Mineralogy Pty Ltd v Western Australia

Constitutional law – State Parliament – Legislative power – Where State of Western Australia entered into agreement concerning mining projects in Pilbara region with Mineralogy Pty Ltd and other parties ("co-proponents") including International Minerals Pty Ltd – Where agreement and 2008 variation set out in schedules to, and thereby formed part of, Iron Ore Processing (Mineralogy Pty Ltd) Agreement Act 2002 (WA) ("State Act") – Where agreement provided that Mineralogy Pty Ltd, alone or with co-proponent, could submit proposals to relevant Minister regarding projects – Where two plaintiff companies submitted proposals to Minister in 2012 and 2013 – Where disputes in relation to 2012 proposal referred to arbitration, resulting in arbitral awards in favour of plaintiffs in 2014 and 2019 – Where in August 2020 Parliament of Western Australia passed Iron Ore Processing (Mineralogy Pty Ltd) Agreement Amendment Act 2020 (WA) ("Amending Act") – Where Amending Act purported to insert new Pt 3 into State Act, including provisions which would deprive 2012 and 2013 proposals of legal effect (s 9) and deprive 2014 and 2019 arbitral awards of legal effect (s 10) – Where plaintiffs commenced proceedings in High Court's original jurisdiction seeking declarations that Amending Act wholly or partly invalid – Whether manner of enactment of Amending Act contravened s 6 of Australia Act 1986 (Cth) – Whether Amending Act exceeded limitation on legislative power of Parliament of Western Australia arising from rule of law or deeply rooted common law rights – Whether ss 9(1), 9(2) and 10(4)-(7) of State Act incompatible with Ch III of Constitution – Whether ss 9(1), 9(2) and 10(4)-(7) of State Act incompatible with s 118 of Constitution.

High Court – Practice – Special case – Where parties agreed to state questions of law for opinion of Full Court – Where special case stated facts and identified documents said to be necessary to enable Court to answer questions of law – Whether facts stated and documents identified sufficient to satisfy Court of necessity of answering questions of law stated in special case for determination of immediate right, duty or liability in controversy between parties.

Words and phrases – "adjudicative function", "advisory", "arbitral awards", "conflict between State laws", "deeply rooted common law rights", "exercise of judicial power", "full faith and credit", "government agreement", "institutional integrity", "interference with judicial power", "legislative power", "limitations on the scope of the legislative power", "manner and form", "necessity of answering the questions stated by the parties", "original jurisdiction", "prudential approach to resolving questions of constitutional validity", "rule of law", "severance", "special case".

Constitution – Ch III, ss 107, 118.

Colonial Laws Validity Act 1865 (Imp) – s 5.

Australia Act 1986 (Cth) – s 6.

Judiciary Act 1903 (Cth) – s 18.

High Court Rules 2004 (Cth) – rr 27.07, 27.08.

Commercial Arbitration Act 2013 (Qld) – ss 35, 36.

Government Agreements Act 1979 (WA).

Iron Ore Processing (Mineralogy Pty Ltd) Agreement Act 2002 (WA) – Pts 2, 3, Schs 1, 2.

Iron Ore Processing (Mineralogy Pty Ltd) Agreement Amendment Act 2020 (WA).