gold mine vs mine

gold mine and mine both are nouns.

Word	Noun	Adjective	Verb	Adverb
gold mine	Yes	No	No	No
mine	Yes	No	Yes	No

As nouns, mine is a hypernym of gold mine; that is, mine is a word with a broader meaning than gold mine:

gold mine (noun)	mine (noun)
a mine where gold ore is found	explosive device that explodes on contact; designed to destroy vehicles or ships or to kill or maim personnel
a good source of something that is desired	excavation in the earth from which ores and minerals are extracted

gold mine (verb)	mine (verb)
	lay mines
	get from the earth by excavation