There were several huge holes, now filled with water and very popular with divers who like to explore the hidden depths, though in fact there's nothing down there that can't equally well be seen in a non-flooded quarry. We just walked around looking at the old workings and found the big engine house which once housed a stationary steam engine that used to pump water from the mines. In fact the engine is still in there and a group had hoped to get an EU grant to restore it to working order, but Brexit will have put a stop to that, of course. :(
The engine house.
This grandiose gateway seemed to lead to miners' accommodation.
The rain more or less stopped for a few hours around midday, so we didn't get too wet. Now we're back home warming up. I want to go back on a day with good light and take the DSLR because there are some very photogenic quarries and old buildings there.