As a surface owner, you will only lease the minerals as agent for State of Texas if the minerals under your tract are RAL (Relinquishment Act Land), often called mineral classified. RAL were properties sold by State after Sept 1, 1895 and before Aug 21, 1931. Sales after that date, State may have reserved 100% of the minerals, including all lease rights, or retained a 1/16 royalty rate or other terms. You would need to research your particular tract. If you only have surface rights, then no one has any legal obligation to notify you when the underlying minerals are leased or included in a unit. If the well is located on your surface tract, then you will be entitled to damages. Or if a pipeline, electric line, road, etc crosses your surface, then you will sign a ROW and receive compensation.