SIMEC Mining's Tahmoor Coking Coal Operation has posted record annual production this year despite initial fears that the mine may close.
Thousands of jobs were put at risk at Tahmoor and South Australia's Whyalla Steelworks when Greensill, a key financial backer of GFG Alliance, collapsed earlier this year.
However, the mine cited record annual production and output 'on the back of significant capital investment by GFG Alliance, strong steel and mining markets, and continuous improvement initiatives'.
SIMEC Mining head of coal mines Peter Vale said the coking coal mine recorded 40-year highs in its yearly, monthly and daily output.
"The team has put in an incredible effort hitting records well above expectation," Mr Vale said.
"Tahmoor's yearly output of nearly three million tonnes was more than 200,000 tonnes better than the previous benchmark, while the coal handling and preparation plant also washed a record 2.8 million tonnes in the full year.
"Our strong performance has come on the back of significant capital investment by GFG Alliance including investment in some new state-of-the-art equipment, a sustained continuous improvement program and backed by a strong focus on maintaining high operational standards."
The Tahmoor mine also received conditional approval from the Independent Planning Commission earlier this year for the Tahmoor South Project - which provides consent for a 10-year extension to the life of the mine.
It is anticipated that the project will create more than 170 new jobs during the construction phase and boost the local economy over the life of the project.
Earlier this year British billionaire owner of the mine, Sanjeev Gupta, announced his confidence in the direction of his restructuring talks with Credit Suisse (CS), saying significant progress has been made towards refinancing his Liberty Steel Group.
Mr Gupta said his newly-formed Restructuring and Transformation Committee were in advanced discussions around a refinancing deal.
It follows "constructive and productive" meetings between the companies in Dubai over the weekend, with significant progress being made towards agreeing on a framework to resolve GFG Alliance's remaining exposure with CS.
"This work includes identifying a positive solution which will allow Liberty to complete the restructuring and refinancing of its UK operations," GFG said.