3 In July 1997, Benaris acquired an exploration permit ("the permit") in respect of an area in Bass Strait for a six year period. On 6 July 1998, it transferred to Origin an 80 per cent undivided interest in that permit. On 10 December 1999, those parties entered into a Joint Operating Agreement ("Joint Operating Agreement"), providing for a joint operating venture to explore for petroleum, appraise the area and, if commercially viable, to develop any field in, and produce petroleum from, the area. The agreement appointed Origin as the operator of the venture. On 26 June 2000, Origin transferred to Woodside a 50 per cent undivided interest in the permit. In return, Woodside was required to act as a sub-contractor to Origin for the purpose of carrying out the seismic and drilling operations in the permit area. Drilling operations were conducted in May 2001, at a cost of approximately $16m. Following analysis of the field data, Origin concluded that the "commitment well" ("Thylacine 1") ought be cased and suspended and advised Benaris and Woodside accordingly. Benaris and Woodside agreed and Thylacine 1 was duly cased. In June 2001, Origin commenced work on a second well, Thylacine 2, intended to provide further information about the lateral extent, volume and likely flow rates from the gas reservoirs within the area. Origin took the view that Benaris was contractually obliged to contribute to the exploration costs of Thylacine 2. Conversely, Benaris contended that the costs remained the responsibility of Origin, in accordance with the original agreement, which assigned an interest in the permit area to Origin. Origin persisted with its demand for contribution. In response, Benaris served a notice claiming that Origin had committed a material breach of the terms of the contract. The notice required Origin to remedy the alleged breach, default of which was said to entitle Benaris to terminate the agreement and require Origin to reassign the 80 per cent interest in the permit. That reassignment would divest Woodside of its interest granted by Origin.