The price is determined by futures contracts and the organizations buying PM they don't really want, from those who don't have any. All the factors you mentioned - new ore discovery, demand/supply, surpluses/deficit, all in production cost, bah bah, yadayada and other metal pumpers' weekly intelligent sounding theory have zero, - 0 - nada influence on the manipulated comex price.
That is simply not true. If it were true, then the price of silver would be $5 on the Comex, etc. The price has stayed above $14 because that is approximately what the all-in production cost is (some may be higher, some a bit lower). By all in costs I mean everything. Some mine companies say they pay $5 or so per ounce for their silver in production costs, but the company shows a loss every year?
A person who is long a Comex contract may stand for delivery of the underlying commodity. This means the short holder has to deliver the metal (through certain procedural mechanisms).
Yes, probably 99% of the Comex players don't stand for delivery but instead use the Comex as a way to gamble on commodities, but if they want the commodity, they are entitled to ask for that. If the Comex price was that far from actual cost (say $5 per ounce), the short would not be able financially to deliver when the price they pay on the street is 3x the Comex price for physical silver.
A few years ago some BS PM pundits were claiming it was not possible to stand for delivery anymore and if you tried, you were secretly paid a "premium" to go away and not stand for delivery. Not true.
FWIW, the Comex type system is not in my opinion a "fair" system for the reasons that you can sell something you don't own at the time you sell it. This is the hocus pocus that does allow for "manipulation" in the sense deep pockets can move the market without ever touching any gold, silver, etc, and this is because so many fail to stand for delivery. If every long stood for delivery, the price would be much higher in my opinion. But that is the way the game is played.
Once they allowed Bitcoin Comex futures that was the death knell for bitcoin for the same reasons.
So while there is what you may call "manipulation" it is held in check to some degree by the fact the long can stand for delivery, then the short has to pay the piper.
Right now I can get 90% junk silver for close to melt. If the "manipulation" really mattered, there would be a $5 premium per ounce instead of close to melt pricing.
Remember, in 2011 silver went to $50 on the Comex. Was the manipulation stopped to allow that, or was that price "manipulation" too?