Southern Oil Refining Pty Ltd v Hydrodec Australia Pty Ltd

Southern Oil Refining Pty Ltd and Hydrodec Australia Pty Ltd were involved in a contractual dispute that reached the courts. Southern Oil Refining, the owner of refinery plant, alleged that Hydrodec Australia, the operator, failed to comply with their contractual obligations, including the installation of additional plant, record-keeping, and maintenance duties. Disputes also arose over the validity of an informal variation of the contract, the enforceability of an expert's determination of the "written down value" of the plant, and the rights of both parties to the plant at the termination of the contract. The court was tasked with interpreting the contract to determine the obligations of each party, the validity of the variation, the binding nature of the expert's determination, and the rights to the plant.

The primary legal issues were the interpretation of the contract concerning the obligations of both parties, including the validity of an informal variation, the enforceability of an expert's determination, and the rights to the plant. The court had to consider whether Hydrodec Australia breached its obligations to maintain expenditure records and submit to audit, and if Southern Oil Refining was entitled to leave the plant behind or if Hydrodec Australia was obliged to remove it. The court also needed to assess whether Southern Oil Refining's obligations to pay tolling fees were contingent on Hydrodec Australia's compliance with their duties, and whether previously paid tolling fees could be recovered as damages. Further, the court examined whether Hydrodec Australia's actions constituted a breach of contract, including interference with Southern Oil Refining's contractors and the mixing of contaminated and non-contaminated feedstock.

In its decision, the court found that the informal variation was effective, and the expert's determination of the "written down value" of the plant was binding. The court held that Hydrodec Australia did not breach its record-keeping obligations but did breach its maintenance duties. Southern Oil Refining was entitled to leave the plant behind, but Hydrodec Australia was not obliged to remove it. The court also ruled that Southern Oil Refining's obligations to pay tolling fees were contingent on Hydrodec Australia's compliance, and previously paid tolling fees could not be recovered as damages. Hydrodec Australia's interference with Southern Oil Refining's contractors constituted a breach of contract, but there was no conversion of the plant. Finally, the court determined that the guarantor was not discharged from their obligations, as there was no consent to the variation, no breach of record-keeping duties, and no interference with cooperation obligations. The court found that the probative value of the character evidence outweighed any prejudicial effect.

The court ordered that Hydrodec Australia must cease interfering with Southern Oil Refining's contractors and manage the refinery feedstock properly. Additionally, Hydrodec Australia was required to comply with its maintenance obligations and remove the plant from the premises within a specified timeframe.