The mine produced 1,023, 590 tonnes of coal in the first quarter, bettering the previous record of 1,010,710t as it resolved heating issues.

“The performance over the last quarter has been nothing short of spectacular and is a clear sign that Carborough Downs has turned a corner,” Masterson said in a letter to staff.

“Whilst I’m not keen to celebrate once-off records or temporary spikes in production, it is important to celebrate milestones when they occur in a period of consistent safe production.”

Masterson said the mine had many impediments to production during the first quarter, including a longwall move. But they “pale into insignificance as we celebrate a record quarter, record month and record week”

The mine’s best week of production is now 178,577t compared to the previous record of 163,000t. Its monthly record is 584,416t compared to the previous record of 465,280t.

Masterson said other key achievements over the quarter include 100hrs of operating time on the longwall and 88m of longwall retreat.

“Outstanding performance at Carborough never comes easily, however, we have shown that with a consistent approach to reliable production, a relentless focus on safety and delays and an energetic approach to breakdowns, we can overcome the challenges and perform at a world class level,” he said.

A “laser focus” on costs over the remainder of the year will be needed to bring bring Carborough in on budget for the year, Masterson said.

Masterson was appointed general manager and senior site executive seven months ago. He was previously employed by the Mastermyne-Redpath joint venture to construct the Kestrel mine extension for Rio Tinto through to the first longwall.