Sec. 2.Election for quartzite and clay used in the production of refractory products-
is not prevented on the date of the enactment of this Act by the operation of any law or rule of law. Such election shall also be effective on and after January 1, 1951, for any taxable year beginning before January 1, 1961, in respect of which an assessment of a deficiency has been made but not collected on or before the date of the enactment of this Act.
26 C.F.R. §1.9005
Sec. 2(f), 75 Stat. 683; 26 U.S.C. 613 note