On September 9, 1993, about 1530 eastern daylight time a Cessna 172, N2347E, collapsed the nose landing gear during a forced landing near North Myrtle Beach, South Carolina. The airplane was operated by Bentco Aerial Patrol under 14 CFR Part 91 and visual flight rules. Visual meteorological conditions prevailed. A flight plan was not filed for the power line patrol flight. The commercial pilot was not injured and the airplane was substantially damaged. Origination of the flight was Athens, Georgia, about 1400 on the same day. The pilot reported that the engine lost power. A forced landing was made in a field. During the landing roll, the nose gear collapsed and the airplane nosed over. Examination of the aircraft engine revealed that the number one exhaust valve had failed. The valve head was found in the engine crankcase, and there was metal contamination found in the valve cover of the number one cylinder. The aircraft owner failed to respond to the request for completion of NTSB Form 6120.1/2, Pilot/Operator Aircraft Accident Report.(See Attached letter of Request and Receipt for Certified Document.)