Ok, so I was trying to run an experiment on the efficiency of coal blocks. I set up a rig with hoppers and furnaces to see which could cook faster while maintaining the constant value of the time the coal is placed in the furnace. I put 63 Coal in one and 7 Coal Blocks in the other. The hoppers were receiving a redstone charge via Redstone Torches so the coal didn't drop. I destroyed the torches with water, but the coal didn't drop. I haven't tried to take it out and put it back in again.

I did a search for duplicates in this snapshot and couldn't find any.

See the attachments if this is really confusing. XD