Slater Bob says the officer found gold by an old copper working … wi heather growing along a fault ... on the other side o’ t’ scar on High Topps (PP3). It is found by Roger (PP19). Later they hide in it from the fire (PP32). Captain Flint and Timothy decide to work the mine and to get Slater Bob to come and help as he had said he'd like to give slates a rest and have another go at metal (PP35).
It is called The mine in The Picts and the Martyrs (PM2). Dick is to help Timothy with some quantatative assays to determine the yield, and later Timothy decides to go to the mine to get some more samples as two of the results ... seem a bit odd (PM22). They climb up to the edge of High Topps, and up to the edge of the Gulch. It was no longer the ravine of last summer (with) the old working half hidden by heather as the heather had been burnt by the fire. The entry was hidden now by huge piles of broken stones and we've begun driving shafls down from above (so there are) small grey piles of broken stone up on the hillside. Slater Bob comes out between the heaps in front of the entry and says You can't go in now ... I'm firing. There is a loud boom from inside the hill and a cloud of smoke and grey dust blows out. Blasting says Dick. Best let it settle says Slater Bob. What about food says Timothy. So they have their food (and drinks) while the dust settles, When they go in Dick notices that the cave was twice the size it had been (PM24).