What Happened To The Mint?

as I understand it....they produced coins with no mint marks those years to stop people from collecting/hoarding them, the mint had to produce as many coins as possible to keep up with the removal of all the silver coins from circulation.

Nothing happened, they made millions of coins! U.S. Coins didn't have mint marks during those three years.

Due to the coin shortage of the early 1960's (caused by the hoarding of 90% silver coins from circulation, once their base metal value exceeded their face value), mint marks were suspended (to prevent collecting coins by mint mark).

Proof coins were also suspended during those three years, 'replaced' with Special Mint Sets.

I am not quite sure why Philly didn't mint any halves but I can tell you one thing- Philadelphia opened a new mint building on 8/14/69 so that might have had something to do with it, just a guess

And here all these years I thought it was due to them running out of money and couldn't afford letters.

West Point is the most recent Mint but I doubt there will ever be a new location.

West Point started out minting Lincoln cents sans mint mark in the 1970s and they currently mint all bullion coins. There was even a special 50th anniversary Roosevelt dime in 1996 minted with the W mint mark- it available in Mint Sets.