mintage vs metal money

mintage and metal money both are nouns.

Word	Noun	Adjective	Verb	Adverb
mintage	Yes	No	No	No
metal money	Yes	No	No	No

As nouns, mintage and metal money are synonyms defined as:

Other synonyms of mintage include coinage, specie.

mintage (noun)	metal money (noun)
act or process of minting coins	coins collectively
coins collectively
fee paid to a mint by the government for minting a coin