Sec. 109.73. DRILLING OPERATIONS: SUSPENSION OF RENT; CONTINUANCE OF LEASE; DUTY TO PREVENT DRAINAGE. (a) If during the term of a lease issued under the provisions of this subchapter the lessee is engaged in actual drilling operations for the discovery of oil, gas, sulphur, or other minerals, no rentals shall be payable as to the tract on which the operations are being conducted as long as t