The proposed plans come after the Indian firm announced plans to sell power projects for $825m last month to scale down debt.
The company said that talks are underway with potential investors and no definitive decision has been made, reported Reuters.
Earlier this year, the 380 workers at the mine have refused to work due to pending wages.
Australia Collie-Preston member Mick Murray was quoted by ABC News as saying: "One of the problems is the price of coal, its just not high enough to sustain the mine
"You know with overheads … the losses continue so it’s quite obvious now it’s just they’ve decided to cut their losses and put it on the market.
"The sale won’t make the mine sustainable. The cost of production is still higher than the coal price they are getting so it doesn’t matter who buys it, something has to change.
Lanco acquired Griffin in 2011 for $760m, and it plans to boost production at the mine to around 18 million tons by 2018.
