Did this explore with a guy from Flickr, Urban_Outlaw, so thanks to him for showing me the way and having a share of the tick orange mud in there
The Flickr set with more shots is here:
http://www.flickr.com/photos/pdtnc/s...7607549746332/
Its 1 mile in & 1 mile back out of slow-going carefull foot placing, the first 10 meters or so being the worst and the rest kind of gets better. I should really buy a pair of waterproof trousers, they would be advisable.

Some further reading:
http://www.lostrailwayswestyorkshire...0new%20line%20...
http://www.forgottenrelics.co.uk/tun...ildersome.html
"The LNWRs new main line into Leeds incorporated a 1 in 70 descent through Gildersome Tunnel - a formidable 2,331-yard structure. When, after its closure, the M62 and M621 were built over it, a section extending from the southern portal was infilled with 30,000 cubic yards of colliery waste for reinforcement. Although this end is now buried, the eerie northern entrance still survives, along with the stone retaining walls of its approach cutting." - www.forgottenrelics.co.uk

The entrance portal:

Looking back at the entrance:

Into the abyss of orange mud:

Did I mention the orange mud?:

Outside the Extended refuge chamber, lighting with bloody big torch and a 4W Flouro:

Inside the Same Refuge chamber, banging my head on the rusty stalactites:

Funky grungy 'litter':

'Creatively' lighted refuge bay:

The bloody fantastic open ventilation shaft, quite a sight after the muddy blackness, a case of 'Click' on a long exposure and go stand still and count to 40!:

The brick wall of the infill, beyond which is colliery waste:

You gotta love crusty stuff... just a shame it was deep and nasty!:

Erm... MUD!:

100 Chains, in or out:

Check the full set on my flickr:
http://www.flickr.com/photos/pdtnc/s...7607549746332/

Equipt:
10'000'000 Candle Power Torch
3 various Cree Q5 LED torches
4Watt Fluorescent strip light
Salami, Cheese and Mustard Sandwich
Wellington boots
LED Lenser head torch (which I have to say is one of the most usefull pieces of kit I've bought)
Camera, lenses, tripod, cable release etc