Activity Description and Location
TGS proposes to acquire multi-client (MC) three-dimensional (3D) marine seismic surveys (MSS) within the North West Shelf Renaissance North (NWSR North) operational area in waters offshore from Western Australia (WA). The recent EP resubmission (2nd March 2018) is in response to NOPSEMA’s Request For Further Written Information.
 Significant reductions to previous EP submissions have been implemented in this revision, including;
Size: the size of the proposed acquisition area has been reduced by approximately 70%.
Validity: the validity of the EP has been reduced by 60% - down from the original 5 years, to 2 years.
3D only: the option for conducting any 2D seismic activity has been removed. Only 3D activity is to occur within the EP acquisition area.
Individual survey size: the maximum allowable survey size has been reduced by 50% to no more than 25,000 km2 of 3D acquisition.
Water depth: the minimum acquisition water depth has been increased by over 30% so that seismic acquisition will not occur in waters shallower than 200 m (previously 150m).
 As a result of these changes the operational area is limited to the Commonwealth waters off the Pilbara coast only and is more than 180 km off Port Hedland, 210 km off Exmouth and 75 km off Barrow Island.  Consequently, these variations further reduce potential environmental impacts while ensuring greater efficiency in the management of uncertainties in future seismic surveys. 
 The broader operational area consists of a full-fold acquisition area plus a 20-km buffer zone around most of this acquisition area. The inshore (eastern) boundary of the acquisition area is contiguous with the 200 m isobath.  TGS do not intend to conduct survey operations over the entire NWSR North operational area. Restrictions within the EP allow for smaller surveys to be undertaken within this larger operational area over the two-year period up to a maximum of ~18% of the total acquisition area. Further temporal and spatial restrictions also define when/where these surveys can take place.
Surveys will be undertaken with a purpose-built vessel. At-sea refuelling may occur but will only take place during daylight hours and not within a minimum distance of 25 km from any emergent land or shallow water features. A support vessel may accompany the survey vessel.
 Operational Details
The proposed 3D marine seismic survey(s) will be similar to previous surveys conducted in Australian waters, with no unique or unusual equipment or operations proposed. The largest sound source that TGS will use for any survey within the operational area will have a capacity no greater than 4,120 cui.
During the proposed survey activities, the survey vessel will traverse a series of pre-determined sail lines within the operational area at a speed of ~4.5 knots. The operating pressure for the seismic acoustic source will be ~2,000 psi, with the 3D acoustic source deployed in two arrays. Independent Marine Fauna Observers will be deployed, ensuring compliance with EPBC Act Policy Statement 2.1 and the mitigation measures identified within the EP.
 Timing of the Activity
Specific commencement dates and durations of individual surveys within the operational area have not yet been determined.