It was hailed as a major coup in the search for evidence of extra-terrestrial life, when the team from the Kuzbassrazrezugol mining company found the ‘disk’ some 40 metres underground, plus a second one which broke.
The disc from the remote region of Volgograd was around 1.2 metres in diameter and weighed roughly 440 lbs – or 31 stone.
Rumours soon circulated that the “remains of extra-terrestrial beings” were found inside.
However, claims the disk is of extra-terrestrial origin have been called into question.
Many viewers of the images being spread across online UFO websites and YouTube channels have pointed out how the object is clearly made of stone, and is unlikely to have ever been able to fly.
The story has also been released by YouTube UFO channel Secureteam10.
Scott Brando, who runs hoax-busting website ufoofinterest.org, has analysed the images and believes they are the result of a known natural phenomenon called concretion.
This is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles.
It occurs with sedimentary rock and soil and often creates remarkably ovoid or spherical shapes that are rock hard.
They have been found all over the globe.
Mr Brando tweeted: “This is the latest video by SecureTeam10: ‘ANCIENT Alien Discs Found By Mining Company?’ That is a known effect named CONCRETION.”
Some viewers of the Secureteam10 video had been left unconvinced.
One person wrote: “Looks like a type of a mill stone.”
Another said: “How could anyone possibly think that is a UFO just because they are saucer shaped.”
Mr Glockner had said in the video the disk was “found to have been coated in a metal known as tungsten… this is a metal that has typically been used in technology that belongs to the military.
“Tungsten has one of the highest melting points and is commonly used in things that are put up in space due to the fact that they can withstand the extremely high temperatures that occur when an object enters the atmosphere.
“They obviously look artificial, they’re all in the shape of a flying saucer … not to mention the fact they were found deep underground in a mine.”
Excavator Boris Glazkov, who found the object, said: “I have to say it wasn’t hard to see as it was really distinctive and large.
“I’ve never seen anything like this object, which is obviously man-made, out here in the middle of nowhere before. It is a real mystery.”
His colleague, Arthur Presnyakov, added: “There were actually two similar objects, but the first one broke as it was being pulled out of the ground by the excavator bucket.
“They obviously look artificial, they’re all in the shape of a flying saucer”
“We thought we saw something sure, because it broke into pieces, but then when the second one appeared we stopped work and carefully removed it from the bucket.”