The Commissioners of the Land Office shall be, and they are hereby authorized to execute supplemental contracts to lessees on all lease contracts embracing more than thirty thousand (30,000) acres in one body without submitting same to bids for the renewal of said leases, providing that if oil and gas, or either of them, are being produced on said tracts of land in paying quantities at the expiration of said leases, that then, and in that event, said leases shall be extended for so long a period of time as gas and oil, or either of them, shall be produced on said tracts of land in paying quantities; Provided, however, that drilling operations shall be commenced within six (6) months from the date of passage of this resolution, and shall be prosecuted with diligence.