30 U.S.C. § 88
If the coal-land laws have been or shall be extended over lands applied for, entered, or patented hereunder the coal deposits therein shall be subject to disposal by the United States in accordance with the provisions of the coal-land laws in force at the time of such disposal. Any person qualified to acquire coal deposits or the right to mine and remove the coal under the laws of the United States shall have the right at all times to enter upon the lands applied for, entered, or patented under sections 86 to 89 of this title, for the purpose of prospecting for coal thereon, if such coal deposits are then subject to disposition, upon the approval by the Secretary of the Interior of a bond or undertaking to be filed with him as security for the payment of all damages to the crops and improvements on such lands by reason of such prospecting. Any person who has acquired from the United States the coal deposits in any such lands, or the right to mine or remove the same, may reenter and occupy so much of the surface thereof as may be required for all purposes reasonably incident to the mining and removal of the coal therefrom, and mine and remove the coal, upon payment of the damages caused thereby to the owner thereof, or upon giving a good and sufficient bond or undertaking in an action instituted in any competent court to ascertain and fix said damages. The owner under such limited patent shall have the right to mine coal for personal use upon the land for domestic purposes at any time prior to the disposal by the United States of the coal deposits. Nothing herein contained shall be held to deny or abridge the right to present and have prompt consideration of applications made under the applicable land laws of the United States for any such surplus lands which have been or may be classified as coal lands with a view of disproving such classification and securing a patent without reservation.
30 U.S.C. § 88