The caving group were in Wales on July 18th and 19th, to visit some mines under the guidance of local expert, Alan. Those of us travelling from Yorkshire were happy to drive away from torrential rain on the Friday to the better conditions in benign North Wales, where it was mildly damp.
Saturday dawned cloudy but dry and by the time we had climbed to the upper entrance to Rhiw Bach mine in Cwm Penmachno we were ready for subterranean coolness. The immense entrance, big enough to admit a modest-sized tank, is barred by gates strong enough to keep one out, but a cunningly-hidden side entrance allows access to flexible objects of human dimensions. Rhiw Bach was a slate mine, and we were shown around stopes – man-made caverns following the best seams of slate – of astonishing size as we descended a series of levels. In one place the marks of shot-holes showed a clear discontinuity at one joint in the strata, indicating that even in the relatively few years since the blasting the strata have shifted. We exited along an adit in which a tramway remains complete with one truck, affording opportunities for free rides as long as other cavers are willing to push, and found ourselves well back down the hill and not far from where our cars were parked.
On Sunday, Alan took us to Parys Mountain Copper Mine on Anglesey. Commencing operations in the bronze age, blossoming in the nineteenth century, and continuing to operate until the 1980s, in its heyday it dominated the world copper market. Even now it is not closed, only mothballed. We saw dynamite still in its wooden box, where it has lain since Victorian times, stone tools used to mine the ore by bronze age workers four thousand years ago, and bits and pieces left by workers in the 1900s. Stalactites and stalagmites have grown in many places, along with great quantities of disgustingly-named “snottite” – slimy threads and curtains created by bacteria that get their energy from the suphide ores in the mine. There are alcoves to better anything the horror movie industry has dreamed up. To add to the air of impending evil, vague whiffs of sulphur come and go, sometimes dispelled by the garlic-odour of arsine gas which comes from arsenic deposits in the mine. Pools of acidic water deeper than you want to know about lie waiting for the unwary passer-by who stands unwisely on a rotting plank.
But with the guidance of someone who understands mines, the horrors are mostly in the mind. We followed largely safe and well-used passages and viewed all these things as might a ghost-train rider in a theme park. When we came out, the sun was shining and we enjoyed a walk round the huge opencast mine before – oh no, dare we mention it? – the traditional GOC Sunday-afternoon cream tea and the long drive home, tired but happy.