Aiden Brookes was camping with friends at the time
A 16-year-old boy was crushed to death by falling stones in a cave which had probably been unsettled by the heat from his camp fire, an inquest heard.
Aiden Brookes, from Bridgnorth in Shropshire, was killed at the nearby Hermitage Caves on 6 April.
The inquest, at Bridgnorth Council Chamber, heard how about 20 young people were at the caves that night and lit a fire at the mouth of one of them.
South Shropshire Coroner Anthony Sibcy recorded a verdict of accidental death.
The hearing was told how Aiden, who was a keen rugby player and cricketer, had fallen asleep next to the camp fire that had been lit.
It was then that the sandstone slab fell on him.
Geology expert Andrew Bowden told the inquest that a pre-exisiting weakness in part of the 1,000-year-old cave would have combined with the heat of the fire to cause about 200kg of rock to fall away from an overhang.
'Very loud bang'
The inquest, which is being held in front of the South Shropshire Coroner, heard how two young people who went to help Aiden had been nominated for bravery awards.
Zakk Griffiths, who is in line for an award from the Royal Humane Society, described in the hearing how he went into the cave with a friend following the roof collapse.
He said that after helping to remove the sandstone from Aiden, he and another teenager lifted him out of the cave and tried to resuscitate him.
Jessica Wright, 19, told the hearing she had also been hit in the rock fall at about 0220 GMT that night.
She said: "At the point where the cave collapsed, Aiden was lying in front of the fire.
"He was smiling and asleep. I got up to change the music over when I heard this deafening rumble and I just remember falling face forward."
Philip West, another young person who had been at the site, said he had been standing outside with some others in a circle when there was a "very loud bang" from the caves.
The 1,000-year-old caves are classed as an ancient monument
He said: "As that bang happened, I looked up and saw very large chunks of rock separating themselves from the roof and to the right of the cave."
Pc Philip Knock described how the scene had been chaotic when he arrived, four minutes after police had been called.
He said: "Everyone there that helped in some way was very brave.
"That cave or that overhang could easily have collapsed further - to put yourself in that area was a very brave thing to do."
The coroner concluded that it was more likely than not that the fire had acted as a "trigger" for the wedge of rock to fall.
The caves, which are classed as a scheduled ancient monument, have been used for years by young people locally as a place to meet.
The inquest heard how the owner of the land, a private estate, was now seeking permission from the government to put up fencing to prevent anyone accessing the caves.