California Code, Fish and Game Code - FGC § 1500.5

(1) If a parcel contains 15 acres or less, the director shall except and reserve to the state all mineral deposits below a depth of 500 feet, without surface rights of entry.

(2) If a parcel contains more than 15 acres, the director shall except and reserve to the state all mineral deposits, together with the rights to prospect for, mine, and remove the deposits.  The rights to prospect for, mine, and remove shall be limited to those areas of the property conveyed that the director, after consultation with the State Lands Commission, determines to be reasonably necessary for the removal of the resources and deposits.