Murphyores Incorporated Pty Ltd v The Commonwealth

Murphyores Incorporated Pty Ltd (the applicant) sought a writ of prohibition against the Commonwealth of Australia (the respondent) to prevent the respondent from proceeding with a proposed inquiry into the applicant's mining operations. The applicant contended that the inquiry, initiated under the *Environment Protection (Impact of Proposals) Act 1974* (Cth), was beyond the constitutional power of the Commonwealth. The matter came before the High Court of Australia.

The central legal issue before the High Court was whether the Commonwealth Parliament had the constitutional authority to enact legislation that would permit the executive government to inquire into and potentially regulate the environmental impact of mining operations conducted by a private company within a State, where those operations were not demonstrably linked to a Commonwealth head of power. Specifically, the Court had to determine if the *Environment Protection (Impact of Proposals) Act 1974* (Cth) validly extended to the subject matter of the proposed inquiry.

The majority of the Court held that the Commonwealth lacked the constitutional power to enact the *Environment Protection (Impact of Proposals) Act 1974* (Cth) in so far as it purported to authorise the executive government to inquire into the environmental impact of mining operations within a State, absent a sufficient nexus to a head of Commonwealth legislative power. The Court reasoned that the Act, as applied to the applicant's activities, sought to regulate matters falling within the residual legislative powers of the States. The Court distinguished between the Commonwealth's power to legislate with respect to its own territories or instrumentalities, and its power to regulate private activities within the States that did not engage a specific Commonwealth head of power.

The Court made absolute the order nisi for a writ of prohibition, restraining the respondent from proceeding with the proposed inquiry.