Engineers drill at Sydney's 2nd airport

Geotechnical work is about to begin start on the site of the proposed second Sydney airport.

Engineers will start drilling 100 boreholes at the 1700 hectare site in Badgerys Creek to profile the subsoil and rock at several locations over the next six weeks, Deputy Prime Minister Warren Truss says.

A draft environmental impact statement for the area is expected in the coming months, while the airport is expected to be in operation by the mid-2020's.