In calculating the annual earnings from a mine they operate, operators can deduct the additional depreciation allowance in respect of property that meets the following conditions:

• The property is class 3 property.
• The property is used in a plant that processes the ore from the mine.

The maximum amount that an operator can deduct for a fiscal year as an additional depreciation allowance is equal to the least of the following amounts:

• 15% of the cost of class 3 property that is used in the operation of the mine. The cost must be at least:
• $300 million, if the property was acquired after March 25, 1997, but before April 1, 1998,
• $150 million, if the property was acquired after December 31, 2003, but before January 1, 2008;
• $50 million;
• the total cost of property used in the operation of the mine that was acquired after March 25, 1997, but before April 1, 1998 (maximum of $350 million), or after December 31, 2003, but before January 1, 2008 (minimum of $150 million and maximum of $200 million), minus the total of all the amounts that the operator deducted as an additional depreciation allowance for previous fiscal years;
• the annual earnings from the mine for the fiscal year before deduction of the additional depreciation allowance, the additional allowance for a northern mine and the additional allowance for a mine situated in Northern Québec.