The Secretary of the Interior, or his authorized representative, is authorized to convey to State or local governmental agencies or to local school authorities all the right, title, and interest of the United States in any land and improvements thereon and personal property used in connection therewith heretofore or hereafter used for Federal Indian school purposes and no longer needed for such purposes: Provided, That the consent of the beneficial owner shall be obtained before the conveyance of title to land held by the United States in trust for an individual Indian or Indian tribe: Provided further, That no more than fifty acres of land shall be transferred under the terms of this section in connection with any single school property conveyed to State or local governmental agencies or to local school authorities. Any conveyance under this section shall reserve all mineral deposits in the land and the right to prospect for and remove such deposits under rules and regulations prescribed by the Secretary of the Interior, shall require the property to be used for school or other public purposes, and shall require the property to be available to Indians and non-Indians on the same terms unless otherwise approved by the Secretary of the Interior. If at any time the Secretary of the Interior determines that the grantee of any such lands, improvements, and personal property has failed to observe the provisions of the transfer agreement and that the failure has continued for at least one year, he may declare a forfeiture of the conveyance and the title conveyed shall thereupon revert to the United States. Such determination by the Secretary of the Interior shall be final. If the grantee of such land fails for a period of one year to observe the provisions of the transfer agreement and the Secretary of the Interior fails to declare a forfeiture of the conveyance, the former beneficial owner, if an individual Indian or an Indian tribe, may petition the United States District Court for the district where the land is located to declare a forfeiture of the conveyance and to vest the title in the United States, in the same trust status as previously existed.