Cal. Pub. Res. Code § 8704

The trustee shall make all reasonable attempts to acquire the mineral and other subsurface rights in any acquisition pursuant to this division. If the trustee is unable to acquire the mineral and other subsurface rights, the trustee may purchase real property upon the trustee expressly finding that the benefits to be derived from the acquisition are substantial and that acquisition of the property without the subsurface rights is in the best interests of the state for the purposes set forth in this division.