Broken Hill Proprietary Company Limited v Municipal Council of Broken Hill

The Broken Hill Proprietary Company Limited, an occupier of a mine within the municipality of Broken Hill, appealed to the Privy Council from a decision of the Full Court of New South Wales. The respondents were the rating authority of the municipality. The case involved the ascertainment of the "unimproved capital value" of the mine for rating purposes under the Local Government Act 1919 (N.S.W.). Specifically, the question was whether the average annual salable value of ore should be calculated by dividing the total value of the ore won over three years by three, or by applying a fraction representing the number of days worked over the number of days in a year.

The Privy Council held that the average annual salable value should be calculated by dividing the total value of the ore won over three years by three. The Court found that the relevant section of the Act referred to actual output, not potential or hypothetical output. The Court also held that a judicial decision on a valuation under the Act for a particular year is not res judicata in respect of a valuation and liability for a subsequent year between the same parties.

The Privy Council allowed the appeal with costs and reversed the decision of the Supreme Court of New South Wales. The Privy Council advised His Majesty accordingly.