunter says the claim highlights the importance of business insurance.

“Australian businesses are underinsured compared with their US and UK counterparts, with recent estimates sitting around the $4.5 billion mark,” he said.

“There is no amount of planning that can anticipate or prepare for a situation like Mount Gibson’s, so having robust insurance cover in place is a sensible move.”