15-32-507. Credit limitation. A credit for each distinct mining operation may not exceed a total of $20 million for all exploration activities under 15-32-503 and accrues at the rate of 50% of the certified expenditures each year. The credit must be applied within 15 tax years after the taking of the credit is approved under 15-32-504. However, the tax year or years in which the credit is applied need not be:

(1) the tax year in which the person first incurs liability for payment of tax based on the person's activity that is the basis of the claim for the credit; or

(2) consecutive tax years.