At 4,300 metres in the Chilean Andes, mine technicians watched a bright disc-like object in clear daylight. Two photographs eventually reached Chile's official aerial-phenomena committee. An analyst called the object unidentified. The investigators themselves also recorded why the case could not be closed.
Most photographic UFO cases become arguments about anonymous images on the internet. Collahuasi is different. The photographs reached CEFAA — Chile's Committee for the Study of Anomalous Aerial Phenomena, operating under the country's civil aviation authority — and were subjected to a formal image analysis that was later released publicly.
The reported setting was unusually favourable: broad daylight, exceptionally clear high-altitude air, multiple workers present and an object said to remain visible long enough for several photographs to be taken. Witnesses described a brilliant flattened disc, roughly five to ten metres across, making short vertical and horizontal movements several hundred metres above the ground.
But the same official record contains the case's weakness. The witnesses did not later engage directly with CEFAA, the exact timing and geometry could not be reconstructed, and the strongest technical conclusion came from a single image analyst. This is not a case where “official UFO” means “officially extraordinary craft.” It means the material examined was not identified.
In mid-April 2013, workers at the Doña Inés de Collahuasi copper-mining operation in Chile's Tarapacá Region reported an unusual bright object during the working day. The mine sits at roughly 4,300 metres above sea level in the Andean altiplano.
The early CEFAA account described the witnesses as professionals working in electricity, electronics and fluid control. They said the object appeared as a bright, flattened disc — sometimes more like a luminous globe depending on angle — and moved in short rising, descending and horizontal segments before eventually departing to the east.
Later press accounts often say roughly thirty-five workers witnessed it for around two hours. The technical case summary itself is less cleanly quantified and speaks more generally of several witnesses and “a couple of hours.” Because CEFAA never obtained full direct witness interviews, the exact witness count, duration, estimated size and altitude should be treated as reported figures rather than instrumentally established measurements.
A bright flattened form is reported above the Collahuasi mining area in clear daylight.
Several images are reportedly made. Two photographs later become the evidential core of the official file.
A group leader/chief engineer forwards the material to Chile's official committee months after the sighting.
The photographs and technical analysis enter public reporting as an officially unresolved case.
The first photograph shows the bright object small in frame above mine infrastructure and open sky. The second, frequently published as an enlargement, shows the form as an elongated luminous disc or capsule-like blur. CEFAA's analyst applied enlargements and filters to both images.
The report argued that filtering revealed a coherent object with differentiated regions: a ring-like perimeter and a brighter central or hemispherical area. It went further, suggesting the brightness on the lower part could represent emitted energy rather than ordinary sunlight.
That final step is where caution becomes essential. Image saturation can create extreme white and black values during processing. Without secure original metadata, exact exposure, orientation, timing and geometry, “self-luminous energy” is an interpretation of pixel values — not a temperature measurement.
CEFAA's published photographic analysis described the material as showing an apparently consistent, solid-looking object. The analyst wrote that the brightest area appeared too intense to be ordinary reflected sunlight and concluded that the object or phenomenon was of great interest and could be classified as a UFO.
Ricardo Bermúdez, then director of CEFAA, publicly said the object did not fit anything known to the committee. But he also stressed that the conclusion represented the determination of only one CEFAA analyst and that caution was still required.
José Lay, CEFAA's international-affairs director, was more explicit about the practical limit: the witnesses were not willing to cooperate with follow-up attempts. Without those interviews the committee could not securely reconstruct camera setup, exact time, viewing direction, motion geometry or the sequence between the two photographs.
The CEFAA image analyst found the object unresolved after optical processing and considered the luminous structure inconsistent with a simple reflection model.
Bermúdez cautioned that this was one analyst's determination. Lay said CEFAA's attempts to obtain direct witness cooperation received no response. Those are not sceptical add-ons — they are part of the official case history.
The CEFAA-linked analysis worked from the submitted frames by reviewing the original image, magnifying the object region and applying contrast/filtering steps intended to make the bright form's boundaries easier to inspect.
The analyst was particularly interested in differentiated brightness around the perimeter and a brighter lower region. Those processed features contributed to the conclusion that the image represented an object or phenomenon worthy of further study.
But the processing does not recover the variables the camera never measured. It does not give an exact range, exact solar angle, true physical diameter, instrument-measured altitude, thermal output or a complete three-dimensional trajectory.
Brightness saturation is not direct thermometry. A witness size estimate is not a measured diameter. Image filtering can make pixel structure easier to discuss without converting an unresolved photograph into a calibrated instrument.
Two case photographs were supplied to CEFAA and publicly analysed. The object is present in the image data examined by the analyst.
The size estimate came from witnesses. Without known range and calibrated geometry, the photograph alone cannot establish those physical dimensions.
This is part of the witness narrative, not a radar or laser-derived altitude. The image contains no independent range measurement.
Pixel saturation and filtered brightness are not direct thermometry. The analyst's energy interpretation is interesting but not independently measured heat output.
A distant balloon, small object nearer the camera, bird, airborne debris or unusual optical effect can all produce a compact bright form against a featureless sky. The reported duration and deliberate-looking motion make some of those candidates less comfortable — if the witness account is accurate — but the photographs alone cannot discriminate them because range is unknown.
A drone was discussed at the time and CEFAA officials said the workers would have been familiar with the noisy drones used in industry and fishing. That is useful testimony, but it is not a technical exclusion of every possible unmanned aircraft. More importantly, the photographs reached CEFAA many months later and the witnesses did not participate directly in the reconstruction.
The most serious challenge to the official image analysis is therefore methodological rather than a single “gotcha” identification. If exact time, camera metadata, image sequence, azimuth, elevation and witness positions cannot be recovered, then claims about the sun angle, physical dimensions, thermal behaviour and impossible manoeuvres become much harder to validate.
Collahuasi is materially stronger than a lone anonymous internet photograph because there is a documented institutional investigation and a reported long-duration daylight observation.
The missing direct witness cooperation and incomplete geometry mean CEFAA could classify the image as unidentified without demonstrating that every mundane explanation had been eliminated.
Collahuasi lies high in the Atacama altiplano, a dry, sparsely populated environment known for exceptionally clear skies. That helps the witness claim in one sense: the object was reportedly seen in bright daylight without cloud obscuration.
It also means distance judgement is difficult. Against a clear blue sky with few depth cues, an isolated object can look larger, nearer or farther than it really is. The environment improves visibility while simultaneously making range estimation harder.
The surviving public evidence is strongest when the CEFAA analysis, contemporary Chilean reporting and later methodological criticism are read together. The page deliberately distinguishes the analyst's technical interpretation from the broader institution's caution.
English translation of the released technical report, including the image-filter discussion, brightness interpretation and final “UFO” classification language.
READ REPORT TRANSLATION →Early Chilean reporting on the 4,300 m location, professional witness group, CEFAA submission date and Bermúdez's description of the case.
OPEN LA TERCERA →Contemporary account of Bermúdez's public statements, the published images, official unresolved status and Chile's broader CEFAA process.
OPEN BIOBIOCHILE →Useful modern synthesis of the official analysis and its limitations: one analyst, uncooperative witnesses, incomplete metadata/geometry and caution around the “self-emitted energy” inference.
OPEN MODERN REVIEW →Collahuasi survives because the State did more than publish a UFO headline. It published photographs, allowed an analyst to argue that the object was anomalous, and also acknowledged the file's limits. Something bright was photographed above a remote Chilean mine. The available images did not yield a conventional identification. But without direct witness reconstruction, reliable metadata and measured range, the case stops short of showing what that something physically was. The reader gets the evidence — and the uncertainty — intact.