Dr Ian Gray - BE, MAppSc, PhD Mangaging Director and Principal Engineer, Sigra Pty Ltd, Australia. Ian Gray has practised as a civil engineer, geotechnical engineer and mining engineer. He has also been heavily involved in petroleum engineering particularly in relation to coal seam gas and mine drainage. Since 1994 he has owned and run Sigra Pty Ltd a company that consults and tests in the fields of geotechnical and ground fluids for the civil, mining and petroleum industries.