And if you pipe the output to a filler, you can get rid of two cave networks at the same time.
Heheh, hadn't thought of that! Using the output from one quarry to fill the previous one? I suppose it could be easily done but I'd want to make sure that I didn't send my valuables into it by mistake.
I usually just set two double chests adjacent to the Quarry and then drop the Filler there when I'm done.