unplanned events (non-emergency)

During exploration, there is the risk of non-hydrocarbon solid objects (e.g. equipment or waste material) being accidentally released overboard from the drill rig or support vessels while within the area of operations. This could occur during lifting operations and vessel transfers or from unsecured cargo loads, manual handling error or lifting equipment/fixture and fittings failure. Examples of solid objects potentially released overboard range from larger objects such as containers to smaller objects such as hazardous and non-hazardous waste items (e.g. batteries, bottles, recyclable items, contaminated waste materials, etc.).
During exploration, there is the risk of environmentally hazardous chemicals and liquids being accidentally spilled and entering the marine environment. This may include fuel, biocides, corrosion inhibitors, refined oil, hydraulic oil, cleaning and cooling agents as well as stored and spent chemicals. Accidental loss of small volumes of these liquids to the marine environment could occur as a result of spill during handling, inadequate bunding and/or inappropriate storage.

The risk and impact risk assessment scoping exercise identified a number of environmental risks that were not considered credible or applicable.  Risks identified as not credible or not applicable do not form part of the risk assessment.

The semi-submersible drill rig and associated support vessels used for the exploration activity may be sourced from overseas locations and brought to the exploration area through international waters. Marine plant or animal species not native to Australia that have been introduced by human activities such as shipping are known as introduced marine pests. Marine pests attach themselves as biofouling to vessel hulls and internal compartments, anchor chains, fishing gear and recreational equipment.  They can also travel in a vessel’s seawater system, including pipes, bilge and ballast water.

There are currently more than 250 introduced marine species in Australia, with 43 found in South Australian waters.  While some are relatively harmless, others may become invasive when outside their natural environment, potentially threatening the environment, human health and the economy.

During exploration, there is the risk of diesel fuel or non-aqueous drilling fluids (NADFs) being accidentally released to the marine environment. This could occur during bunkering and transfer operations between the support vessels and the drill rig.

Due to the distance of the exploration activity from the nearest land, the drill rig will require refuelling.  During this process, a diesel spill could occur as a result of bunkering hose failure, coupling failures, loss of connection, overfilling or leaking flanges, valves and hose connections. NADFs could be accidentally released to the marine environment if there is a failure of the rig’s drill fluid system, equipment failure or accidental valve release.