After finally getting a copy of "Anthracite Railroads in the 70's Volume 1: Wilmington and Northern Branch," I sat down and thoroughly enjoyed it this afternoon.

Midway through the program, a short train bound for Grace Mine included a Burlington Northern covered hopper right behind the locomotives. What would that car have carried?

Could it have been powdered bentonite used for pelletizing ore?

Agree with Tom. If you look at the photos in the first two entries of this thread, you can see the "silo" to the right of the big structure with covered hoppers sitting there. My understanding is this was the Bentonite storage bin.

Clay it is. Bentonite, a clay of volcanic origin, was loaded out at Casper, Wyoming on the BN (nee-CB&Q) line. This clay was used to bind the refined ore into pellets. Photos in the society's Bee Line show the empty train with these cars, usually two, in front of the caboose. Assume as the train was immediately loaded and turned for the run to Bethlehem that the clay cars were cutout by the plant's shifter before loading the ore. Never learned what made this clay special to incur the cost of cross country shipping. Was it the binding ability or what it did or did not do in the furnace? When I was working the programmed tie gang on the main line between Reading and the Phila. Div. marker in the spring of 1970, this train made a daily appearance coming on the main at Birdsboro late morning around eleven. Power was three to five ALCO RS3 pulling 90T and 100T hoppers with occasional 55T hoppers appearing in the longer trains.

Bentonite expands significantly when mixed with water and is not readily mined (quarried) in all parts of the country. As far as switching out the cars, the Grace Mine crew did all of the switching with their road engines, which including setouts of the Public Delivery Track in Joanna, as well as pickups at the Lower Yard in Birdsboro, pickups/setouts at Company Farm and Joanna Storage.

The Beth Steel switcher was used mostly for moving foreign ore cars through the shakers.