Posted by Andy Clayton on July 16, 2002 at 20:27:33 from 195.93.34.176 user cousin_jack.
In Reply to: Re: Mines - surface versus deep posted by Robert Dilley on July 16, 2002 at 17:43:05:
Coming from Cornwall I've always enjoyed the mining in P.P. So I'll add a couple of points. First, to Prue, although Cornwall is famous for it's tin mines, for most of its history copper was far more important, and many other minerals were dug out from there in considerable quantities too. Notably lead, silver, zinc, arsenic, tungston, and uranium. There isn't much that hasn't been found there, I think diamonds are one of the few exceptions.
When a lode, or piece of mineralised ground, is found it often exists like a slice of meat in a sandwich. Coal of course is laid down horizontaly, but with minerals the 'sandwich' is often near the vertical. To get all this valuable ore out, horizontal levels are driven along the course of the lode at intervals (10 fathoms or 60' in Cornwall) and then the ground containing the ore between adjacent levels is hacked out leaving huge underground voids. This hacking out is where the ore is actualy won and the voids are called 'stopes'. They are mentioned in the excellent link on coniston copper mines a couple of postings ago. In an active mine these spaces are traversed by wooden stagings and kept in a reasonable state of repair, in old abadoned mines they of course get rotten and dangerous.
Another problem is the butresses which keep the 'hanging wall' and the 'foot wall' (the two slices of bread in our sandwich analogy) apart. When a mine is being closed down, as this rock still contains rich ore from the lode, it is often quarried out for sale, the stability of the mine no longer being an issue, to the ex-owners.
If you MUST explore old workings, go with someone who knows what they are doing, an amature with a torch is asking for trouble. The young S, A's & D's were lucky to survive P.P. even without the fell fire!