People seeking to impress their friends on Instagram are ruining hidden industrial heritage sites by leaving litter and graffiti, cavers have said.

A group of volunteers removed 30 discarded inflatable dinghies from an abandoned 19th-century mine in ­Gwynedd after the site became popular. A video shot by Hell on Earth, a group of explorers, showed the mine surrounded by rubbish such as bin ­liners, glow sticks and human waste. The group can be seen removing ­dinghies from the mine, which was once used to dispose of cars.

Anthony Taylor, 42, a caver, said a YouTube clip of dumped cars at the site had had six million views, prompting people to want to visit and post images on Instagram. “They are beautiful places, and a lot of people don’t want them to be ruined,” Taylor told the BBC. “Instagram seems to be the killer of a lot of things. People turn up, take a picture and then leave [a mess].”

The slate mine is on private land near Corris Uchaf, where mining took place between 1820 and the early 1970s. The use of the mine as a dumping ground for cars and televisions means it lends itself to photography as the rusting metal is illuminated by shafts of sunlight.

Taylor, of Aberystwyth, Ceredigion, said he first visited in 2022. “It’s a ­bizarre environment, probably one of the oddest places in the world. How ­often do you see hundreds of cars ­underground with lights coming on to them from the sun?

“From about 30ft in, the spray painting starts, and it was ­awful. When you get to the end, it was just a sea of boats, inflatable dinghies everywhere.”

He added: “The whole reason people want to visit a place like this is because they’ve seen it on the internet and think, ‘That’s an amazing place to go and see’ — so why would you trash it? The people that go to these places, ­influencers they call themselves … they go because they’ve got inherent value to them. Why destroy it for everyone else?”

Several clean-up operations were held by cavers last month.