I'd spotted it off to the side of the road, planned to investigate - it's well hidden, off a main highway, driven past a hundred times before I spotted, it's visible only for a second. And so, rainy evening, planned to explore...
Water streaming from the ceiling, still flooded, it goes back perhaps forty yards - some interesting crystals forming on the walls (too powdery & fragile to collect), and colourful mineralizations, but all in all a bust.