A CAVER died when a shard of rock, weighing three to four tons, fell and crushed him as he crawled in a passageway.

But the reason for the rockfall in a narrow passageway in Bull Pot, Kingsdale, still remained a mystery, said coroner Rob Turnbull.

Yorkshire Subterranean Society member Shahrzad Mohamadi, of Leeds, told the Skipton inquest how she heard the sound of Gordon Aitken, a fellow society member, crawling on pebbles just before a loud thud.

They had completed three pitches down the cave on February 14, this year, and Mr Aitken, of Lancaster, had gone to explore a passage.

"I had stopped to take a drink when I heard a noise - like something huge had fallen. I shouted 'Gordon, are you OK' but I heard nothing. I knew something terrible had happened," said Miss Mohamadi.

"I entered the passaged where I had to stoop low and and saw him on the floor with a rock on top of him. I checked if he was breathing, but he wasn't."

Cave Rescue Organisation member Martin Colledge, of Hawes Road, Ingleton, said he knew the passageway and when he entered, he saw Mr Aitken with his back to him, kneeling on one leg and with the other stretched out behind.

"His back was sloping away and there was a large flake of rock on his back and head," said Mr Colledge.

It was too heavy to lift, so the rock was broken up and removed in pieces before Mr Aitken was stretchered out of the cave where he was pronounced dead by a doctor at the cave entrance.

Mr Turnbull confirmed there had been a minor earth tremor in recent days before the accident but an expert at the British Geological Society believed it was too small to have dislodged the rock.

Mr Turnbull, who recorded a verdict that Mr Aitken, had died as a result of an accident, said the 50-year-old had been a keen and experience caver for many years.