Manhattan Project and the San Juan Extension

About a year ago, we had an extensive thread on the role of the RGS in hauling yellow cake and other western slope uranium ores related to the Manhattan project. Apparently, some of the ore was shipped to the Durango smelter for reduction. But where did it go from there?
More specifically, did any of it (either raw ore or reduced product) travel over Cumbres? Stephen Hart's article, ATOMIC NARROW GAUGE, states it went from Durango to an Army processing plant in Utah. But how? By truck? By the D&RGW over Cumbres and then by s.g. over Tennessee Pass and back to Utah?
I've always been fascinated by the technological contrast and irony in this story. But if the San Juan Extension played a role, perhaps the story would also capture the attention/interest of visitors to the C&TS today.
Brian