Section 317.374 - Depletion(1) To the extent that the amount allowed as a deduction for depletion under section 611 of the Internal Revenue Code exceeds, or is less than, the amount determined as the Oregon depletion allowance under subsection (2) or (3) of this section, to derive Oregon taxable income, the difference shall be added to or subtracted from federal taxable income.(2) For purposes of subsection (1) of this section, in the case of timber, mines, oil and gas wells, and other natural deposits, except in the case of metal mines as provided in subsection (3) of this section, the Oregon depletion allowance shall be a reasonable allowance according to the peculiar conditions in each case. The reasonable allowance in all cases shall be computed on the cost of the property.(3) In the case of metal mines, the Oregon depletion allowance may be the amount allowed under subsection (2) of this section or an amount equal to 15 percent of the gross income from the property during the taxable year, not to exceed 50 percent of the net income of the taxpayer (computed without allowance for depletion) from the property. In its first return made under this chapter, the taxpayer must state as to each property with respect to which the taxpayer has any item of income or deduction (in case of metal mines), whether it elects to have depletion allowance for each such property for the taxable year computed with or without reference to percentage depletion. An election once exercised under this section cannot thereafter be changed by the taxpayer, and the depletion allowance in respect to each such property will for all succeeding taxable years be computed in accordance with the election so made.