Byron said:
I'm leaning towards robbery esp after this article about an insider stealing similar amounts of gold in San Fran:
http://www.usmint.gov/kids/coinnews/mintfacilities/sfo/#thieves
Considerations:
"By April of 1854, a new facility had been built and its coin presses began turning miners' gold into coins."
But the found coins are dated from 1847
"Although most of the coins were minted in San Francisco, one $5 gold piece came from as far away as Georgia."
"....found him guilty of stealing the $30,000 in gold double eagles....."
It is not stated that every coin found was a double eagle, but I got this of Wiki.
1866-S $20 Double Eagle/no motto valued at around $1 million
1866-S $20 Double Eagle/with motto PCGS MS62+ (finest known)
1873 $20 Double Eagle (Closed 3) graded MS62 (tied finest known)
1877-S $20 Double Eagle PCGS MS65 (tied finest known)
1888-S $20 Double Eagle (four) PCGS MS64 (tied for finest known)
1889-S $20 Double Eagle (two) graded PCGS MS65 (tied for finest known)
1894-S $20 Double Eagle PCGS MS65 (tied for finest known)
A total of 1,373 were $20 coins, 50 were $10 coins and four were $5 coins. They were dated from 1847 to 1894, [....] Most were minted in San Francisco.
Not sure that the find matches the theft that closely, by coin denomination and type tough. Did they even mint $5 Double Eagles?
1,500 coins were said to be stolen, 1,427 were found. So it's close enough. One presumes he spent some before getting caught?
I'd say it was feasible. But not confirmed!