Code of Federal Regulations Title 43. Public Lands:  Interior § 43.3837.21 How do I notify the delinquent co-claimant that I want to acquire his or her interests?

(a) You must give the delinquent co-claimant written notice by mail using registered or certified mail, return receipt requested, or by personal service;  or

(b) If, after diligent search, you cannot locate the delinquent co-claimant, you must publish notification in a newspaper nearest the location of the claims or sites at least once a week for 90 days.