Hi Phil, I remember that range being put in. I think they were eventually expecting plenty of water from the Shilbottle side - the future of the mine
I'm fairly sure they have a purpose made pumping borehole that intersects the drift which will be just open at the bottom (flooded) end, basically a big hole in the drift roof. Don't think it's connected into that range, but I could be wrong.
Before Ellington closed they built a large pumping station - enormous pumps and motors, they might even have been 3.3kv, about a mile inbye side of the last used "Brass Thill" Drift. It will still be sitting there, submerged.
They do like big pumping and ventilation projects just before they close pits for some reason.