I have it on good authority that the Tailrace level (further down the valley) drains Grove Rake, but there isn't much coming out of it at the moment. This hole led into the Rispey Mine - before it appeared there was no sign,as far as I could see, of where the water went. The Rispey shaft, to which it must be connected, is about a hundred yards downstream but I haven't been close enough to see if it is flooded up to the collar. There certainly is no water flowing out of it.
Haven't been into Grove Rake for a few years, but the water level in the Firestone incline is rising and since there is (was) a direct connection at the bottom into the main Grove Rake workings, the water there must be quite deep by now.