30 CFR § 41.30
Address of record and telephone number.
The address of record and telephone number required under this part shall be
considered the operator's official address and telephone number for purposes
of the Act. Service of documents upon the operator may be proved by a post
office return receipt showing that the documents could not be delivered to
such operator at the address of record because the operator had moved without
leaving a forwarding address or because delivery was not accepted at that
address, or because no such address existed. However, operators may request
service by delivery to another appropriate address provided by the operator.
The telephone number required under this part will be used in connection with
proposed civil penalty assessments as provided in 30 CFR part 100