Many of my relatives worked in the pits South of Barnsley in and around the Elsecar area. I have found the following resources useful.
Maps - The Godfrey Edition maps are great value about £2;50 each, they have plenty available of the Barnsley area in addition to the 15" to the mile detail there are plenty of historical notes, extracts from local directories etc on the back along with references. The Elsecar sheet has, I think 4 coal pits on it.
http://www.alangodfreymaps.co.uk/barnsley.htm The British Geographical Survey have a geological map of the Barnsley Area which shows the coal seam outcrops and some pit locations. There is also a "memoir" that accompanies the map, this is pretty technical but does give you some great details on the coal seams and the maps and diagrams give you an insight into some of the difficulties encountered underground.
They are available here:
http://shop.bgs.ac.uk/Bookshop/product.cfm?p_id=CA37C http://shop.bgs.ac.uk/Bookshop/product.cfm?p_id=EM087 Books
Aristocratic Enterprise: The Fitzwilliam Industrial Undertakings, 1795-1857 by Graham Mee. Out of print but available on ABE for about £8. This is book about the Fitzwilliams who ran the mines around Elsecar until the formation of the NCB. This book covers the period whilst they moved from what were basically drift mines into "deep" drained by pumps. It's a fascinating read as the Fitzwilliams were perhaps the most generous mine owners in the country and there pits were pretty well managed. There is also a discussion the iron making and other industries they got involved in.
Black Diamonds by Catherine Bailey - More about the Fitzwilliams and their aristocratic antics but some great photographs and descriptions of the lives of the miners and not a bad read. Still in print and available
Pen & Sword books are based in Barnsley and produce several books about the coal mining industry in the area, there web site focuses on their military books but if you search for "Barnsley" plenty of mining books come up.
There is also this article
http://www.irsociety.co.uk/Archives/54/Lidgett.htm Which is about a very small pit to the south of Elsecar but goes into a lot of details about how the railways were crucial to a pits success again some good maps and photos showing the area and one of a miner down a pit.
I'm no expert and some of the sources I have suggested might not be perfect but I have found all of them interesting and useful.
Good Luck
Gavin