Height 611 UFO incident refers to an alleged UFO crash in Dalnegorsk, Primorsky Krai, Soviet Union, on January 29, 1986. Height 611 (also known as Mount Izvestkovaya) is a hill located on the territory of the town.
A reddish ball was noticed by the inhabitants of the town at around 8 PM on that date. Eyewitnesses say that the ball appeared to be the size of half of the moon’s disc. The ball was flying parallel to the ground; there were no sounds accompanying the flight. It was later determined that the speed of the object was approximately 15 m/s (34 mph), and that it was flying about 700–800 meters above the ground. When the object reached Height 611, it started to descend and then crashed into the hill. All witnesses but one say there was no sound when the object reached the ground.
The process of the descent was described differently by eyewitnesses. Some said the object fell down with a flash and was not visible after that; others claimed it oscillated in altitude above the hill, radiating light of varying intensity as it went up and down. The light given off by the object was described by some like a forest fire, which lasted for approximately one hour.
Some rocks at the impact site had drops of silvery metal, which were later determined to be lead. The type of lead found on Height 611 was different from the lead found in local lead deposits. Also, black, glassy, drop-shaped beads and mesh fragments were found at the site. In all, approximately 70 g of lead, 5 g of mesh fragments, and 40 g of beads were discovered. The radiation level of the landing ground was normal. The group took pictures of the site using two different cameras; however, the film later developed as blank.
Chemical analyses of the beads showed they were mostly composed of lead, silicon, and iron. Some of the drops contained significant amounts of zinc, bismuth, and rare earth elements. An analysis of the soil, rocks, and burnt wood taken from the landing ground was also performed. It was noted that the chemical composition was similar to the composition of similar samples taken from the site of the Tunguska event.
The mesh fragments were also analyzed. The material of which the fragments were composed did not dissolve in strong acids and organic solvents, even when exposed to high temperatures for prolonged periods of time. One of the mesh fragments was discovered to be composed of scandium, gold, lanthanum, sodium, and samarium. An analysis of another mesh fragment showed gold, silver, and nickel. After that fragment was heated in a vacuum, the analysis no longer showed these elements; however, molybdenum and rhenium were detected.
The concentration of gold detected in one of the mesh fragments was equivalent to 1,100 g per metric ton. This is much higher than gold deposits in the region, which become economic to extract when the concentration of gold reaches 4 g per metric ton. There are no gold deposits in Dalnegorsk that contain gold at concentrations high enough to extract.
Similar flying balls were detected over the territory of Dalnegorsky, Kavalerovsky District, Olginsky, and Terneysky District of Primorsky Krai in November 1987. One of the balls was noticed above Height 611 illuminating the ground on the peak of the hill. The descriptions of these balls given by witnesses match the descriptions of the UFO that crashed on Height 611 in 1986.
A claim of a UFO landing on Height 611 was also made in 1989.