The caver who sparked a massive rescue operation, when he became trapped underground at Wombeyan Caves for almost 48 hours, breached regulations to enter the locked-up cave.Geoffrey McDonnell, 46, entered the gated and locked Bouverie cave without a permit and was not registered on the accommodation books of the Wombeyan Caves Camping Reserve, the National Parks and Wildlife Service said.Rescuers said a discarded drink bottle left at the entrance to the cave was the only sign to alert rescuers of Mr McDonnell's location."He is very lucky - had he not left that drink bottle at the entrance to the cave he would probably still be down there now," said the service's area manager Kim de Govrik."He breached the National Parks Act and could face a $300 fine for unauthorised entry to the cave but he may be in breach of other regulations ... we will discuss it with police and see what action they want to take, too."Mr McDonnell, from St Mary's near Penrith, is an experienced caver, keen cave photographer and is well known in the Sydney caving community.He arrived at the campsite about 3pm on Friday ahead of other members of the Sydney University Speleological Society, set up his tent and shortly after set off to explore the Bouverie cave system alone with his camera."The Bouverie is a fairly pristine cave and it has some very sensitive areas and some unique formations that are fairly delicate, which is why it is gated and locked so he found an alternative access," Mr de Govrik said.Wombeyan Caves acting manager David Smith discovered the trapped Mr McDonnell about 42 hours later, on Sunday morning, but it was still another 11 hours before the caver was brought up to ground at 9pm."We explored the cave and every step of the way we were calling out to him but because of the nature of these caves, sound doesn't travel very well," Mr Smith said."Eventually further on I heard a weak murmur calling for help ... he looked like a ghost."The operation involved the Police Rescue Squad, the Volunteer Rescue Association and the Care Flight Helicopter service. Five Wollongong volunteers from the South Coast Rescue Squad, Ian Donald, Wayne Dreghorn, Glen Johnson, Ashlea Donald and Aiden Blair were also called in to help.Ms Donald, who along with Mr Blair was enlisted to climb into the cave and help pull out Mr McDonnell, said she didn't consider herself a hero.Mr McDonnell remains at Westmead Hospital in a stable condition, being treated for dehydration and minor lacerations.