Paragraph 18
The provisions of the mining lease or order shall have effect subject to the provision that the aggregate amount of the rent, royalties and other sums payable by the mineral operator by virtue of the lease or order for any year which is either—
the year beginning with the operative date of the compulsory rights order, or
a year beginning with an anniversary of that date and falling within the period of occupation,
shall not exceed the aggregate amount of the rent, royalties and other sums which would have been payable by the mineral operator thereunder for that year if the compulsory rights order had not been made, and he had exercised the relevant rights and facilities in the manner in which, and to the extent to which, he might reasonably have been expected to exercise them in those circumstances.