salt working vs excavation

salt working and excavation both are nouns.

Word	Noun	Adjective	Verb	Adverb
salt working	Yes	No	No	No
excavation	Yes	No	No	No

As nouns, excavation is a hypernym of salt working; that is, excavation is a word with a broader meaning than salt working:

Other hypernyms of salt working include mining.

salt working (noun)	excavation (noun)
The manufacture of salt.	the act of extracting ores or coal etc from the earth
	the act of digging
	a hole in the ground made by excavating
	the site of an archeological exploration