Sec. 613. Percentage Depletion. *  *  *

(c) Definition of gross income from property. For purposes of this section:

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(2) Mining. The term “mining” includes not merely the extraction of the ores or minerals from the ground but also the treatment processes considered as mining described in paragraph (4) (and the treatment processes necessary or incidental thereto), and so much of the transportation of ores or minerals (whether or not by common carrier) from the point of extraction from the ground to the plants or mills in which such treatment processes are applied thereto as is not in excess of 50 miles unless the Secretary or his delegate finds that the physical and other requirements are such that the ore or mineral must be transported a greater distance to such plants or mills.

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(4) Treatment processes considered as mining. The following treatment processes where applied by the mine owner or operator shall be considered as mining to the extent they are applied to the ore or mineral in respect of which he is entitled to a deduction for depletion under section 611:

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(F) In the case of calcium carbonates and other minerals when used in making cement—all processes (other than preheating of the kiln feed) applied prior to the introduction of the kiln feed into the kiln, but not including any subsequent process;

(b) Election. Under section 302(c)(2) of the Act, the taxpayer, in the case of calcium carbonates or other minerals when used by him in making cement, may elect to apply the provisions of section 613(c) (2) and (4) of the 1954 Code as amended in lieu of the corresponding provisions of prior law. The taxpayer must make the election in accordance with §1.9003-4 on or before November 15, 1960, and the election shall become irrevocable on November 15, 1960.

(c) Years to which the election is applicable. If the election described in paragraph (b) of this section is made by the taxpayer, the provisions of section 613(c) (2) and (4) as amended by section 302(b) of the Act apply to all taxable years beginning before January 1, 1961, in respect of which:

(1) The assessment of any deficiency,

(2) Refund or credit of any overpayment,

(3) Commencement of a suit for recovery of a refund under section 7405 of the Internal Revenue Code of 1954,

is not prevented on September 14, 1960, by the operation of any law or rule of law. The election also applies to taxable years beginning before January 1, 1961, in respect of which an assessment of a deficiency has been made but not collected on or before September 14, 1960.