 This has meant that the pit has been filled with approximately 10 billion litres of sea water, with a significant marine eco-system forming within the bounds of the former working pit.Due to the dense nature of the marine fauna within the Main Pit, Mount Gibson Iron plan to utilise numerous substantial blasts within the water filled pit in order to extract all marine creatures before dewatering operations are commenced.A Seawall will then be built around the ocean side of the pit in order to keep the ocean out.