Examples of private rail carriers

I'm wondering if anyone knows of companies that own railroads which only transport their own goods (i.e. industrial railways operated by a non-railroad company).

For example, I know USG operates a narrow-gauge railway in Plaster City which exclusively hauls gypsum from their mine and Coors has a railway within their Golden, CO plant. I'm looking for other examples within the United States.

January 2021 issue of Trains magazine has an article discussing the Cumberland Mines RR in southwestern PA. Originally mine and RR were owned/operated by US Steel; today by Contura Energy. Sole operation is to transport output of the mine to Monongahela River for transloading to barges. Standard gauge but no connection to the national rail network. Article discusses how rolling stock acquisitions need be barged from Norfolk Southern across river.

Muskingum Ry of American Electric Power [AEP].
Here is thread:
muskingum-electric-t14715.html?sid=42f7 ... e0c8abd5eb

Cartier Railroad in Quebec which is not connected to anything but a rail ferry, owned now y Arcelor Mittal.
Quebec North Shore & Labrador owned by Iron Ore Company of Canada, it is a common carrier connects to three or four other private railways plus a former line owned by First Nations.

Do not have much tiume to look up more, I am sure plenty can add mopre.

Both the Cartier and the QNSL connect to rail ferries.

US Sugar in Florida operates a sizable internal system, which connects to the SCFE shortline. It's the last of it's kind remaining on the US mainland, but not the last in NA.

Southwestern Portland Cement Co operated the Mojave Northern between a quarry and a plant, featuring one of the last SDP35 engines. It's now part of CEMEX.

Fletcher Granite in MA has a short-but-surreal line from their quarry pit to the Pan Am main, recently reactivated after a long hiatus. I'm not sure if it still runs to the pit.

The Branford Steam Railroad in CT primarily operates to bring stone to barges on Long Island Sound. It doesn't use steam. It's technically a common carrier but in effect only serves the quarry.

The Fletcher Granite operation does not run to the pit (anymore). There is large granite block resting on the rails just North of Route 40.

New Hampshire Northcoast exists primarily to get aggregate from NH to Boston Sand and Gravel in Boston. BSG owns NHN, any other freight besides gravel is "gravy".