Sure, because prospectors can afford more gold than they're ever likely to find in a year. IOW, no, it is not only not likely, it verges on impossible. It requires that Australia wasn't invisible to seafarers for over 40,000 years, which isn't any great leap.
Sure, because prospectors can afford more gold than they’re ever likely to find in a year.
I’ll quibble a bit on the idea that a prospector losing a good luck piece requires that Australia was invisible to seafarers.
A anecdote that might be appropriate. When I taught history I involved my students in a program called Ancient Coins in Education. They would each receive a genuine 2nd, 3rd or 4th century Roman coin and attempt to identify the Emperor date, etc. Kids liked it. One day a student brought in some Byzantine coins that she said her uncle found while working on a bridge here in the U.S. Don’t know how or why 1400 year old coins got there, but I doubt the Byzantines got to America.