Tex. Agric. Code § 59.029
If, during a period a person is indebted to the board for land purchased with financial assistance under this chapter, the person executes or there exists a lease or contract of sale of oil, gas, or other minerals, chemicals, hard metals, timber, sand, gravel, or other material that covers the land purchased from the board that would result in the depletion of the corpus of the land, not less than one-half of all bonus money, delay rentals, or royalties received as consideration for or payment under the oil, gas, or mineral lease and not less than one-half of all money received under a lease or contract of sale of other minerals, chemicals, hard metals, timber, sand, gravel, or other material shall be paid to the board by the lessee under the lease or the buyer under the contract of sale. The board shall apply those payments to the satisfaction of the indebtedness.
Tex. Agric. Code § 59.029