Subject, in case of clause (iii), to the conditions of an istimrari sanad and to the provisions of any law for the time being in force, a landlord shall have a right--
         (i) where in any area bighori is charged at customary rate and cotton is grown on more than one-fourth of the irrigable area of the holding of a tenant, to charge rent on the land in excess of the one-fourth area on which cotton is grown at a rate specified in the second proviso to section 64;
         (ii) at all reasonable times, to enter, or depute his servant, agent or surveyor to enter, upon any land comprised in his estate for the purpose of surveying and measuring such land or for any other lawful purpose; and
         (iii) if he has a proprietary interest in an istimrari estate, to open of work a mine or grant a lease for the purpose, or to undertake, or to issue a licence to any other person to undertake, prospecting work for discovering new sources of supply of minerals.