Yeah, as the mint has the best knowledge on the subject of our currency. They are experts on the materials & composition of each coin. I think they’re in the best position to understand each metal used as well as how plentiful or scarce it may be.
Also, precedent exists where by the composition was changed of the Kennedy, Morgan, penny, & Liberty. I may have gotten 1 or two wrong but silver and copper % have changed, especially during wars. The mint can continue to create fancy limited edition, first press stuff made of pure everything: silver, gold, platinum to still satisfy the numismatic population,