The lease shall grant the exclusive right to drill for and produce all oil, gas, sulphur and other mineral deposits in the leased land and be for a primary term of 10 years and for so long thereafter as oil, gas, sulphur or other minerals are produced in paying quantities from the leased land, or lessee is diligently conducting producing, drilling, deepening, repairing, redrilling or other necessary lease or well maintenance operations on the leased land, or is excused from conducting such operations under the terms of the lease.