Judge Thomas Ingram's sentencing decision was released yesterday.
He found Stainton was building a safety barrier - a 1.5m high bund - in front of a steep slope to stop vehicles falling, when his loader fell.
The judge said the company had identified the risk the slope posed.
"In the course of addressing that hazard, the employee was killed by the very hazard he was sent to address."
The practice of building a bund was industry standard and mine inspectors had never raised concerns about it before.
Judge Thomas said OceanaGold's handling of the aftermath of Stainton's death was "exemplary" and praised its efforts to alleviate the family's suffering and prevent the accident from recurring.
He said the company paid the family $200,000, helped with tangi costs and shut down the mine for a week after the death for cultural and safety reasons at a cost of more than $1 million.
"After shutting the mine for a week ... the defendant came up with a unique and innovative method of preventing any recurrence of the events which left to Mr Stainton's death," Judge Thomas said.
That involved placing steel bollards along open slopes, a non-industry standard procedure.
OceanaGold Waihi general manager Bernie O'Leary said the company deeply regretted the loss of one of its staff and accepted that it was responsible for his death.
"Tip was our colleague, friend and a member of our Mines Rescue Team," O'Leary said.
"He died at our mine, on our watch. We accept responsibility for what happened and have been working alongside his family to make sure that as a company, as workmates, and as friends, we continue to do everything possible to support them and prevent this from ever happening again."
Craig Marriott of Worksafe said the case had highlighted that the requirement for businesses to manage risks to workers "extends to the risks inherent in the actions taken to mitigate known risks".
Company's sentence for worker's death
Judge Thomas Ingram ordered OceanaGold to pay:
- a fine of $378,000
- reparation of $350,000
- court costs of $3672