He said this was only the second sentencing for a workplace death under the new workplace health and safety laws introduced in 2016, where important legal principles were still to be resolved but said the company would continue to support the miner's family.
"This appeal is not something we would initiate, but we understand why the wider insurance industry is looking for clarity in this area and that this becomes, to some extent, a test case," he said.
OceanaGold would not disclose the insurance company that made the appeal.
The company was ordered to pay a fine of $378,000, reparation of $350,000 and court costs of $3672.
O'Leary said that this was in addition to a significant sum already paid to the family by the mining company.
"Irrespective of the outcome of this appeal, we will make sure that the family is looked after and do not face the risk of reduced reparations on appeal. Our first priority is to make sure that we look after our own."