metal money vs mintage

metal money and mintage both are nouns.

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

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

Other synonyms of metal money include coinage, specie.

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