Mining exploration and development costs

Official source

(A) In general With respect to each mine or other natural deposit (other than an oil, gas, or geothermal well) of the taxpayer, the amount allowable as a deduction under section 616(a) or 617(a) (determined without regard to section 291(b)) in computing the regular tax for costs paid or incurred after December 31, 1986 , shall be capitalized and amortized ratably over the 10-year period beginning with the taxable year in which the expenditures were made.

(B) Loss allowed If a loss is sustained with respect to any property described in subparagraph (A), a deduction shall be allowed for the expenditures described in subparagraph (A) for the taxable year in which such loss is sustained in an amount equal to the lesser of— (i) the amount allowable under section 165(a) for the expenditures if they had remained capitalized, or (ii) the amount of such expenditures which have not previously been amortized under subparagraph (A).

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Mining exploration and development costs

Official source

(A) In general With respect to each mine or other natural deposit (other than an oil, gas, or geothermal well) of the taxpayer, the amount allowable as a deduction under section 616(a) or 617(a) (determined without regard to section 291(b)) in computing the regular tax for costs paid or incurred after December 31, 1986 , shall be capitalized and amortized ratably over the 10-year period beginning with the taxable year in which the expenditures were made.

(B) Loss allowed If a loss is sustained with respect to any property described in subparagraph (A), a deduction shall be allowed for the expenditures described in subparagraph (A) for the taxable year in which such loss is sustained in an amount equal to the lesser of— (i) the amount allowable under section 165(a) for the expenditures if they had remained capitalized, or (ii) the amount of such expenditures which have not previously been amortized under subparagraph (A).