The Treasury actually lent out all it's silver to The Manhattan Project.
That's a rather sweeping statement, do you have a source for it?
the magnets needed so much copper for windings that the Army had to borrow almost 15,000 tons of silver bullion from the United States Treasury to fabricate into strips and wind on to coils as a substitute for copper. Treasury silver was also used to manufacture the busbars that ran around the top of the racetracks.