Spectrum proposes to conduct a 2D and 3D seismic survey in the Browse Basin. No unique or unusual equipment or operations are proposed. The survey will be conducted using a purpose-built seismic survey vessel. The maximum survey area extent is approximately 6,331km2 over the 3D survey area, and includes a total of 191 km over the nine identified 2D sail lines and is located entirely within Commonwealth waters. The survey vessel will not enter State waters or Commonwealth Marine Reserves at any point during the activity. Water depths in the survey area are in the range of 3 to 430 m with the shallowest water depths located around Heywood shoal, however the survey vessel will not fire the seismic source in water depths of less than 30 m.
The survey area indicates the area within which 3D seismic will occur.  In addition, the 2D lines shown will be acquired.  The seismic source will be discharged at full power within the survey area and along the 2D lines only.  The operational area is used for conducting operations ancillary to achieving full-fold coverage within the survey area.  Activities conducted in the Operational Area include: acoustic emissions below full power for the purpose of ‘soft start’ or ‘fauna alert’ procedures; miscellaneous maintenance operations; and, vessel turns at the end of each sail line, necessary for the vessel to change to a new sail line.
To allow for contingency in event of prolonged shut down periods, weather or equipment/vessel issues, a conservative time of 90 days (3 months) is assessed for in this EP.  If surveys are conducted separately, there may be a period of time between the activities being undertaken, the total duration of the separate surveys will however take 3 months.  If this does occur, this will trigger new commencement notifications to stakeholders.