An Indian resource company planning to develop Queensland's largest coal mine says it will employ Australian workers before it considers overseas labour options.

Adani Mining has finalised the purchase of the Moray Downs cattle station in central Queensland's Galilee Basin, paving the way for its giant Carmichael coal mine project.

It is set to become the state's biggest coal mine and will have its own town and airstrip.

Unions and both sides of politics have criticised a proposal to fly-in workers directly from overseas, with reports Adani officials were talking to the Federal Government about special visas to fill jobs with foreign labour.

But a spokesperson for the company has denied it has applied for the special visas.

"Australian workers will always be the first preference for Adani," the spokesperson said in a statement.

"We have always maintained that Adani Mining will exhaust all available work sources for projects within Australia before using overseas workers."

The company says it will train Australian workers if it cannot employ enough skilled personnel.

Earlier, Queensland-based federal MP Bob Katter said any proposed mechanism to bring in overseas mining workers would make Labor Party pioneers "roll in their graves".

"This is not about them not being able to get people, this is about getting people to work for nothing in this country," he said.

"And they will undermine the wages of every single person in this country if we allow this to happen.

"Now this has got to be fought and fought tenaciously."

Change of ownership

The company has finalised the purchase of the cattle property from grazier Graeme Acton.

The mine would produce about 60 million tonnes per year, with a mine life of more than a century.

If the project goes ahead, Adani says it would be the largest investment by an Indian company in Australia.

Adani says exports would predominantly service the Indian domestic power market.

Meanwhile, AgForce president Brent Finlay says the rural lobby group is concerned about the sale of grazing land for mining.

"Any change of ownership or any change of land use, particularly when it's very good agricultural land, is a concern to us," he said.

"Whether the whole area's going to be taken out of agricultural production or whether only a small area will be and the rest still used for agricultural production, we'd like to know as soon as we can."