Wollongong Coal, formerly known as Gujarat NRE Coking Coal, is allegedly sacking the 36 remaining permanent mine workers at the Russell Vale coal mine, 100km south of Sydney, Australia.
The company's latest decision comes after 80 miners were made redundant recently as it could not obtain approval for expanded underground mining operations earlier in 2015.
The company sought approvals in a bid to extract 4.7 million tonnes of coal from eight new longwall mines for a period of five years.
At that time, it was believed that the mine would be put on care and maintenance, and the company would continue to seek approval to expand it.
Australia's Construction, Forestry, Mining and Energy Union (CFMEU) Mining and Energy Division South West District trade union vice-president Bob Timbs said: "We're concerned that this is another opportunistic attempt to deliberately close the mine, terminate the current enterprise agreement, and then re-open the mine using a contract workforce."
Wollongong Coal has not yet made a public statement on the latest allegations.
India-based Jindal Steel and Power recently announced the closure of the Russell Vale colliery due to weak market conditions. The shutdown of the mine comes amid widening losses reported by Wollongong Coal, which operates it.