Collahuasi copper mine disc photographs

The Collahuasi copper mine sits on the altiplano of Chile's Tarapacá Region, at the eastern edge of the Atacama. Its workings lie more than 4,200 meters above sea level. Some retellings later put the disc at over 14,000 feet. That was the mine. The witnesses placed the object about 600 meters above the ground.

April 2013. Daytime, under an absolutely clear sky. The exact day was never published. Four technicians were at the mine, specialists in electricity, electronics and fluid control. Then something approached slowly.

It was "a flattened disc, of brilliant color," 5 to 10 meters in diameter. It made no sound. "It performed ascending, descending and horizontal movements in short lengths." At times it took on "the shape of a shining balloon, although the most evident shape was that of a silvery, fixed and static disk." The witnesses were left with the impression that its movements were under control.

It stayed for more than an hour. Then it headed off to the east. One of the technicians had taken two photographs with a Kenox Samsung S860 camera.

The witnesses kept quiet at first, for fear of being ridiculed. Months later the photographer showed the images to the mine's chief engineer, who asked for copies. In February 2014 the engineer sent them to CEFAA, the Comité de Estudios de Fenómenos Aéreos Anómalos. It is part of Chile's civil aviation authority, the DGAC.

A senior image analyst at the DGAC Meteorological Office saw "a solid object reflecting the sunlight" in the first photo. The second showed "an extremely luminous half sphere" that "emitted its own energy that does not coincide with the natural sunlight."

A meteorologist ruled out a lenticular cloud. Drones, aircraft, weather balloons and military exercises were ruled out too. CEFAA director Gen. Ricardo Bermúdez described "a silver disc, about 10 metres in diameter, that made vertical and horizontal movements no airplane can perform." The verdict came in July 2014. "It is an object or phenomenon of great interest, and it can be qualified as a UFO."

On July 4, 2014, Leslie Kean reported the case for HuffPost. Bruce Maccabee, a retired US Navy physicist, studied the photos for her. "This is clearly not a normal thing seen in the sky," he said, calling the case "worthy of further study." Chilean outlets spoke of 35 workers and professionals and a sighting of about two hours. In April 2015 the story surged again through the Mirror, The Black Vault and Fox News, now described as "footage." No video by the witnesses is known to exist.

CEFAA urged caution. Bermúdez said this was "the determination of only one CEFAA analyst among several." José Lay said the witnesses "were not willing to cooperate" and attempts to contact them drew "no reply." The Dutch sceptic blog Kloptdatwel called the analysis a PowerPoint presentation, questioned its temperature claims and asked why an hour of watching produced only two photos with no reference points for size or distance. Its readers suggested window reflections or dust on the lens or sensor.

No hoax was ever alleged. No explanation was ever settled. According to BioBioChile, the disc joined the roughly 3% of Chilean sightings since 1998 that CEFAA has officially called UFOs. Metabunk researchers traced a later CEFAA case, the 2014 Chilean Navy helicopter video, to an airliner. That case is often confused with this one. The Collahuasi material was filed "for future reference or comparison purposes."