A complete diagnostic review was undertaken and revealed damage to the motor stator coil, which was repaired, allowing the mill to restart last week ahead of schedule.

Previously, the mill hadn’t been expected to be back in action until the end of the September quarter.

Svedala is the largest mill at Olympic Dam, but the two smaller grinding mills continued at full capacity since the incident.

Production will be ramped up in the coming weeks with a full return to production expected by the end of July.

The impact on Olympic Dam’s copper production is 60,000-70,000 tonnes.

Olympic Dam asset president Jacqui McGill congratulated the team who worked on the Svedala stator repair project.

"The project has been a fantastic example of what Olympic Dam can achieve when we all work together,” she said.

Olympic Dam produced 111,000t in the nine months to March 31.