20Amendment of assessment

20 Amendment of assessment (1) The Secretary may, subject to this Act, at any time amend an assessment notwithstanding that royalty may have been paid pursuant to it. (2) If a royalty payer has not made to the Secretary a full and true disclosure of all the material facts necessary for an assessment and there has been an avoidance of royalty, whether pursuant to an arrangement under section 4G or otherwise, the Secretary may: (a) if the avoidance of royalty is due to fraud or evasion – at any time; and (b) in any other case – within 6 years after the date upon which the royalty became due and payable under the assessment; amend the assessment to correct an error in calculation or a mistake of fact, or to prevent avoidance of royalty, as the case may be. (3) If a royalty payer has made to the Secretary a full and true disclosure of all the material facts necessary for the Secretary's assessment, and an assessment is made after that disclosure, no amendment of the assessment varying the liability of the royalty payer in any particular shall be made except to correct an error in calculation or a mistake of fact, and no such amendment shall be made after the expiration of 3 years from the date upon which the royalty became due and payable under that assessment. (4) Despite subsections (2) and (3), if an assessment for a royalty year is based on an estimate of the value of a saleable mineral commodity sold or removed without sale in that year from a

Part II Imposition and assessment, &c., of royalty Mineral Royalty Act 1982 37 production unit because the value was not ascertainable at the end of that year, the Secretary may, any time within 3 years after ascertaining the value of that mineral commodity, amend the assessment on the basis of that value, to ensure the completeness and accuracy of the assessment. (5) Despite subsections (2) and (3), if the assessment of net value in respect of a royalty year includes eligible exploration expenditure within the meaning of paragraph (a) of the definition of eligible exploration expenditure, the Secretary may, at any time within 3 years after refusing to issue a certificate under section 7 in respect of any part of that expenditure claimed, amend the assessment so as to ensure its completeness and accuracy on the basis of eligible exploration expenditure.