That is correct on how a breaker works, some of them. Some of the older breakers don't use a cone. The coal is brought in on the mine run line to a sizing table on the top floor of the breaker. First line is a mix of mine run that is sized Pea to Stove.(mine run is coal with rock still in the mix) First line has a screen that nothing larger than Buck can go through. Buck and under is sent through to a sluice table. Which is ran just the opposite of running gold, since rock is denser than coal. Coal is then collected in a tank and resent to the top of the breaker via the Pea line. Ran across a set of sizing tables and in to the product bins for shipping. Now stove to pea is sent to the magnetite tank. The mix goes in the tank and the coal is forced across the heavy water by water jets. The vessel rock, and jack stone sink, and remove by a paddle wheel scraper. Coal is sent back up to the top and sized the same way as the finer coal sizes.