Alinta LGA Limited (Formerly The Australian Gas Light Company) & Anor v Mine Subsidence Board

The High Court of Australia considered an appeal by Alinta LGA Limited (formerly The Australian Gas Light Company) and another party against a decision of the Supreme Court of New South Wales. The dispute concerned the interpretation and application of the *Mine Subsidence Compensation Act 1961* (NSW) and its predecessor legislation, specifically in relation to claims for compensation for damage to underground infrastructure caused by mine subsidence. The core of the disagreement lay in whether the Mine Subsidence Board was liable to compensate Alinta for the cost of repairing and protecting its gas mains from the effects of mine subsidence.

The central legal issues before the High Court were: (1) whether the Board had a statutory duty to compensate Alinta for the damage sustained by its gas mains due to mine subsidence, and (2) whether the Board's liability extended to the cost of preventative measures and repairs undertaken by Alinta to mitigate future damage. The Court was required to determine the scope of the Board's obligations under the relevant legislation, particularly concerning damage to underground infrastructure not directly owned by the claimant but essential for public utility.

The High Court held that the *Mine Subsidence Compensation Act 1961* (NSW) imposed a statutory duty on the Mine Subsidence Board to compensate owners for damage to their improvements caused by mine subsidence. However, the Court clarified that this compensation was limited to the actual damage suffered and did not extend to the cost of preventative works or the cost of future repairs undertaken by the owner to protect their infrastructure. The Court reasoned that the legislation was designed to compensate for loss, not to fund ongoing maintenance or upgrades of public utilities. The appeal was therefore dismissed, upholding the Supreme Court's decision that the Board was not liable for the preventative measures claimed by Alinta.