As from the date of the passing of this Act until the valuation date, all persons interested in coal or a mine of coal shall be treated as holding their respective interests in a fiduciary capacity for giving effect to the provisions of this Part of this Act, and as being subject accordingly to an obligation to refrain from any dealing therewith (not being a disposition or other dealing which might reasonably have been effected in the ordinary course of business if this Act had not been passed) calculated to give a factitious or artificial value to a holding or to prejudice the interests or powers to be acquired by the Commission under this Part of this Act.