Gotta love the old style of writing where they prime you by explaining the underlying theory. These days technical documents like this (both government and private industry) just say "do X because we said so, trust us".

>if the drum is tipped over at this point, a greenish liquid slag flows out. This quickly hardens to a cement-like mass.

Knocking the drum over with the forklift was probably the highlight of that private's month.

I particularly like the humor that seems to be universally woven into older NSA documents. I can see why people would want to work there, if you have no moral issues with the nature of the job, it must be (have been?) an interesting, challenging job in a pretty good environment.