So when I was contacted by the Corris Mine Explorers, a group dedicated to the exploration of a 172-year-old slate mine deep under the Braichgoch mountain, I was immediately excited by the prospect of clambering around in the nether regions of God's green earth.

Afterall, with the summer we've endured there is little to do topside, so why not remove myself from fresh air and daylight and explore part of Wales' industrial revolution.

Mark Waite was my leader for the day. He's a jovial man, approximately six-foot-tall and overflowing with energy, and barring those who worked in the Corris mine between 1836 and 1971 no-one knows their way around the caves like Mark does.

"I could get myself out of here blindfolded if I had to," he explained, so wearing hiking boots and a helmet topped with a battery-powered headlamp I met with him at the Craft Centre in Corris and made my way to the entrance to begin the three-hour tour.

The first thing that strikes you is how dark and damp it is underground. Your eyes take a while to adjust and to start with you rely heavily on your head lamp.

About 15 minutes into the tour your eyes become focused. By this point you have already had the initial wow factor of being underground and removed from the everyday goings on that are happening above your head.
Now you are able to start exploring the historic slate mine workings just as they were when they were abandoned by the miners 40 years ago, covering almost two miles of tunnels and underground chambers.

"Look at this," shouts Mark, with an enthusiastic tone in his voice as he proceeds to show me a packet of Golden Wonder crisps marked with a price of just 6d.

This is just one of many remaining artefacts that remain in the two-metre square mines. Working winches, boxes of explosives, cigarette packets and tools all add to the experience.

Slate from these valleys was mined and transported throughout the world as roofing slates and as slate slabs, used for water tanks, architecture, gravestones and much more. But in 1971, with the face of slate mining rapidly changing and profits dwindling, the mine in Corris was shut forever. Until now that is.

Visits must be pre-booked and there is a minimum age limit of 13-years-old where the child is accompanied by an adult; otherwise the age limit is 18. There is no maximum age limit but participants will be asked to sign a document confirming their level of health and fitness. You must be capable of walking two miles at a brisk pace, climbing steep paths and squeezing through hatchways about 60 centimetres square.

Cap lamp, helmet, lamp belt and safety slips for the trip – which last approximately three hours – are provided on arrival, but be aware that you may get dirty and could have to walk through ankle deep water. Wellingtons are the recommended footwear, although I found hiking boots more than adequate. Also, you need to bear in mind that the temperature underground is about eight degree centigrade all year round.

This really is a fantastic opportunity to explore a quarry which in 1878 employed 250 men and produced 7,000 tons of slab and roofing slate.

If you want to be part of a small group to be taken into the old working by an experienced guide then contact Corris Mine Explorers at the Corris Craft Centre on 01654 761244.