An attempt to stage the world’s deepest underground rave will be made one week today in Gwynedd.

On Thursday, 15 October, a limited group of ballot winners will enter the abandoned Cwmorthin slate mine near Blaenau for the attempt.

G-SHOCK is making the attempt to stage the world's deepest underground rave at the furthest point under the earth in the UK that the public can reach. Evidence will be documented and submitted for independent recognition after the rave.

Roni Size will perform a one-off session created for the underground chamber. The music will not stop at the speakers. Vibration transducers and specialist field-recording equipment will send the performance into the mine and capture the way its frequencies move through slate, mud and water.

For Size, the setting marks a return to his underground roots. Emerging from Bristol’s sound-system and rave scenes, he helped shape the early sound of jungle and drum and bass before bringing the genre to wider audiences with Reprazent, whose debut album New Forms won the 1997 Mercury Prize. At Cwmorthin, he brings that experimental spirit back underground for a performance unlike any other.

Size said: "Back in Bristol, we’d put on a party wherever we could, and some of the sounds came from what we called happy accidents, playing a track at the wrong speed, hearing something that sounds new but still works. Raves could take place in some crazy and unexpected places, on someone's front lawn, down in tunnels, but what I've always done is play to the environment, and the crowd. The set is a living, breathing thing that reflects the people there with you. 

“That’s the spirit I want to take into Cwmorthin. By the time we’re 1,375 feet underground, everyone there will already have shared an adventure. And how much more could you reflect the environment, than by pumping a set into the mountain, hearing the sound travelling through the slate, rock and mud, and bringing it back into the mix. It's the most underground of underground raves ever."

Using specialist field-recording techniques, elements of Roni Size’s set will be driven into the mountain and picked back up as they move through it. Vibration transducers will send sound into the slate, while geophones and hydrophones capture what travels through the rock, water and mud - creating a signal chain that runs through the mine to capture the real sound of the underground. 

The sound engineering team used a convolution reverb to measure the mine’s impulse response. They will use specialist field-recording techniques and playback technology including high-fidelity geo-acoustic coupling, via which the energy of the venue is transferred into the rock wall and captured live - putting the set into the geology of Snowdonia and vice versa, to channel the mine’s geology into the set.

The result will be a final mix shaped by one of the harshest environments imaginable, with Eryri’s lithoacoustic signature cut into the recording. G-SHOCK Radio will broadcast the set via Starlink from Cwmorthin Quarry on 15th October, with the full performance available afterwards on Mixcloud.

There is no shopfront at Cwmorthin. Guests begin with a guided mountain approach, then move below ground in darkness. They will travel through mud and water, traverse ravines and descend sheer rock faces to reach the event.

Cwmorthin is not a venue made to look extreme. It is a former slate mine, reached through a professionally guided underground route where darkness, cold water, loose rock and vertical drops are part of the journey.

Places will be allocated through a public ballot via https://gshock.casio.com/uk/mudman, with entries closing tomorrow, Friday, 9 October. Successful entrants will join the guided descent into Cwmorthin and attendance will be limited to those who meet the necessary age, fitness, and equipment requirements. The descent and performance will be documented as part of the world-record submission.

The event will be the first place the new £200 GDG-B100 MUDMAN watch can be bought, ahead of its general release.