Did Stauffer sell out to Rhodia or Rhone-Poulenc (or two names for same company?) Rarus crews did their plant trackwork under contract and weren't always thrilled by the spontaneous combustion as they pulled the spikes and the trapped phosphorus dust became exposed to air.

Stauffer also had a phospate/phosphorus operation at Sage Junction aka Leefe, Wyoming (SW corner off UP). The only info I can find on it was it was a Superfund cleanup site and they had a GE 70 ton (possibly to Silver Bow then to a mine reload above Conda, now gone). The best timeline I can determine is that it closed before Silver Bow.

There is still an active plant (originally Stauffer, then R?, now Agrium) on the UP branch at Conda north of Soda Springs, Idaho. The open pit phosphate mines are on the north end of the branch where the former B&AP Gp7 is now used as a switcher to load cars. UP moves the phosphate ore cars between the mine and plant, apparently at night. Agrium at Conda has some locos, a small GE for the dumper and one or two leased SWs for outbound loads. There is another phosphorus plant closer to Soda Springs (name escapes me) that also had their own switcher if I recall. Their phosphate mines are also to the north but a private heavy haul truck mine road provides delivery.

The last I was up there the Dry Valley Railroad (private) was still largely intact but long unused. This was built and operated by Western Railroad Builders (xMilw SD10s and leased xARR F7s)for a few years supplying phosphate ore to some outside plant.

Isn't the JR Simplot plant (with their own switchers) just west of Pocatello another phosphorus plant? Supplied with phosphate ore by UP from a branch to the south?

I was told that the phosphate ore is slightly radioactive, part of the reason for the cleanup but surprisingly the uses don't seem to be restricted.