The screening at Conneaut is new in the last few months and on a trial basis. ET was the only blast furnaces in US Steel NOT using screened pellets, and it was limiting capability, so the decision was made to switch.
The fines, regardless of chemistry, are not ideal for the furnaces and can choke off the wind. Gary has a sintering plant and the fines will likely go there. Introducing the fines back into the screened pellets, even at low quantity, would defeat the purpose of screening in the first place. Using them in any significant quantity at one time in the furnace could really be detrimental.
Part of the reason that fines were also at issue at ET is all of the handling. Pellets go into storage piles at Minntac, then get loaded onto a train at Minntac, dumped on the ground at Two Harbors, loaded into a lake vessel, dumped on the ground at Conneaut, loaded into railcars, then dumped in the pit or into the bins at ET. Lots of mechanical wear that breaks down the pellet.
The one sided unloading is a drawback, and the size of the trestle is not ideal for maneuvering the door opener machine at ET. Other than that, most of the gripe is the usual resistance to any type of change.
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