It has a State Forest "occupation permit" but the Department of Investment and Industry (DII) was yet to give approval to start drilling.

A Cockatoo spokesman said they expected to gain apporval by April and were negotiating with drilling contractors to start drilling 30 bore holes in Belanglo by June.

The mining firm, which recently bought a lease covering Berrima and Sutton Forest, has been unable to gain access to landowners' properties for exploration and was relying on the government to help it fulfil its lease requirements.

Mining lease AUTH349 expires in November and the company must fulfil certain "work requirements" before the government can issue another three-year renewal. But lease renewals are at the discretion of the department.

"The company submitted in February an application for approval to conduct exploration activities, which include a seismic survey and drilling of exploration bore holes. This application is currently under review and has not yet been approved," a DII spokeswoman said.

Cockatoo sent down its big guns for the meeting, including a counterpart from Korean steel manufacturing giant POSCO, which is bankrolling the project.

Managing director Mark Lochternberg continually told the council and gallery that Cockatoo still had no idea what method of mining they could use or where a mine might be located, but after the meeting he conceded they did.

"We've got a reasonable idea about the coal quality because we can look at other mines that are mining the Wongawilli seam either today or historically and infer from that the quality and where it is likely to be," he said.

He said longwall mining had not been ruled out as the potential mining method used.

"As a generalisation longwall mining is more economically viable than board and pillar mining typically," he said.

"It's difficult to guarantee with respect to mining operations and the likely method of mining operation, yeah, we've got an idea but we do have an obligation to efficiently and effectively mine all of the coal."

Cockatoo community liaison officer Julie Gander initially ruled out public meetings but due to public pressure, particularly from the Southern Highlands Coal Action Group, Mr Lochternberg said they would hold a meeting.

Cockatoo said it wanted landowners to agree to exploration before going to court.