A single item duct cannot keep up with a max speed quarry. I just tried it, and it can't. Note that this is not a complaint, just a statement of my test result. All you get is dirt and cobblestone, and a tiny few other items, and everything else filled up the (wooden) chest and overflowed just before it hit bedrock. If the quarry hits a cave or other gap, then it will catch up as the mining head passes over empty blocks and stops filling the first slot with cobble. I haven't tried more ducts or glowstone ducts, I'm doing that now.I've never had an issue with the item ducts keeping up.
*Edit* Impulse Item Ducts seem to be much more effective, occasionally a few items get stuck in the chest but it catches up on the backlog much more quickly than a regular duct. By the time you can run a quarry at max speed, a bit of liquid glowstone shouldn't break the bank.
			
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