Barbara.
This link should get you to the Durham Mining Museum web - Spital Tongues Colliery - www.dmm.org.uk/colliery/s068.htm
This mine sent its coal to the River Tyne down a specially built tunnel under the streets of the city, which made it rather unique. Part of the tunnel open to the public and can be visted (see the mine index on Aditnow and look for Victoria - Unknown - NZ ). There are a few pictures taken a couple of years ago showing the tunnel. During the last War it was used as a Air Raid Bunker, hence the the concrete floor.
A good book to get hold of is "Views of the Collieries in the Counties of Northumberland and Durham" - T.H.Hair - First published 1844. This gives a very good idea of the state of play in the North East mining industry with some very good prints of various collieries.
Another book is the "The Art of Mining Thomas Hair's Watercolours of the Great Northern Coalfield"by Douglas Glendinning.
Another book is "The Miners of Northumberland and Durham" - by Richard Fynnes, first published in the 1870's, these books have been reprinted over the years and turn up on www.abebooks.co.uk or mining type book shops such as Moore books
Never mind Northumberland and Durham we got split into another county named "Tyne & Wear" back in the 70's, and we are still working why and what is it supposed to be!!!!!
Best of Luck
John_L