Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
fŏdīna, ae, f. [id.; a place from which a mineral is dug], a pit, mine: argenti, Varr. R. R. 1, 2, 22; Vitr. 7, 7 (also written in one word argentifodina, v. h. v.); Dig. 27, 9, 3 al.; Plin. 33, 6, 31, § 98.