Operators can deduct the additional allowance for a northern mine in calculating their annual earnings from a northern mine if the processing of ore from the mine began before March 31, 2010.

Operators can deduct the allowance for the fiscal year in which processing of the ore began and for the nine subsequent fiscal years.

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

• the annual earnings from the mine before deduction of the additional allowance for a northern mine;
• the cumulative mine expenses at the end of the fiscal year.

Cumulative northern mine expenses

Cumulative northern mine expenses are equal to 166 2/3% of the cost of property situated in Québec that is acquired after May 9, 1995, and that is used in processing ore from the mine, minus the amounts that the operator deducted as an additional allowance for a northern mine for previous fiscal years.