Section 18
SEC. 18. If at any time after the date of the award and before the issuance of patent, it is proven to the satisfaction of the Chief of the Bureau of Public Lands, after due notice to the purchaser that the purchaser has voluntarily abandoned the land for more than one year at any one time, or has otherwise failed to comply with the requirements of the law, then the land shall revert to the Government and all prior payments of purchase money shall be forfeited.